2022-01-24 19:39:24

by Mathieu Desnoyers

Subject: [RFC PATCH 04/15] selftests/rseq: Remove volatile from __rseq_abi

This is done in preparation for the selftest uplift to become compatible
with glibc-2.35.

All accesses to the __rseq_abi fields are volatile, but remove the
volatile from the TLS variable declaration, otherwise we are stuck with
volatile for the upcoming rseq_get_abi() helper.

Signed-off-by: Mathieu Desnoyers <[email protected]>
---
tools/testing/selftests/rseq/rseq.c | 4 ++--
tools/testing/selftests/rseq/rseq.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
index bfe1b2692ffc..1f905b60728a 100644
--- a/tools/testing/selftests/rseq/rseq.c
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -30,7 +30,7 @@
#include "../kselftest.h"
#include "rseq.h"

-__thread volatile struct rseq_abi __rseq_abi = {
+__thread struct rseq_abi __rseq_abi = {
.cpu_id = RSEQ_ABI_CPU_ID_UNINITIALIZED,
};

@@ -92,7 +92,7 @@ int rseq_register_current_thread(void)
goto end;
}
if (errno != EBUSY)
- __rseq_abi.cpu_id = RSEQ_ABI_CPU_ID_REGISTRATION_FAILED;
+ RSEQ_WRITE_ONCE(__rseq_abi.cpu_id, RSEQ_ABI_CPU_ID_REGISTRATION_FAILED);
ret = -1;
__rseq_refcount--;
end:
diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
index cb6bbc53b586..d580f8e9c001 100644
--- a/tools/testing/selftests/rseq/rseq.h
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -43,7 +43,7 @@
#define RSEQ_INJECT_FAILED
#endif

-extern __thread volatile struct rseq_abi __rseq_abi;
+extern __thread struct rseq_abi __rseq_abi;
extern int __rseq_handled;

#define rseq_likely(x) __builtin_expect(!!(x), 1)
@@ -139,7 +139,7 @@ static inline uint32_t rseq_current_cpu(void)

static inline void rseq_clear_rseq_cs(void)
{
- __rseq_abi.rseq_cs.arch.ptr = 0;
+ RSEQ_WRITE_ONCE(__rseq_abi.rseq_cs.arch.ptr, 0);
}

/*
--
2.17.1

2022-02-03 19:18:05

by tip-bot2 for Alexey Makhalov

Subject: [tip: sched/core] selftests/rseq: Remove volatile from __rseq_abi

The following commit has been merged into the sched/core branch of tip:

Commit-ID: 94b80a19ebfe347a01301d750040a61c38200e2b
Gitweb: https://git.kernel.org/tip/94b80a19ebfe347a01301d750040a61c38200e2b
Author: Mathieu Desnoyers <[email protected]>
AuthorDate: Mon, 24 Jan 2022 12:12:42 -05:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Wed, 02 Feb 2022 13:11:34 +01:00

selftests/rseq: Remove volatile from __rseq_abi

This is done in preparation for the selftest uplift to become compatible
with glibc-2.35.

All accesses to the __rseq_abi fields are volatile, but remove the
volatile from the TLS variable declaration, otherwise we are stuck with
volatile for the upcoming rseq_get_abi() helper.

Signed-off-by: Mathieu Desnoyers <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
tools/testing/selftests/rseq/rseq.c | 4 ++--
tools/testing/selftests/rseq/rseq.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
index bfe1b26..1f905b6 100644
--- a/tools/testing/selftests/rseq/rseq.c
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -30,7 +30,7 @@
#include "../kselftest.h"
#include "rseq.h"

-__thread volatile struct rseq_abi __rseq_abi = {
+__thread struct rseq_abi __rseq_abi = {
.cpu_id = RSEQ_ABI_CPU_ID_UNINITIALIZED,
};

@@ -92,7 +92,7 @@ int rseq_register_current_thread(void)
goto end;
}
if (errno != EBUSY)
- __rseq_abi.cpu_id = RSEQ_ABI_CPU_ID_REGISTRATION_FAILED;
+ RSEQ_WRITE_ONCE(__rseq_abi.cpu_id, RSEQ_ABI_CPU_ID_REGISTRATION_FAILED);
ret = -1;
__rseq_refcount--;
end:
diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
index cb6bbc5..d580f8e 100644
--- a/tools/testing/selftests/rseq/rseq.h
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -43,7 +43,7 @@
#define RSEQ_INJECT_FAILED
#endif

-extern __thread volatile struct rseq_abi __rseq_abi;
+extern __thread struct rseq_abi __rseq_abi;
extern int __rseq_handled;

#define rseq_likely(x) __builtin_expect(!!(x), 1)
@@ -139,7 +139,7 @@ static inline uint32_t rseq_current_cpu(void)

static inline void rseq_clear_rseq_cs(void)
{
- __rseq_abi.rseq_cs.arch.ptr = 0;
+ RSEQ_WRITE_ONCE(__rseq_abi.rseq_cs.arch.ptr, 0);
}

/*