Random number generator updates for Linux 6.12-rc1.

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Merge tag 'random-6.12-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:
 "Originally I'd planned on sending each of the vDSO getrandom()
  architecture ports to their respective arch trees. But as we started
  to work on this, we found lots of interesting issues in the shared
  code and infrastructure, the fixes for which the various archs needed
  to base their work.

  So in the end, this turned into a nice collaborative effort fixing up
  issues and porting to 5 new architectures -- arm64, powerpc64,
  powerpc32, s390x, and loongarch64 -- with everybody pitching in and
  commenting on each other's code. It was a fun development cycle.

  This contains:

   - Numerous fixups to the vDSO selftest infrastructure, getting it
     running successfully on more platforms, and fixing bugs in it.

   - Additions to the vDSO getrandom & chacha selftests. Basically every
     time manual review unearthed a bug in a revision of an arch patch,
     or an ambiguity, the tests were augmented.

     By the time the last arch was submitted for review, s390x, v1 of
     the series was essentially fine right out of the gate.

   - Fixes to the the generic C implementation of vDSO getrandom, to
     build and run successfully on all archs, decoupling it from
     assumptions we had (unintentionally) made on x86_64 that didn't
     carry through to the other architectures.

   - Port of vDSO getrandom to LoongArch64, from Xi Ruoyao and acked by
     Huacai Chen.

   - Port of vDSO getrandom to ARM64, from Adhemerval Zanella and acked
     by Will Deacon.

   - Port of vDSO getrandom to PowerPC, in both 32-bit and 64-bit
     varieties, from Christophe Leroy and acked by Michael Ellerman.

   - Port of vDSO getrandom to S390X from Heiko Carstens, the arch
     maintainer.

  While it'd be natural for there to be things to fix up over the course
  of the development cycle, these patches got a decent amount of review
  from a fairly diverse crew of folks on the mailing lists, and, for the
  most part, they've been cooking in linux-next, which has been helpful
  for ironing out build issues.

  In terms of architectures, I think that mostly takes care of the
  important 64-bit archs with hardware still being produced and running
  production loads in settings where vDSO getrandom is likely to help.

  Arguably there's still RISC-V left, and we'll see for 6.13 whether
  they find it useful and submit a port"

* tag 'random-6.12-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (47 commits)
  selftests: vDSO: check cpu caps before running chacha test
  s390/vdso: Wire up getrandom() vdso implementation
  s390/vdso: Move vdso symbol handling to separate header file
  s390/vdso: Allow alternatives in vdso code
  s390/module: Provide find_section() helper
  s390/facility: Let test_facility() generate static branch if possible
  s390/alternatives: Remove ALT_FACILITY_EARLY
  s390/facility: Disable compile time optimization for decompressor code
  selftests: vDSO: fix vdso_config for s390
  selftests: vDSO: fix ELF hash table entry size for s390x
  powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO64
  powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO32
  powerpc/vdso: Refactor CFLAGS for CVDSO build
  powerpc/vdso32: Add crtsavres
  mm: Define VM_DROPPABLE for powerpc/32
  powerpc/vdso: Fix VDSO data access when running in a non-root time namespace
  selftests: vDSO: don't include generated headers for chacha test
  arm64: vDSO: Wire up getrandom() vDSO implementation
  arm64: alternative: make alternative_has_cap_likely() VDSO compatible
  selftests: vDSO: also test counter in vdso_test_chacha
  ...

Documentation/ABI/stable/vdso

@@ -9,9 +9,11 @@ maps an ELF DSO into that program's address space.  This DSO is called
 the vDSO and it often contains useful and highly-optimized alternatives
 to real syscalls.
 
-These functions are called just like ordinary C function according to
+These functions are called according to your platform's ABI. On many
-your platform's ABI.  Call them from a sensible context.  (For example,
+platforms they are called just like ordinary C function. On other platforms
-if you set CS on x86 to something strange, the vDSO functions are
+(ex: powerpc) they are called with the same convention as system calls which
+is different from ordinary C functions. Call them from a sensible context.
+(For example, if you set CS on x86 to something strange, the vDSO functions are
 within their rights to crash.)  In addition, if you pass a bad
 pointer to a vDSO function, you might get SIGSEGV instead of -EFAULT.
 

arch/arm64/Kconfig

@@ -263,6 +263,7 @@ config ARM64
 	select TRACE_IRQFLAGS_NMI_SUPPORT
 	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select USER_STACKTRACE_SUPPORT
+	select VDSO_GETRANDOM
 	help
 	  ARM 64-bit (AArch64) Linux support.
 

arch/arm64/include/asm/alternative-macros.h

@@ -230,7 +230,11 @@ alternative_has_cap_likely(const unsigned long cpucap)
 		return false;
 
 	asm goto(
+#ifdef BUILD_VDSO
+	ALTERNATIVE("b	%l[l_no]", "nop", %[cpucap])
+#else
 	ALTERNATIVE_CB("b	%l[l_no]", %[cpucap], alt_cb_patch_nops)
+#endif
 	:
 	: [cpucap] "i" (cpucap)
 	:

arch/arm64/include/asm/mman.h

@@ -2,9 +2,11 @@
 #ifndef __ASM_MMAN_H__
 #define __ASM_MMAN_H__
 
+#include <uapi/asm/mman.h>
+
+#ifndef BUILD_VDSO
 #include <linux/compiler.h>
 #include <linux/types.h>
-#include <uapi/asm/mman.h>
 
 static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
 	unsigned long pkey)
@@ -68,4 +70,6 @@ static inline bool arch_validate_flags(unsigned long vm_flags)
 }
 #define arch_validate_flags(vm_flags) arch_validate_flags(vm_flags)
 
+#endif /* !BUILD_VDSO */
+
 #endif /* ! __ASM_MMAN_H__ */

arch/arm64/include/asm/vdso/getrandom.h

@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_VDSO_GETRANDOM_H
+#define __ASM_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/unistd.h>
+#include <asm/vdso/vsyscall.h>
+#include <vdso/datapage.h>
+
+/**
+ * getrandom_syscall - Invoke the getrandom() syscall.
+ * @buffer:	Destination buffer to fill with random bytes.
+ * @len:	Size of @buffer in bytes.
+ * @flags:	Zero or more GRND_* flags.
+ * Returns:	The number of random bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t getrandom_syscall(void *_buffer, size_t _len, unsigned int _flags)
+{
+	register void *buffer asm ("x0") = _buffer;
+	register size_t len asm ("x1") = _len;
+	register unsigned int flags asm ("x2") = _flags;
+	register long ret asm ("x0");
+	register long nr asm ("x8") = __NR_getrandom;
+
+	asm volatile(
+	"       svc #0\n"
+	: "=r" (ret)
+	: "r" (buffer), "r" (len), "r" (flags), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
+static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
+{
+	/*
+	 * The RNG data is in the real VVAR data page, but if a task belongs to a time namespace
+	 * then VVAR_DATA_PAGE_OFFSET points to the namespace-specific VVAR page and VVAR_TIMENS_
+	 * PAGE_OFFSET points to the real VVAR page.
+	 */
+	if (IS_ENABLED(CONFIG_TIME_NS) && _vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS)
+		return (void *)&_vdso_rng_data + VVAR_TIMENS_PAGE_OFFSET * (1UL << CONFIG_PAGE_SHIFT);
+	return &_vdso_rng_data;
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETRANDOM_H */

arch/arm64/include/asm/vdso/vsyscall.h

@@ -2,11 +2,19 @@
 #ifndef __ASM_VDSO_VSYSCALL_H
 #define __ASM_VDSO_VSYSCALL_H
 
+#define __VDSO_RND_DATA_OFFSET  480
+
 #ifndef __ASSEMBLY__
 
 #include <linux/timekeeper_internal.h>
 #include <vdso/datapage.h>
 
+enum vvar_pages {
+	VVAR_DATA_PAGE_OFFSET,
+	VVAR_TIMENS_PAGE_OFFSET,
+	VVAR_NR_PAGES,
+};
+
 #define VDSO_PRECISION_MASK	~(0xFF00ULL<<48)
 
 extern struct vdso_data *vdso_data;
@@ -21,6 +29,13 @@ struct vdso_data *__arm64_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __arm64_get_k_vdso_data
 
+static __always_inline
+struct vdso_rng_data *__arm64_get_k_vdso_rnd_data(void)
+{
+	return (void *)vdso_data + __VDSO_RND_DATA_OFFSET;
+}
+#define __arch_get_k_vdso_rng_data __arm64_get_k_vdso_rnd_data
+
 static __always_inline
 void __arm64_update_vsyscall(struct vdso_data *vdata, struct timekeeper *tk)
 {

arch/arm64/kernel/vdso.c

@@ -34,12 +34,6 @@ enum vdso_abi {
 	VDSO_ABI_AA32,
 };
 
-enum vvar_pages {
-	VVAR_DATA_PAGE_OFFSET,
-	VVAR_TIMENS_PAGE_OFFSET,
-	VVAR_NR_PAGES,
-};
-
 struct vdso_abi_info {
 	const char *name;
 	const char *vdso_code_start;

arch/arm64/kernel/vdso/Makefile

@@ -9,7 +9,7 @@
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
 
-obj-vdso := vgettimeofday.o note.o sigreturn.o
+obj-vdso := vgettimeofday.o note.o sigreturn.o vgetrandom.o vgetrandom-chacha.o
 
 # Build rules
 targets := $(obj-vdso) vdso.so vdso.so.dbg
@@ -34,19 +34,28 @@ ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
 
 # -Wmissing-prototypes and -Wmissing-declarations are removed from
-# the CFLAGS of vgettimeofday.c to make possible to build the
+# the CFLAGS to make possible to build the kernel with CONFIG_WERROR enabled.
-# kernel with CONFIG_WERROR enabled.
+CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
-CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
+			$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
-				$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
+			$(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
-				$(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
+			-Wmissing-prototypes -Wmissing-declarations
-				-Wmissing-prototypes -Wmissing-declarations
 
-CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
+CC_FLAGS_ADD_VDSO := -O2 -mcmodel=tiny -fasynchronous-unwind-tables
+
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_REMOVE_VDSO)
+CFLAGS_REMOVE_vgetrandom.o = $(CC_FLAGS_REMOVE_VDSO)
+
+CFLAGS_vgettimeofday.o = $(CC_FLAGS_ADD_VDSO)
+CFLAGS_vgetrandom.o = $(CC_FLAGS_ADD_VDSO)
 
 ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
 endif
 
+ifneq ($(c-getrandom-y),)
+  CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
+endif
+
 targets += vdso.lds
 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 

arch/arm64/kernel/vdso/vdso.lds.S

@@ -11,7 +11,9 @@
 #include <linux/const.h>
 #include <asm/page.h>
 #include <asm/vdso.h>
+#include <asm/vdso/vsyscall.h>
 #include <asm-generic/vmlinux.lds.h>
+#include <vdso/datapage.h>
 
 OUTPUT_FORMAT("elf64-littleaarch64", "elf64-bigaarch64", "elf64-littleaarch64")
 OUTPUT_ARCH(aarch64)
@@ -19,6 +21,7 @@ OUTPUT_ARCH(aarch64)
 SECTIONS
 {
 	PROVIDE(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE);
+	PROVIDE(_vdso_rng_data = _vdso_data + __VDSO_RND_DATA_OFFSET);
 #ifdef CONFIG_TIME_NS
 	PROVIDE(_timens_data = _vdso_data + PAGE_SIZE);
 #endif
@@ -102,6 +105,7 @@ VERSION
 		__kernel_gettimeofday;
 		__kernel_clock_gettime;
 		__kernel_clock_getres;
+		__kernel_getrandom;
 	local: *;
 	};
 }

arch/arm64/kernel/vdso/vgetrandom-chacha.S

@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/linkage.h>
+#include <asm/cache.h>
+#include <asm/assembler.h>
+
+	.text
+
+#define state0		v0
+#define state1		v1
+#define state2		v2
+#define state3		v3
+#define copy0		v4
+#define copy0_q		q4
+#define copy1		v5
+#define copy2		v6
+#define copy3		v7
+#define copy3_d		d7
+#define one_d		d16
+#define one_q		q16
+#define one_v		v16
+#define tmp		v17
+#define rot8		v18
+
+/*
+ * ARM64 ChaCha20 implementation meant for vDSO.  Produces a given positive
+ * number of blocks of output with nonce 0, taking an input key and 8-bytes
+ * counter.  Importantly does not spill to the stack.
+ *
+ * This implementation avoids d8-d15 because they are callee-save in user
+ * space.
+ *
+ * void __arch_chacha20_blocks_nostack(uint8_t *dst_bytes,
+ *				       const uint8_t *key,
+ * 				       uint32_t *counter,
+ *				       size_t nblocks)
+ *
+ * 	x0: output bytes
+ *	x1: 32-byte key input
+ *	x2: 8-byte counter input/output
+ *	x3: number of 64-byte block to write to output
+ */
+SYM_FUNC_START(__arch_chacha20_blocks_nostack)
+
+	/* copy0 = "expand 32-byte k" */
+	mov_q		x8, 0x3320646e61707865
+	mov_q		x9, 0x6b20657479622d32
+	mov		copy0.d[0], x8
+	mov		copy0.d[1], x9
+
+	/* copy1,copy2 = key */
+	ld1		{ copy1.4s, copy2.4s }, [x1]
+	/* copy3 = counter || zero nonce  */
+	ld1		{ copy3.2s }, [x2]
+
+	movi		one_v.2s, #1
+	uzp1		one_v.4s, one_v.4s, one_v.4s
+
+.Lblock:
+	/* copy state to auxiliary vectors for the final add after the permute.  */
+	mov		state0.16b, copy0.16b
+	mov		state1.16b, copy1.16b
+	mov		state2.16b, copy2.16b
+	mov		state3.16b, copy3.16b
+
+	mov		w4, 20
+.Lpermute:
+	/*
+	 * Permute one 64-byte block where the state matrix is stored in the four NEON
+	 * registers state0-state3.  It performs matrix operations on four words in parallel,
+	 * but requires shuffling to rearrange the words after each round.
+	 */
+
+.Ldoubleround:
+	/* state0 += state1, state3 = rotl32(state3 ^ state0, 16) */
+	add		state0.4s, state0.4s, state1.4s
+	eor		state3.16b, state3.16b, state0.16b
+	rev32		state3.8h, state3.8h
+
+	/* state2 += state3, state1 = rotl32(state1 ^ state2, 12) */
+	add		state2.4s, state2.4s, state3.4s
+	eor		tmp.16b, state1.16b, state2.16b
+	shl		state1.4s, tmp.4s, #12
+	sri		state1.4s, tmp.4s, #20
+
+	/* state0 += state1, state3 = rotl32(state3 ^ state0, 8) */
+	add		state0.4s, state0.4s, state1.4s
+	eor		tmp.16b, state3.16b, state0.16b
+	shl		state3.4s, tmp.4s, #8
+	sri		state3.4s, tmp.4s, #24
+
+	/* state2 += state3, state1 = rotl32(state1 ^ state2, 7) */
+	add		state2.4s, state2.4s, state3.4s
+	eor		tmp.16b, state1.16b, state2.16b
+	shl		state1.4s, tmp.4s, #7
+	sri		state1.4s, tmp.4s, #25
+
+	/* state1[0,1,2,3] = state1[1,2,3,0] */
+	ext		state1.16b, state1.16b, state1.16b, #4
+	/* state2[0,1,2,3] = state2[2,3,0,1] */
+	ext		state2.16b, state2.16b, state2.16b, #8
+	/* state3[0,1,2,3] = state3[1,2,3,0] */
+	ext		state3.16b, state3.16b, state3.16b, #12
+
+	/* state0 += state1, state3 = rotl32(state3 ^ state0, 16) */
+	add		state0.4s, state0.4s, state1.4s
+	eor		state3.16b, state3.16b, state0.16b
+	rev32		state3.8h, state3.8h
+
+	/* state2 += state3, state1 = rotl32(state1 ^ state2, 12) */
+	add		state2.4s, state2.4s, state3.4s
+	eor		tmp.16b, state1.16b, state2.16b
+	shl		state1.4s, tmp.4s, #12
+	sri		state1.4s, tmp.4s, #20
+
+	/* state0 += state1, state3 = rotl32(state3 ^ state0, 8) */
+	add		state0.4s, state0.4s, state1.4s
+	eor		tmp.16b, state3.16b, state0.16b
+	shl		state3.4s, tmp.4s, #8
+	sri		state3.4s, tmp.4s, #24
+
+	/* state2 += state3, state1 = rotl32(state1 ^ state2, 7) */
+	add		state2.4s, state2.4s, state3.4s
+	eor		tmp.16b, state1.16b, state2.16b
+	shl		state1.4s, tmp.4s, #7
+	sri		state1.4s, tmp.4s, #25
+
+	/* state1[0,1,2,3] = state1[3,0,1,2] */
+	ext		state1.16b, state1.16b, state1.16b, #12
+	/* state2[0,1,2,3] = state2[2,3,0,1] */
+	ext		state2.16b, state2.16b, state2.16b, #8
+	/* state3[0,1,2,3] = state3[1,2,3,0] */
+	ext		state3.16b, state3.16b, state3.16b, #4
+
+	subs		w4, w4, #2
+	b.ne		.Ldoubleround
+
+	/* output0 = state0 + state0 */
+	add		state0.4s, state0.4s, copy0.4s
+	/* output1 = state1 + state1 */
+	add		state1.4s, state1.4s, copy1.4s
+	/* output2 = state2 + state2 */
+	add		state2.4s, state2.4s, copy2.4s
+	/* output2 = state3 + state3 */
+	add		state3.4s, state3.4s, copy3.4s
+	st1		{ state0.16b - state3.16b }, [x0]
+
+	/*
+	 * ++copy3.counter, the 'add' clears the upper half of the SIMD register
+	 * which is the expected behaviour here.
+	 */
+	add		copy3_d, copy3_d, one_d
+
+	/* output += 64, --nblocks */
+	add		x0, x0, 64
+	subs		x3, x3, #1
+	b.ne		.Lblock
+
+	/* counter = copy3.counter */
+	st1		{ copy3.2s }, [x2]
+
+	/* Zero out the potentially sensitive regs, in case nothing uses these again. */
+	movi		state0.16b, #0
+	movi		state1.16b, #0
+	movi		state2.16b, #0
+	movi		state3.16b, #0
+	movi		copy1.16b, #0
+	movi		copy2.16b, #0
+	ret
+SYM_FUNC_END(__arch_chacha20_blocks_nostack)
+
+emit_aarch64_feature_1_and

