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Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull x86 fixes from Thomas Gleixner:
 "Yet another pile of melted spectrum related changes:

   - sanitize the array_index_nospec protection mechanism: Remove the
     overengineered array_index_nospec_mask_check() magic and allow
     const-qualified types as index to avoid temporary storage in a
     non-const local variable.

   - make the microcode loader more robust by properly propagating error
     codes. Provide information about new feature bits after micro code
     was updated so administrators can act upon.

   - optimizations of the entry ASM code which reduce code footprint and
     make the code simpler and faster.

   - fix the {pmd,pud}_{set,clear}_flags() implementations to work
     properly on paravirt kernels by removing the address translation
     operations.

   - revert the harmful vmexit_fill_RSB() optimization

   - use IBRS around firmware calls

   - teach objtool about retpolines and add annotations for indirect
     jumps and calls.

   - explicitly disable jumplabel patching in __init code and handle
     patching failures properly instead of silently ignoring them.

   - remove indirect paravirt calls for writing the speculation control
     MSR as these calls are obviously proving the same attack vector
     which is tried to be mitigated.

   - a few small fixes which address build issues with recent compiler
     and assembler versions"

* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
  KVM/VMX: Optimize vmx_vcpu_run() and svm_vcpu_run() by marking the RDMSR path as unlikely()
  KVM/x86: Remove indirect MSR op calls from SPEC_CTRL
  objtool, retpolines: Integrate objtool with retpoline support more closely
  x86/entry/64: Simplify ENCODE_FRAME_POINTER
  extable: Make init_kernel_text() global
  jump_label: Warn on failed jump_label patching attempt
  jump_label: Explicitly disable jump labels in __init code
  x86/entry/64: Open-code switch_to_thread_stack()
  x86/entry/64: Move ASM_CLAC to interrupt_entry()
  x86/entry/64: Remove 'interrupt' macro
  x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry()
  x86/entry/64: Move ENTER_IRQ_STACK from interrupt macro to interrupt_entry
  x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper function
  x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP
  objtool: Add module specific retpoline rules
  objtool: Add retpoline validation
  objtool: Use existing global variables for options
  x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()
  x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
  x86/paravirt, objtool: Annotate indirect calls
  ...
This commit is contained in:
Linus Torvalds 2018-02-26 09:34:21 -08:00
commit 85a2d939c0
51 changed files with 604 additions and 303 deletions
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5
Makefile
View File

@ -489,6 +489,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
endif
RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
export RETPOLINE_CFLAGS
ifeq ($(config-targets),1)
# ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend

1
arch/x86/Kconfig
View File

@ -430,6 +430,7 @@ config GOLDFISH
config RETPOLINE
bool "Avoid speculative indirect branches in kernel"
default y
select STACK_VALIDATION if HAVE_STACK_VALIDATION
help
Compile kernel with the retpoline compiler options to guard against
kernel-to-user data leaks by avoiding speculative indirect

1
arch/x86/Makefile
View File

@ -232,7 +232,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
ifneq ($(RETPOLINE_CFLAGS),)
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
endif

34
arch/x86/entry/calling.h
View File

@ -97,7 +97,7 @@ For 32-bit we have the following conventions - kernel is built with
#define SIZEOF_PTREGS 21*8
.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax
.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax save_ret=0
/*
* Push registers and sanitize registers of values that a
* speculation attack might otherwise want to exploit. The
@ -105,32 +105,41 @@ For 32-bit we have the following conventions - kernel is built with
* could be put to use in a speculative execution gadget.
* Interleave XOR with PUSH for better uop scheduling:
*/
.if \save_ret
pushq %rsi /* pt_regs->si */
movq 8(%rsp), %rsi /* temporarily store the return address in %rsi */
movq %rdi, 8(%rsp) /* pt_regs->di (overwriting original return address) */
.else
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
.endif
pushq \rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq \rax /* pt_regs->ax */
pushq %r8 /* pt_regs->r8 */
xorq %r8, %r8 /* nospec r8 */
xorl %r8d, %r8d /* nospec r8 */
pushq %r9 /* pt_regs->r9 */
xorq %r9, %r9 /* nospec r9 */
xorl %r9d, %r9d /* nospec r9 */
pushq %r10 /* pt_regs->r10 */
xorq %r10, %r10 /* nospec r10 */
xorl %r10d, %r10d /* nospec r10 */
pushq %r11 /* pt_regs->r11 */
xorq %r11, %r11 /* nospec r11*/
xorl %r11d, %r11d /* nospec r11*/
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx*/
pushq %rbp /* pt_regs->rbp */
xorl %ebp, %ebp /* nospec rbp*/
pushq %r12 /* pt_regs->r12 */
xorq %r12, %r12 /* nospec r12*/
xorl %r12d, %r12d /* nospec r12*/
pushq %r13 /* pt_regs->r13 */
xorq %r13, %r13 /* nospec r13*/
xorl %r13d, %r13d /* nospec r13*/
pushq %r14 /* pt_regs->r14 */
xorq %r14, %r14 /* nospec r14*/
xorl %r14d, %r14d /* nospec r14*/
pushq %r15 /* pt_regs->r15 */
xorq %r15, %r15 /* nospec r15*/
xorl %r15d, %r15d /* nospec r15*/
UNWIND_HINT_REGS
.if \save_ret
pushq %rsi /* return address on top of stack */
.endif
.endm
.macro POP_REGS pop_rdi=1 skip_r11rcx=0
@ -172,12 +181,7 @@ For 32-bit we have the following conventions - kernel is built with
*/
.macro ENCODE_FRAME_POINTER ptregs_offset=0
#ifdef CONFIG_FRAME_POINTER
.if \ptregs_offset
leaq \ptregs_offset(%rsp), %rbp
.else
mov %rsp, %rbp
.endif
orq $0x1, %rbp
leaq 1+\ptregs_offset(%rsp), %rbp
#endif
.endm

3
arch/x86/entry/entry_32.S
View File

@ -252,8 +252,7 @@ ENTRY(__switch_to_asm)
* exist, overwrite the RSB with entries which capture
* speculative execution to prevent attack.
*/
/* Clobbers %ebx */
FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
#endif
/* restore callee-saved registers */

