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arm64: cpufeature: make cpus_have_cap() noinstr-safe

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Currently it isn't safe to use cpus_have_cap() from noinstr code as
test_bit() is explicitly instrumented, and were cpus_have_cap() placed
out-of-line, cpus_have_cap() itself could be instrumented.

Make cpus_have_cap() noinstr safe by marking it __always_inline and
using arch_test_bit().

Aside from the prevention of instrumentation, there should be no
functional change as a result of this patch.

Signed-off-by: Mark Rutland <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: James Morse <[email protected]>
Cc: Joey Gouly <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Will Deacon <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>
This commit is contained in:
Mark Rutland authored and Catalin Marinas committed 2022-09-16 17:15:02 +01:00
1 parent b90cb10531
commit 92b4b5619f
1 file changed
+2 -2
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arch/arm64/include/asm/cpufeature.h
+2 -2
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@@ -448,11 +448,11 @@ static __always_inline bool system_capabilities_finalized(void)
*
* Before the capability is detected, this returns false.
*/
static inline bool cpus_have_cap(unsigned int num)
static __always_inline bool cpus_have_cap(unsigned int num)
{
if (num >= ARM64_NCAPS)
return false;
return test_bit(num, cpu_hwcaps);
return arch_test_bit(num, cpu_hwcaps);
}
/*