arch/arm64/kernel/vdso/vgetrandom.c

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <uapi/asm-generic/errno.h>
+
+typeof(__cvdso_getrandom) __kernel_getrandom;
+
+ssize_t __kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+	if (alternative_has_cap_likely(ARM64_HAS_FPSIMD))
+		return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len);
+
+	if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags))
+		return -ENOSYS;
+	return getrandom_syscall(buffer, len, flags);
+}

arch/loongarch/Kconfig

@@ -191,6 +191,7 @@ config LOONGARCH
 	select TRACE_IRQFLAGS_SUPPORT
 	select USE_PERCPU_NUMA_NODE_ID
 	select USER_STACKTRACE_SUPPORT
+	select VDSO_GETRANDOM
 	select ZONE_DMA32
 
 config 32BIT

arch/loongarch/include/asm/vdso/getrandom.h

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Xi Ruoyao <xry111@xry111.site>. All Rights Reserved.
+ */
+#ifndef __ASM_VDSO_GETRANDOM_H
+#define __ASM_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/unistd.h>
+#include <asm/vdso/vdso.h>
+
+static __always_inline ssize_t getrandom_syscall(void *_buffer, size_t _len, unsigned int _flags)
+{
+	register long ret asm("a0");
+	register long nr asm("a7") = __NR_getrandom;
+	register void *buffer asm("a0") = _buffer;
+	register size_t len asm("a1") = _len;
+	register unsigned int flags asm("a2") = _flags;
+
+	asm volatile(
+	"      syscall 0\n"
+	: "+r" (ret)
+	: "r" (nr), "r" (buffer), "r" (len), "r" (flags)
+	: "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8",
+	  "memory");
+
+	return ret;
+}
+
+static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
+{
+	return (const struct vdso_rng_data *)(get_vdso_data() + VVAR_LOONGARCH_PAGES_START *
+	       PAGE_SIZE + offsetof(struct loongarch_vdso_data, rng_data));
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETRANDOM_H */

arch/loongarch/include/asm/vdso/vdso.h

@@ -4,6 +4,9 @@
  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
  */
 
+#ifndef _ASM_VDSO_VDSO_H
+#define _ASM_VDSO_VDSO_H
+
 #ifndef __ASSEMBLY__
 
 #include <asm/asm.h>
@@ -16,6 +19,7 @@ struct vdso_pcpu_data {
 
 struct loongarch_vdso_data {
 	struct vdso_pcpu_data pdata[NR_CPUS];
+	struct vdso_rng_data rng_data;
 };
 
 /*
@@ -63,3 +67,5 @@ static inline unsigned long get_vdso_data(void)
 }
 
 #endif /* __ASSEMBLY__ */
+
+#endif

arch/loongarch/include/asm/vdso/vsyscall.h

@@ -8,6 +8,7 @@
 #include <vdso/datapage.h>
 
 extern struct vdso_data *vdso_data;
+extern struct vdso_rng_data *vdso_rng_data;
 
 /*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
@@ -19,6 +20,13 @@ struct vdso_data *__loongarch_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __loongarch_get_k_vdso_data
 
+static __always_inline
+struct vdso_rng_data *__loongarch_get_k_vdso_rng_data(void)
+{
+	return vdso_rng_data;
+}
+#define __arch_get_k_vdso_rng_data __loongarch_get_k_vdso_rng_data
+
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 

arch/loongarch/kernel/vdso.c

@@ -37,6 +37,7 @@ static union {
 static struct page *vdso_pages[] = { NULL };
 struct vdso_data *vdso_data = generic_vdso_data.data;
 struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata;
+struct vdso_rng_data *vdso_rng_data = &loongarch_vdso_data.vdata.rng_data;
 
 static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
 {

arch/loongarch/vdso/Makefile

@@ -4,7 +4,8 @@
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
 
-obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o sigreturn.o
+obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o vgetrandom.o \
+              vgetrandom-chacha.o sigreturn.o
 
 # Common compiler flags between ABIs.
 ccflags-vdso := \
@@ -29,6 +30,10 @@ ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
 endif
 
+ifneq ($(c-getrandom-y),)
+  CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
+endif
+
 # VDSO linker flags.
 ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
 	$(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \

arch/loongarch/vdso/vdso.lds.S

@@ -62,6 +62,7 @@ VERSION
 		__vdso_clock_getres;
 		__vdso_clock_gettime;
 		__vdso_gettimeofday;
+		__vdso_getrandom;
 		__vdso_rt_sigreturn;
 	local: *;
 	};

arch/loongarch/vdso/vgetrandom-chacha.S

@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Xi Ruoyao <xry111@xry111.site>. All Rights Reserved.
+ */
+
+#include <asm/asm.h>
+#include <asm/regdef.h>
+#include <linux/linkage.h>
+
+.text
+
+/* Salsa20 quarter-round */
+.macro	QR	a b c d
+	add.w		\a, \a, \b
+	xor		\d, \d, \a
+	rotri.w		\d, \d, 16
+
+	add.w		\c, \c, \d
+	xor		\b, \b, \c
+	rotri.w		\b, \b, 20
+
+	add.w		\a, \a, \b
+	xor		\d, \d, \a
+	rotri.w		\d, \d, 24
+
+	add.w		\c, \c, \d
+	xor		\b, \b, \c
+	rotri.w		\b, \b, 25
+.endm
+
+/*
+ * Very basic LoongArch implementation of ChaCha20. Produces a given positive
+ * number of blocks of output with a nonce of 0, taking an input key and
+ * 8-byte counter. Importantly does not spill to the stack. Its arguments
+ * are:
+ *
+ *	a0: output bytes
+ *	a1: 32-byte key input
+ *	a2: 8-byte counter input/output
+ *	a3: number of 64-byte blocks to write to output
+ */
+SYM_FUNC_START(__arch_chacha20_blocks_nostack)
+
+/* We don't need a frame pointer */
+#define s9		fp
+
+#define output		a0
+#define key		a1
+#define counter		a2
+#define nblocks		a3
+#define i		a4
+#define state0		s0
+#define state1		s1
+#define state2		s2
+#define state3		s3
+#define state4		s4
+#define state5		s5
+#define state6		s6
+#define state7		s7
+#define state8		s8
+#define state9		s9
+#define state10		a5
+#define state11		a6
+#define state12		a7
+#define state13		t0
+#define state14		t1
+#define state15		t2
+#define cnt_lo		t3
+#define cnt_hi		t4
+#define copy0		t5
+#define copy1		t6
+#define copy2		t7
+
+/* Reuse i as copy3 */
+#define copy3		i
+
+	/*
+	 * The ABI requires s0-s9 saved, and sp aligned to 16-byte.
+	 * This does not violate the stack-less requirement: no sensitive data
+	 * is spilled onto the stack.
+	 */
+	PTR_ADDI	sp, sp, (-SZREG * 10) & STACK_ALIGN
+	REG_S		s0, sp, 0
+	REG_S		s1, sp, SZREG
+	REG_S		s2, sp, SZREG * 2
+	REG_S		s3, sp, SZREG * 3
+	REG_S		s4, sp, SZREG * 4
+	REG_S		s5, sp, SZREG * 5
+	REG_S		s6, sp, SZREG * 6
+	REG_S		s7, sp, SZREG * 7
+	REG_S		s8, sp, SZREG * 8
+	REG_S		s9, sp, SZREG * 9
+
+	li.w		copy0, 0x61707865
+	li.w		copy1, 0x3320646e
+	li.w		copy2, 0x79622d32
+
+	ld.w		cnt_lo, counter, 0
+	ld.w		cnt_hi, counter, 4
+
+.Lblock:
+	/* state[0,1,2,3] = "expand 32-byte k" */
+	move		state0, copy0
+	move		state1, copy1
+	move		state2, copy2
+	li.w		state3, 0x6b206574
+
+	/* state[4,5,..,11] = key */
+	ld.w		state4, key, 0
+	ld.w		state5, key, 4
+	ld.w		state6, key, 8
+	ld.w		state7, key, 12
+	ld.w		state8, key, 16
+	ld.w		state9, key, 20
+	ld.w		state10, key, 24
+	ld.w		state11, key, 28
+
+	/* state[12,13] = counter */
+	move		state12, cnt_lo
+	move		state13, cnt_hi
+
+	/* state[14,15] = 0 */
+	move		state14, zero
+	move		state15, zero
+
+	li.w		i, 10
+.Lpermute:
+	/* odd round */
+	QR		state0, state4, state8, state12
+	QR		state1, state5, state9, state13
+	QR		state2, state6, state10, state14
+	QR		state3, state7, state11, state15
+
+	/* even round */
+	QR		state0, state5, state10, state15
+	QR		state1, state6, state11, state12
+	QR		state2, state7, state8, state13
+	QR		state3, state4, state9, state14
+
+	addi.w		i, i, -1
+	bnez		i, .Lpermute
+
+	/*
+	 * copy[3] = "expa", materialize it here because copy[3] shares the
+	 * same register with i which just became dead.
+	 */
+	li.w		copy3, 0x6b206574
+
+	/* output[0,1,2,3] = copy[0,1,2,3] + state[0,1,2,3] */
+	add.w		state0, state0, copy0
+	add.w		state1, state1, copy1
+	add.w		state2, state2, copy2
+	add.w		state3, state3, copy3
+	st.w		state0, output, 0
+	st.w		state1, output, 4
+	st.w		state2, output, 8
+	st.w		state3, output, 12
+
+	/* from now on state[0,1,2,3] are scratch registers  */
+
+	/* state[0,1,2,3] = lo32(key) */
+	ld.w		state0, key, 0
+	ld.w		state1, key, 4
+	ld.w		state2, key, 8
+	ld.w		state3, key, 12
+
+	/* output[4,5,6,7] = state[0,1,2,3] + state[4,5,6,7] */
+	add.w		state4, state4, state0
+	add.w		state5, state5, state1
+	add.w		state6, state6, state2
+	add.w		state7, state7, state3
+	st.w		state4, output, 16
+	st.w		state5, output, 20
+	st.w		state6, output, 24
+	st.w		state7, output, 28
+
+	/* state[0,1,2,3] = hi32(key) */
+	ld.w		state0, key, 16
+	ld.w		state1, key, 20
+	ld.w		state2, key, 24
+	ld.w		state3, key, 28
+
+	/* output[8,9,10,11] = state[0,1,2,3] + state[8,9,10,11] */
+	add.w		state8, state8, state0
+	add.w		state9, state9, state1
+	add.w		state10, state10, state2
+	add.w		state11, state11, state3
+	st.w		state8, output, 32
+	st.w		state9, output, 36
+	st.w		state10, output, 40
+	st.w		state11, output, 44
+
+	/* output[12,13,14,15] = state[12,13,14,15] + [cnt_lo, cnt_hi, 0, 0] */
+	add.w		state12, state12, cnt_lo
+	add.w		state13, state13, cnt_hi
+	st.w		state12, output, 48
+	st.w		state13, output, 52
+	st.w		state14, output, 56
+	st.w		state15, output, 60
+
+	/* ++counter  */
+	addi.w		cnt_lo, cnt_lo, 1
+	sltui		state0, cnt_lo, 1
+	add.w		cnt_hi, cnt_hi, state0
+
+	/* output += 64 */
+	PTR_ADDI	output, output, 64
+	/* --nblocks */
+	PTR_ADDI	nblocks, nblocks, -1
+	bnez		nblocks, .Lblock
+
+	/* counter = [cnt_lo, cnt_hi] */
+	st.w		cnt_lo, counter, 0
+	st.w		cnt_hi, counter, 4
+
+	/*
+	 * Zero out the potentially sensitive regs, in case nothing uses these
+	 * again. As at now copy[0,1,2,3] just contains "expand 32-byte k" and
+	 * state[0,...,9] are s0-s9 those we'll restore in the epilogue, so we
+	 * only need to zero state[11,...,15].
+	 */
+	move		state10, zero
+	move		state11, zero
+	move		state12, zero
+	move		state13, zero
+	move		state14, zero
+	move		state15, zero
+
+	REG_L		s0, sp, 0
+	REG_L		s1, sp, SZREG
+	REG_L		s2, sp, SZREG * 2
+	REG_L		s3, sp, SZREG * 3
+	REG_L		s4, sp, SZREG * 4
+	REG_L		s5, sp, SZREG * 5
+	REG_L		s6, sp, SZREG * 6
+	REG_L		s7, sp, SZREG * 7
+	REG_L		s8, sp, SZREG * 8
+	REG_L		s9, sp, SZREG * 9
+	PTR_ADDI	sp, sp, -((-SZREG * 10) & STACK_ALIGN)
+
+	jr		ra
+SYM_FUNC_END(__arch_chacha20_blocks_nostack)

arch/loongarch/vdso/vgetrandom.c

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Xi Ruoyao <xry111@xry111.site>. All Rights Reserved.
+ */
+#include <linux/types.h>
+
+ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+	return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len);
+}

arch/powerpc/Kconfig

@@ -311,6 +311,7 @@ config PPC
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
 	select TRACE_IRQFLAGS_SUPPORT
+	select VDSO_GETRANDOM
 	#
 	# Please keep this list sorted alphabetically.
 	#

arch/powerpc/include/asm/mman.h

@@ -6,7 +6,7 @@
 
 #include <uapi/asm/mman.h>
 
-#ifdef CONFIG_PPC64
+#if defined(CONFIG_PPC64) && !defined(BUILD_VDSO)
 