153
arch/x86/entry/entry_64.S
View File

@ -364,8 +364,7 @@ ENTRY(__switch_to_asm)
* exist, overwrite the RSB with entries which capture
* speculative execution to prevent attack.
*/
/* Clobbers %rbx */
FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
#endif
/* restore callee-saved registers */
@ -449,9 +448,19 @@ END(irq_entries_start)
*
* The invariant is that, if irq_count != -1, then the IRQ stack is in use.
*/
.macro ENTER_IRQ_STACK regs=1 old_rsp
.macro ENTER_IRQ_STACK regs=1 old_rsp save_ret=0
DEBUG_ENTRY_ASSERT_IRQS_OFF
.if \save_ret
/*
* If save_ret is set, the original stack contains one additional
* entry -- the return address. Therefore, move the address one
* entry below %rsp to \old_rsp.
*/
leaq 8(%rsp), \old_rsp
.else
movq %rsp, \old_rsp
.endif
.if \regs
UNWIND_HINT_REGS base=\old_rsp
@ -497,6 +506,15 @@ END(irq_entries_start)
.if \regs
UNWIND_HINT_REGS indirect=1
.endif
.if \save_ret
/*
* Push the return address to the stack. This return address can
* be found at the "real" original RSP, which was offset by 8 at
* the beginning of this macro.
*/
pushq -8(\old_rsp)
.endif
.endm
/*
@ -520,27 +538,65 @@ END(irq_entries_start)
.endm
/*
* Interrupt entry/exit.
* Interrupt entry helper function.
*
* Interrupt entry points save only callee clobbered registers in fast path.
*
* Entry runs with interrupts off.
* Entry runs with interrupts off. Stack layout at entry:
* +----------------------------------------------------+
* | regs->ss |
* | regs->rsp |
* | regs->eflags |
* | regs->cs |
* | regs->ip |
* +----------------------------------------------------+
* | regs->orig_ax = ~(interrupt number) |
* +----------------------------------------------------+
* | return address |
* +----------------------------------------------------+
*/
/* 0(%rsp): ~(interrupt number) */
.macro interrupt func
ENTRY(interrupt_entry)
UNWIND_HINT_FUNC
ASM_CLAC
cld
testb $3, CS-ORIG_RAX(%rsp)
testb $3, CS-ORIG_RAX+8(%rsp)
jz 1f
SWAPGS
call switch_to_thread_stack
/*
* Switch to the thread stack. The IRET frame and orig_ax are
* on the stack, as well as the return address. RDI..R12 are
* not (yet) on the stack and space has not (yet) been
* allocated for them.
*/
pushq %rdi
/* Need to switch before accessing the thread stack. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
movq %rsp, %rdi
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/*
* We have RDI, return address, and orig_ax on the stack on
* top of the IRET frame. That means offset=24
*/
UNWIND_HINT_IRET_REGS base=%rdi offset=24
pushq 7*8(%rdi) /* regs->ss */
pushq 6*8(%rdi) /* regs->rsp */
pushq 5*8(%rdi) /* regs->eflags */
pushq 4*8(%rdi) /* regs->cs */
pushq 3*8(%rdi) /* regs->ip */
pushq 2*8(%rdi) /* regs->orig_ax */
pushq 8(%rdi) /* return address */
UNWIND_HINT_FUNC
movq (%rdi), %rdi
1:
PUSH_AND_CLEAR_REGS
ENCODE_FRAME_POINTER
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
testb $3, CS(%rsp)
testb $3, CS+8(%rsp)
jz 1f
/*
@ -548,7 +604,7 @@ END(irq_entries_start)
*
* We need to tell lockdep that IRQs are off. We can't do this until
* we fix gsbase, and we should do it before enter_from_user_mode
* (which can take locks). Since TRACE_IRQS_OFF idempotent,
* (which can take locks). Since TRACE_IRQS_OFF is idempotent,
* the simplest way to handle it is to just call it twice if
* we enter from user mode. There's no reason to optimize this since
* TRACE_IRQS_OFF is a no-op if lockdep is off.
@ -558,12 +614,15 @@ END(irq_entries_start)
CALL_enter_from_user_mode
1:
ENTER_IRQ_STACK old_rsp=%rdi
ENTER_IRQ_STACK old_rsp=%rdi save_ret=1
/* We entered an interrupt context - irqs are off: */
TRACE_IRQS_OFF
call \func /* rdi points to pt_regs */
.endm
ret
END(interrupt_entry)
/* Interrupt entry/exit. */
/*
* The interrupt stubs push (~vector+0x80) onto the stack and
@ -571,9 +630,10 @@ END(irq_entries_start)
*/
.p2align CONFIG_X86_L1_CACHE_SHIFT
common_interrupt:
ASM_CLAC
addq $-0x80, (%rsp) /* Adjust vector to [-256, -1] range */
interrupt do_IRQ
call interrupt_entry
UNWIND_HINT_REGS indirect=1
call do_IRQ /* rdi points to pt_regs */
/* 0(%rsp): old RSP */
ret_from_intr:
DISABLE_INTERRUPTS(CLBR_ANY)
@ -766,10 +826,11 @@ END(common_interrupt)
.macro apicinterrupt3 num sym do_sym
ENTRY(\sym)
UNWIND_HINT_IRET_REGS
ASM_CLAC
pushq $~(\num)
.Lcommon_\sym:
interrupt \do_sym
call interrupt_entry
UNWIND_HINT_REGS indirect=1
call \do_sym /* rdi points to pt_regs */
jmp ret_from_intr
END(\sym)
.endm
@ -832,34 +893,6 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt
*/
#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
/*
* Switch to the thread stack. This is called with the IRET frame and
* orig_ax on the stack. (That is, RDI..R12 are not on the stack and
* space has not been allocated for them.)
*/
ENTRY(switch_to_thread_stack)
UNWIND_HINT_FUNC
pushq %rdi
/* Need to switch before accessing the thread stack. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
movq %rsp, %rdi
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI
pushq 7*8(%rdi) /* regs->ss */
pushq 6*8(%rdi) /* regs->rsp */
pushq 5*8(%rdi) /* regs->eflags */
pushq 4*8(%rdi) /* regs->cs */
pushq 3*8(%rdi) /* regs->ip */
pushq 2*8(%rdi) /* regs->orig_ax */
pushq 8(%rdi) /* return address */
UNWIND_HINT_FUNC
movq (%rdi), %rdi
ret
END(switch_to_thread_stack)
.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1
ENTRY(\sym)
UNWIND_HINT_IRET_REGS offset=\has_error_code*8
@ -875,12 +908,8 @@ ENTRY(\sym)
pushq $-1 /* ORIG_RAX: no syscall to restart */
.endif
/* Save all registers in pt_regs */
PUSH_AND_CLEAR_REGS
ENCODE_FRAME_POINTER
.if \paranoid < 2
testb $3, CS(%rsp) /* If coming from userspace, switch stacks */
testb $3, CS-ORIG_RAX(%rsp) /* If coming from userspace, switch stacks */
jnz .Lfrom_usermode_switch_stack_\@
.endif
@ -1130,13 +1159,15 @@ idtentry machine_check do_mce has_error_code=0 paranoid=1
#endif
/*
* Switch gs if needed.
* Save all registers in pt_regs, and switch gs if needed.
* Use slow, but surefire "are we in kernel?" check.
* Return: ebx=0: need swapgs on exit, ebx=1: otherwise
*/
ENTRY(paranoid_entry)
UNWIND_HINT_FUNC
cld
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
movl $1, %ebx
movl $MSR_GS_BASE, %ecx
rdmsr
@ -1181,12 +1212,14 @@ ENTRY(paranoid_exit)
END(paranoid_exit)
/*
* Switch gs if needed.
* Save all registers in pt_regs, and switch GS if needed.
* Return: EBX=0: came from user mode; EBX=1: otherwise
*/
ENTRY(error_entry)
UNWIND_HINT_REGS offset=8
UNWIND_HINT_FUNC
cld
PUSH_AND_CLEAR_REGS save_ret=1
ENCODE_FRAME_POINTER 8
testb $3, CS+8(%rsp)
jz .Lerror_kernelspace
@ -1577,8 +1610,6 @@ end_repeat_nmi:
* frame to point back to repeat_nmi.
*/
pushq $-1 /* ORIG_RAX: no syscall to restart */
PUSH_AND_CLEAR_REGS
ENCODE_FRAME_POINTER
/*
* Use paranoid_entry to handle SWAPGS, but no need to use paranoid_exit

