From: "wuqiang.matt" <wuqiang.matt@bytedance.com>
To: vgupta@kernel.org, bcain@quicinc.com, jonas@southpole.se,
stefan.kristiansson@saunalahti.fi, shorne@gmail.com,
geert@linux-m68k.org, andi.shyti@linux.intel.com,
mingo@kernel.org, palmer@rivosinc.com, andrzej.hajda@intel.com,
arnd@arndb.de, peterz@infradead.orgm, mhiramat@kernel.org
Cc: linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, mattwu@163.com,
linux@roeck-us.ne, "wuqiang.matt" <wuqiang.matt@bytedance.com>
Subject: [PATCH v2 1/4] locking/atomic: arc: data size checking in arch_cmpxchg
Date: Sat, 4 Nov 2023 17:16:12 +0800 [thread overview]
Message-ID: <20231104091615.4884-2-wuqiang.matt@bytedance.com> (raw)
In-Reply-To: <20231104091615.4884-1-wuqiang.matt@bytedance.com>
Macro __cmpxchg() renamed to __cmpxchg_32() to emphasize it's explicit
support of 32bit data size, BUILD_BUG_ON() added to avoid any possible
misuses with unsupported data types.
In case CONFIG_ARC_HAS_LLSC is undefined, arch_cmpxchg() uses spinlock
to accomplish SMP-safety, so the BUILD_BUG_ON checking is uncecessary.
Signed-off-by: wuqiang.matt <wuqiang.matt@bytedance.com>
---
arch/arc/include/asm/cmpxchg.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index e138fde067de..bf46514f6f12 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -18,14 +18,16 @@
* if (*ptr == @old)
* *ptr = @new
*/
-#define __cmpxchg(ptr, old, new) \
+#define __cmpxchg_32(ptr, old, new) \
({ \
__typeof__(*(ptr)) _prev; \
\
+ BUILD_BUG_ON(sizeof(*(ptr)) != 4); \
+ \
__asm__ __volatile__( \
- "1: llock %0, [%1] \n" \
+ "1: llock %0, [%1] \n" \
" brne %0, %2, 2f \n" \
- " scond %3, [%1] \n" \
+ " scond %3, [%1] \n" \
" bnz 1b \n" \
"2: \n" \
: "=&r"(_prev) /* Early clobber prevent reg reuse */ \
@@ -47,7 +49,7 @@
\
switch(sizeof((_p_))) { \
case 4: \
- _prev_ = __cmpxchg(_p_, _o_, _n_); \
+ _prev_ = __cmpxchg_32(_p_, _o_, _n_); \
break; \
default: \
BUILD_BUG(); \
@@ -65,8 +67,6 @@
__typeof__(*(ptr)) _prev_; \
unsigned long __flags; \
\
- BUILD_BUG_ON(sizeof(_p_) != 4); \
- \
/* \
* spin lock/unlock provide the needed smp_mb() before/after \
*/ \
--
2.40.1
next prev parent reply other threads:[~2023-11-04 9:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-04 9:16 [PATCH v2 0/4] locking/atomic: arch_cmpxchg[64]_local undefined wuqiang.matt
2023-11-04 9:16 ` wuqiang.matt [this message]
2023-11-08 1:02 ` [PATCH v2 1/4] locking/atomic: arc: data size checking in arch_cmpxchg Masami Hiramatsu
2023-11-04 9:16 ` [PATCH v2 2/4] locking/atomic: arc: arch_cmpxchg[64]_local undefined wuqiang.matt
2023-11-08 1:02 ` Masami Hiramatsu
2023-11-04 9:16 ` [PATCH v2 3/4] locking/atomic: openrisc: " wuqiang.matt
2023-11-08 1:03 ` Masami Hiramatsu
2023-11-04 9:16 ` [PATCH v2 4/4] locking/atomic: hexagon: " wuqiang.matt
2023-11-08 1:04 ` Masami Hiramatsu
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