 #include <asm/cputable.h>
 #include <linux/mm.h>

arch/powerpc/include/asm/vdso/getrandom.h

@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+#ifndef _ASM_POWERPC_VDSO_GETRANDOM_H
+#define _ASM_POWERPC_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+static __always_inline int do_syscall_3(const unsigned long _r0, const unsigned long _r3,
+					const unsigned long _r4, const unsigned long _r5)
+{
+	register long r0 asm("r0") = _r0;
+	register unsigned long r3 asm("r3") = _r3;
+	register unsigned long r4 asm("r4") = _r4;
+	register unsigned long r5 asm("r5") = _r5;
+	register int ret asm ("r3");
+
+	asm volatile(
+		"       sc\n"
+		"	bns+	1f\n"
+		"	neg	%0, %0\n"
+		"1:\n"
+	: "=r" (ret), "+r" (r4), "+r" (r5), "+r" (r0)
+	: "r" (r3)
+	: "memory", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "cr0", "ctr");
+
+	return ret;
+}
+
+/**
+ * getrandom_syscall - Invoke the getrandom() syscall.
+ * @buffer:	Destination buffer to fill with random bytes.
+ * @len:	Size of @buffer in bytes.
+ * @flags:	Zero or more GRND_* flags.
+ * Returns:	The number of bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
+{
+	return do_syscall_3(__NR_getrandom, (unsigned long)buffer,
+			    (unsigned long)len, (unsigned long)flags);
+}
+
+static __always_inline struct vdso_rng_data *__arch_get_vdso_rng_data(void)
+{
+	return NULL;
+}
+
+ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state,
+			     size_t opaque_len, const struct vdso_rng_data *vd);
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_POWERPC_VDSO_GETRANDOM_H */

arch/powerpc/include/asm/vdso/vsyscall.h

@@ -17,6 +17,12 @@ struct vdso_data *__arch_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __arch_get_k_vdso_data
 
+static __always_inline
+struct vdso_rng_data *__arch_get_k_vdso_rng_data(void)
+{
+	return &vdso_data->rng_data;
+}
+
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 

arch/powerpc/include/asm/vdso_datapage.h

@@ -83,6 +83,7 @@ struct vdso_arch_data {
 	__u32 compat_syscall_map[SYSCALL_MAP_SIZE];	/* Map of compat syscalls */
 
 	struct vdso_data data[CS_BASES];
+	struct vdso_rng_data rng_data;
 };
 
 #else /* CONFIG_PPC64 */
@@ -95,6 +96,7 @@ struct vdso_arch_data {
 	__u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */
 	__u32 compat_syscall_map[0];	/* No compat syscalls on PPC32 */
 	struct vdso_data data[CS_BASES];
+	struct vdso_rng_data rng_data;
 };
 
 #endif /* CONFIG_PPC64 */
@@ -111,6 +113,21 @@ extern struct vdso_arch_data *vdso_data;
 	addi	\ptr, \ptr, (_vdso_datapage - 999b)@l
 .endm
 
+#include <asm/asm-offsets.h>
+#include <asm/page.h>
+
+.macro get_realdatapage ptr scratch
+	get_datapage \ptr
+#ifdef CONFIG_TIME_NS
+	lwz	\scratch, VDSO_CLOCKMODE_OFFSET(\ptr)
+	xoris	\scratch, \scratch, VDSO_CLOCKMODE_TIMENS@h
+	xori	\scratch, \scratch, VDSO_CLOCKMODE_TIMENS@l
+	cntlzw	\scratch, \scratch
+	rlwinm	\scratch, \scratch, PAGE_SHIFT - 5, 1 << PAGE_SHIFT
+	add	\ptr, \ptr, \scratch
+#endif
+.endm
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */

arch/powerpc/kernel/asm-offsets.c

@@ -335,6 +335,7 @@ int main(void)
 
 	/* datapage offsets for use by vdso */
 	OFFSET(VDSO_DATA_OFFSET, vdso_arch_data, data);
+	OFFSET(VDSO_RNG_DATA_OFFSET, vdso_arch_data, rng_data);
 	OFFSET(CFG_TB_TICKS_PER_SEC, vdso_arch_data, tb_ticks_per_sec);
 #ifdef CONFIG_PPC64
 	OFFSET(CFG_ICACHE_BLOCKSZ, vdso_arch_data, icache_block_size);
@@ -346,6 +347,8 @@ int main(void)
 #else
 	OFFSET(CFG_SYSCALL_MAP32, vdso_arch_data, syscall_map);
 #endif
+	OFFSET(VDSO_CLOCKMODE_OFFSET, vdso_arch_data, data[0].clock_mode);
+	DEFINE(VDSO_CLOCKMODE_TIMENS, VDSO_CLOCKMODE_TIMENS);
 
 #ifdef CONFIG_BUG
 	DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry));

arch/powerpc/kernel/vdso/Makefile

@@ -8,30 +8,21 @@ include $(srctree)/lib/vdso/Makefile
 obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o note-32.o getcpu-32.o
 obj-vdso64 = sigtramp64-64.o gettimeofday-64.o datapage-64.o cacheflush-64.o note-64.o getcpu-64.o
 
+obj-vdso32 += getrandom-32.o vgetrandom-chacha-32.o
+obj-vdso64 += getrandom-64.o vgetrandom-chacha-64.o
+
 ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday-32.o += -include $(c-gettimeofday-y)
-  CFLAGS_vgettimeofday-32.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
-  CFLAGS_vgettimeofday-32.o += $(call cc-option, -fno-stack-protector)
-  CFLAGS_vgettimeofday-32.o += -DDISABLE_BRANCH_PROFILING
-  CFLAGS_vgettimeofday-32.o += -ffreestanding -fasynchronous-unwind-tables
-  CFLAGS_REMOVE_vgettimeofday-32.o = $(CC_FLAGS_FTRACE)
-  CFLAGS_REMOVE_vgettimeofday-32.o += -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
-  # This flag is supported by clang for 64-bit but not 32-bit so it will cause
-  # an unused command line flag warning for this file.
-  ifdef CONFIG_CC_IS_CLANG
-  CFLAGS_REMOVE_vgettimeofday-32.o += -fno-stack-clash-protection
-  endif
-  CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y)
-  CFLAGS_vgettimeofday-64.o += $(DISABLE_LATENT_ENTROPY_PLUGIN)
-  CFLAGS_vgettimeofday-64.o += $(call cc-option, -fno-stack-protector)
-  CFLAGS_vgettimeofday-64.o += -DDISABLE_BRANCH_PROFILING
-  CFLAGS_vgettimeofday-64.o += -ffreestanding -fasynchronous-unwind-tables
-  CFLAGS_REMOVE_vgettimeofday-64.o = $(CC_FLAGS_FTRACE)
 # Go prior to 1.16.x assumes r30 is not clobbered by any VDSO code. That used to be true
 # by accident when the VDSO was hand-written asm code, but may not be now that the VDSO is
 # compiler generated. To avoid breaking Go tell GCC not to use r30. Impact on code
 # generation is minimal, it will just use r29 instead.
-  CFLAGS_vgettimeofday-64.o += $(call cc-option, -ffixed-r30)
+  CFLAGS_vgettimeofday-64.o += -include $(c-gettimeofday-y) $(call cc-option, -ffixed-r30)
+endif
+
+ifneq ($(c-getrandom-y),)
+  CFLAGS_vgetrandom-32.o += -include $(c-getrandom-y)
+  CFLAGS_vgetrandom-64.o += -include $(c-getrandom-y) $(call cc-option, -ffixed-r30)
 endif
 
 # Build rules
@@ -42,12 +33,18 @@ else
     VDSOCC := $(CC)
 endif
 
-targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o
+targets := $(obj-vdso32) vdso32.so.dbg vgettimeofday-32.o vgetrandom-32.o
+targets += crtsavres-32.o
 obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
-targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o
+targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o vgetrandom-64.o
 obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
 
-ccflags-y := -fno-common -fno-builtin
+ccflags-y := -fno-common -fno-builtin -DBUILD_VDSO
+ccflags-y += $(DISABLE_LATENT_ENTROPY_PLUGIN)
+ccflags-y += $(call cc-option, -fno-stack-protector)
+ccflags-y += -DDISABLE_BRANCH_PROFILING
+ccflags-y += -ffreestanding -fasynchronous-unwind-tables
+ccflags-remove-y := $(CC_FLAGS_FTRACE)
 ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack $(CLANG_FLAGS)
 ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
 ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
@@ -56,6 +53,12 @@ ldflags-$(CONFIG_LD_ORPHAN_WARN) += -Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WAR
 ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) -Wa$(comma)%, $(KBUILD_CFLAGS))
 
 CC32FLAGS := -m32
+CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
+  # This flag is supported by clang for 64-bit but not 32-bit so it will cause
+  # an unused command line flag warning for this file.
+ifdef CONFIG_CC_IS_CLANG
+CC32FLAGSREMOVE += -fno-stack-clash-protection
+endif
 LD32FLAGS := -Wl,-soname=linux-vdso32.so.1
 AS32FLAGS := -D__VDSO32__
 
@@ -68,20 +71,26 @@ targets += vdso64.lds
 CPPFLAGS_vdso64.lds += -P -C
 
 # link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o FORCE
+$(obj)/vdso32.so.dbg: $(obj)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday-32.o $(obj)/vgetrandom-32.o $(obj)/crtsavres-32.o FORCE
 	$(call if_changed,vdso32ld_and_check)
-$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o FORCE
+$(obj)/vdso64.so.dbg: $(obj)/vdso64.lds $(obj-vdso64) $(obj)/vgettimeofday-64.o $(obj)/vgetrandom-64.o FORCE
 	$(call if_changed,vdso64ld_and_check)
 
 # assembly rules for the .S files
 $(obj-vdso32): %-32.o: %.S FORCE
 	$(call if_changed_dep,vdso32as)
+$(obj)/crtsavres-32.o: %-32.o: $(srctree)/arch/powerpc/lib/crtsavres.S FORCE
+	$(call if_changed_dep,vdso32as)
 $(obj)/vgettimeofday-32.o: %-32.o: %.c FORCE
 	$(call if_changed_dep,vdso32cc)
+$(obj)/vgetrandom-32.o: %-32.o: %.c FORCE
+	$(call if_changed_dep,vdso32cc)
 $(obj-vdso64): %-64.o: %.S FORCE
 	$(call if_changed_dep,vdso64as)
 $(obj)/vgettimeofday-64.o: %-64.o: %.c FORCE
 	$(call if_changed_dep,cc_o_c)
+$(obj)/vgetrandom-64.o: %-64.o: %.c FORCE
+	$(call if_changed_dep,cc_o_c)
 
 # Generate VDSO offsets using helper script
 gen-vdso32sym := $(src)/gen_vdso32_offsets.sh
@@ -102,7 +111,7 @@ quiet_cmd_vdso32ld_and_check = VDSO32L $@
 quiet_cmd_vdso32as = VDSO32A $@
       cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) $(AS32FLAGS) -c -o $@ $<
 quiet_cmd_vdso32cc = VDSO32C $@
-      cmd_vdso32cc = $(VDSOCC) $(c_flags) $(CC32FLAGS) -c -o $@ $<
+      cmd_vdso32cc = $(VDSOCC) $(filter-out $(CC32FLAGSREMOVE), $(c_flags)) $(CC32FLAGS) -c -o $@ $<
 
 quiet_cmd_vdso64ld_and_check = VDSO64L $@
       cmd_vdso64ld_and_check = $(VDSOCC) $(ldflags-y) $(LD64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)

arch/powerpc/kernel/vdso/cacheflush.S

@@ -30,7 +30,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
 #ifdef CONFIG_PPC64
 	mflr	r12
   .cfi_register lr,r12
-	get_datapage	r10
+	get_realdatapage	r10, r11
 	mtlr	r12
   .cfi_restore	lr
 #endif

arch/powerpc/kernel/vdso/datapage.S

@@ -28,7 +28,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map)
 	mflr	r12
   .cfi_register lr,r12
 	mr.	r4,r3
-	get_datapage	r3
+	get_realdatapage	r3, r11
 	mtlr	r12
 #ifdef __powerpc64__
 	addi	r3,r3,CFG_SYSCALL_MAP64
@@ -52,7 +52,7 @@ V_FUNCTION_BEGIN(__kernel_get_tbfreq)
   .cfi_startproc
 	mflr	r12
   .cfi_register lr,r12
-	get_datapage	r3
+	get_realdatapage	r3, r11
 #ifndef __powerpc64__
 	lwz	r4,(CFG_TB_TICKS_PER_SEC + 4)(r3)
 #endif

arch/powerpc/kernel/vdso/getrandom.S

@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Userland implementation of getrandom() for processes
+ * for use in the vDSO
+ *
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+#include <asm/processor.h>
+#include <asm/ppc_asm.h>
+#include <asm/vdso.h>
+#include <asm/vdso_datapage.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+
+/*
+ * The macro sets two stack frames, one for the caller and one for the callee
+ * because there are no requirement for the caller to set a stack frame when
+ * calling VDSO so it may have omitted to set one, especially on PPC64
+ */
+
+.macro cvdso_call funct
+  .cfi_startproc
+	PPC_STLU	r1, -PPC_MIN_STKFRM(r1)
+  .cfi_adjust_cfa_offset PPC_MIN_STKFRM
+	mflr		r0
+	PPC_STLU	r1, -PPC_MIN_STKFRM(r1)
+  .cfi_adjust_cfa_offset PPC_MIN_STKFRM
+	PPC_STL		r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
+  .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF
+#ifdef __powerpc64__
+	PPC_STL		r2, PPC_MIN_STKFRM + STK_GOT(r1)
+  .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT
+#endif
+	get_realdatapage	r8, r11
+	addi		r8, r8, VDSO_RNG_DATA_OFFSET
+	bl		CFUNC(DOTSYM(\funct))
+	PPC_LL		r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1)
+#ifdef __powerpc64__
+	PPC_LL		r2, PPC_MIN_STKFRM + STK_GOT(r1)
+  .cfi_restore r2
+#endif
+	cmpwi		r3, 0
+	mtlr		r0
+	addi		r1, r1, 2 * PPC_MIN_STKFRM
+  .cfi_restore lr
+  .cfi_def_cfa_offset 0
+	crclr		so
+	bgelr+
+	crset		so
+	neg		r3, r3
+	blr
+  .cfi_endproc
+.endm
+
+	.text
+V_FUNCTION_BEGIN(__kernel_getrandom)
+	cvdso_call __c_kernel_getrandom
+V_FUNCTION_END(__kernel_getrandom)

arch/powerpc/kernel/vdso/gettimeofday.S

@@ -118,16 +118,3 @@ V_FUNCTION_END(__kernel_clock_getres)
 V_FUNCTION_BEGIN(__kernel_time)
 	cvdso_call __c_kernel_time call_time=1
 V_FUNCTION_END(__kernel_time)
-
-/* Routines for restoring integer registers, called by the compiler.  */
-/* Called with r11 pointing to the stack header word of the caller of the */
-/* function, just beyond the end of the integer restore area.  */
-#ifndef __powerpc64__
-_GLOBAL(_restgpr_31_x)
-_GLOBAL(_rest32gpr_31_x)
-	lwz	r0,4(r11)
-	lwz	r31,-4(r11)
-	mtlr	r0
-	mr	r1,r11
-	blr
-#endif

arch/powerpc/kernel/vdso/vdso32.lds.S

@@ -130,6 +130,7 @@ VERSION
 #if defined(CONFIG_PPC64) || !defined(CONFIG_SMP)
 		__kernel_getcpu;
 #endif
+		__kernel_getrandom;
 
 	local: *;
 	};

arch/powerpc/kernel/vdso/vdso64.lds.S

@@ -123,6 +123,7 @@ VERSION
 		__kernel_sigtramp_rt64;
 		__kernel_getcpu;
 		__kernel_time;
+		__kernel_getrandom;
 
 	local: *;
 	};