71
arch/x86/entry/entry_64_compat.S
View File

@ -85,25 +85,25 @@ ENTRY(entry_SYSENTER_compat)
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
xorq %r8, %r8 /* nospec r8 */
xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
xorq %r9, %r9 /* nospec r9 */
xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
xorq %r10, %r10 /* nospec r10 */
xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
xorq %r11, %r11 /* nospec r11 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp (will be overwritten) */
xorl %ebp, %ebp /* nospec rbp */
pushq $0 /* pt_regs->r12 = 0 */
xorq %r12, %r12 /* nospec r12 */
xorl %r12d, %r12d /* nospec r12 */
pushq $0 /* pt_regs->r13 = 0 */
xorq %r13, %r13 /* nospec r13 */
xorl %r13d, %r13d /* nospec r13 */
pushq $0 /* pt_regs->r14 = 0 */
xorq %r14, %r14 /* nospec r14 */
xorl %r14d, %r14d /* nospec r14 */
pushq $0 /* pt_regs->r15 = 0 */
xorq %r15, %r15 /* nospec r15 */
xorl %r15d, %r15d /* nospec r15 */
cld
/*
@ -224,25 +224,25 @@ GLOBAL(entry_SYSCALL_compat_after_hwframe)
pushq %rbp /* pt_regs->cx (stashed in bp) */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
xorq %r8, %r8 /* nospec r8 */
xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
xorq %r9, %r9 /* nospec r9 */
xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
xorq %r10, %r10 /* nospec r10 */
xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
xorq %r11, %r11 /* nospec r11 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp (will be overwritten) */
xorl %ebp, %ebp /* nospec rbp */
pushq $0 /* pt_regs->r12 = 0 */
xorq %r12, %r12 /* nospec r12 */
xorl %r12d, %r12d /* nospec r12 */
pushq $0 /* pt_regs->r13 = 0 */
xorq %r13, %r13 /* nospec r13 */
xorl %r13d, %r13d /* nospec r13 */
pushq $0 /* pt_regs->r14 = 0 */
xorq %r14, %r14 /* nospec r14 */
xorl %r14d, %r14d /* nospec r14 */
pushq $0 /* pt_regs->r15 = 0 */
xorq %r15, %r15 /* nospec r15 */
xorl %r15d, %r15d /* nospec r15 */
/*
* User mode is traced as though IRQs are on, and SYSENTER
@ -298,9 +298,9 @@ sysret32_from_system_call:
*/
SWITCH_TO_USER_CR3_NOSTACK scratch_reg=%r8 scratch_reg2=%r9
xorq %r8, %r8
xorq %r9, %r9
xorq %r10, %r10
xorl %r8d, %r8d
xorl %r9d, %r9d
xorl %r10d, %r10d
swapgs
sysretl
END(entry_SYSCALL_compat)
@ -347,10 +347,23 @@ ENTRY(entry_INT80_compat)
*/
movl %eax, %eax
/* switch to thread stack expects orig_ax and rdi to be pushed */
pushq %rax /* pt_regs->orig_ax */
pushq %rdi /* pt_regs->di */
/* switch to thread stack expects orig_ax to be pushed */
call switch_to_thread_stack
/* Need to switch before accessing the thread stack. */
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi
movq %rsp, %rdi
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq 6*8(%rdi) /* regs->ss */
pushq 5*8(%rdi) /* regs->rsp */
pushq 4*8(%rdi) /* regs->eflags */
pushq 3*8(%rdi) /* regs->cs */
pushq 2*8(%rdi) /* regs->ip */
pushq 1*8(%rdi) /* regs->orig_ax */
movq (%rdi), %rdi /* restore %rdi */
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
@ -358,25 +371,25 @@ ENTRY(entry_INT80_compat)
pushq %rcx /* pt_regs->cx */
pushq $-ENOSYS /* pt_regs->ax */
pushq $0 /* pt_regs->r8 = 0 */
xorq %r8, %r8 /* nospec r8 */
xorl %r8d, %r8d /* nospec r8 */
pushq $0 /* pt_regs->r9 = 0 */
xorq %r9, %r9 /* nospec r9 */
xorl %r9d, %r9d /* nospec r9 */
pushq $0 /* pt_regs->r10 = 0 */
xorq %r10, %r10 /* nospec r10 */
xorl %r10d, %r10d /* nospec r10 */
pushq $0 /* pt_regs->r11 = 0 */
xorq %r11, %r11 /* nospec r11 */
xorl %r11d, %r11d /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp */
xorl %ebp, %ebp /* nospec rbp */
pushq %r12 /* pt_regs->r12 */
xorq %r12, %r12 /* nospec r12 */
xorl %r12d, %r12d /* nospec r12 */
pushq %r13 /* pt_regs->r13 */
xorq %r13, %r13 /* nospec r13 */
xorl %r13d, %r13d /* nospec r13 */
pushq %r14 /* pt_regs->r14 */
xorq %r14, %r14 /* nospec r14 */
xorl %r14d, %r14d /* nospec r14 */
pushq %r15 /* pt_regs->r15 */
xorq %r15, %r15 /* nospec r15 */
xorl %r15d, %r15d /* nospec r15 */
cld
/*

6
arch/x86/include/asm/apm.h
View File

@ -7,6 +7,8 @@
#ifndef _ASM_X86_MACH_DEFAULT_APM_H
#define _ASM_X86_MACH_DEFAULT_APM_H
#include <asm/nospec-branch.h>
#ifdef APM_ZERO_SEGS
# define APM_DO_ZERO_SEGS \
"pushl %%ds\n\t" \
@ -32,6 +34,7 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in,
* N.B. We do NOT need a cld after the BIOS call
* because we always save and restore the flags.
*/
firmware_restrict_branch_speculation_start();
__asm__ __volatile__(APM_DO_ZERO_SEGS
"pushl %%edi\n\t"
"pushl %%ebp\n\t"
@ -44,6 +47,7 @@ static inline void apm_bios_call_asm(u32 func, u32 ebx_in, u32 ecx_in,
"=S" (*esi)
: "a" (func), "b" (ebx_in), "c" (ecx_in)
: "memory", "cc");
firmware_restrict_branch_speculation_end();
}
static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
@ -56,6 +60,7 @@ static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
* N.B. We do NOT need a cld after the BIOS call
* because we always save and restore the flags.
*/
firmware_restrict_branch_speculation_start();
__asm__ __volatile__(APM_DO_ZERO_SEGS
"pushl %%edi\n\t"
"pushl %%ebp\n\t"
@ -68,6 +73,7 @@ static inline bool apm_bios_call_simple_asm(u32 func, u32 ebx_in,
"=S" (si)
: "a" (func), "b" (ebx_in), "c" (ecx_in)
: "memory", "cc");
firmware_restrict_branch_speculation_end();
return error;
}

3
arch/x86/include/asm/asm-prototypes.h
View File

@ -38,7 +38,4 @@ INDIRECT_THUNK(dx)
INDIRECT_THUNK(si)
INDIRECT_THUNK(di)
INDIRECT_THUNK(bp)
asmlinkage void __fill_rsb(void);
asmlinkage void __clear_rsb(void);
#endif /* CONFIG_RETPOLINE */

1
arch/x86/include/asm/cpufeatures.h
View File

@ -213,6 +213,7 @@
#define X86_FEATURE_SEV ( 7*32+20) /* AMD Secure Encrypted Virtualization */
#define X86_FEATURE_USE_IBPB ( 7*32+21) /* "" Indirect Branch Prediction Barrier enabled */
#define X86_FEATURE_USE_IBRS_FW ( 7*32+22) /* "" Use IBRS during runtime firmware calls */
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */

17
arch/x86/include/asm/efi.h
View File

@ -6,6 +6,7 @@
#include <asm/pgtable.h>
#include <asm/processor-flags.h>
#include <asm/tlb.h>
#include <asm/nospec-branch.h>
/*
* We map the EFI regions needed for runtime services non-contiguously,
@ -36,8 +37,18 @@
extern asmlinkage unsigned long efi_call_phys(void *, ...);
#define arch_efi_call_virt_setup() kernel_fpu_begin()
#define arch_efi_call_virt_teardown() kernel_fpu_end()
#define arch_efi_call_virt_setup() \
({ \
kernel_fpu_begin(); \
firmware_restrict_branch_speculation_start(); \
})
#define arch_efi_call_virt_teardown() \
({ \
firmware_restrict_branch_speculation_end(); \
kernel_fpu_end(); \
})
/*
* Wrap all the virtual calls in a way that forces the parameters on the stack.
@ -73,6 +84,7 @@ struct efi_scratch {
efi_sync_low_kernel_mappings(); \
preempt_disable(); \
__kernel_fpu_begin(); \
firmware_restrict_branch_speculation_start(); \
\
if (efi_scratch.use_pgd) { \
efi_scratch.prev_cr3 = __read_cr3(); \
@ -91,6 +103,7 @@ struct efi_scratch {
__flush_tlb_all(); \
} \
\
firmware_restrict_branch_speculation_end(); \
__kernel_fpu_end(); \
preempt_enable(); \
})

9
arch/x86/include/asm/microcode.h
View File

@ -37,7 +37,12 @@ struct cpu_signature {
struct device;
enum ucode_state { UCODE_ERROR, UCODE_OK, UCODE_NFOUND };
enum ucode_state {
UCODE_OK = 0,
UCODE_UPDATED,
UCODE_NFOUND,
UCODE_ERROR,
};
struct microcode_ops {
enum ucode_state (*request_microcode_user) (int cpu,
@ -54,7 +59,7 @@ struct microcode_ops {
* are being called.
* See also the "Synchronization" section in microcode_core.c.
*/
int (*apply_microcode) (int cpu);
enum ucode_state (*apply_microcode) (int cpu);
int (*collect_cpu_info) (int cpu, struct cpu_signature *csig);
};

