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linux/tools/testing/selftests/rseq/rseq-arm.h
Mathieu Desnoyers ee8a84c60b rseq/selftests: Fix Thumb mode build failure on arm32 
Using ".arm .inst" for the arm signature introduces build issues for
programs compiled in Thumb mode because the assembler stays in the
arm mode for the rest of the inline assembly. Revert to using a ".word"
to express the signature as data instead.

The choice of signature is a valid trap instruction on arm32 little
endian, where both code and data are little endian.

ARMv6+ big endian (BE8) generates mixed endianness code vs data:
little-endian code and big-endian data. The data value of the signature
needs to have its byte order reversed to generate the trap instruction.

Prior to ARMv6, -mbig-endian generates big-endian code and data
(which match), so the endianness of the data representation of the
signature should not be reversed. However, the choice between BE32
and BE8 is done by the linker, so we cannot know whether code and
data endianness will be mixed before the linker is invoked. So rather
than try to play tricks with the linker, the rseq signature is simply
data (not a trap instruction) prior to ARMv6 on big endian. This is
why the signature is expressed as data (.word) rather than as
instruction (.inst) in assembler.

Because a ".word" is used to emit the signature, it will be interpreted
as a literal pool by a disassembler, not as an actual instruction.
Considering that the signature is not meant to be executed except in
scenarios where the program execution is completely bogus, this should
not be an issue.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Will Deacon <will.deacon@arm.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Joel Fernandes <joelaf@google.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Dave Watson <davejwatson@fb.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Andi Kleen <andi@firstfloor.org>
CC: linux-kselftest@vger.kernel.org
CC: "H . Peter Anvin" <hpa@zytor.com>
CC: Chris Lameter <cl@linux.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
CC: Paul Turner <pjt@google.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ben Maurer <bmaurer@fb.com>
CC: linux-api@vger.kernel.org
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Carlos O'Donell <carlos@redhat.com>
CC: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2019-07-08 13:00:41 -06:00