arch/powerpc/kernel/vdso/vgetrandom-chacha.S

@@ -0,0 +1,365 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/ppc_asm.h>
+
+#define	dst_bytes	r3
+#define	key		r4
+#define	counter		r5
+#define	nblocks		r6
+
+#define	idx_r0		r0
+#define	val4		r4
+
+#define	const0		0x61707865
+#define	const1		0x3320646e
+#define	const2		0x79622d32
+#define	const3		0x6b206574
+
+#define	key0		r5
+#define	key1		r6
+#define	key2		r7
+#define	key3		r8
+#define	key4		r9
+#define	key5		r10
+#define	key6		r11
+#define	key7		r12
+
+#define	counter0	r14
+#define	counter1	r15
+
+#define	state0		r16
+#define	state1		r17
+#define	state2		r18
+#define	state3		r19
+#define	state4		r20
+#define	state5		r21
+#define	state6		r22
+#define	state7		r23
+#define	state8		r24
+#define	state9		r25
+#define	state10		r26
+#define	state11		r27
+#define	state12		r28
+#define	state13		r29
+#define	state14		r30
+#define	state15		r31
+
+.macro quarterround4 a1 b1 c1 d1 a2 b2 c2 d2 a3 b3 c3 d3 a4 b4 c4 d4
+	add	\a1, \a1, \b1
+	add	\a2, \a2, \b2
+	add	\a3, \a3, \b3
+	add	\a4, \a4, \b4
+	xor	\d1, \d1, \a1
+	xor	\d2, \d2, \a2
+	xor	\d3, \d3, \a3
+	xor	\d4, \d4, \a4
+	rotlwi	\d1, \d1, 16
+	rotlwi	\d2, \d2, 16
+	rotlwi	\d3, \d3, 16
+	rotlwi	\d4, \d4, 16
+	add	\c1, \c1, \d1
+	add	\c2, \c2, \d2
+	add	\c3, \c3, \d3
+	add	\c4, \c4, \d4
+	xor	\b1, \b1, \c1
+	xor	\b2, \b2, \c2
+	xor	\b3, \b3, \c3
+	xor	\b4, \b4, \c4
+	rotlwi	\b1, \b1, 12
+	rotlwi	\b2, \b2, 12
+	rotlwi	\b3, \b3, 12
+	rotlwi	\b4, \b4, 12
+	add	\a1, \a1, \b1
+	add	\a2, \a2, \b2
+	add	\a3, \a3, \b3
+	add	\a4, \a4, \b4
+	xor	\d1, \d1, \a1
+	xor	\d2, \d2, \a2
+	xor	\d3, \d3, \a3
+	xor	\d4, \d4, \a4
+	rotlwi	\d1, \d1, 8
+	rotlwi	\d2, \d2, 8
+	rotlwi	\d3, \d3, 8
+	rotlwi	\d4, \d4, 8
+	add	\c1, \c1, \d1
+	add	\c2, \c2, \d2
+	add	\c3, \c3, \d3
+	add	\c4, \c4, \d4
+	xor	\b1, \b1, \c1
+	xor	\b2, \b2, \c2
+	xor	\b3, \b3, \c3
+	xor	\b4, \b4, \c4
+	rotlwi	\b1, \b1, 7
+	rotlwi	\b2, \b2, 7
+	rotlwi	\b3, \b3, 7
+	rotlwi	\b4, \b4, 7
+.endm
+
+#define QUARTERROUND4(a1,b1,c1,d1,a2,b2,c2,d2,a3,b3,c3,d3,a4,b4,c4,d4) \
+	quarterround4 state##a1 state##b1 state##c1 state##d1 \
+		      state##a2 state##b2 state##c2 state##d2 \
+		      state##a3 state##b3 state##c3 state##d3 \
+		      state##a4 state##b4 state##c4 state##d4
+
+/*
+ * Very basic 32 bits implementation of ChaCha20. Produces a given positive number
+ * of blocks of output with a nonce of 0, taking an input key and 8-byte
+ * counter. Importantly does not spill to the stack. Its arguments are:
+ *
+ *	r3: output bytes
+ *	r4: 32-byte key input
+ *	r5: 8-byte counter input/output (saved on stack)
+ *	r6: number of 64-byte blocks to write to output
+ *
+ *	r0: counter of blocks (initialised with r6)
+ *	r4: Value '4' after key has been read.
+ *	r5-r12: key
+ *	r14-r15: counter
+ *	r16-r31: state
+ */
+SYM_FUNC_START(__arch_chacha20_blocks_nostack)
+#ifdef __powerpc64__
+	std	counter, -216(r1)
+
+	std	r14, -144(r1)
+	std	r15, -136(r1)
+	std	r16, -128(r1)
+	std	r17, -120(r1)
+	std	r18, -112(r1)
+	std	r19, -104(r1)
+	std	r20, -96(r1)
+	std	r21, -88(r1)
+	std	r22, -80(r1)
+	std	r23, -72(r1)
+	std	r24, -64(r1)
+	std	r25, -56(r1)
+	std	r26, -48(r1)
+	std	r27, -40(r1)
+	std	r28, -32(r1)
+	std	r29, -24(r1)
+	std	r30, -16(r1)
+	std	r31, -8(r1)
+#else
+	stwu	r1, -96(r1)
+	stw	counter, 20(r1)
+#ifdef __BIG_ENDIAN__
+	stmw	r14, 24(r1)
+#else
+	stw	r14, 24(r1)
+	stw	r15, 28(r1)
+	stw	r16, 32(r1)
+	stw	r17, 36(r1)
+	stw	r18, 40(r1)
+	stw	r19, 44(r1)
+	stw	r20, 48(r1)
+	stw	r21, 52(r1)
+	stw	r22, 56(r1)
+	stw	r23, 60(r1)
+	stw	r24, 64(r1)
+	stw	r25, 68(r1)
+	stw	r26, 72(r1)
+	stw	r27, 76(r1)
+	stw	r28, 80(r1)
+	stw	r29, 84(r1)
+	stw	r30, 88(r1)
+	stw	r31, 92(r1)
+#endif
+#endif	/* __powerpc64__ */
+
+	lwz	counter0, 0(counter)
+	lwz	counter1, 4(counter)
+#ifdef __powerpc64__
+	rldimi	counter0, counter1, 32, 0
+#endif
+	mr	idx_r0, nblocks
+	subi	dst_bytes, dst_bytes, 4
+
+	lwz	key0, 0(key)
+	lwz	key1, 4(key)
+	lwz	key2, 8(key)
+	lwz	key3, 12(key)
+	lwz	key4, 16(key)
+	lwz	key5, 20(key)
+	lwz	key6, 24(key)
+	lwz	key7, 28(key)
+
+	li	val4, 4
+.Lblock:
+	li	r31, 10
+
+	lis	state0, const0@ha
+	lis	state1, const1@ha
+	lis	state2, const2@ha
+	lis	state3, const3@ha
+	addi	state0, state0, const0@l
+	addi	state1, state1, const1@l
+	addi	state2, state2, const2@l
+	addi	state3, state3, const3@l
+
+	mtctr	r31
+
+	mr	state4, key0
+	mr	state5, key1
+	mr	state6, key2
+	mr	state7, key3
+	mr	state8, key4
+	mr	state9, key5
+	mr	state10, key6
+	mr	state11, key7
+
+	mr	state12, counter0
+	mr	state13, counter1
+
+	li	state14, 0
+	li	state15, 0
+
+.Lpermute:
+	QUARTERROUND4( 0, 4, 8,12, 1, 5, 9,13, 2, 6,10,14, 3, 7,11,15)
+	QUARTERROUND4( 0, 5,10,15, 1, 6,11,12, 2, 7, 8,13, 3, 4, 9,14)
+
+	bdnz	.Lpermute
+
+	addis	state0, state0, const0@ha
+	addis	state1, state1, const1@ha
+	addis	state2, state2, const2@ha
+	addis	state3, state3, const3@ha
+	addi	state0, state0, const0@l
+	addi	state1, state1, const1@l
+	addi	state2, state2, const2@l
+	addi	state3, state3, const3@l
+
+	add	state4, state4, key0
+	add	state5, state5, key1
+	add	state6, state6, key2
+	add	state7, state7, key3
+	add	state8, state8, key4
+	add	state9, state9, key5
+	add	state10, state10, key6
+	add	state11, state11, key7
+
+	add	state12, state12, counter0
+	add	state13, state13, counter1
+
+#ifdef __BIG_ENDIAN__
+	stwbrx	state0, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state1, 0, dst_bytes
+	stwbrx	state2, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state3, 0, dst_bytes
+	stwbrx	state4, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state5, 0, dst_bytes
+	stwbrx	state6, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state7, 0, dst_bytes
+	stwbrx	state8, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state9, 0, dst_bytes
+	stwbrx	state10, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state11, 0, dst_bytes
+	stwbrx	state12, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state13, 0, dst_bytes
+	stwbrx	state14, val4, dst_bytes
+	addi	dst_bytes, dst_bytes, 8
+	stwbrx	state15, 0, dst_bytes
+#else
+	stw	state0, 4(dst_bytes)
+	stw	state1, 8(dst_bytes)
+	stw	state2, 12(dst_bytes)
+	stw	state3, 16(dst_bytes)
+	stw	state4, 20(dst_bytes)
+	stw	state5, 24(dst_bytes)
+	stw	state6, 28(dst_bytes)
+	stw	state7, 32(dst_bytes)
+	stw	state8, 36(dst_bytes)
+	stw	state9, 40(dst_bytes)
+	stw	state10, 44(dst_bytes)
+	stw	state11, 48(dst_bytes)
+	stw	state12, 52(dst_bytes)
+	stw	state13, 56(dst_bytes)
+	stw	state14, 60(dst_bytes)
+	stwu	state15, 64(dst_bytes)
+#endif
+
+	subic.	idx_r0, idx_r0, 1	/* subi. can't use r0 as source */
+
+#ifdef __powerpc64__
+	addi	counter0, counter0, 1
+	srdi	counter1, counter0, 32
+#else
+	addic	counter0, counter0, 1
+	addze	counter1, counter1
+#endif
+
+	bne	.Lblock
+
+#ifdef __powerpc64__
+	ld	counter, -216(r1)
+#else
+	lwz	counter, 20(r1)
+#endif
+	stw	counter0, 0(counter)
+	stw	counter1, 4(counter)
+
+	li	r6, 0
+	li	r7, 0
+	li	r8, 0
+	li	r9, 0
+	li	r10, 0
+	li	r11, 0
+	li	r12, 0
+
+#ifdef __powerpc64__
+	ld	r14, -144(r1)
+	ld	r15, -136(r1)
+	ld	r16, -128(r1)
+	ld	r17, -120(r1)
+	ld	r18, -112(r1)
+	ld	r19, -104(r1)
+	ld	r20, -96(r1)
+	ld	r21, -88(r1)
+	ld	r22, -80(r1)
+	ld	r23, -72(r1)
+	ld	r24, -64(r1)
+	ld	r25, -56(r1)
+	ld	r26, -48(r1)
+	ld	r27, -40(r1)
+	ld	r28, -32(r1)
+	ld	r29, -24(r1)
+	ld	r30, -16(r1)
+	ld	r31, -8(r1)
+#else
+#ifdef __BIG_ENDIAN__
+	lmw	r14, 24(r1)
+#else
+	lwz	r14, 24(r1)
+	lwz	r15, 28(r1)
+	lwz	r16, 32(r1)
+	lwz	r17, 36(r1)
+	lwz	r18, 40(r1)
+	lwz	r19, 44(r1)
+	lwz	r20, 48(r1)
+	lwz	r21, 52(r1)
+	lwz	r22, 56(r1)
+	lwz	r23, 60(r1)
+	lwz	r24, 64(r1)
+	lwz	r25, 68(r1)
+	lwz	r26, 72(r1)
+	lwz	r27, 76(r1)
+	lwz	r28, 80(r1)
+	lwz	r29, 84(r1)
+	lwz	r30, 88(r1)
+	lwz	r31, 92(r1)
+#endif
+	addi	r1, r1, 96
+#endif	/* __powerpc64__ */
+	blr
+SYM_FUNC_END(__arch_chacha20_blocks_nostack)

arch/powerpc/kernel/vdso/vgetrandom.c

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Powerpc userspace implementation of getrandom()
+ *
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+#include <linux/time.h>
+#include <linux/types.h>
+
+ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state,
+			     size_t opaque_len, const struct vdso_rng_data *vd)
+{
+	return __cvdso_getrandom_data(vd, buffer, len, flags, opaque_state, opaque_len);
+}

arch/s390/Kconfig

@@ -243,6 +243,7 @@ config S390
 	select TRACE_IRQFLAGS_SUPPORT
 	select TTY
 	select USER_STACKTRACE_SUPPORT
+	select VDSO_GETRANDOM
 	select VIRT_CPU_ACCOUNTING
 	select ZONE_DMA
 	# Note: keep the above list sorted alphabetically

arch/s390/include/asm/alternative.h

@@ -39,11 +39,7 @@
 #define ALT_TYPE_SHIFT		20
 #define ALT_CTX_SHIFT		28
 
-#define ALT_FACILITY_EARLY(facility)	(ALT_CTX_EARLY << ALT_CTX_SHIFT		| \
+#define ALT_FACILITY(facility)		(ALT_CTX_EARLY << ALT_CTX_SHIFT		| \
-					 ALT_TYPE_FACILITY << ALT_TYPE_SHIFT	| \
-					 (facility) << ALT_DATA_SHIFT)
-
-#define ALT_FACILITY(facility)		(ALT_CTX_LATE << ALT_CTX_SHIFT		| \
 					 ALT_TYPE_FACILITY << ALT_TYPE_SHIFT	| \
 					 (facility) << ALT_DATA_SHIFT)
 

arch/s390/include/asm/facility.h

@@ -14,7 +14,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/preempt.h>
-
+#include <asm/alternative.h>
 #include <asm/lowcore.h>
 
 #define MAX_FACILITY_BIT (sizeof(stfle_fac_list) * 8)
@@ -39,28 +39,51 @@ static inline void __clear_facility(unsigned long nr, void *facilities)
 	ptr[nr >> 3] &= ~(0x80 >> (nr & 7));
 }
 
-static inline int __test_facility(unsigned long nr, void *facilities)
+static __always_inline bool __test_facility(unsigned long nr, void *facilities)
 {
 	unsigned char *ptr;
 
 	if (nr >= MAX_FACILITY_BIT)
-		return 0;
+		return false;
 	ptr = (unsigned char *) facilities + (nr >> 3);
 	return (*ptr & (0x80 >> (nr & 7))) != 0;
 }
 
+/*
+ * __test_facility_constant() generates a single instruction branch. If the
+ * tested facility is available (likely) the branch is patched into a nop.
+ *
+ * Do not use this function unless you know what you are doing. All users are
+ * supposed to use test_facility() which will do the right thing.
+ */
+static __always_inline bool __test_facility_constant(unsigned long nr)
+{
+	asm goto(
+		ALTERNATIVE("brcl 15,%l[l_no]", "brcl 0,0", ALT_FACILITY(%[nr]))
+		:
+		: [nr] "i" (nr)
+		:
+		: l_no);
+	return true;
+l_no:
+	return false;
+}
+
 /*
  * The test_facility function uses the bit ordering where the MSB is bit 0.
  * That makes it easier to query facility bits with the bit number as
  * documented in the Principles of Operation.
  */
-static inline int test_facility(unsigned long nr)
+static __always_inline bool test_facility(unsigned long nr)
 {
 	unsigned long facilities_als[] = { FACILITIES_ALS };
 