1
arch/x86/include/asm/mmu_context.h
View File

@ -74,6 +74,7 @@ static inline void *ldt_slot_va(int slot)
return (void *)(LDT_BASE_ADDR + LDT_SLOT_STRIDE * slot);
#else
BUG();
return (void *)fix_to_virt(FIX_HOLE);
#endif
}

138
arch/x86/include/asm/nospec-branch.h
View File

@ -8,6 +8,50 @@
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
/*
* Fill the CPU return stack buffer.
*
* Each entry in the RSB, if used for a speculative 'ret', contains an
* infinite 'pause; lfence; jmp' loop to capture speculative execution.
*
* This is required in various cases for retpoline and IBRS-based
* mitigations for the Spectre variant 2 vulnerability. Sometimes to
* eliminate potentially bogus entries from the RSB, and sometimes
* purely to ensure that it doesn't get empty, which on some CPUs would
* allow predictions from other (unwanted!) sources to be used.
*
* We define a CPP macro such that it can be used from both .S files and
* inline assembly. It's possible to do a .macro and then include that
* from C via asm(".include <asm/nospec-branch.h>") but let's not go there.
*/
#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
#define RSB_FILL_LOOPS 16 /* To avoid underflow */
/*
* Google experimented with loop-unrolling and this turned out to be
* the optimal version — two calls, each with their own speculation
* trap should their return address end up getting used, in a loop.
*/
#define __FILL_RETURN_BUFFER(reg, nr, sp) \
mov $(nr/2), reg; \
771: \
call 772f; \
773: /* speculation trap */ \
pause; \
lfence; \
jmp 773b; \
772: \
call 774f; \
775: /* speculation trap */ \
pause; \
lfence; \
jmp 775b; \
774: \
dec reg; \
jnz 771b; \
add $(BITS_PER_LONG/8) * nr, sp;
#ifdef __ASSEMBLY__
/*
@ -23,6 +67,18 @@
.popsection
.endm
/*
* This should be used immediately before an indirect jump/call. It tells
* objtool the subsequent indirect jump/call is vouched safe for retpoline
* builds.
*/
.macro ANNOTATE_RETPOLINE_SAFE
.Lannotate_\@:
.pushsection .discard.retpoline_safe
_ASM_PTR .Lannotate_\@
.popsection
.endm
/*
* These are the bare retpoline primitives for indirect jmp and call.
* Do not use these directly; they only exist to make the ALTERNATIVE
@ -59,9 +115,9 @@
.macro JMP_NOSPEC reg:req
#ifdef CONFIG_RETPOLINE
ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE_2 __stringify(jmp *\reg), \
ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg), \
__stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \
__stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
#else
jmp *\reg
#endif
@ -70,18 +126,25 @@
.macro CALL_NOSPEC reg:req
#ifdef CONFIG_RETPOLINE
ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE_2 __stringify(call *\reg), \
ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg), \
__stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\
__stringify(lfence; call *\reg), X86_FEATURE_RETPOLINE_AMD
__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RETPOLINE_AMD
#else
call *\reg
#endif
.endm
/* This clobbers the BX register */
.macro FILL_RETURN_BUFFER nr:req ftr:req
/*
* A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP
* monstrosity above, manually.
*/
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
#ifdef CONFIG_RETPOLINE
ALTERNATIVE "", "call __clear_rsb", \ftr
ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE "jmp .Lskip_rsb_\@", \
__stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \
\ftr
.Lskip_rsb_\@:
#endif
.endm
@ -93,6 +156,12 @@
".long 999b - .\n\t" \
".popsection\n\t"
#define ANNOTATE_RETPOLINE_SAFE \
"999:\n\t" \
".pushsection .discard.retpoline_safe\n\t" \
_ASM_PTR " 999b\n\t" \
".popsection\n\t"
#if defined(CONFIG_X86_64) && defined(RETPOLINE)
/*
@ -102,6 +171,7 @@
# define CALL_NOSPEC \
ANNOTATE_NOSPEC_ALTERNATIVE \
ALTERNATIVE( \
ANNOTATE_RETPOLINE_SAFE \
"call *%[thunk_target]\n", \
"call __x86_indirect_thunk_%V[thunk_target]\n", \
X86_FEATURE_RETPOLINE)
@ -156,26 +226,54 @@ extern char __indirect_thunk_end[];
static inline void vmexit_fill_RSB(void)
{
#ifdef CONFIG_RETPOLINE
alternative_input("",
"call __fill_rsb",
X86_FEATURE_RETPOLINE,
ASM_NO_INPUT_CLOBBER(_ASM_BX, "memory"));
unsigned long loops;
asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE("jmp 910f",
__stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
X86_FEATURE_RETPOLINE)
"910:"
: "=r" (loops), ASM_CALL_CONSTRAINT
: : "memory" );
#endif
}
#define alternative_msr_write(_msr, _val, _feature) \
asm volatile(ALTERNATIVE("", \
"movl %[msr], %%ecx\n\t" \
"movl %[val], %%eax\n\t" \
"movl $0, %%edx\n\t" \
"wrmsr", \
_feature) \
: : [msr] "i" (_msr), [val] "i" (_val) \
: "eax", "ecx", "edx", "memory")
static inline void indirect_branch_prediction_barrier(void)
{
asm volatile(ALTERNATIVE("",
"movl %[msr], %%ecx\n\t"
"movl %[val], %%eax\n\t"
"movl $0, %%edx\n\t"
"wrmsr",
X86_FEATURE_USE_IBPB)
: : [msr] "i" (MSR_IA32_PRED_CMD),
[val] "i" (PRED_CMD_IBPB)
: "eax", "ecx", "edx", "memory");
alternative_msr_write(MSR_IA32_PRED_CMD, PRED_CMD_IBPB,
X86_FEATURE_USE_IBPB);
}
/*
* With retpoline, we must use IBRS to restrict branch prediction
* before calling into firmware.
*
* (Implemented as CPP macros due to header hell.)
*/
#define firmware_restrict_branch_speculation_start() \
do { \
preempt_disable(); \
alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS, \
X86_FEATURE_USE_IBRS_FW); \
} while (0)
#define firmware_restrict_branch_speculation_end() \
do { \
alternative_msr_write(MSR_IA32_SPEC_CTRL, 0, \
X86_FEATURE_USE_IBRS_FW); \
preempt_enable(); \
} while (0)
#endif /* __ASSEMBLY__ */
/*

17
arch/x86/include/asm/paravirt.h
View File

@ -7,6 +7,7 @@
#ifdef CONFIG_PARAVIRT
#include <asm/pgtable_types.h>
#include <asm/asm.h>
#include <asm/nospec-branch.h>
#include <asm/paravirt_types.h>
@ -879,23 +880,27 @@ extern void default_banner(void);
#define INTERRUPT_RETURN \
PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_iret), CLBR_NONE, \
jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_iret))
ANNOTATE_RETPOLINE_SAFE; \
jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_iret);)
#define DISABLE_INTERRUPTS(clobbers) \
PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_irq_disable), clobbers, \
PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
ANNOTATE_RETPOLINE_SAFE; \
call PARA_INDIRECT(pv_irq_ops+PV_IRQ_irq_disable); \
PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
#define ENABLE_INTERRUPTS(clobbers) \
PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_irq_enable), clobbers, \
PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
ANNOTATE_RETPOLINE_SAFE; \
call PARA_INDIRECT(pv_irq_ops+PV_IRQ_irq_enable); \
PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
#ifdef CONFIG_X86_32
#define GET_CR0_INTO_EAX \
push %ecx; push %edx; \
ANNOTATE_RETPOLINE_SAFE; \
call PARA_INDIRECT(pv_cpu_ops+PV_CPU_read_cr0); \
pop %edx; pop %ecx
#else /* !CONFIG_X86_32 */
@ -917,21 +922,25 @@ extern void default_banner(void);
*/
#define SWAPGS \
PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_swapgs), CLBR_NONE, \
call PARA_INDIRECT(pv_cpu_ops+PV_CPU_swapgs) \
ANNOTATE_RETPOLINE_SAFE; \
call PARA_INDIRECT(pv_cpu_ops+PV_CPU_swapgs); \
)
#define GET_CR2_INTO_RAX \
call PARA_INDIRECT(pv_mmu_ops+PV_MMU_read_cr2)
ANNOTATE_RETPOLINE_SAFE; \
call PARA_INDIRECT(pv_mmu_ops+PV_MMU_read_cr2);
#define USERGS_SYSRET64 \
PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64), \
CLBR_NONE, \
jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret64))
ANNOTATE_RETPOLINE_SAFE; \
jmp PARA_INDIRECT(pv_cpu_ops+PV_CPU_usergs_sysret64);)
#ifdef CONFIG_DEBUG_ENTRY
#define SAVE_FLAGS(clobbers) \
PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_save_fl), clobbers, \
PV_SAVE_REGS(clobbers | CLBR_CALLEE_SAVE); \
ANNOTATE_RETPOLINE_SAFE; \
call PARA_INDIRECT(pv_irq_ops+PV_IRQ_save_fl); \
PV_RESTORE_REGS(clobbers | CLBR_CALLEE_SAVE);)
#endif

