2023-05-03 20:16:22

by Mathieu Desnoyers

[permalink] [raw]
Subject: [RFC PATCH 2/3] selftests/rseq: Fix arm64 buggy load-acquire/store-release macros

The arm64 load-acquire/store-release macros from the Linux kernel rseq
selftests are buggy. Remplace them by a working implementation.

Signed-off-by: Mathieu Desnoyers <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Peter Zijlstra <[email protected]>
---
tools/testing/selftests/rseq/rseq-arm64.h | 58 ++++++++++++-----------
1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/tools/testing/selftests/rseq/rseq-arm64.h b/tools/testing/selftests/rseq/rseq-arm64.h
index 85b90977e7e6..21e1626a7235 100644
--- a/tools/testing/selftests/rseq/rseq-arm64.h
+++ b/tools/testing/selftests/rseq/rseq-arm64.h
@@ -27,59 +27,61 @@

#define rseq_smp_load_acquire(p) \
__extension__ ({ \
- __typeof(*p) ____p1; \
- switch (sizeof(*p)) { \
+ union { rseq_unqual_scalar_typeof(*(p)) __val; char __c[sizeof(*(p))]; } __u; \
+ switch (sizeof(*(p))) { \
case 1: \
- asm volatile ("ldarb %w0, %1" \
- : "=r" (*(__u8 *)p) \
- : "Q" (*p) : "memory"); \
+ __asm__ __volatile__ ("ldarb %w0, %1" \
+ : "=r" (*(__u8 *)__u.__c) \
+ : "Q" (*(p)) : "memory"); \
break; \
case 2: \
- asm volatile ("ldarh %w0, %1" \
- : "=r" (*(__u16 *)p) \
- : "Q" (*p) : "memory"); \
+ __asm__ __volatile__ ("ldarh %w0, %1" \
+ : "=r" (*(__u16 *)__u.__c) \
+ : "Q" (*(p)) : "memory"); \
break; \
case 4: \
- asm volatile ("ldar %w0, %1" \
- : "=r" (*(__u32 *)p) \
- : "Q" (*p) : "memory"); \
+ __asm__ __volatile__ ("ldar %w0, %1" \
+ : "=r" (*(__u32 *)__u.__c) \
+ : "Q" (*(p)) : "memory"); \
break; \
case 8: \
- asm volatile ("ldar %0, %1" \
- : "=r" (*(__u64 *)p) \
- : "Q" (*p) : "memory"); \
+ __asm__ __volatile__ ("ldar %0, %1" \
+ : "=r" (*(__u64 *)__u.__c) \
+ : "Q" (*(p)) : "memory"); \
break; \
} \
- ____p1; \
+ (rseq_unqual_scalar_typeof(*(p)))__u.__val; \
})

#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()

#define rseq_smp_store_release(p, v) \
do { \
- switch (sizeof(*p)) { \
+ union { rseq_unqual_scalar_typeof(*(p)) __val; char __c[sizeof(*(p))]; } __u = \
+ { .__val = (rseq_unqual_scalar_typeof(*(p))) (v) }; \
+ switch (sizeof(*(p))) { \
case 1: \
- asm volatile ("stlrb %w1, %0" \
- : "=Q" (*p) \
- : "r" ((__u8)v) \
+ __asm__ __volatile__ ("stlrb %w1, %0" \
+ : "=Q" (*(p)) \
+ : "r" (*(__u8 *)__u.__c) \
: "memory"); \
break; \
case 2: \
- asm volatile ("stlrh %w1, %0" \
- : "=Q" (*p) \
- : "r" ((__u16)v) \
+ __asm__ __volatile__ ("stlrh %w1, %0" \
+ : "=Q" (*(p)) \
+ : "r" (*(__u16 *)__u.__c) \
: "memory"); \
break; \
case 4: \
- asm volatile ("stlr %w1, %0" \
- : "=Q" (*p) \
- : "r" ((__u32)v) \
+ __asm__ __volatile__ ("stlr %w1, %0" \
+ : "=Q" (*(p)) \
+ : "r" (*(__u32 *)__u.__c) \
: "memory"); \
break; \
case 8: \
- asm volatile ("stlr %1, %0" \
- : "=Q" (*p) \
- : "r" ((__u64)v) \
+ __asm__ __volatile__ ("stlr %1, %0" \
+ : "=Q" (*(p)) \
+ : "r" (*(__u64 *)__u.__c) \
: "memory"); \
break; \
} \
--
2.25.1