23 Nov
2017
23 Nov
'17
8:57 a.m.
On Thu, Nov 23, 2017 at 09:55:11AM +0100, Peter Zijlstra wrote:
On Tue, Nov 21, 2017 at 09:18:53AM -0500, Mathieu Desnoyers wrote:
+static inline __attribute__((always_inline)) +int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv,
int cpu)+{
- __asm__ __volatile__ goto (
RSEQ_ASM_DEFINE_TABLE(3, __rseq_table, 0x0, 0x0, 1f, 2f-1f, 4f)RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
"cmpq %[v], %[expect]\n\t""jnz 5f\n\t"
Also, I'm confused between the abort and cmpfail cases.
In would expect the cpu_id compare to also result in cmpfail, that is, I would only expect the kernel to result in abort.
/* final store */"movq %[newv], %[v]\n\t""2:\n\t"RSEQ_ASM_DEFINE_ABORT(4, __rseq_failure, RSEQ_SIG, "", abort)RSEQ_ASM_DEFINE_CMPFAIL(5, __rseq_failure, "", cmpfail): /* 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): "memory", "cc", "rax": abort, cmpfail- );
- return 0;
+abort:
- return -1;
Which then would suggest this be -EINTR or something like that.
+cmpfail:
- return 1;
+}
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