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locking/atomic: x86: add preprocessor symbols

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Some atomics can be implemented in several different ways, e.g.
FULL/ACQUIRE/RELEASE ordered atomics can be implemented in terms of
RELAXED atomics, and ACQUIRE/RELEASE/RELAXED can be implemented in terms
of FULL ordered atomics. Other atomics are optional, and don't exist in
some configurations (e.g. not all architectures implement the 128-bit
cmpxchg ops).

Subsequent patches will require that architectures define a preprocessor
symbol for any atomic (or ordering variant) which is optional. This will
make the fallback ifdeffery more robust, and simplify future changes.

Add the required definitions to arch/x86.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230605070124.3741859-13-mark.rutland@arm.com
This commit is contained in:
Mark Rutland
2023-06-05 08:01:09 +01:00
committed by Peter Zijlstra
parent 358c449afa
commit 5bef003538
1 changed files with 4 additions and 0 deletions
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4
arch/x86/include/asm/cmpxchg_64.h
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@@ -45,11 +45,13 @@ static __always_inline u128 arch_cmpxchg128(volatile u128 *ptr, u128 old, u128 n
{
return __arch_cmpxchg128(ptr, old, new, LOCK_PREFIX);
}
#define arch_cmpxchg128 arch_cmpxchg128
static __always_inline u128 arch_cmpxchg128_local(volatile u128 *ptr, u128 old, u128 new)
{
return __arch_cmpxchg128(ptr, old, new,);
}
#define arch_cmpxchg128_local arch_cmpxchg128_local
#define __arch_try_cmpxchg128(_ptr, _oldp, _new, _lock) \
({ \
@@ -75,11 +77,13 @@ static __always_inline bool arch_try_cmpxchg128(volatile u128 *ptr, u128 *oldp,
{
return __arch_try_cmpxchg128(ptr, oldp, new, LOCK_PREFIX);
}
#define arch_try_cmpxchg128 arch_try_cmpxchg128
static __always_inline bool arch_try_cmpxchg128_local(volatile u128 *ptr, u128 *oldp, u128 new)
{
return __arch_try_cmpxchg128(ptr, oldp, new,);
}
#define arch_try_cmpxchg128_local arch_try_cmpxchg128_local
#define system_has_cmpxchg128() boot_cpu_has(X86_FEATURE_CX16)