5
arch/x86/include/asm/paravirt_types.h
View File

@ -43,6 +43,7 @@
#include <asm/desc_defs.h>
#include <asm/kmap_types.h>
#include <asm/pgtable_types.h>
#include <asm/nospec-branch.h>
struct page;
struct thread_struct;
@ -392,7 +393,9 @@ int paravirt_disable_iospace(void);
* offset into the paravirt_patch_template structure, and can therefore be
* freely converted back into a structure offset.
*/
#define PARAVIRT_CALL "call *%c[paravirt_opptr];"
#define PARAVIRT_CALL \
ANNOTATE_RETPOLINE_SAFE \
"call *%c[paravirt_opptr];"
/*
* These macros are intended to wrap calls through one of the paravirt

8
arch/x86/include/asm/pgtable.h
View File

@ -350,14 +350,14 @@ static inline pmd_t pmd_set_flags(pmd_t pmd, pmdval_t set)
{
pmdval_t v = native_pmd_val(pmd);
return __pmd(v | set);
return native_make_pmd(v | set);
}
static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear)
{
pmdval_t v = native_pmd_val(pmd);
return __pmd(v & ~clear);
return native_make_pmd(v & ~clear);
}
static inline pmd_t pmd_mkold(pmd_t pmd)
@ -409,14 +409,14 @@ static inline pud_t pud_set_flags(pud_t pud, pudval_t set)
{
pudval_t v = native_pud_val(pud);
return __pud(v | set);
return native_make_pud(v | set);
}
static inline pud_t pud_clear_flags(pud_t pud, pudval_t clear)
{
pudval_t v = native_pud_val(pud);
return __pud(v & ~clear);
return native_make_pud(v & ~clear);
}
static inline pud_t pud_mkold(pud_t pud)

10
arch/x86/include/asm/pgtable_types.h
View File

@ -323,6 +323,11 @@ static inline pudval_t native_pud_val(pud_t pud)
#else
#include <asm-generic/pgtable-nopud.h>
static inline pud_t native_make_pud(pudval_t val)
{
return (pud_t) { .p4d.pgd = native_make_pgd(val) };
}
static inline pudval_t native_pud_val(pud_t pud)
{
return native_pgd_val(pud.p4d.pgd);
@ -344,6 +349,11 @@ static inline pmdval_t native_pmd_val(pmd_t pmd)
#else
#include <asm-generic/pgtable-nopmd.h>
static inline pmd_t native_make_pmd(pmdval_t val)
{
return (pmd_t) { .pud.p4d.pgd = native_make_pgd(val) };
}
static inline pmdval_t native_pmd_val(pmd_t pmd)
{
return native_pgd_val(pmd.pud.p4d.pgd);

1
arch/x86/include/asm/processor.h
View File

@ -977,4 +977,5 @@ bool xen_set_default_idle(void);
void stop_this_cpu(void *dummy);
void df_debug(struct pt_regs *regs, long error_code);
void microcode_check(void);
#endif /* _ASM_X86_PROCESSOR_H */

4
arch/x86/include/asm/refcount.h
View File

@ -67,13 +67,13 @@ static __always_inline __must_check
bool refcount_sub_and_test(unsigned int i, refcount_t *r)
{
GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl", REFCOUNT_CHECK_LT_ZERO,
r->refs.counter, "er", i, "%0", e);
r->refs.counter, "er", i, "%0", e, "cx");
}
static __always_inline __must_check bool refcount_dec_and_test(refcount_t *r)
{
GEN_UNARY_SUFFIXED_RMWcc(LOCK_PREFIX "decl", REFCOUNT_CHECK_LT_ZERO,
r->refs.counter, "%0", e);
r->refs.counter, "%0", e, "cx");
}
static __always_inline __must_check

16
arch/x86/include/asm/rmwcc.h
View File

@ -2,8 +2,7 @@
#ifndef _ASM_X86_RMWcc
#define _ASM_X86_RMWcc
#define __CLOBBERS_MEM "memory"
#define __CLOBBERS_MEM_CC_CX "memory", "cc", "cx"
#define __CLOBBERS_MEM(clb...) "memory", ## clb
#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)
@ -40,18 +39,19 @@ do { \
#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */
#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
__GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM)
__GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM())
#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc) \
#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc, clobbers...)\
__GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc, \
__CLOBBERS_MEM_CC_CX)
__CLOBBERS_MEM(clobbers))
#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
__GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc, \
__CLOBBERS_MEM, vcon (val))
__CLOBBERS_MEM(), vcon (val))
#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc) \
#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc, \
clobbers...) \
__GEN_RMWcc(op __BINARY_RMWcc_ARG arg0 "\n\t" suffix, var, cc, \
__CLOBBERS_MEM_CC_CX, vcon (val))
__CLOBBERS_MEM(clobbers), vcon (val))
#endif /* _ASM_X86_RMWcc */

2
arch/x86/kernel/apic/io_apic.c
View File

@ -1603,7 +1603,7 @@ static void __init delay_with_tsc(void)
do {
rep_nop();
now = rdtsc();
} while ((now - start) < 40000000000UL / HZ &&
} while ((now - start) < 40000000000ULL / HZ &&
time_before_eq(jiffies, end));
}

12
arch/x86/kernel/cpu/bugs.c
View File

@ -300,6 +300,15 @@ retpoline_auto:
setup_force_cpu_cap(X86_FEATURE_USE_IBPB);
pr_info("Spectre v2 mitigation: Enabling Indirect Branch Prediction Barrier\n");
}
/*
* Retpoline means the kernel is safe because it has no indirect
* branches. But firmware isn't, so use IBRS to protect that.
*/
if (boot_cpu_has(X86_FEATURE_IBRS)) {
setup_force_cpu_cap(X86_FEATURE_USE_IBRS_FW);
pr_info("Enabling Restricted Speculation for firmware calls\n");
}
}
#undef pr_fmt
@ -326,8 +335,9 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
return sprintf(buf, "Not affected\n");
return sprintf(buf, "%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
return sprintf(buf, "%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "",
boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
spectre_v2_module_string());
}
#endif

30
arch/x86/kernel/cpu/common.c
View File

@ -1749,3 +1749,33 @@ static int __init init_cpu_syscore(void)
return 0;
}
core_initcall(init_cpu_syscore);
/*
* The microcode loader calls this upon late microcode load to recheck features,
* only when microcode has been updated. Caller holds microcode_mutex and CPU
* hotplug lock.
*/
void microcode_check(void)
{
struct cpuinfo_x86 info;
perf_check_microcode();
/* Reload CPUID max function as it might've changed. */
info.cpuid_level = cpuid_eax(0);
/*
* Copy all capability leafs to pick up the synthetic ones so that
* memcmp() below doesn't fail on that. The ones coming from CPUID will
* get overwritten in get_cpu_cap().
*/
memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability));
get_cpu_cap(&info);
if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)))
return;
pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");
pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n");
}