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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* rseq-arm.h
*
* (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
/*
* - ARM little endian
*
* RSEQ_SIG uses the udf A32 instruction with an uncommon immediate operand
* value 0x5de3. This traps if user-space reaches this instruction by mistake,
* and the uncommon operand ensures the kernel does not move the instruction
* pointer to attacker-controlled code on rseq abort.
*
* The instruction pattern in the A32 instruction set is:
*
* e7f5def3 udf #24035 ; 0x5de3
*
* This translates to the following instruction pattern in the T16 instruction
* set:
*
* little endian:
* def3 udf #243 ; 0xf3
* e7f5 b.n <7f5>
*
* - ARMv6+ big endian (BE8):
*
* ARMv6+ -mbig-endian generates mixed endianness code vs data: little-endian
* code and big-endian data. The data value of the signature needs to have its
* byte order reversed to generate the trap instruction:
*
* Data: 0xf3def5e7
*
* Translates to this A32 instruction pattern:
*
* e7f5def3 udf #24035 ; 0x5de3
*
* Translates to this T16 instruction pattern:
*
* def3 udf #243 ; 0xf3
* e7f5 b.n <7f5>
*
* - Prior to ARMv6 big endian (BE32):
*
* Prior to ARMv6, -mbig-endian generates big-endian code and data
* (which match), so the endianness of the data representation of the
* signature should not be reversed. However, the choice between BE32
* and BE8 is done by the linker, so we cannot know whether code and
* data endianness will be mixed before the linker is invoked. So rather
* than try to play tricks with the linker, the rseq signature is simply
* data (not a trap instruction) prior to ARMv6 on big endian. This is
* why the signature is expressed as data (.word) rather than as
* instruction (.inst) in assembler.
*/
#ifdef __ARMEB__
#define RSEQ_SIG 0xf3def5e7 /* udf #24035 ; 0x5de3 (ARMv6+) */
#else
#define RSEQ_SIG 0xe7f5def3 /* udf #24035 ; 0x5de3 */
#endif
#define rseq_smp_mb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
#define rseq_smp_rmb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
#define rseq_smp_wmb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
#define rseq_smp_load_acquire(p) \
__extension__ ({ \
__typeof(*p) ____p1 = RSEQ_READ_ONCE(*p); \
rseq_smp_mb(); \
____p1; \
})
#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()
#define rseq_smp_store_release(p, v) \
do { \
rseq_smp_mb(); \
RSEQ_WRITE_ONCE(*p, v); \
} while (0)
#ifdef RSEQ_SKIP_FASTPATH
#include "rseq-skip.h"
#else /* !RSEQ_SKIP_FASTPATH */
#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \
post_commit_offset, abort_ip) \
".pushsection __rseq_cs, \"aw\"\n\t" \
".balign 32\n\t" \
__rseq_str(label) ":\n\t" \
".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
".popsection\n\t" \
".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
".word " __rseq_str(label) "b, 0x0\n\t" \
".popsection\n\t"
#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
(post_commit_ip - start_ip), abort_ip)
/*
* Exit points of a rseq critical section consist of all instructions outside
* of the critical section where a critical section can either branch to or
* reach through the normal course of its execution. The abort IP and the
* post-commit IP are already part of the __rseq_cs section and should not be
* explicitly defined as additional exit points. Knowing all exit points is
* useful to assist debuggers stepping over the critical section.
*/
#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
".pushsection __rseq_exit_point_array, \"aw\"\n\t" \
".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) ", 0x0\n\t" \
".popsection\n\t"
#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
RSEQ_INJECT_ASM(1) \
"adr r0, " __rseq_str(cs_label) "\n\t" \
"str r0, %[" __rseq_str(rseq_cs) "]\n\t" \
__rseq_str(label) ":\n\t"
#define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label) \
RSEQ_INJECT_ASM(2) \
"ldr r0, %[" __rseq_str(current_cpu_id) "]\n\t" \
"cmp %[" __rseq_str(cpu_id) "], r0\n\t" \
"bne " __rseq_str(label) "\n\t"
#define __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, \
abort_label, version, flags, \
start_ip, post_commit_offset, abort_ip) \
".balign 32\n\t" \
__rseq_str(table_label) ":\n\t" \
".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
".word " __rseq_str(RSEQ_SIG) "\n\t" \
__rseq_str(label) ":\n\t" \
teardown \
"b %l[" __rseq_str(abort_label) "]\n\t"
#define RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, abort_label, \
start_ip, post_commit_ip, abort_ip) \
__RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, \
abort_label, 0x0, 0x0, start_ip, \
(post_commit_ip - start_ip), abort_ip)
#define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label) \
__rseq_str(label) ":\n\t" \
teardown \
"b %l[" __rseq_str(cmpfail_label) "]\n\t"
#define rseq_workaround_gcc_asm_size_guess() __asm__ __volatile__("")
static inline __attribute__((always_inline))
int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
{
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
#endif
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[error2]\n\t"
#endif
/* final store */
"str %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(5)
"b 5f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
"5:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_bug("cpu_id comparison failed");
error2:
rseq_bug("expected value comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
off_t voffp, intptr_t *load, int cpu)
{
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
#endif
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expectnot], r0\n\t"
"beq %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
"ldr r0, %[v]\n\t"
"cmp %[expectnot], r0\n\t"
"beq %l[error2]\n\t"
#endif
"str r0, %[load]\n\t"
"add r0, %[voffp]\n\t"
"ldr r0, [r0]\n\t"
/* final store */
"str r0, %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(5)
"b 5f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
"5:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
/* final store input */
[v] "m" (*v),
[expectnot] "r" (expectnot),
[voffp] "Ir" (voffp),
[load] "m" (*load)
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_bug("cpu_id comparison failed");
error2:
rseq_bug("expected value comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_addv(intptr_t *v, intptr_t count, int cpu)
{
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
#endif
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
#endif
"ldr r0, %[v]\n\t"
"add r0, %[count]\n\t"
/* final store */
"str r0, %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(4)
"b 5f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