-	if (__builtin_constant_p(nr) && nr < sizeof(facilities_als) * 8) {
+	if (!__is_defined(__DECOMPRESSOR) && __builtin_constant_p(nr)) {
-		if (__test_facility(nr, &facilities_als))
+		if (nr < sizeof(facilities_als) * 8) {
-			return 1;
+			if (__test_facility(nr, &facilities_als))
+				return true;
+		}
+		return __test_facility_constant(nr);
 	}
 	return __test_facility(nr, &stfle_fac_list);
 }

arch/s390/include/asm/fpu-insn-asm.h

@@ -407,6 +407,28 @@
 	MRXBOPC	0, 0x0E, v1
 .endm
 
+/* VECTOR STORE BYTE REVERSED ELEMENTS */
+	.macro	VSTBR	vr1, disp, index="%r0", base, m
+	VX_NUM	v1, \vr1
+	GR_NUM	x2, \index
+	GR_NUM	b2, \base
+	.word	0xE600 | ((v1&15) << 4) | (x2&15)
+	.word	(b2 << 12) | (\disp)
+	MRXBOPC	\m, 0x0E, v1
+.endm
+.macro	VSTBRH	vr1, disp, index="%r0", base
+	VSTBR	\vr1, \disp, \index, \base, 1
+.endm
+.macro	VSTBRF	vr1, disp, index="%r0", base
+	VSTBR	\vr1, \disp, \index, \base, 2
+.endm
+.macro	VSTBRG	vr1, disp, index="%r0", base
+	VSTBR	\vr1, \disp, \index, \base, 3
+.endm
+.macro	VSTBRQ	vr1, disp, index="%r0", base
+	VSTBR	\vr1, \disp, \index, \base, 4
+.endm
+
 /* VECTOR STORE MULTIPLE */
 .macro	VSTM	vfrom, vto, disp, base, hint=3
 	VX_NUM	v1, \vfrom

arch/s390/include/asm/module.h

@@ -38,4 +38,18 @@ struct mod_arch_specific {
 #endif /* CONFIG_FUNCTION_TRACER */
 };
 
+static inline const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
+					   const Elf_Shdr *sechdrs,
+					   const char *name)
+{
+	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+	const Elf_Shdr *s, *se;
+
+	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
+		if (strcmp(name, secstrs + s->sh_name) == 0)
+			return s;
+	}
+	return NULL;
+}
+
 #endif /* _ASM_S390_MODULE_H */

arch/s390/include/asm/vdso-symbols.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __S390_VDSO_SYMBOLS_H__
+#define __S390_VDSO_SYMBOLS_H__
+
+#include <generated/vdso64-offsets.h>
+#ifdef CONFIG_COMPAT
+#include <generated/vdso32-offsets.h>
+#endif
+
+#define VDSO64_SYMBOL(tsk, name) ((tsk)->mm->context.vdso_base + (vdso64_offset_##name))
+#ifdef CONFIG_COMPAT
+#define VDSO32_SYMBOL(tsk, name) ((tsk)->mm->context.vdso_base + (vdso32_offset_##name))
+#else
+#define VDSO32_SYMBOL(tsk, name) (-1UL)
+#endif
+
+#endif /* __S390_VDSO_SYMBOLS_H__ */

arch/s390/include/asm/vdso.h

@@ -6,18 +6,6 @@
 
 #ifndef __ASSEMBLY__
 
-#include <generated/vdso64-offsets.h>
-#ifdef CONFIG_COMPAT
-#include <generated/vdso32-offsets.h>
-#endif
-
-#define VDSO64_SYMBOL(tsk, name) ((tsk)->mm->context.vdso_base + (vdso64_offset_##name))
-#ifdef CONFIG_COMPAT
-#define VDSO32_SYMBOL(tsk, name) ((tsk)->mm->context.vdso_base + (vdso32_offset_##name))
-#else
-#define VDSO32_SYMBOL(tsk, name) (-1UL)
-#endif
-
 extern struct vdso_data *vdso_data;
 
 int vdso_getcpu_init(void);

arch/s390/include/asm/vdso/getrandom.h

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_VDSO_GETRANDOM_H
+#define __ASM_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+#include <vdso/datapage.h>
+#include <asm/vdso/vsyscall.h>
+#include <asm/syscall.h>
+#include <asm/unistd.h>
+#include <asm/page.h>
+
+/**
+ * getrandom_syscall - Invoke the getrandom() syscall.
+ * @buffer:	Destination buffer to fill with random bytes.
+ * @len:	Size of @buffer in bytes.
+ * @flags:	Zero or more GRND_* flags.
+ * Returns:	The number of random bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
+{
+	return syscall3(__NR_getrandom, (long)buffer, (long)len, (long)flags);
+}
+
+static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
+{
+	/*
+	 * The RNG data is in the real VVAR data page, but if a task belongs to a time namespace
+	 * then VVAR_DATA_PAGE_OFFSET points to the namespace-specific VVAR page and VVAR_TIMENS_
+	 * PAGE_OFFSET points to the real VVAR page.
+	 */
+	if (IS_ENABLED(CONFIG_TIME_NS) && _vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS)
+		return (void *)&_vdso_rng_data + VVAR_TIMENS_PAGE_OFFSET * PAGE_SIZE;
+	return &_vdso_rng_data;
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETRANDOM_H */

arch/s390/include/asm/vdso/vsyscall.h

@@ -2,12 +2,21 @@
 #ifndef __ASM_VDSO_VSYSCALL_H
 #define __ASM_VDSO_VSYSCALL_H
 
+#define __VDSO_RND_DATA_OFFSET	768
+
 #ifndef __ASSEMBLY__
 
 #include <linux/hrtimer.h>
 #include <linux/timekeeper_internal.h>
 #include <vdso/datapage.h>
 #include <asm/vdso.h>
+
+enum vvar_pages {
+	VVAR_DATA_PAGE_OFFSET,
+	VVAR_TIMENS_PAGE_OFFSET,
+	VVAR_NR_PAGES
+};
+
 /*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
@@ -18,6 +27,12 @@ static __always_inline struct vdso_data *__s390_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __s390_get_k_vdso_data
 
+static __always_inline struct vdso_rng_data *__s390_get_k_vdso_rnd_data(void)
+{
+	return (void *)vdso_data + __VDSO_RND_DATA_OFFSET;
+}
+#define __arch_get_k_vdso_rng_data __s390_get_k_vdso_rnd_data
+
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 

arch/s390/kernel/compat_signal.c

@@ -24,11 +24,11 @@
 #include <linux/tty.h>
 #include <linux/personality.h>
 #include <linux/binfmts.h>
+#include <asm/vdso-symbols.h>
 #include <asm/access-regs.h>
 #include <asm/ucontext.h>
 #include <linux/uaccess.h>
 #include <asm/lowcore.h>
-#include <asm/vdso.h>
 #include <asm/fpu.h>
 #include "compat_linux.h"
 #include "compat_ptrace.h"

arch/s390/kernel/entry.S

@@ -42,7 +42,7 @@ _LPP_OFFSET	= __LC_LPP
 
 	.macro LPSWEY address, lpswe
 	ALTERNATIVE_2 "b \lpswe;nopr", \
-		".insn siy,0xeb0000000071,\address,0", ALT_FACILITY_EARLY(193),		\
+		".insn siy,0xeb0000000071,\address,0", ALT_FACILITY(193),		\
 		__stringify(.insn siy,0xeb0000000071,LOWCORE_ALT_ADDRESS+\address,0),	\
 		ALT_LOWCORE
 	.endm

arch/s390/kernel/signal.c

@@ -30,9 +30,9 @@
 #include <linux/compat.h>
 #include <asm/ucontext.h>
 #include <linux/uaccess.h>
+#include <asm/vdso-symbols.h>
 #include <asm/access-regs.h>
 #include <asm/lowcore.h>
-#include <asm/vdso.h>
 #include "entry.h"
 
 /*

arch/s390/kernel/vdso.c

@@ -12,12 +12,15 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
 #include <linux/time_namespace.h>
 #include <linux/random.h>
 #include <vdso/datapage.h>
+#include <asm/vdso/vsyscall.h>
+#include <asm/alternative.h>
 #include <asm/vdso.h>
 
 extern char vdso64_start[], vdso64_end[];
@@ -29,12 +32,6 @@ static union vdso_data_store vdso_data_store __page_aligned_data;
 
 struct vdso_data *vdso_data = vdso_data_store.data;
 
-enum vvar_pages {
-	VVAR_DATA_PAGE_OFFSET,
-	VVAR_TIMENS_PAGE_OFFSET,
-	VVAR_NR_PAGES,
-};
-
 #ifdef CONFIG_TIME_NS
 struct vdso_data *arch_get_vdso_data(void *vvar_page)
 {
@@ -250,8 +247,25 @@ static struct page ** __init vdso_setup_pages(void *start, void *end)
 	return pagelist;
 }
 
+static void vdso_apply_alternatives(void)
+{
+	const struct elf64_shdr *alt, *shdr;
+	struct alt_instr *start, *end;
+	const struct elf64_hdr *hdr;
+
+	hdr = (struct elf64_hdr *)vdso64_start;
+	shdr = (void *)hdr + hdr->e_shoff;
+	alt = find_section(hdr, shdr, ".altinstructions");
+	if (!alt)
+		return;
+	start = (void *)hdr + alt->sh_offset;
+	end = (void *)hdr + alt->sh_offset + alt->sh_size;
+	apply_alternatives(start, end);
+}
+
 static int __init vdso_init(void)
 {
+	vdso_apply_alternatives();
 	vdso64_mapping.pages = vdso_setup_pages(vdso64_start, vdso64_end);
 	if (IS_ENABLED(CONFIG_COMPAT))
 		vdso32_mapping.pages = vdso_setup_pages(vdso32_start, vdso32_end);

arch/s390/kernel/vdso64/Makefile

@@ -3,12 +3,17 @@
 
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
-obj-vdso64 = vdso_user_wrapper.o note.o
+obj-vdso64 = vdso_user_wrapper.o note.o vgetrandom-chacha.o
-obj-cvdso64 = vdso64_generic.o getcpu.o
+obj-cvdso64 = vdso64_generic.o getcpu.o vgetrandom.o
 VDSO_CFLAGS_REMOVE := -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE) $(CC_FLAGS_CHECK_STACK)
 CFLAGS_REMOVE_getcpu.o = $(VDSO_CFLAGS_REMOVE)
+CFLAGS_REMOVE_vgetrandom.o = $(VDSO_CFLAGS_REMOVE)
 CFLAGS_REMOVE_vdso64_generic.o = $(VDSO_CFLAGS_REMOVE)
 
+ifneq ($(c-getrandom-y),)
+	CFLAGS_vgetrandom.o += -include $(c-getrandom-y)
+endif
+
 # Build rules
 
 targets := $(obj-vdso64) $(obj-cvdso64) vdso64.so vdso64.so.dbg

arch/s390/kernel/vdso64/vdso.h

@@ -10,5 +10,6 @@ int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unuse
 int __s390_vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
 int __s390_vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
 int __s390_vdso_clock_getres(clockid_t clock, struct __kernel_timespec *ts);
+ssize_t __kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len);
 
 #endif /* __ARCH_S390_KERNEL_VDSO64_VDSO_H */

arch/s390/kernel/vdso64/vdso64.lds.S

@@ -4,6 +4,7 @@
  * library
  */
 
+#include <asm/vdso/vsyscall.h>
 #include <asm/page.h>
 #include <asm/vdso.h>
 
@@ -13,6 +14,7 @@ OUTPUT_ARCH(s390:64-bit)
 SECTIONS
 {
 	PROVIDE(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE);
+	PROVIDE(_vdso_rng_data = _vdso_data + __VDSO_RND_DATA_OFFSET);
 #ifdef CONFIG_TIME_NS
 	PROVIDE(_timens_data = _vdso_data + PAGE_SIZE);
 #endif
@@ -42,6 +44,10 @@ SECTIONS
 	.rodata		: { *(.rodata .rodata.* .gnu.linkonce.r.*) }
 	.rodata1	: { *(.rodata1) }
 
+	. = ALIGN(8);
+	.altinstructions	: { *(.altinstructions) }
+	.altinstr_replacement	: { *(.altinstr_replacement) }
+
 	.dynamic	: { *(.dynamic) }		:text	:dynamic
 
 	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
@@ -140,6 +146,7 @@ VERSION
 		__kernel_restart_syscall;
 		__kernel_rt_sigreturn;
 		__kernel_sigreturn;
+		__kernel_getrandom;
 	local: *;
 	};
 }

