From e546cd48ccc456074ddb8920732aef4af65d7ca7 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 24 Jan 2022 12:12:43 -0500 Subject: selftests/rseq: Introduce rseq_get_abi() helper This is done in preparation for the selftest uplift to become compatible with glibc-2.35. glibc-2.35 exposes the rseq per-thread data in the TCB, accessible at an offset from the thread pointer, rather than through an actual Thread-Local Storage (TLS) variable, as the kernel selftests initially expected. Introduce a rseq_get_abi() helper, initially using the __rseq_abi TLS variable, in preparation for changing this userspace ABI for one which is compatible with glibc-2.35. Note that the __rseq_abi TLS and glibc-2.35's ABI for per-thread data cannot actively coexist in a process, because the kernel supports only a single rseq registration per thread. Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220124171253.22072-6-mathieu.desnoyers@efficios.com --- tools/testing/selftests/rseq/rseq.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'tools/testing/selftests/rseq/rseq.h') diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h index d580f8e9c001..ca668a2af172 100644 --- a/tools/testing/selftests/rseq/rseq.h +++ b/tools/testing/selftests/rseq/rseq.h @@ -46,6 +46,11 @@ extern __thread struct rseq_abi __rseq_abi; extern int __rseq_handled; +static inline struct rseq_abi *rseq_get_abi(void) +{ + return &__rseq_abi; +} + #define rseq_likely(x) __builtin_expect(!!(x), 1) #define rseq_unlikely(x) __builtin_expect(!!(x), 0) #define rseq_barrier() __asm__ __volatile__("" : : : "memory") @@ -108,7 +113,7 @@ int32_t rseq_fallback_current_cpu(void); */ static inline int32_t rseq_current_cpu_raw(void) { - return RSEQ_ACCESS_ONCE(__rseq_abi.cpu_id); + return RSEQ_ACCESS_ONCE(rseq_get_abi()->cpu_id); } /* @@ -124,7 +129,7 @@ static inline int32_t rseq_current_cpu_raw(void) */ static inline uint32_t rseq_cpu_start(void) { - return RSEQ_ACCESS_ONCE(__rseq_abi.cpu_id_start); + return RSEQ_ACCESS_ONCE(rseq_get_abi()->cpu_id_start); } static inline uint32_t rseq_current_cpu(void) @@ -139,7 +144,7 @@ static inline uint32_t rseq_current_cpu(void) static inline void rseq_clear_rseq_cs(void) { - RSEQ_WRITE_ONCE(__rseq_abi.rseq_cs.arch.ptr, 0); + RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0); } /* -- cgit v1.2.3