"5:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
[v] "m" (*v),
[count] "Ir" (count)
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort
#ifdef RSEQ_COMPARE_TWICE
, error1
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_bug("cpu_id comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
intptr_t *v2, intptr_t newv2,
intptr_t newv, int cpu)
{
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
#endif
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[error2]\n\t"
#endif
/* try store */
"str %[newv2], %[v2]\n\t"
RSEQ_INJECT_ASM(5)
/* final store */
"str %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
"b 5f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
"5:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
/* try store input */
[v2] "m" (*v2),
[newv2] "r" (newv2),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_bug("cpu_id comparison failed");
error2:
rseq_bug("expected value comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
intptr_t *v2, intptr_t newv2,
intptr_t newv, int cpu)
{
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
#endif
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[error2]\n\t"
#endif
/* try store */
"str %[newv2], %[v2]\n\t"
RSEQ_INJECT_ASM(5)
"dmb\n\t" /* full mb provides store-release */
/* final store */
"str %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
"b 5f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
"5:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
/* try store input */
[v2] "m" (*v2),
[newv2] "r" (newv2),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_bug("cpu_id comparison failed");
error2:
rseq_bug("expected value comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
intptr_t *v2, intptr_t expect2,
intptr_t newv, int cpu)
{
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
#endif
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
"ldr r0, %[v2]\n\t"
"cmp %[expect2], r0\n\t"
"bne %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(5)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne %l[error2]\n\t"
"ldr r0, %[v2]\n\t"
"cmp %[expect2], r0\n\t"
"bne %l[error3]\n\t"
#endif
/* final store */
"str %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
"b 5f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
"5:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
/* cmp2 input */
[v2] "m" (*v2),
[expect2] "r" (expect2),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2, error3
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_bug("cpu_id comparison failed");
error2:
rseq_bug("1st expected value comparison failed");
error3:
rseq_bug("2nd expected value comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
void *dst, void *src, size_t len,
intptr_t newv, int cpu)
{
uint32_t rseq_scratch[3];
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
#endif
"str %[src], %[rseq_scratch0]\n\t"
"str %[dst], %[rseq_scratch1]\n\t"
"str %[len], %[rseq_scratch2]\n\t"
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne 5f\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne 7f\n\t"
#endif
/* try memcpy */
"cmp %[len], #0\n\t" \
"beq 333f\n\t" \
"222:\n\t" \
"ldrb %%r0, [%[src]]\n\t" \
"strb %%r0, [%[dst]]\n\t" \
"adds %[src], #1\n\t" \
"adds %[dst], #1\n\t" \
"subs %[len], #1\n\t" \
"bne 222b\n\t" \
"333:\n\t" \
RSEQ_INJECT_ASM(5)
/* final store */
"str %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t"
"b 8f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
abort, 1b, 2b, 4f)
RSEQ_ASM_DEFINE_CMPFAIL(5,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
cmpfail)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_CMPFAIL(6,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
error1)
RSEQ_ASM_DEFINE_CMPFAIL(7,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
error2)
#endif
"8:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv),
/* try memcpy input */
[dst] "r" (dst),
[src] "r" (src),
[len] "r" (len),
[rseq_scratch0] "m" (rseq_scratch[0]),
[rseq_scratch1] "m" (rseq_scratch[1]),
[rseq_scratch2] "m" (rseq_scratch[2])
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_workaround_gcc_asm_size_guess();
rseq_bug("cpu_id comparison failed");
error2:
rseq_workaround_gcc_asm_size_guess();
rseq_bug("expected value comparison failed");
#endif
}
static inline __attribute__((always_inline))
int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
void *dst, void *src, size_t len,
intptr_t newv, int cpu)
{
uint32_t rseq_scratch[3];
RSEQ_INJECT_C(9)
rseq_workaround_gcc_asm_size_guess();
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
#endif
"str %[src], %[rseq_scratch0]\n\t"
"str %[dst], %[rseq_scratch1]\n\t"
"str %[len], %[rseq_scratch2]\n\t"
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne 5f\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
"ldr r0, %[v]\n\t"
"cmp %[expect], r0\n\t"
"bne 7f\n\t"
#endif
/* try memcpy */
"cmp %[len], #0\n\t" \
"beq 333f\n\t" \
"222:\n\t" \
"ldrb %%r0, [%[src]]\n\t" \
"strb %%r0, [%[dst]]\n\t" \
"adds %[src], #1\n\t" \
"adds %[dst], #1\n\t" \
"subs %[len], #1\n\t" \
"bne 222b\n\t" \
"333:\n\t" \
RSEQ_INJECT_ASM(5)
"dmb\n\t" /* full mb provides store-release */
/* final store */
"str %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t"
"b 8f\n\t"
RSEQ_ASM_DEFINE_ABORT(3, 4,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
abort, 1b, 2b, 4f)
RSEQ_ASM_DEFINE_CMPFAIL(5,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
cmpfail)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_CMPFAIL(6,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
error1)
RSEQ_ASM_DEFINE_CMPFAIL(7,
/* teardown */
"ldr %[len], %[rseq_scratch2]\n\t"
"ldr %[dst], %[rseq_scratch1]\n\t"
"ldr %[src], %[rseq_scratch0]\n\t",
error2)
#endif
"8:\n\t"
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (__rseq_abi.cpu_id),
[rseq_cs] "m" (__rseq_abi.rseq_cs),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv),
/* try memcpy input */
[dst] "r" (dst),
[src] "r" (src),
[len] "r" (len),
[rseq_scratch0] "m" (rseq_scratch[0]),
[rseq_scratch1] "m" (rseq_scratch[1]),
[rseq_scratch2] "m" (rseq_scratch[2])
RSEQ_INJECT_INPUT
: "r0", "memory", "cc"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_workaround_gcc_asm_size_guess();
return 0;
abort:
rseq_workaround_gcc_asm_size_guess();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_workaround_gcc_asm_size_guess();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_workaround_gcc_asm_size_guess();
rseq_bug("cpu_id comparison failed");
error2:
rseq_workaround_gcc_asm_size_guess();
rseq_bug("expected value comparison failed");
#endif
}
#endif /* !RSEQ_SKIP_FASTPATH */
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