10
arch/x86/kernel/cpu/microcode/amd.c
View File

@ -498,7 +498,7 @@ static unsigned int verify_patch_size(u8 family, u32 patch_size,
return patch_size;
}
static int apply_microcode_amd(int cpu)
static enum ucode_state apply_microcode_amd(int cpu)
{
struct cpuinfo_x86 *c = &cpu_data(cpu);
struct microcode_amd *mc_amd;
@ -512,7 +512,7 @@ static int apply_microcode_amd(int cpu)
p = find_patch(cpu);
if (!p)
return 0;
return UCODE_NFOUND;
mc_amd = p->data;
uci->mc = p->data;
@ -523,13 +523,13 @@ static int apply_microcode_amd(int cpu)
if (rev >= mc_amd->hdr.patch_id) {
c->microcode = rev;
uci->cpu_sig.rev = rev;
return 0;
return UCODE_OK;
}
if (__apply_microcode_amd(mc_amd)) {
pr_err("CPU%d: update failed for patch_level=0x%08x\n",
cpu, mc_amd->hdr.patch_id);
return -1;
return UCODE_ERROR;
}
pr_info("CPU%d: new patch_level=0x%08x\n", cpu,
mc_amd->hdr.patch_id);
@ -537,7 +537,7 @@ static int apply_microcode_amd(int cpu)
uci->cpu_sig.rev = mc_amd->hdr.patch_id;
c->microcode = mc_amd->hdr.patch_id;
return 0;
return UCODE_UPDATED;
}
static int install_equiv_cpu_table(const u8 *buf)

37
arch/x86/kernel/cpu/microcode/core.c
View File

@ -374,7 +374,7 @@ static int collect_cpu_info(int cpu)
}
struct apply_microcode_ctx {
int err;
enum ucode_state err;
};
static void apply_microcode_local(void *arg)
@ -489,31 +489,30 @@ static void __exit microcode_dev_exit(void)
/* fake device for request_firmware */
static struct platform_device *microcode_pdev;
static int reload_for_cpu(int cpu)
static enum ucode_state reload_for_cpu(int cpu)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
enum ucode_state ustate;
int err = 0;
if (!uci->valid)
return err;
return UCODE_OK;
ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
if (ustate == UCODE_OK)
apply_microcode_on_target(cpu);
else
if (ustate == UCODE_ERROR)
err = -EINVAL;
return err;
if (ustate != UCODE_OK)
return ustate;
return apply_microcode_on_target(cpu);
}
static ssize_t reload_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
enum ucode_state tmp_ret = UCODE_OK;
bool do_callback = false;
unsigned long val;
ssize_t ret = 0;
int cpu;
ssize_t ret = 0, tmp_ret;
ret = kstrtoul(buf, 0, &val);
if (ret)
@ -526,15 +525,21 @@ static ssize_t reload_store(struct device *dev,
mutex_lock(&microcode_mutex);
for_each_online_cpu(cpu) {
tmp_ret = reload_for_cpu(cpu);
if (tmp_ret != 0)
if (tmp_ret > UCODE_NFOUND) {
pr_warn("Error reloading microcode on CPU %d\n", cpu);
/* save retval of the first encountered reload error */
/* set retval for the first encountered reload error */
if (!ret)
ret = tmp_ret;
ret = -EINVAL;
}
if (!ret)
perf_check_microcode();
if (tmp_ret == UCODE_UPDATED)
do_callback = true;
}
if (!ret && do_callback)
microcode_check();
mutex_unlock(&microcode_mutex);
put_online_cpus();

10
arch/x86/kernel/cpu/microcode/intel.c
View File

@ -772,7 +772,7 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
return 0;
}
static int apply_microcode_intel(int cpu)
static enum ucode_state apply_microcode_intel(int cpu)
{
struct microcode_intel *mc;
struct ucode_cpu_info *uci;
@ -782,7 +782,7 @@ static int apply_microcode_intel(int cpu)
/* We should bind the task to the CPU */
if (WARN_ON(raw_smp_processor_id() != cpu))
return -1;
return UCODE_ERROR;
uci = ucode_cpu_info + cpu;
mc = uci->mc;
@ -790,7 +790,7 @@ static int apply_microcode_intel(int cpu)
/* Look for a newer patch in our cache: */
mc = find_patch(uci);
if (!mc)
return 0;
return UCODE_NFOUND;
}
/* write microcode via MSR 0x79 */
@ -801,7 +801,7 @@ static int apply_microcode_intel(int cpu)
if (rev != mc->hdr.rev) {
pr_err("CPU%d update to revision 0x%x failed\n",
cpu, mc->hdr.rev);
return -1;
return UCODE_ERROR;
}
if (rev != prev_rev) {
@ -818,7 +818,7 @@ static int apply_microcode_intel(int cpu)
uci->cpu_sig.rev = rev;
c->microcode = rev;
return 0;
return UCODE_UPDATED;
}
static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,

2
arch/x86/kernel/head_64.S
View File

@ -23,6 +23,7 @@
#include <asm/nops.h>
#include "../entry/calling.h"
#include <asm/export.h>
#include <asm/nospec-branch.h>
#ifdef CONFIG_PARAVIRT
#include <asm/asm-offsets.h>
@ -134,6 +135,7 @@ ENTRY(secondary_startup_64)
/* Ensure I am executing from virtual addresses */
movq $1f, %rax
ANNOTATE_RETPOLINE_SAFE
jmp *%rax
1:
UNWIND_HINT_EMPTY

3
arch/x86/kernel/unwind_orc.c
View File

@ -5,7 +5,6 @@
#include <asm/unwind.h>
#include <asm/orc_types.h>
#include <asm/orc_lookup.h>
#include <asm/sections.h>
#define orc_warn(fmt, ...) \
printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__)
@ -148,7 +147,7 @@ static struct orc_entry *orc_find(unsigned long ip)
}
/* vmlinux .init slow lookup: */
if (ip >= (unsigned long)_sinittext && ip < (unsigned long)_einittext)
if (init_kernel_text(ip))
return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
__stop_orc_unwind_ip - __start_orc_unwind_ip, ip);

9
arch/x86/kvm/svm.c
View File

@ -49,6 +49,7 @@
#include <asm/debugreg.h>
#include <asm/kvm_para.h>
#include <asm/irq_remapping.h>
#include <asm/microcode.h>
#include <asm/nospec-branch.h>
#include <asm/virtext.h>
@ -5364,7 +5365,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
* being speculatively taken.
*/
if (svm->spec_ctrl)
wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
native_wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
asm volatile (
"push %%" _ASM_BP "; \n\t"
@ -5473,11 +5474,11 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
* If the L02 MSR bitmap does not intercept the MSR, then we need to
* save it.
*/
if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
rdmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
svm->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
if (svm->spec_ctrl)
wrmsrl(MSR_IA32_SPEC_CTRL, 0);
native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();

9
arch/x86/kvm/vmx.c
View File

@ -51,6 +51,7 @@
#include <asm/apic.h>
#include <asm/irq_remapping.h>
#include <asm/mmu_context.h>
#include <asm/microcode.h>
#include <asm/nospec-branch.h>
#include "trace.h"
@ -9453,7 +9454,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
* being speculatively taken.
*/
if (vmx->spec_ctrl)
wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
native_wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
vmx->__launched = vmx->loaded_vmcs->launched;
asm(
@ -9588,11 +9589,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
* If the L02 MSR bitmap does not intercept the MSR, then we need to
* save it.
*/
if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
rdmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
vmx->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
if (vmx->spec_ctrl)
wrmsrl(MSR_IA32_SPEC_CTRL, 0);
native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();

1
arch/x86/lib/Makefile
View File

@ -28,7 +28,6 @@ lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
lib-$(CONFIG_RETPOLINE) += retpoline.o
OBJECT_FILES_NON_STANDARD_retpoline.o :=y
obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o