arch/s390/kernel/vdso64/vgetrandom-chacha.S

@@ -0,0 +1,185 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <asm/alternative.h>
+#include <asm/fpu-insn.h>
+
+#define STATE0	%v0
+#define STATE1	%v1
+#define STATE2	%v2
+#define STATE3	%v3
+#define COPY0	%v4
+#define COPY1	%v5
+#define COPY2	%v6
+#define COPY3	%v7
+#define PERM4	%v16
+#define PERM8	%v17
+#define PERM12	%v18
+#define BEPERM	%v19
+#define TMP0	%v20
+#define TMP1	%v21
+#define TMP2	%v22
+#define TMP3	%v23
+
+	.section .rodata
+
+	.balign 128
+.Lconstants:
+	.long	0x61707865,0x3320646e,0x79622d32,0x6b206574 # endian-neutral
+	.long	0x04050607,0x08090a0b,0x0c0d0e0f,0x00010203 # rotl  4 bytes
+	.long	0x08090a0b,0x0c0d0e0f,0x00010203,0x04050607 # rotl  8 bytes
+	.long	0x0c0d0e0f,0x00010203,0x04050607,0x08090a0b # rotl 12 bytes
+	.long	0x03020100,0x07060504,0x0b0a0908,0x0f0e0d0c # byte swap
+
+	.text
+/*
+ * s390 ChaCha20 implementation meant for vDSO. Produces a given positive
+ * number of blocks of output with nonce 0, taking an input key and 8-bytes
+ * counter. Does not spill to the stack.
+ *
+ * void __arch_chacha20_blocks_nostack(uint8_t *dst_bytes,
+ *				       const uint8_t *key,
+ *				       uint32_t *counter,
+ *				       size_t nblocks)
+ */
+SYM_FUNC_START(__arch_chacha20_blocks_nostack)
+	larl	%r1,.Lconstants
+
+	/* COPY0 = "expand 32-byte k" */
+	VL	COPY0,0,,%r1
+
+	/* PERM4-PERM12,BEPERM = byte selectors for VPERM */
+	VLM	PERM4,BEPERM,16,%r1
+
+	/* COPY1,COPY2 = key */
+	VLM	COPY1,COPY2,0,%r3
+
+	/* COPY3 = counter || zero nonce  */
+	lg	%r3,0(%r4)
+	VZERO	COPY3
+	VLVGG	COPY3,%r3,0
+
+	lghi	%r1,0
+.Lblock:
+	VLR	STATE0,COPY0
+	VLR	STATE1,COPY1
+	VLR	STATE2,COPY2
+	VLR	STATE3,COPY3
+
+	lghi	%r0,10
+.Ldoubleround:
+	/* STATE0 += STATE1, STATE3 = rotl32(STATE3 ^ STATE0, 16) */
+	VAF	STATE0,STATE0,STATE1
+	VX	STATE3,STATE3,STATE0
+	VERLLF	STATE3,STATE3,16
+
+	/* STATE2 += STATE3, STATE1 = rotl32(STATE1 ^ STATE2, 12) */
+	VAF	STATE2,STATE2,STATE3
+	VX	STATE1,STATE1,STATE2
+	VERLLF	STATE1,STATE1,12
+
+	/* STATE0 += STATE1, STATE3 = rotl32(STATE3 ^ STATE0, 8) */
+	VAF	STATE0,STATE0,STATE1
+	VX	STATE3,STATE3,STATE0
+	VERLLF	STATE3,STATE3,8
+
+	/* STATE2 += STATE3, STATE1 = rotl32(STATE1 ^ STATE2, 7) */
+	VAF	STATE2,STATE2,STATE3
+	VX	STATE1,STATE1,STATE2
+	VERLLF	STATE1,STATE1,7
+
+	/* STATE1[0,1,2,3] = STATE1[1,2,3,0] */
+	VPERM	STATE1,STATE1,STATE1,PERM4
+	/* STATE2[0,1,2,3] = STATE2[2,3,0,1] */
+	VPERM	STATE2,STATE2,STATE2,PERM8
+	/* STATE3[0,1,2,3] = STATE3[3,0,1,2] */
+	VPERM	STATE3,STATE3,STATE3,PERM12
+
+	/* STATE0 += STATE1, STATE3 = rotl32(STATE3 ^ STATE0, 16) */
+	VAF	STATE0,STATE0,STATE1
+	VX	STATE3,STATE3,STATE0
+	VERLLF	STATE3,STATE3,16
+
+	/* STATE2 += STATE3, STATE1 = rotl32(STATE1 ^ STATE2, 12) */
+	VAF	STATE2,STATE2,STATE3
+	VX	STATE1,STATE1,STATE2
+	VERLLF	STATE1,STATE1,12
+
+	/* STATE0 += STATE1, STATE3 = rotl32(STATE3 ^ STATE0, 8) */
+	VAF	STATE0,STATE0,STATE1
+	VX	STATE3,STATE3,STATE0
+	VERLLF	STATE3,STATE3,8
+
+	/* STATE2 += STATE3, STATE1 = rotl32(STATE1 ^ STATE2, 7) */
+	VAF	STATE2,STATE2,STATE3
+	VX	STATE1,STATE1,STATE2
+	VERLLF	STATE1,STATE1,7
+
+	/* STATE1[0,1,2,3] = STATE1[3,0,1,2] */
+	VPERM	STATE1,STATE1,STATE1,PERM12
+	/* STATE2[0,1,2,3] = STATE2[2,3,0,1] */
+	VPERM	STATE2,STATE2,STATE2,PERM8
+	/* STATE3[0,1,2,3] = STATE3[1,2,3,0] */
+	VPERM	STATE3,STATE3,STATE3,PERM4
+	brctg	%r0,.Ldoubleround
+
+	/* OUTPUT0 = STATE0 + STATE0 */
+	VAF	STATE0,STATE0,COPY0
+	/* OUTPUT1 = STATE1 + STATE1 */
+	VAF	STATE1,STATE1,COPY1
+	/* OUTPUT2 = STATE2 + STATE2 */
+	VAF	STATE2,STATE2,COPY2
+	/* OUTPUT2 = STATE3 + STATE3 */
+	VAF	STATE3,STATE3,COPY3
+
+	/*
+	 * 32 bit wise little endian store to OUTPUT. If the vector
+	 * enhancement facility 2 is not installed use the slow path.
+	 */
+	ALTERNATIVE "brc 0xf,.Lstoreslow", "nop", ALT_FACILITY(148)
+	VSTBRF	STATE0,0,,%r2
+	VSTBRF	STATE1,16,,%r2
+	VSTBRF	STATE2,32,,%r2
+	VSTBRF	STATE3,48,,%r2
+.Lstoredone:
+
+	/* ++COPY3.COUNTER */
+	/* alsih %r3,1 */
+	.insn	rilu,0xcc0a00000000,%r3,1
+	alcr	%r3,%r1
+	VLVGG	COPY3,%r3,0
+
+	/* OUTPUT += 64, --NBLOCKS */
+	aghi	%r2,64
+	brctg	%r5,.Lblock
+
+	/* COUNTER = COPY3.COUNTER */
+	stg	%r3,0(%r4)
+
+	/* Zero out potentially sensitive regs */
+	VZERO	STATE0
+	VZERO	STATE1
+	VZERO	STATE2
+	VZERO	STATE3
+	VZERO	COPY1
+	VZERO	COPY2
+
+	/* Early exit if TMP0-TMP3 have not been used */
+	ALTERNATIVE "nopr", "br %r14", ALT_FACILITY(148)
+
+	VZERO	TMP0
+	VZERO	TMP1
+	VZERO	TMP2
+	VZERO	TMP3
+
+	br	%r14
+
+.Lstoreslow:
+	/* Convert STATE to little endian format and store to OUTPUT */
+	VPERM	TMP0,STATE0,STATE0,BEPERM
+	VPERM	TMP1,STATE1,STATE1,BEPERM
+	VPERM	TMP2,STATE2,STATE2,BEPERM
+	VPERM	TMP3,STATE3,STATE3,BEPERM
+	VSTM	TMP0,TMP3,0,%r2
+	j	.Lstoredone
+SYM_FUNC_END(__arch_chacha20_blocks_nostack)

arch/s390/kernel/vdso64/vgetrandom.c

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <asm/facility.h>
+#include <uapi/asm-generic/errno.h>
+#include "vdso.h"
+
+ssize_t __kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+	if (test_facility(129))
+		return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len);
+	if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags))
+		return -ENOSYS;
+	return getrandom_syscall(buffer, len, flags);
+}

arch/x86/entry/vdso/vgetrandom.c

@@ -6,8 +6,6 @@
 
 #include "../../../../lib/vdso/getrandom.c"
 
-ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len);
-
 ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
 {
 	return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len);

arch/x86/entry/vdso/vma.c

@@ -38,6 +38,9 @@ struct vdso_data *arch_get_vdso_data(void *vvar_page)
 }
 #undef EMIT_VVAR
 
+DEFINE_VVAR(struct vdso_data, _vdso_data);
+DEFINE_VVAR_SINGLE(struct vdso_rng_data, _vdso_rng_data);
+
 unsigned int vclocks_used __read_mostly;
 
 #if defined(CONFIG_X86_64)

arch/x86/include/asm/pvclock.h

@@ -5,6 +5,7 @@
 #include <asm/clocksource.h>
 #include <asm/pvclock-abi.h>
 
+struct timespec64;
 /* some helper functions for xen and kvm pv clock sources */
 u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
 u64 pvclock_clocksource_read_nowd(struct pvclock_vcpu_time_info *src);

arch/x86/include/asm/vdso/getrandom.h

@@ -37,19 +37,6 @@ static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void
 	return &__vdso_rng_data;
 }
 
-/**
- * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
- * @dst_bytes:	Destination buffer to hold @nblocks * 64 bytes of output.
- * @key:	32-byte input key.
- * @counter:	8-byte counter, read on input and updated on return.
- * @nblocks:	Number of blocks to generate.
- *
- * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
- * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
- * leaking into forked child processes.
- */
-extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
-
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_VDSO_GETRANDOM_H */

arch/x86/include/asm/vdso/vsyscall.h

@@ -9,9 +9,6 @@
 #include <asm/vgtod.h>
 #include <asm/vvar.h>
 
-DEFINE_VVAR(struct vdso_data, _vdso_data);
-DEFINE_VVAR_SINGLE(struct vdso_rng_data, _vdso_rng_data);
-
 /*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
@@ -22,6 +19,13 @@ struct vdso_data *__x86_get_k_vdso_data(void)
 }
 #define __arch_get_k_vdso_data __x86_get_k_vdso_data
 
+static __always_inline
+struct vdso_rng_data *__x86_get_k_vdso_rng_data(void)
+{
+	return &_vdso_rng_data;
+}
+#define __arch_get_k_vdso_rng_data __x86_get_k_vdso_rng_data
+
 /* The asm-generic header needs to be included after the definitions above */
 #include <asm-generic/vdso/vsyscall.h>
 

drivers/char/random.c

@@ -59,6 +59,7 @@
 #ifdef CONFIG_VDSO_GETRANDOM
 #include <vdso/getrandom.h>
 #include <vdso/datapage.h>
+#include <vdso/vsyscall.h>
 #endif
 #include <asm/archrandom.h>
 #include <asm/processor.h>
@@ -281,8 +282,15 @@ static void crng_reseed(struct work_struct *work)
 	 * former to arrive at the latter. Use smp_store_release so that this
 	 * is ordered with the write above to base_crng.generation. Pairs with
 	 * the smp_rmb() before the syscall in the vDSO code.
+	 *
+	 * Cast to unsigned long for 32-bit architectures, since atomic 64-bit
+	 * operations are not supported on those architectures. This is safe
+	 * because base_crng.generation is a 32-bit value. On big-endian
+	 * architectures it will be stored in the upper 32 bits, but that's okay
+	 * because the vDSO side only checks whether the value changed, without
+	 * actually using or interpreting the value.
 	 */
-	smp_store_release(&_vdso_rng_data.generation, next_gen + 1);
+	smp_store_release((unsigned long *)&__arch_get_k_vdso_rng_data()->generation, next_gen + 1);
 #endif
 	if (!static_branch_likely(&crng_is_ready))
 		crng_init = CRNG_READY;
@@ -735,7 +743,7 @@ static void __cold _credit_init_bits(size_t bits)
 			queue_work(system_unbound_wq, &set_ready);
 		atomic_notifier_call_chain(&random_ready_notifier, 0, NULL);
 #ifdef CONFIG_VDSO_GETRANDOM
-		WRITE_ONCE(_vdso_rng_data.is_ready, true);
+		WRITE_ONCE(__arch_get_k_vdso_rng_data()->is_ready, true);
 #endif
 		wake_up_interruptible(&crng_init_wait);
 		kill_fasync(&fasync, SIGIO, POLL_IN);

fs/proc/task_mmu.c

@@ -989,8 +989,10 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 #ifdef CONFIG_X86_USER_SHADOW_STACK
 		[ilog2(VM_SHADOW_STACK)] = "ss",
 #endif
-#ifdef CONFIG_64BIT
+#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
 		[ilog2(VM_DROPPABLE)] = "dp",
+#endif
+#ifdef CONFIG_64BIT
 		[ilog2(VM_SEALED)] = "sl",
 #endif
 	};

include/asm-generic/unaligned.h

@@ -8,16 +8,7 @@
  */
 #include <linux/unaligned/packed_struct.h>
 #include <asm/byteorder.h>
-
+#include <vdso/unaligned.h>
-#define __get_unaligned_t(type, ptr) ({						\
-	const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);	\
-	__pptr->x;								\
-})
-
-#define __put_unaligned_t(type, val, ptr) do {					\
-	struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);		\
-	__pptr->x = (val);							\
-} while (0)
 
 #define get_unaligned(ptr)	__get_unaligned_t(typeof(*(ptr)), (ptr))
 #define put_unaligned(val, ptr) __put_unaligned_t(typeof(*(ptr)), (val), (ptr))

include/linux/mm.h

@@ -367,7 +367,7 @@ extern unsigned int kobjsize(const void *objp);
 
 #if defined(CONFIG_X86)
 # define VM_PAT		VM_ARCH_1	/* PAT reserves whole VMA at once (x86) */
-#elif defined(CONFIG_PPC)
+#elif defined(CONFIG_PPC64)
 # define VM_SAO		VM_ARCH_1	/* Strong Access Ordering (powerpc) */
 #elif defined(CONFIG_PARISC)
 # define VM_GROWSUP	VM_ARCH_1
@@ -417,6 +417,8 @@ extern unsigned int kobjsize(const void *objp);
 #ifdef CONFIG_64BIT
 #define VM_DROPPABLE_BIT	40
 #define VM_DROPPABLE		BIT(VM_DROPPABLE_BIT)
+#elif defined(CONFIG_PPC32)
+#define VM_DROPPABLE		VM_ARCH_1
 #else
 #define VM_DROPPABLE		VM_NONE
 #endif

include/trace/events/mmflags.h

@@ -143,7 +143,7 @@ IF_HAVE_PG_ARCH_X(arch_3)
 
 #if defined(CONFIG_X86)
 #define __VM_ARCH_SPECIFIC_1 {VM_PAT,     "pat"           }
-#elif defined(CONFIG_PPC)
+#elif defined(CONFIG_PPC64)
 #define __VM_ARCH_SPECIFIC_1 {VM_SAO,     "sao"           }
 #elif defined(CONFIG_PARISC)
 #define __VM_ARCH_SPECIFIC_1 {VM_GROWSUP,	"growsup"	}
@@ -165,7 +165,7 @@ IF_HAVE_PG_ARCH_X(arch_3)
 # define IF_HAVE_UFFD_MINOR(flag, name)
 #endif
 
-#ifdef CONFIG_64BIT
+#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
 # define IF_HAVE_VM_DROPPABLE(flag, name) {flag, name},
 #else
 # define IF_HAVE_VM_DROPPABLE(flag, name)

include/vdso/getrandom.h

@@ -43,4 +43,32 @@ struct vgetrandom_state {
 	bool 			in_use;
 };
 
+/**
+ * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
+ * @dst_bytes:	Destination buffer to hold @nblocks * 64 bytes of output.
+ * @key:	32-byte input key.
+ * @counter:	8-byte counter, read on input and updated on return.
+ * @nblocks:	Number of blocks to generate.
+ *
+ * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
+ * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
+ * leaking into forked child processes.
+ */
+extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
+
+/**
+ * __vdso_getrandom - Architecture-specific vDSO implementation of getrandom() syscall.
+ * @buffer:		Passed to __cvdso_getrandom().
+ * @len:		Passed to __cvdso_getrandom().
+ * @flags:		Passed to __cvdso_getrandom().
+ * @opaque_state:	Passed to __cvdso_getrandom().
+ * @opaque_len:		Passed to __cvdso_getrandom();
+ *
+ * This function is implemented by making a single call to to __cvdso_getrandom(), whose
+ * documentation may be consulted for more information.
+ *
+ * Returns:	The return value of __cvdso_getrandom().
+ */
+extern ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len);
+
 #endif /* _VDSO_GETRANDOM_H */

include/vdso/helpers.h

@@ -4,6 +4,7 @@
 
 #ifndef __ASSEMBLY__
 
+#include <asm/barrier.h>
 #include <vdso/datapage.h>
 
 static __always_inline u32 vdso_read_begin(const struct vdso_data *vd)

include/vdso/unaligned.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_UNALIGNED_H
+#define __VDSO_UNALIGNED_H
+
+#define __get_unaligned_t(type, ptr) ({						\
+	const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);	\
+	__pptr->x;								\
+})
+
+#define __put_unaligned_t(type, val, ptr) do {					\
+	struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);		\
+	__pptr->x = (val);							\
+} while (0)
+
+#endif /* __VDSO_UNALIGNED_H */

lib/vdso/Makefile

@@ -4,6 +4,7 @@ GENERIC_VDSO_MK_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
 GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH))
 
 c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix $(GENERIC_VDSO_DIR), gettimeofday.c)
+c-getrandom-$(CONFIG_VDSO_GETRANDOM) := $(addprefix $(GENERIC_VDSO_DIR), getrandom.c)
 
 # This cmd checks that the vdso library does not contain dynamic relocations.
 # It has to be called after the linking of the vdso library and requires it

lib/vdso/getrandom.c

@@ -3,15 +3,19 @@
  * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
-#include <linux/cache.h>
+#include <linux/array_size.h>
-#include <linux/kernel.h>
+#include <linux/minmax.h>
-#include <linux/time64.h>
 #include <vdso/datapage.h>
 #include <vdso/getrandom.h>
+#include <vdso/unaligned.h>
 #include <asm/vdso/getrandom.h>
-#include <asm/vdso/vsyscall.h>
-#include <asm/unaligned.h>
 #include <uapi/linux/mman.h>
+#include <uapi/linux/random.h>
+
+#undef PAGE_SIZE
+#undef PAGE_MASK
+#define PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
+#define PAGE_MASK (~(PAGE_SIZE - 1))
 
 #define MEMCPY_AND_ZERO_SRC(type, dst, src, len) do {				\
 	while (len >= sizeof(type)) {						\
@@ -68,16 +72,17 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_
 	struct vgetrandom_state *state = opaque_state;
 	size_t batch_len, nblocks, orig_len = len;
 	bool in_use, have_retried = false;
-	unsigned long current_generation;
 	void *orig_buffer = buffer;
+	u64 current_generation;
 	u32 counter[2] = { 0 };
 
 	if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags)) {
-		*(struct vgetrandom_opaque_params *)opaque_state = (struct vgetrandom_opaque_params) {
+		struct vgetrandom_opaque_params *params = opaque_state;
-			.size_of_opaque_state = sizeof(*state),
+		params->size_of_opaque_state = sizeof(*state);
-			.mmap_prot = PROT_READ | PROT_WRITE,
+		params->mmap_prot = PROT_READ | PROT_WRITE;
-			.mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS
+		params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
-		};
+		for (size_t i = 0; i < ARRAY_SIZE(params->reserved); ++i)
+			params->reserved[i] = 0;
 		return 0;
 	}
 

tools/arch/arm64/vdso

@@ -0,0 +1 @@
+../../../arch/arm64/kernel/vdso

tools/arch/loongarch/vdso

@@ -0,0 +1 @@
+../../../arch/loongarch/vdso

tools/arch/powerpc/vdso

@@ -0,0 +1 @@
+../../../arch/powerpc/kernel/vdso

tools/arch/s390/vdso

@@ -0,0 +1 @@
+../../../arch/s390/kernel/vdso64

tools/arch/x86/vdso

@@ -0,0 +1 @@
+../../../arch/x86/entry/vdso/

tools/include/asm/alternative.h

@@ -2,8 +2,18 @@
 #ifndef _TOOLS_ASM_ALTERNATIVE_ASM_H
 #define _TOOLS_ASM_ALTERNATIVE_ASM_H
 
