From: Peter Oskolkov <posk@xxxxxxxxxx> commit ea366dd79c05fcd4cf5e225d2de8a3a7c293160c upstream. This patch adds rseq_offset_deref_addv() function to tools/testing/selftests/rseq/rseq-x86.h, to be used in a selftest in the next patch in the patchset. Once an architecture adds support for this function they should define "RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV". Signed-off-by: Peter Oskolkov <posk@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20200923233618.2572849-2-posk@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/rseq/rseq-x86.h | 57 ++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) --- a/tools/testing/selftests/rseq/rseq-x86.h +++ b/tools/testing/selftests/rseq/rseq-x86.h @@ -279,6 +279,63 @@ error1: #endif } +#define RSEQ_ARCH_HAS_OFFSET_DEREF_ADDV + +/* + * pval = *(ptr+off) + * *pval += inc; + */ +static inline __attribute__((always_inline)) +int rseq_offset_deref_addv(intptr_t *ptr, off_t off, intptr_t inc, 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_OFFSET(%[rseq_abi])) + RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f) + RSEQ_INJECT_ASM(3) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1]) +#endif + /* get p+v */ + "movq %[ptr], %%rbx\n\t" + "addq %[off], %%rbx\n\t" + /* get pv */ + "movq (%%rbx), %%rcx\n\t" + /* *pv += inc */ + "addq %[inc], (%%rcx)\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), + [rseq_abi] "r" (&__rseq_abi), + /* final store input */ + [ptr] "m" (*ptr), + [off] "er" (off), + [inc] "er" (inc) + : "memory", "cc", "rax", "rbx", "rcx" + RSEQ_INJECT_CLOBBER + : abort +#ifdef RSEQ_COMPARE_TWICE + , error1 +#endif + ); + return 0; +abort: + 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,