56
arch/x86/lib/retpoline.S
View File

@ -7,7 +7,6 @@
#include <asm/alternative-asm.h>
#include <asm/export.h>
#include <asm/nospec-branch.h>
#include <asm/bitsperlong.h>
.macro THUNK reg
.section .text.__x86.indirect_thunk
@ -47,58 +46,3 @@ GENERATE_THUNK(r13)
GENERATE_THUNK(r14)
GENERATE_THUNK(r15)
#endif
/*
* Fill the CPU return stack buffer.
*
* Each entry in the RSB, if used for a speculative 'ret', contains an
* infinite 'pause; lfence; jmp' loop to capture speculative execution.
*
* This is required in various cases for retpoline and IBRS-based
* mitigations for the Spectre variant 2 vulnerability. Sometimes to
* eliminate potentially bogus entries from the RSB, and sometimes
* purely to ensure that it doesn't get empty, which on some CPUs would
* allow predictions from other (unwanted!) sources to be used.
*
* Google experimented with loop-unrolling and this turned out to be
* the optimal version - two calls, each with their own speculation
* trap should their return address end up getting used, in a loop.
*/
.macro STUFF_RSB nr:req sp:req
mov $(\nr / 2), %_ASM_BX
.align 16
771:
call 772f
773: /* speculation trap */
pause
lfence
jmp 773b
.align 16
772:
call 774f
775: /* speculation trap */
pause
lfence
jmp 775b
.align 16
774:
dec %_ASM_BX
jnz 771b
add $((BITS_PER_LONG/8) * \nr), \sp
.endm
#define RSB_FILL_LOOPS 16 /* To avoid underflow */
ENTRY(__fill_rsb)
STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP
ret
END(__fill_rsb)
EXPORT_SYMBOL_GPL(__fill_rsb)
#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
ENTRY(__clear_rsb)
STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP
ret
END(__clear_rsb)
EXPORT_SYMBOL_GPL(__clear_rsb)

4
arch/x86/mm/fault.c
View File

@ -1248,10 +1248,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
tsk = current;
mm = tsk->mm;
/*
* Detect and handle instructions that would cause a page fault for
* both a tracked kernel page and a userspace page.
*/
prefetchw(&mm->mmap_sem);
if (unlikely(kmmio_fault(regs, address)))

2
arch/x86/mm/mem_encrypt_boot.S
View File

@ -15,6 +15,7 @@
#include <asm/page.h>
#include <asm/processor-flags.h>
#include <asm/msr-index.h>
#include <asm/nospec-branch.h>
.text
.code64
@ -59,6 +60,7 @@ ENTRY(sme_encrypt_execute)
movq %rax, %r8 /* Workarea encryption routine */
addq $PAGE_SIZE, %r8 /* Workarea intermediate copy buffer */
ANNOTATE_RETPOLINE_SAFE
call *%rax /* Call the encryption routine */
pop %r12

2
arch/x86/realmode/rm/trampoline_64.S
View File

@ -102,7 +102,7 @@ ENTRY(startup_32)
* don't we'll eventually crash trying to execute encrypted
* instructions.
*/
bt $TH_FLAGS_SME_ACTIVE_BIT, pa_tr_flags
btl $TH_FLAGS_SME_ACTIVE_BIT, pa_tr_flags
jnc .Ldone
movl $MSR_K8_SYSCFG, %ecx
rdmsr

5
include/linux/compiler-clang.h
View File

@ -27,3 +27,8 @@
#if __has_feature(address_sanitizer)
#define __SANITIZE_ADDRESS__
#endif
/* Clang doesn't have a way to turn it off per-function, yet. */
#ifdef __noretpoline
#undef __noretpoline
#endif

4
include/linux/compiler-gcc.h
View File

@ -93,6 +93,10 @@
#define __weak __attribute__((weak))
#define __alias(symbol) __attribute__((alias(#symbol)))
#ifdef RETPOLINE
#define __noretpoline __attribute__((indirect_branch("keep")))
#endif
/*
* it doesn't make sense on ARM (currently the only user of __naked)
* to trace naked functions because then mcount is called without

8
include/linux/init.h
View File

@ -6,10 +6,10 @@
#include <linux/types.h>
/* Built-in __init functions needn't be compiled with retpoline */
#if defined(RETPOLINE) && !defined(MODULE)
#define __noretpoline __attribute__((indirect_branch("keep")))
#if defined(__noretpoline) && !defined(MODULE)
#define __noinitretpoline __noretpoline
#else
#define __noretpoline
#define __noinitretpoline
#endif
/* These macros are used to mark some functions or
@ -47,7 +47,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
#define __init __section(.init.text) __cold __latent_entropy __noretpoline
#define __init __section(.init.text) __cold __latent_entropy __noinitretpoline
#define __initdata __section(.init.data)
#define __initconst __section(.init.rodata)
#define __exitdata __section(.exit.data)

3
include/linux/jump_label.h
View File

@ -151,6 +151,7 @@ extern struct jump_entry __start___jump_table[];
extern struct jump_entry __stop___jump_table[];
extern void jump_label_init(void);
extern void jump_label_invalidate_init(void);
extern void jump_label_lock(void);
extern void jump_label_unlock(void);
extern void arch_jump_label_transform(struct jump_entry *entry,
@ -198,6 +199,8 @@ static __always_inline void jump_label_init(void)
static_key_initialized = true;
}
static inline void jump_label_invalidate_init(void) {}
static __always_inline bool static_key_false(struct static_key *key)
{
if (unlikely(static_key_count(key) > 0))

1
include/linux/kernel.h
View File

@ -472,6 +472,7 @@ extern bool parse_option_str(const char *str, const char *option);
extern char *next_arg(char *args, char **param, char **val);
extern int core_kernel_text(unsigned long addr);
extern int init_kernel_text(unsigned long addr);
extern int core_kernel_data(unsigned long addr);
extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);

26
include/linux/nospec.h
View File

@ -5,6 +5,7 @@
#ifndef _LINUX_NOSPEC_H
#define _LINUX_NOSPEC_H
#include <asm/barrier.h>
/**
* array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
@ -29,26 +30,6 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
}
#endif
/*
* Warn developers about inappropriate array_index_nospec() usage.
*
* Even if the CPU speculates past the WARN_ONCE branch, the
* sign bit of @index is taken into account when generating the
* mask.
*
* This warning is compiled out when the compiler can infer that
* @index and @size are less than LONG_MAX.
*/
#define array_index_mask_nospec_check(index, size) \
({ \
if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX, \
"array_index_nospec() limited to range of [0, LONG_MAX]\n")) \
_mask = 0; \
else \
_mask = array_index_mask_nospec(index, size); \
_mask; \
})
/*
* array_index_nospec - sanitize an array index after a bounds check
*
@ -67,12 +48,11 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
({ \
typeof(index) _i = (index); \
typeof(size) _s = (size); \
unsigned long _mask = array_index_mask_nospec_check(_i, _s); \
unsigned long _mask = array_index_mask_nospec(_i, _s); \
\
BUILD_BUG_ON(sizeof(_i) > sizeof(long)); \
BUILD_BUG_ON(sizeof(_s) > sizeof(long)); \
\
_i &= _mask; \
_i; \
(typeof(_i)) (_i & _mask); \
})
#endif /* _LINUX_NOSPEC_H */

2
init/main.c
View File

@ -89,6 +89,7 @@
#include <linux/io.h>
#include <linux/cache.h>
#include <linux/rodata_test.h>
#include <linux/jump_label.h>
#include <asm/io.h>
#include <asm/bugs.h>
@ -1000,6 +1001,7 @@ static int __ref kernel_init(void *unused)
/* need to finish all async __init code before freeing the memory */
async_synchronize_full();
ftrace_free_init_mem();
jump_label_invalidate_init();
free_initmem();
mark_readonly();
system_state = SYSTEM_RUNNING;

2
kernel/extable.c
View File

@ -64,7 +64,7 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
return e;
}
static inline int init_kernel_text(unsigned long addr)
int init_kernel_text(unsigned long addr)
{
if (addr >= (unsigned long)_sinittext &&
addr < (unsigned long)_einittext)

25
kernel/jump_label.c
View File

@ -366,12 +366,15 @@ static void __jump_label_update(struct static_key *key,
{
for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
/*
* entry->code set to 0 invalidates module init text sections
* kernel_text_address() verifies we are not in core kernel
* init code, see jump_label_invalidate_module_init().
* An entry->code of 0 indicates an entry which has been
* disabled because it was in an init text area.
*/
if (entry->code && kernel_text_address(entry->code))
if (entry->code) {
if (kernel_text_address(entry->code))
arch_jump_label_transform(entry, jump_label_type(entry));
else
WARN_ONCE(1, "can't patch jump_label at %pS", (void *)entry->code);
}
}
}
@ -417,6 +420,19 @@ void __init jump_label_init(void)
cpus_read_unlock();
}
/* Disable any jump label entries in __init code */
void __init jump_label_invalidate_init(void)
{
struct jump_entry *iter_start = __start___jump_table;
struct jump_entry *iter_stop = __stop___jump_table;
struct jump_entry *iter;
for (iter = iter_start; iter < iter_stop; iter++) {
if (init_kernel_text(iter->code))
iter->code = 0;
}
}
#ifdef CONFIG_MODULES
static enum jump_label_type jump_label_init_type(struct jump_entry *entry)
@ -633,6 +649,7 @@ static void jump_label_del_module(struct module *mod)
}
}
/* Disable any jump label entries in module init code */
static void jump_label_invalidate_module_init(struct module *mod)
{
struct jump_entry *iter_start = mod->jump_entries;