+#if defined(__s390x__)
+#ifdef __ASSEMBLY__
+.macro ALTERNATIVE oldinstr, newinstr, feature
+	\oldinstr
+.endm
+#endif
+#else
+
 /* Just disable it so we can build arch/x86/lib/memcpy_64.S for perf bench: */
 
 #define ALTERNATIVE #
 
 #endif
+
+#endif

tools/include/linux/compiler.h

@@ -2,6 +2,8 @@
 #ifndef _TOOLS_LINUX_COMPILER_H_
 #define _TOOLS_LINUX_COMPILER_H_
 
+#ifndef __ASSEMBLY__
+
 #include <linux/compiler_types.h>
 
 #ifndef __compiletime_error
@@ -224,4 +226,6 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
 	__asm__ ("" : "=r" (var) : "0" (var))
 #endif
 
+#endif /* __ASSEMBLY__ */
+
 #endif /* _TOOLS_LINUX_COMPILER_H */

tools/include/linux/linkage.h

@@ -1,4 +1,8 @@
 #ifndef _TOOLS_INCLUDE_LINUX_LINKAGE_H
 #define _TOOLS_INCLUDE_LINUX_LINKAGE_H
 
+#define SYM_FUNC_START(x) .globl x; x:
+
+#define SYM_FUNC_END(x)
+
 #endif /* _TOOLS_INCLUDE_LINUX_LINKAGE_H */

tools/testing/selftests/vDSO/Makefile

@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-uname_M := $(shell uname -m 2>/dev/null || echo not)
+include ../../../scripts/Makefile.arch
-ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
-SODIUM := $(shell pkg-config --libs libsodium 2>/dev/null)
 
 TEST_GEN_PROGS := vdso_test_gettimeofday
 TEST_GEN_PROGS += vdso_test_getcpu
@@ -11,14 +9,12 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64))
 TEST_GEN_PROGS += vdso_standalone_test_x86
 endif
 TEST_GEN_PROGS += vdso_test_correctness
-ifeq ($(uname_M),x86_64)
+ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
-ifneq ($(SODIUM),)
 TEST_GEN_PROGS += vdso_test_chacha
 endif
-endif
 
-CFLAGS := -std=gnu99
+CFLAGS := -std=gnu99 -O2
 
 ifeq ($(CONFIG_X86_32),y)
 LDLIBS += -lgcc_s
@@ -38,11 +34,12 @@ $(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl
 
 $(OUTPUT)/vdso_test_getrandom: parse_vdso.c
 $(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \
+                                         $(KHDR_INCLUDES) \
                                          -isystem $(top_srcdir)/include/uapi
 
-$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/arch/$(ARCH)/entry/vdso/vgetrandom-chacha.S
+$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S
 $(OUTPUT)/vdso_test_chacha: CFLAGS += -idirafter $(top_srcdir)/tools/include \
-                                      -isystem $(top_srcdir)/arch/$(ARCH)/include \
+                                      -idirafter $(top_srcdir)/tools/include/generated \
-                                      -isystem $(top_srcdir)/include \
+                                      -idirafter $(top_srcdir)/arch/$(SRCARCH)/include \
-                                      -D__ASSEMBLY__ -DBULID_VDSO -DCONFIG_FUNCTION_ALIGNMENT=0 \
+                                      -idirafter $(top_srcdir)/include \
-                                      -Wa,--noexecstack $(SODIUM)
+                                      -D__ASSEMBLY__ -Wa,--noexecstack

tools/testing/selftests/vDSO/parse_vdso.c

@@ -36,6 +36,12 @@
 #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x)
 #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x)
 
+#ifdef __s390x__
+#define ELF_HASH_ENTRY ELF(Xword)
+#else
+#define ELF_HASH_ENTRY ELF(Word)
+#endif
+
 static struct vdso_info
 {
 	bool valid;
@@ -47,8 +53,8 @@ static struct vdso_info
 	/* Symbol table */
 	ELF(Sym) *symtab;
 	const char *symstrings;
-	ELF(Word) *bucket, *chain;
+	ELF_HASH_ENTRY *bucket, *chain;
-	ELF(Word) nbucket, nchain;
+	ELF_HASH_ENTRY nbucket, nchain;
 
 	/* Version table */
 	ELF(Versym) *versym;
@@ -115,7 +121,7 @@ void vdso_init_from_sysinfo_ehdr(uintptr_t base)
 	/*
 	 * Fish out the useful bits of the dynamic table.
 	 */
-	ELF(Word) *hash = 0;
+	ELF_HASH_ENTRY *hash = 0;
 	vdso_info.symstrings = 0;
 	vdso_info.symtab = 0;
 	vdso_info.versym = 0;
@@ -133,7 +139,7 @@ void vdso_init_from_sysinfo_ehdr(uintptr_t base)
 				 + vdso_info.load_offset);
 			break;
 		case DT_HASH:
-			hash = (ELF(Word) *)
+			hash = (ELF_HASH_ENTRY *)
 				((uintptr_t)dyn[i].d_un.d_ptr
 				 + vdso_info.load_offset);
 			break;
@@ -216,7 +222,8 @@ void *vdso_sym(const char *version, const char *name)
 		ELF(Sym) *sym = &vdso_info.symtab[chain];
 
 		/* Check for a defined global or weak function w/ right name. */
-		if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC)
+		if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC &&
+		    ELF64_ST_TYPE(sym->st_info) != STT_NOTYPE)
 			continue;
 		if (ELF64_ST_BIND(sym->st_info) != STB_GLOBAL &&
 		    ELF64_ST_BIND(sym->st_info) != STB_WEAK)

tools/testing/selftests/vDSO/vdso_call.h

@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Macro to call vDSO functions
+ *
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+#ifndef __VDSO_CALL_H__
+#define __VDSO_CALL_H__
+
+#ifdef __powerpc__
+
+#define LOADARGS_1(fn, __arg1) do {					\
+	_r0 = fn;							\
+	_r3 = (long)__arg1;						\
+} while (0)
+
+#define LOADARGS_2(fn, __arg1, __arg2) do {				\
+	_r0 = fn;							\
+	_r3 = (long)__arg1;						\
+	_r4 = (long)__arg2;						\
+} while (0)
+
+#define LOADARGS_3(fn, __arg1, __arg2, __arg3) do {			\
+	_r0 = fn;							\
+	_r3 = (long)__arg1;						\
+	_r4 = (long)__arg2;						\
+	_r5 = (long)__arg3;						\
+} while (0)
+
+#define LOADARGS_5(fn, __arg1, __arg2, __arg3, __arg4, __arg5) do {	\
+	_r0 = fn;							\
+	_r3 = (long)__arg1;						\
+	_r4 = (long)__arg2;						\
+	_r5 = (long)__arg3;						\
+	_r6 = (long)__arg4;						\
+	_r7 = (long)__arg5;						\
+} while (0)
+
+#define VDSO_CALL(fn, nr, args...) ({					\
+	register void *_r0 asm ("r0");					\
+	register long _r3 asm ("r3");					\
+	register long _r4 asm ("r4");					\
+	register long _r5 asm ("r5");					\
+	register long _r6 asm ("r6");					\
+	register long _r7 asm ("r7");					\
+	register long _r8 asm ("r8");					\
+	register long _rval asm ("r3");					\
+									\
+	LOADARGS_##nr(fn, args);					\
+									\
+	asm volatile(							\
+		"	mtctr %0\n"					\
+		"	bctrl\n"					\
+		"	bns+	1f\n"					\
+		"	neg	3, 3\n"					\
+		"1:"							\
+		: "+r" (_r0), "=r" (_r3), "+r" (_r4), "+r" (_r5),	\
+		  "+r" (_r6), "+r" (_r7), "+r" (_r8)			\
+		: "r" (_rval)						\
+		: "r9", "r10", "r11", "r12", "cr0", "cr1", "cr5",	\
+		  "cr6", "cr7", "xer", "lr", "ctr", "memory"		\
+	);								\
+	_rval;								\
+})
+
+#else
+#define VDSO_CALL(fn, nr, args...)	fn(args)
+#endif
+
+#endif

tools/testing/selftests/vDSO/vdso_config.h

@@ -18,18 +18,18 @@
 #elif defined(__aarch64__)
 #define VDSO_VERSION		3
 #define VDSO_NAMES		0
+#elif defined(__powerpc64__)
+#define VDSO_VERSION		1
+#define VDSO_NAMES		0
 #elif defined(__powerpc__)
 #define VDSO_VERSION		1
 #define VDSO_NAMES		0
 #define VDSO_32BIT		1
-#elif defined(__powerpc64__)
+#elif defined (__s390__) && !defined(__s390x__)
-#define VDSO_VERSION		1
-#define VDSO_NAMES		0
-#elif defined (__s390__)
 #define VDSO_VERSION		2
 #define VDSO_NAMES		0
 #define VDSO_32BIT		1
-#elif defined (__s390X__)
+#elif defined (__s390x__)
 #define VDSO_VERSION		2
 #define VDSO_NAMES		0
 #elif defined(__mips__)
@@ -68,16 +68,15 @@ static const char *versions[7] = {
 	"LINUX_5.10"
 };
 
-static const char *names[2][6] = {
+static const char *names[2][7] = {
 	{
 		"__kernel_gettimeofday",
 		"__kernel_clock_gettime",
 		"__kernel_time",
 		"__kernel_clock_getres",
 		"__kernel_getcpu",
-#if defined(VDSO_32BIT)
 		"__kernel_clock_gettime64",
-#endif
+		"__kernel_getrandom",
 	},
 	{
 		"__vdso_gettimeofday",
@@ -85,9 +84,8 @@ static const char *names[2][6] = {
 		"__vdso_time",
 		"__vdso_clock_getres",
 		"__vdso_getcpu",
-#if defined(VDSO_32BIT)
 		"__vdso_clock_gettime64",
-#endif
+		"__vdso_getrandom",
 	},
 };
 

tools/testing/selftests/vDSO/vdso_test_abi.c

@@ -20,10 +20,8 @@
 
 #include "../kselftest.h"
 #include "vdso_config.h"
-
+#include "vdso_call.h"
-extern void *vdso_sym(const char *version, const char *name);
+#include "parse_vdso.h"
-extern void vdso_init_from_sysinfo_ehdr(uintptr_t base);
-extern void vdso_init_from_auxv(void *auxv);
 
 static const char *version;
 static const char **name;
@@ -61,7 +59,7 @@ static void vdso_test_gettimeofday(void)
 	}
 
 	struct timeval tv;
-	long ret = vdso_gettimeofday(&tv, 0);
+	long ret = VDSO_CALL(vdso_gettimeofday, 2, &tv, 0);
 
 	if (ret == 0) {
 		ksft_print_msg("The time is %lld.%06lld\n",
@@ -86,7 +84,7 @@ static void vdso_test_clock_gettime(clockid_t clk_id)
 	}
 
 	struct timespec ts;
-	long ret = vdso_clock_gettime(clk_id, &ts);
+	long ret = VDSO_CALL(vdso_clock_gettime, 2, clk_id, &ts);
 
 	if (ret == 0) {
 		ksft_print_msg("The time is %lld.%06lld\n",
@@ -111,7 +109,7 @@ static void vdso_test_time(void)
 		return;
 	}
 
-	long ret = vdso_time(NULL);
+	long ret = VDSO_CALL(vdso_time, 1, NULL);
 
 	if (ret > 0) {
 		ksft_print_msg("The time in hours since January 1, 1970 is %lld\n",
@@ -138,7 +136,7 @@ static void vdso_test_clock_getres(clockid_t clk_id)
 	}
 
 	struct timespec ts, sys_ts;
-	long ret = vdso_clock_getres(clk_id, &ts);
+	long ret = VDSO_CALL(vdso_clock_getres, 2, clk_id, &ts);
 
 	if (ret == 0) {
 		ksft_print_msg("The vdso resolution is %lld %lld\n",

tools/testing/selftests/vDSO/vdso_test_chacha.c

@@ -3,23 +3,90 @@
  * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
-#include <sodium/crypto_stream_chacha20.h>
+#include <tools/le_byteshift.h>
 #include <sys/random.h>
+#include <sys/auxv.h>
 #include <string.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include "../kselftest.h"
 
-extern void __arch_chacha20_blocks_nostack(uint8_t *dst_bytes, const uint8_t *key, uint32_t *counter, size_t nblocks);
+#if defined(__aarch64__)
+static bool cpu_has_capabilities(void)
+{
+	return getauxval(AT_HWCAP) & HWCAP_ASIMD;
+}
+#elif defined(__s390x__)
+static bool cpu_has_capabilities(void)
+{
+	return getauxval(AT_HWCAP) & HWCAP_S390_VXRS;
+}
+#else
+static bool cpu_has_capabilities(void)
+{
+	return true;
+}
+#endif
+
+static uint32_t rol32(uint32_t word, unsigned int shift)
+{
+	return (word << (shift & 31)) | (word >> ((-shift) & 31));
+}
+
+static void reference_chacha20_blocks(uint8_t *dst_bytes, const uint32_t *key, uint32_t *counter, size_t nblocks)
+{
+	uint32_t s[16] = {
+		0x61707865U, 0x3320646eU, 0x79622d32U, 0x6b206574U,
+		key[0], key[1], key[2], key[3], key[4], key[5], key[6], key[7],
+		counter[0], counter[1], 0, 0
+	};
+
+	while (nblocks--) {
+		uint32_t x[16];
+		memcpy(x, s, sizeof(x));
+		for (unsigned int r = 0; r < 20; r += 2) {
+		#define QR(a, b, c, d) ( \
+			x[a] += x[b], \
+			x[d] = rol32(x[d] ^ x[a], 16), \
+			x[c] += x[d], \
+			x[b] = rol32(x[b] ^ x[c], 12), \
+			x[a] += x[b], \
+			x[d] = rol32(x[d] ^ x[a], 8), \
+			x[c] += x[d], \
+			x[b] = rol32(x[b] ^ x[c], 7))
+
+			QR(0, 4, 8, 12);
+			QR(1, 5, 9, 13);
+			QR(2, 6, 10, 14);
+			QR(3, 7, 11, 15);
+			QR(0, 5, 10, 15);
+			QR(1, 6, 11, 12);
+			QR(2, 7, 8, 13);
+			QR(3, 4, 9, 14);
+		}
+		for (unsigned int i = 0; i < 16; ++i, dst_bytes += sizeof(uint32_t))
+			put_unaligned_le32(x[i] + s[i], dst_bytes);
+		if (!++s[12])
+			++s[13];
+	}
+	counter[0] = s[12];
+	counter[1] = s[13];
+}
+
+typedef uint8_t u8;
+typedef uint32_t u32;
+typedef uint64_t u64;
+#include <vdso/getrandom.h>
 
 int main(int argc, char *argv[])
 {
 	enum { TRIALS = 1000, BLOCKS = 128, BLOCK_SIZE = 64 };
-	static const uint8_t nonce[8] = { 0 };
+	uint32_t key[8], counter1[2], counter2[2];
-	uint32_t counter[2];
-	uint8_t key[32];
 	uint8_t output1[BLOCK_SIZE * BLOCKS], output2[BLOCK_SIZE * BLOCKS];
 
