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| author | Will Deacon <will.deacon@arm.com> | 2013-02-04 12:12:33 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2013-02-11 18:16:41 +0000 |
| commit | 3a0310eb369aae985d6409d8ff1340146578e5c1 (patch) | |
| tree | 8b1796a500d2dd694c924a57ee4502f31b15ef8b /arch/arm64/include/asm/futex.h | |
| parent | c0e01d5d8f15c085236df184e5bc3d79a8b700cd (diff) | |
| download | linux-3a0310eb369aae985d6409d8ff1340146578e5c1.tar.gz linux-3a0310eb369aae985d6409d8ff1340146578e5c1.tar.bz2 linux-3a0310eb369aae985d6409d8ff1340146578e5c1.zip | |
arm64: atomics: fix grossly inconsistent asm constraints for exclusives
Our uses of inline asm constraints for atomic operations are fairly
wild and varied. We basically need to guarantee the following:
1. Any instructions with barrier implications
(load-acquire/store-release) have a "memory" clobber
2. When performing exclusive accesses, the addresing mode is generated
using the "Q" constraint
3. Atomic blocks which use the condition flags, have a "cc" clobber
This patch addresses these concerns which, as well as fixing the
semantics of the code, stops GCC complaining about impossible asm
constraints.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/futex.h')
| -rw-r--r-- | arch/arm64/include/asm/futex.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index 3468ae8439fa..c582fa316366 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -39,7 +39,7 @@ " .popsection\n" \ : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp) \ : "r" (oparg), "Ir" (-EFAULT) \ - : "cc") + : "cc", "memory") static inline int futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) |