8
scripts/Makefile.build
View File

@ -256,6 +256,8 @@ __objtool_obj := $(objtree)/tools/objtool/objtool
objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
objtool_args += $(if $(part-of-module), --module,)
ifndef CONFIG_FRAME_POINTER
objtool_args += --no-fp
endif
@ -264,6 +266,12 @@ objtool_args += --no-unreachable
else
objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
endif
ifdef CONFIG_RETPOLINE
ifneq ($(RETPOLINE_CFLAGS),)
objtool_args += --retpoline
endif
endif
ifdef CONFIG_MODVERSIONS
objtool_o = $(@D)/.tmp_$(@F)

6
tools/objtool/builtin-check.c
View File

@ -29,7 +29,7 @@
#include "builtin.h"
#include "check.h"
bool no_fp, no_unreachable;
bool no_fp, no_unreachable, retpoline, module;
static const char * const check_usage[] = {
"objtool check [<options>] file.o",
@ -39,6 +39,8 @@ static const char * const check_usage[] = {
const struct option check_options[] = {
OPT_BOOLEAN('f', "no-fp", &no_fp, "Skip frame pointer validation"),
OPT_BOOLEAN('u', "no-unreachable", &no_unreachable, "Skip 'unreachable instruction' warnings"),
OPT_BOOLEAN('r', "retpoline", &retpoline, "Validate retpoline assumptions"),
OPT_BOOLEAN('m', "module", &module, "Indicates the object will be part of a kernel module"),
OPT_END(),
};
@ -53,5 +55,5 @@ int cmd_check(int argc, const char **argv)
objname = argv[0];
return check(objname, no_fp, no_unreachable, false);
return check(objname, false);
}

6
tools/objtool/builtin-orc.c
View File

@ -25,7 +25,6 @@
*/
#include <string.h>
#include <subcmd/parse-options.h>
#include "builtin.h"
#include "check.h"
@ -36,9 +35,6 @@ static const char *orc_usage[] = {
NULL,
};
extern const struct option check_options[];
extern bool no_fp, no_unreachable;
int cmd_orc(int argc, const char **argv)
{
const char *objname;
@ -54,7 +50,7 @@ int cmd_orc(int argc, const char **argv)
objname = argv[0];
return check(objname, no_fp, no_unreachable, true);
return check(objname, true);
}
if (!strcmp(argv[0], "dump")) {

5
tools/objtool/builtin.h
View File

@ -17,6 +17,11 @@
#ifndef _BUILTIN_H
#define _BUILTIN_H
#include <subcmd/parse-options.h>
extern const struct option check_options[];
extern bool no_fp, no_unreachable, retpoline, module;
extern int cmd_check(int argc, const char **argv);
extern int cmd_orc(int argc, const char **argv);

98
tools/objtool/check.c
View File

@ -18,6 +18,7 @@
#include <string.h>
#include <stdlib.h>
#include "builtin.h"
#include "check.h"
#include "elf.h"
#include "special.h"
@ -33,7 +34,6 @@ struct alternative {
};
const char *objname;
static bool no_fp;
struct cfi_state initial_func_cfi;
struct instruction *find_insn(struct objtool_file *file,
@ -497,6 +497,7 @@ static int add_jump_destinations(struct objtool_file *file)
* disguise, so convert them accordingly.
*/
insn->type = INSN_JUMP_DYNAMIC;
insn->retpoline_safe = true;
continue;
} else {
/* sibling call */
@ -548,6 +549,7 @@ static int add_call_destinations(struct objtool_file *file)
if (!insn->call_dest && !insn->ignore) {
WARN_FUNC("unsupported intra-function call",
insn->sec, insn->offset);
if (retpoline)
WARN("If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.");
return -1;
}
@ -1108,6 +1110,54 @@ static int read_unwind_hints(struct objtool_file *file)
return 0;
}
static int read_retpoline_hints(struct objtool_file *file)
{
struct section *sec, *relasec;
struct instruction *insn;
struct rela *rela;
int i;
sec = find_section_by_name(file->elf, ".discard.retpoline_safe");
if (!sec)
return 0;
relasec = sec->rela;
if (!relasec) {
WARN("missing .rela.discard.retpoline_safe section");
return -1;
}
if (sec->len % sizeof(unsigned long)) {
WARN("retpoline_safe size mismatch: %d %ld", sec->len, sizeof(unsigned long));
return -1;
}
for (i = 0; i < sec->len / sizeof(unsigned long); i++) {
rela = find_rela_by_dest(sec, i * sizeof(unsigned long));
if (!rela) {
WARN("can't find rela for retpoline_safe[%d]", i);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
if (!insn) {
WARN("can't find insn for retpoline_safe[%d]", i);
return -1;
}
if (insn->type != INSN_JUMP_DYNAMIC &&
insn->type != INSN_CALL_DYNAMIC) {
WARN_FUNC("retpoline_safe hint not a indirect jump/call",
insn->sec, insn->offset);
return -1;
}
insn->retpoline_safe = true;
}
return 0;
}
static int decode_sections(struct objtool_file *file)
{
int ret;
@ -1146,6 +1196,10 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;
ret = read_retpoline_hints(file);
if (ret)
return ret;
return 0;
}
@ -1891,6 +1945,38 @@ static int validate_unwind_hints(struct objtool_file *file)
return warnings;
}
static int validate_retpoline(struct objtool_file *file)
{
struct instruction *insn;
int warnings = 0;
for_each_insn(file, insn) {
if (insn->type != INSN_JUMP_DYNAMIC &&
insn->type != INSN_CALL_DYNAMIC)
continue;
if (insn->retpoline_safe)
continue;
/*
* .init.text code is ran before userspace and thus doesn't
* strictly need retpolines, except for modules which are
* loaded late, they very much do need retpoline in their
* .init.text
*/
if (!strcmp(insn->sec->name, ".init.text") && !module)
continue;
WARN_FUNC("indirect %s found in RETPOLINE build",
insn->sec, insn->offset,
insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call");
warnings++;
}
return warnings;
}
static bool is_kasan_insn(struct instruction *insn)
{
return (insn->type == INSN_CALL &&
@ -2022,13 +2108,12 @@ static void cleanup(struct objtool_file *file)
elf_close(file->elf);
}
int check(const char *_objname, bool _no_fp, bool no_unreachable, bool orc)
int check(const char *_objname, bool orc)
{
struct objtool_file file;
int ret, warnings = 0;
objname = _objname;
no_fp = _no_fp;
file.elf = elf_open(objname, orc ? O_RDWR : O_RDONLY);
if (!file.elf)
@ -2052,6 +2137,13 @@ int check(const char *_objname, bool _no_fp, bool no_unreachable, bool orc)
if (list_empty(&file.insn_list))
goto out;
if (retpoline) {
ret = validate_retpoline(&file);
if (ret < 0)
return ret;
warnings += ret;
}
ret = validate_functions(&file);
if (ret < 0)
goto out;

3
tools/objtool/check.h
View File

@ -45,6 +45,7 @@ struct instruction {
unsigned char type;
unsigned long immediate;
bool alt_group, visited, dead_end, ignore, hint, save, restore, ignore_alts;
bool retpoline_safe;
struct symbol *call_dest;
struct instruction *jump_dest;
struct instruction *first_jump_src;
@ -63,7 +64,7 @@ struct objtool_file {
bool ignore_unreachables, c_file, hints;
};
int check(const char *objname, bool no_fp, bool no_unreachable, bool orc);
int check(const char *objname, bool orc);
struct instruction *find_insn(struct objtool_file *file,
struct section *sec, unsigned long offset);