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linux/tools/testing/selftests/rseq/rseq-s390.h
Mathieu Desnoyers b53823fb2e selftests/rseq: Fix: work-around asm goto compiler bugs 
gcc and clang each have their own compiler bugs with respect to asm
goto. Implement a work-around for compiler versions known to have those
bugs.

gcc prior to 4.8.2 miscompiles asm goto.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670

gcc prior to 8.1.0 miscompiles asm goto at O1.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103908

clang prior to version 13.0.1 miscompiles asm goto at O2.
https://github.com/llvm/llvm-project/issues/52735

Work around these issues by adding a volatile inline asm with
memory clobber in the fallthrough after the asm goto and at each
label target.  Emit this for all compilers in case other similar
issues are found in the future.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-14-mathieu.desnoyers@efficios.com
2022-02-02 13:11:37 +01:00

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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* RSEQ_SIG uses the trap4 instruction. As Linux does not make use of the
* access-register mode nor the linkage stack this instruction will always
* cause a special-operation exception (the trap-enabled bit in the DUCT
* is and will stay 0). The instruction pattern is
* b2 ff 0f ff trap4 4095(%r0)
*/
#define RSEQ_SIG 0xB2FF0FFF
#define rseq_smp_mb() __asm__ __volatile__ ("bcr 15,0" ::: "memory")
#define rseq_smp_rmb() rseq_smp_mb()
#define rseq_smp_wmb() rseq_smp_mb()
#define rseq_smp_load_acquire(p) \
__extension__ ({ \
__typeof(*p) ____p1 = RSEQ_READ_ONCE(*p); \
rseq_barrier(); \
____p1; \
})
#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()
#define rseq_smp_store_release(p, v) \
do { \
rseq_barrier(); \
RSEQ_WRITE_ONCE(*p, v); \
} while (0)
#ifdef RSEQ_SKIP_FASTPATH
#include "rseq-skip.h"
#else /* !RSEQ_SKIP_FASTPATH */
#ifdef __s390x__
#define LONG_L "lg"
#define LONG_S "stg"
#define LONG_LT_R "ltgr"
#define LONG_CMP "cg"
#define LONG_CMP_R "cgr"
#define LONG_ADDI "aghi"
#define LONG_ADD_R "agr"
#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" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
".popsection\n\t" \
".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
".quad " __rseq_str(label) "b\n\t" \
".popsection\n\t"
/*
* 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" \
".quad " __rseq_str(start_ip) ", " __rseq_str(exit_ip) "\n\t" \
".popsection\n\t"
#elif __s390__
#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" \
".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) "\n\t" \
".popsection\n\t" \
".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
".long 0x0, " __rseq_str(label) "b\n\t" \
".popsection\n\t"
/*
* 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" \
".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) "\n\t" \
".popsection\n\t"
#define LONG_L "l"
#define LONG_S "st"
#define LONG_LT_R "ltr"
#define LONG_CMP "c"
#define LONG_CMP_R "cr"
#define LONG_ADDI "ahi"
#define LONG_ADD_R "ar"
#endif
#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)
#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
RSEQ_INJECT_ASM(1) \
"larl %%r0, " __rseq_str(cs_label) "\n\t" \
LONG_S " %%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) \
"c %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
"jnz " __rseq_str(label) "\n\t"
#define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label) \
".pushsection __rseq_failure, \"ax\"\n\t" \
".long " __rseq_str(RSEQ_SIG) "\n\t" \
__rseq_str(label) ":\n\t" \
teardown \
"jg %l[" __rseq_str(abort_label) "]\n\t" \
".popsection\n\t"
#define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label) \
".pushsection __rseq_failure, \"ax\"\n\t" \
__rseq_str(label) ":\n\t" \
teardown \
"jg %l[" __rseq_str(cmpfail_label) "]\n\t" \
".popsection\n\t"
static inline __attribute__((always_inline))
int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
{
RSEQ_INJECT_C(9)
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, 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, 3b, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
LONG_CMP " %[expect], %[v]\n\t"
"jnz %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