 	ksft_print_header();
+	if (!cpu_has_capabilities())
+		ksft_exit_skip("Required CPU capabilities missing\n");
 	ksft_set_plan(1);
 
 	for (unsigned int trial = 0; trial < TRIALS; ++trial) {
@@ -27,17 +94,33 @@ int main(int argc, char *argv[])
 			printf("getrandom() failed!\n");
 			return KSFT_SKIP;
 		}
-		crypto_stream_chacha20(output1, sizeof(output1), nonce, key);
+		memset(counter1, 0, sizeof(counter1));
+		reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 		for (unsigned int split = 0; split < BLOCKS; ++split) {
 			memset(output2, 'X', sizeof(output2));
-			memset(counter, 0, sizeof(counter));
+			memset(counter2, 0, sizeof(counter2));
 			if (split)
-				__arch_chacha20_blocks_nostack(output2, key, counter, split);
+				__arch_chacha20_blocks_nostack(output2, key, counter2, split);
-			__arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter, BLOCKS - split);
+			__arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter2, BLOCKS - split);
-			if (memcmp(output1, output2, sizeof(output1)))
+			if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
 				return KSFT_FAIL;
 		}
 	}
+	memset(counter1, 0, sizeof(counter1));
+	counter1[0] = (uint32_t)-BLOCKS + 2;
+	memset(counter2, 0, sizeof(counter2));
+	counter2[0] = (uint32_t)-BLOCKS + 2;
+
+	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
+	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
+	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
+		return KSFT_FAIL;
+
+	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
+	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
+	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
+		return KSFT_FAIL;
+
 	ksft_test_result_pass("chacha: PASS\n");
 	return KSFT_PASS;
 }

tools/testing/selftests/vDSO/vdso_test_correctness.c

@@ -20,6 +20,7 @@
 #include <limits.h>
 
 #include "vdso_config.h"
+#include "vdso_call.h"
 #include "../kselftest.h"
 
 static const char **name;
@@ -114,6 +115,12 @@ static void fill_function_pointers()
 	if (!vdso)
 		vdso = dlopen("linux-gate.so.1",
 			      RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+	if (!vdso)
+		vdso = dlopen("linux-vdso32.so.1",
+			      RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
+	if (!vdso)
+		vdso = dlopen("linux-vdso64.so.1",
+			      RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
 	if (!vdso) {
 		printf("[WARN]\tfailed to find vDSO\n");
 		return;
@@ -180,7 +187,7 @@ static void test_getcpu(void)
 
 		ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0);
 		if (vdso_getcpu)
-			ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0);
+			ret_vdso = VDSO_CALL(vdso_getcpu, 3, &cpu_vdso, &node_vdso, 0);
 		if (vgetcpu)
 			ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
 
@@ -263,7 +270,7 @@ static void test_one_clock_gettime(int clock, const char *name)
 
 	if (sys_clock_gettime(clock, &start) < 0) {
 		if (errno == EINVAL) {
-			vdso_ret = vdso_clock_gettime(clock, &vdso);
+			vdso_ret = VDSO_CALL(vdso_clock_gettime, 2, clock, &vdso);
 			if (vdso_ret == -EINVAL) {
 				printf("[OK]\tNo such clock.\n");
 			} else {
@@ -276,7 +283,7 @@ static void test_one_clock_gettime(int clock, const char *name)
 		return;
 	}
 
-	vdso_ret = vdso_clock_gettime(clock, &vdso);
+	vdso_ret = VDSO_CALL(vdso_clock_gettime, 2, clock, &vdso);
 	end_ret = sys_clock_gettime(clock, &end);
 
 	if (vdso_ret != 0 || end_ret != 0) {
@@ -325,7 +332,7 @@ static void test_one_clock_gettime64(int clock, const char *name)
 
 	if (sys_clock_gettime64(clock, &start) < 0) {
 		if (errno == EINVAL) {
-			vdso_ret = vdso_clock_gettime64(clock, &vdso);
+			vdso_ret = VDSO_CALL(vdso_clock_gettime64, 2, clock, &vdso);
 			if (vdso_ret == -EINVAL) {
 				printf("[OK]\tNo such clock.\n");
 			} else {
@@ -338,7 +345,7 @@ static void test_one_clock_gettime64(int clock, const char *name)
 		return;
 	}
 
-	vdso_ret = vdso_clock_gettime64(clock, &vdso);
+	vdso_ret = VDSO_CALL(vdso_clock_gettime64, 2, clock, &vdso);
 	end_ret = sys_clock_gettime64(clock, &end);
 
 	if (vdso_ret != 0 || end_ret != 0) {
@@ -395,7 +402,7 @@ static void test_gettimeofday(void)
 		return;
 	}
 
-	vdso_ret = vdso_gettimeofday(&vdso, &vdso_tz);
+	vdso_ret = VDSO_CALL(vdso_gettimeofday, 2, &vdso, &vdso_tz);
 	end_ret = sys_gettimeofday(&end, NULL);
 
 	if (vdso_ret != 0 || end_ret != 0) {
@@ -425,7 +432,7 @@ static void test_gettimeofday(void)
 	}
 
 	/* And make sure that passing NULL for tz doesn't crash. */
-	vdso_gettimeofday(&vdso, NULL);
+	VDSO_CALL(vdso_gettimeofday, 2, &vdso, NULL);
 }
 
 int main(int argc, char **argv)

tools/testing/selftests/vDSO/vdso_test_getcpu.c

@@ -14,6 +14,7 @@
 #include "../kselftest.h"
 #include "parse_vdso.h"
 #include "vdso_config.h"
+#include "vdso_call.h"
 
 struct getcpu_cache;
 typedef long (*getcpu_t)(unsigned int *, unsigned int *,
@@ -42,7 +43,7 @@ int main(int argc, char **argv)
 		return KSFT_SKIP;
 	}
 
-	ret = get_cpu(&cpu, &node, 0);
+	ret = VDSO_CALL(get_cpu, 3, &cpu, &node, 0);
 	if (ret == 0) {
 		printf("Running on CPU %u node %u\n", cpu, node);
 	} else {

tools/testing/selftests/vDSO/vdso_test_getrandom.c

@@ -16,11 +16,17 @@
 #include <sys/mman.h>
 #include <sys/random.h>
 #include <sys/syscall.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
 #include <sys/types.h>
 #include <linux/random.h>
+#include <linux/compiler.h>
+#include <linux/ptrace.h>
 
 #include "../kselftest.h"
 #include "parse_vdso.h"
+#include "vdso_config.h"
+#include "vdso_call.h"
 
 #ifndef timespecsub
 #define	timespecsub(tsp, usp, vsp)					\
@@ -38,50 +44,43 @@ static struct {
 	pthread_mutex_t lock;
 	void **states;
 	size_t len, cap;
-} grnd_allocator = {
-	.lock = PTHREAD_MUTEX_INITIALIZER
-};
-
-static struct {
 	ssize_t(*fn)(void *, size_t, unsigned long, void *, size_t);
-	pthread_key_t key;
-	pthread_once_t initialized;
 	struct vgetrandom_opaque_params params;
-} grnd_ctx = {
+} vgrnd = {
-	.initialized = PTHREAD_ONCE_INIT
+	.lock = PTHREAD_MUTEX_INITIALIZER
 };
 
 static void *vgetrandom_get_state(void)
 {
 	void *state = NULL;
 
-	pthread_mutex_lock(&grnd_allocator.lock);
+	pthread_mutex_lock(&vgrnd.lock);
-	if (!grnd_allocator.len) {
+	if (!vgrnd.len) {
 		size_t page_size = getpagesize();
 		size_t new_cap;
 		size_t alloc_size, num = sysconf(_SC_NPROCESSORS_ONLN); /* Just a decent heuristic. */
 		void *new_block, *new_states;
 
-		alloc_size = (num * grnd_ctx.params.size_of_opaque_state + page_size - 1) & (~(page_size - 1));
+		alloc_size = (num * vgrnd.params.size_of_opaque_state + page_size - 1) & (~(page_size - 1));
-		num = (page_size / grnd_ctx.params.size_of_opaque_state) * (alloc_size / page_size);
+		num = (page_size / vgrnd.params.size_of_opaque_state) * (alloc_size / page_size);
-		new_block = mmap(0, alloc_size, grnd_ctx.params.mmap_prot, grnd_ctx.params.mmap_flags, -1, 0);
+		new_block = mmap(0, alloc_size, vgrnd.params.mmap_prot, vgrnd.params.mmap_flags, -1, 0);
 		if (new_block == MAP_FAILED)
 			goto out;
 
-		new_cap = grnd_allocator.cap + num;
+		new_cap = vgrnd.cap + num;
-		new_states = reallocarray(grnd_allocator.states, new_cap, sizeof(*grnd_allocator.states));
+		new_states = reallocarray(vgrnd.states, new_cap, sizeof(*vgrnd.states));
 		if (!new_states)
 			goto unmap;
-		grnd_allocator.cap = new_cap;
+		vgrnd.cap = new_cap;
-		grnd_allocator.states = new_states;
+		vgrnd.states = new_states;
 
 		for (size_t i = 0; i < num; ++i) {
-			if (((uintptr_t)new_block & (page_size - 1)) + grnd_ctx.params.size_of_opaque_state > page_size)
+			if (((uintptr_t)new_block & (page_size - 1)) + vgrnd.params.size_of_opaque_state > page_size)
 				new_block = (void *)(((uintptr_t)new_block + page_size - 1) & (~(page_size - 1)));
-			grnd_allocator.states[i] = new_block;
+			vgrnd.states[i] = new_block;
-			new_block += grnd_ctx.params.size_of_opaque_state;
+			new_block += vgrnd.params.size_of_opaque_state;
 		}
-		grnd_allocator.len = num;
+		vgrnd.len = num;
 		goto success;
 
 	unmap:
@@ -89,10 +88,10 @@ static void *vgetrandom_get_state(void)
 		goto out;
 	}
 success:
-	state = grnd_allocator.states[--grnd_allocator.len];
+	state = vgrnd.states[--vgrnd.len];
 
 out:
-	pthread_mutex_unlock(&grnd_allocator.lock);
+	pthread_mutex_unlock(&vgrnd.lock);
 	return state;
 }
 
@@ -100,27 +99,33 @@ static void vgetrandom_put_state(void *state)
 {
 	if (!state)
 		return;
-	pthread_mutex_lock(&grnd_allocator.lock);
+	pthread_mutex_lock(&vgrnd.lock);
-	grnd_allocator.states[grnd_allocator.len++] = state;
+	vgrnd.states[vgrnd.len++] = state;
-	pthread_mutex_unlock(&grnd_allocator.lock);
+	pthread_mutex_unlock(&vgrnd.lock);
 }
 
 static void vgetrandom_init(void)
 {
-	if (pthread_key_create(&grnd_ctx.key, vgetrandom_put_state) != 0)
+	const char *version = versions[VDSO_VERSION];
-		return;
+	const char *name = names[VDSO_NAMES][6];
 	unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
+	size_t ret;
+
 	if (!sysinfo_ehdr) {
 		printf("AT_SYSINFO_EHDR is not present!\n");
 		exit(KSFT_SKIP);
 	}
 	vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
-	grnd_ctx.fn = (__typeof__(grnd_ctx.fn))vdso_sym("LINUX_2.6", "__vdso_getrandom");
+	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
-	if (!grnd_ctx.fn) {
+	if (!vgrnd.fn) {
-		printf("__vdso_getrandom is missing!\n");
+		printf("%s is missing!\n", name);
 		exit(KSFT_FAIL);
 	}
-	if (grnd_ctx.fn(NULL, 0, 0, &grnd_ctx.params, ~0UL) != 0) {
+	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
+	if (ret == -ENOSYS) {
+		printf("unsupported architecture\n");
+		exit(KSFT_SKIP);
+	} else if (ret) {
 		printf("failed to fetch vgetrandom params!\n");
 		exit(KSFT_FAIL);
 	}
@@ -128,27 +133,21 @@ static void vgetrandom_init(void)
 
 static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
 {
-	void *state;
+	static __thread void *state;
 
-	pthread_once(&grnd_ctx.initialized, vgetrandom_init);
-	state = pthread_getspecific(grnd_ctx.key);
 	if (!state) {
 		state = vgetrandom_get_state();
-		if (pthread_setspecific(grnd_ctx.key, state) != 0) {
-			vgetrandom_put_state(state);
-			state = NULL;
-		}
 		if (!state) {
 			printf("vgetrandom_get_state failed!\n");
 			exit(KSFT_FAIL);
 		}
 	}
-	return grnd_ctx.fn(buf, len, flags, state, grnd_ctx.params.size_of_opaque_state);
+	return VDSO_CALL(vgrnd.fn, 5, buf, len, flags, state, vgrnd.params.size_of_opaque_state);
 }
 
 enum { TRIALS = 25000000, THREADS = 256 };
 
-static void *test_vdso_getrandom(void *)
+static void *test_vdso_getrandom(void *ctx)
 {
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
@@ -158,7 +157,7 @@ static void *test_vdso_getrandom(void *)
 	return NULL;
 }
 
-static void *test_libc_getrandom(void *)
+static void *test_libc_getrandom(void *ctx)
 {
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
@@ -168,7 +167,7 @@ static void *test_libc_getrandom(void *)
 	return NULL;
 }
 
-static void *test_syscall_getrandom(void *)
+static void *test_syscall_getrandom(void *ctx)
 {
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
@@ -244,9 +243,10 @@ static void fill(void)
 static void kselftest(void)
 {
 	uint8_t weird_size[1263];
+	pid_t child;
 
 	ksft_print_header();
-	ksft_set_plan(1);
+	ksft_set_plan(2);
 
 	for (size_t i = 0; i < 1000; ++i) {
 		ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0);
@@ -255,6 +255,42 @@ static void kselftest(void)
 	}
 
 	ksft_test_result_pass("getrandom: PASS\n");
+
+	unshare(CLONE_NEWUSER);
+	assert(unshare(CLONE_NEWTIME) == 0);
+	child = fork();
+	assert(child >= 0);
+	if (!child) {
+		vgetrandom_init();
+		child = getpid();
+		assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
+		assert(kill(child, SIGSTOP) == 0);
+		assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
+		_exit(0);
+	}
+	for (;;) {
+		struct ptrace_syscall_info info = { 0 };
+		int status, ret;
+		assert(waitpid(child, &status, 0) >= 0);
+		if (WIFEXITED(status)) {
+			if (WEXITSTATUS(status) != 0)
+				exit(KSFT_FAIL);
+			break;
+		}
+		assert(WIFSTOPPED(status));
+		if (WSTOPSIG(status) == SIGSTOP)
+			assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
+		else if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
+			assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
+			if (info.op == PTRACE_SYSCALL_INFO_ENTRY && info.entry.nr == __NR_getrandom &&
+			    info.entry.args[0] == (uintptr_t)weird_size && info.entry.args[1] == sizeof(weird_size))
+				exit(KSFT_FAIL);
+		}
+		assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
+	}
+
+	ksft_test_result_pass("getrandom timens: PASS\n");
+
 	exit(KSFT_PASS);
 }
 
@@ -265,6 +301,8 @@ static void usage(const char *argv0)
 
 int main(int argc, char *argv[])
 {
+	vgetrandom_init();
+
 	if (argc == 1) {
 		kselftest();
 		return 0;

tools/testing/selftests/vDSO/vdso_test_gettimeofday.c

@@ -19,6 +19,7 @@
 #include "../kselftest.h"
 #include "parse_vdso.h"
 #include "vdso_config.h"
+#include "vdso_call.h"
 
 int main(int argc, char **argv)
 {
@@ -43,7 +44,7 @@ int main(int argc, char **argv)
 	}
 
 	struct timeval tv;
-	long ret = gtod(&tv, 0);
+	long ret = VDSO_CALL(gtod, 2, &tv, 0);
 
 	if (ret == 0) {
 		printf("The time is %lld.%06lld\n",