LONG_CMP " %[expect], %[v]\n\t"
"jnz %l[error2]\n\t"
#endif
/* final store */
LONG_S " %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(5)
RSEQ_ASM_DEFINE_ABORT(4, "", abort)
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (rseq_get_abi()->cpu_id),
[rseq_cs] "m" (rseq_get_abi()->rseq_cs.arch.ptr),
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "memory", "cc", "r0"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_after_asm_goto();
return 0;
abort:
rseq_after_asm_goto();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_after_asm_goto();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_after_asm_goto();
rseq_bug("cpu_id comparison failed");
error2:
rseq_after_asm_goto();
rseq_bug("expected value comparison failed");
#endif
}
/*
* Compare @v against @expectnot. When it does _not_ match, load @v
* into @load, and store the content of *@v + voffp into @v.
*/
static inline __attribute__((always_inline))
int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
long voffp, intptr_t *load, int cpu)
{
RSEQ_INJECT_C(9)
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, 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, 3b, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
LONG_L " %%r1, %[v]\n\t"
LONG_CMP_R " %%r1, %[expectnot]\n\t"
"je %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
LONG_L " %%r1, %[v]\n\t"
LONG_CMP_R " %%r1, %[expectnot]\n\t"
"je %l[error2]\n\t"
#endif
LONG_S " %%r1, %[load]\n\t"
LONG_ADD_R " %%r1, %[voffp]\n\t"
LONG_L " %%r1, 0(%%r1)\n\t"
/* final store */
LONG_S " %%r1, %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(5)
RSEQ_ASM_DEFINE_ABORT(4, "", abort)
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (rseq_get_abi()->cpu_id),
[rseq_cs] "m" (rseq_get_abi()->rseq_cs.arch.ptr),
/* final store input */
[v] "m" (*v),
[expectnot] "r" (expectnot),
[voffp] "r" (voffp),
[load] "m" (*load)
RSEQ_INJECT_INPUT
: "memory", "cc", "r0", "r1"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_after_asm_goto();
return 0;
abort:
rseq_after_asm_goto();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_after_asm_goto();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_after_asm_goto();
rseq_bug("cpu_id comparison failed");
error2:
rseq_after_asm_goto();
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)
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, 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, 3b, 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
LONG_L " %%r0, %[v]\n\t"
LONG_ADD_R " %%r0, %[count]\n\t"
/* final store */
LONG_S " %%r0, %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(4)
RSEQ_ASM_DEFINE_ABORT(4, "", abort)
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (rseq_get_abi()->cpu_id),
[rseq_cs] "m" (rseq_get_abi()->rseq_cs.arch.ptr),
/* final store input */
[v] "m" (*v),
[count] "r" (count)
RSEQ_INJECT_INPUT
: "memory", "cc", "r0"
RSEQ_INJECT_CLOBBER
: abort
#ifdef RSEQ_COMPARE_TWICE
, error1
#endif
);
rseq_after_asm_goto();
return 0;
abort:
rseq_after_asm_goto();
RSEQ_INJECT_FAILED
return -1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_after_asm_goto();
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)
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, 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, 3b, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
LONG_CMP " %[expect], %[v]\n\t"
"jnz %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
LONG_CMP " %[expect], %[v]\n\t"
"jnz %l[error2]\n\t"
#endif
/* try store */
LONG_S " %[newv2], %[v2]\n\t"
RSEQ_INJECT_ASM(5)
/* final store */
LONG_S " %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
RSEQ_ASM_DEFINE_ABORT(4, "", abort)
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (rseq_get_abi()->cpu_id),
[rseq_cs] "m" (rseq_get_abi()->rseq_cs.arch.ptr),
/* try store input */
[v2] "m" (*v2),
[newv2] "r" (newv2),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "memory", "cc", "r0"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_after_asm_goto();
return 0;
abort:
rseq_after_asm_goto();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_after_asm_goto();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_after_asm_goto();
rseq_bug("cpu_id comparison failed");
error2:
rseq_after_asm_goto();
rseq_bug("expected value comparison failed");
#endif
}
/* s390 is TSO. */
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)
{
return rseq_cmpeqv_trystorev_storev(v, expect, v2, newv2, newv, cpu);
}
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)
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, 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, 3b, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
LONG_CMP " %[expect], %[v]\n\t"
"jnz %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(4)
LONG_CMP " %[expect2], %[v2]\n\t"
"jnz %l[cmpfail]\n\t"
RSEQ_INJECT_ASM(5)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
LONG_CMP " %[expect], %[v]\n\t"
"jnz %l[error2]\n\t"
LONG_CMP " %[expect2], %[v2]\n\t"
"jnz %l[error3]\n\t"
#endif
/* final store */
LONG_S " %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
RSEQ_ASM_DEFINE_ABORT(4, "", abort)
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (rseq_get_abi()->cpu_id),
[rseq_cs] "m" (rseq_get_abi()->rseq_cs.arch.ptr),
/* cmp2 input */
[v2] "m" (*v2),
[expect2] "r" (expect2),
/* final store input */
[v] "m" (*v),
[expect] "r" (expect),
[newv] "r" (newv)
RSEQ_INJECT_INPUT
: "memory", "cc", "r0"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2, error3
#endif
);
rseq_after_asm_goto();
return 0;
abort:
rseq_after_asm_goto();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_after_asm_goto();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_after_asm_goto();
rseq_bug("cpu_id comparison failed");
error2:
rseq_after_asm_goto();
rseq_bug("1st expected value comparison failed");
error3:
rseq_after_asm_goto();
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)
{
uint64_t rseq_scratch[3];
RSEQ_INJECT_C(9)
__asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, 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
LONG_S " %[src], %[rseq_scratch0]\n\t"
LONG_S " %[dst], %[rseq_scratch1]\n\t"
LONG_S " %[len], %[rseq_scratch2]\n\t"
/* Start rseq by storing table entry pointer into rseq_cs. */
RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
RSEQ_INJECT_ASM(3)
LONG_CMP " %[expect], %[v]\n\t"
"jnz 5f\n\t"
RSEQ_INJECT_ASM(4)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
LONG_CMP " %[expect], %[v]\n\t"
"jnz 7f\n\t"
#endif
/* try memcpy */
LONG_LT_R " %[len], %[len]\n\t"
"jz 333f\n\t"
"222:\n\t"
"ic %%r0,0(%[src])\n\t"
"stc %%r0,0(%[dst])\n\t"
LONG_ADDI " %[src], 1\n\t"
LONG_ADDI " %[dst], 1\n\t"
LONG_ADDI " %[len], -1\n\t"
"jnz 222b\n\t"
"333:\n\t"
RSEQ_INJECT_ASM(5)
/* final store */
LONG_S " %[newv], %[v]\n\t"
"2:\n\t"
RSEQ_INJECT_ASM(6)
/* teardown */
LONG_L " %[len], %[rseq_scratch2]\n\t"
LONG_L " %[dst], %[rseq_scratch1]\n\t"
LONG_L " %[src], %[rseq_scratch0]\n\t"
RSEQ_ASM_DEFINE_ABORT(4,
LONG_L " %[len], %[rseq_scratch2]\n\t"
LONG_L " %[dst], %[rseq_scratch1]\n\t"
LONG_L " %[src], %[rseq_scratch0]\n\t",
abort)
RSEQ_ASM_DEFINE_CMPFAIL(5,
LONG_L " %[len], %[rseq_scratch2]\n\t"
LONG_L " %[dst], %[rseq_scratch1]\n\t"
LONG_L " %[src], %[rseq_scratch0]\n\t",
cmpfail)
#ifdef RSEQ_COMPARE_TWICE
RSEQ_ASM_DEFINE_CMPFAIL(6,
LONG_L " %[len], %[rseq_scratch2]\n\t"
LONG_L " %[dst], %[rseq_scratch1]\n\t"
LONG_L " %[src], %[rseq_scratch0]\n\t",
error1)
RSEQ_ASM_DEFINE_CMPFAIL(7,
LONG_L " %[len], %[rseq_scratch2]\n\t"
LONG_L " %[dst], %[rseq_scratch1]\n\t"
LONG_L " %[src], %[rseq_scratch0]\n\t",
error2)
#endif
: /* gcc asm goto does not allow outputs */
: [cpu_id] "r" (cpu),
[current_cpu_id] "m" (rseq_get_abi()->cpu_id),
[rseq_cs] "m" (rseq_get_abi()->rseq_cs.arch.ptr),
/* 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
: "memory", "cc", "r0"
RSEQ_INJECT_CLOBBER
: abort, cmpfail
#ifdef RSEQ_COMPARE_TWICE
, error1, error2
#endif
);
rseq_after_asm_goto();
return 0;
abort:
rseq_after_asm_goto();
RSEQ_INJECT_FAILED
return -1;
cmpfail:
rseq_after_asm_goto();
return 1;
#ifdef RSEQ_COMPARE_TWICE
error1:
rseq_after_asm_goto();
rseq_bug("cpu_id comparison failed");
error2:
rseq_after_asm_goto();
rseq_bug("expected value comparison failed");
#endif
}
/* s390 is TSO. */
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)
{
return rseq_cmpeqv_trymemcpy_storev(v, expect, dst, src, len,
newv, cpu);
}
#endif /* !RSEQ_SKIP_FASTPATH */
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