arm64: make is_ttbrX_addr() noinstr-safe
authorMark Rutland <mark.rutland@arm.com>
Mon, 14 Nov 2022 14:40:42 +0000 (14:40 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 31 Dec 2022 12:14:39 +0000 (13:14 +0100)
commit9d05c20b0ac97a688f6f6747da45b4d1e287b806
tree390805cc6bc31d8c1e80e9b13d6d0c2223a0810c
parent98a5b1265a36e9d843a51ddd6c9fa02da50d2c57
arm64: make is_ttbrX_addr() noinstr-safe

[ Upstream commit d8c1d798a2e5091128c391c6dadcc9be334af3f5 ]

We use is_ttbr0_addr() in noinstr code, but as it's only marked as
inline, it's theoretically possible for the compiler to place it
out-of-line and instrument it, which would be problematic.

Mark is_ttbr0_addr() as __always_inline such that that can safely be
used from noinstr code. For consistency, do the same to is_ttbr1_addr().
Note that while is_ttbr1_addr() calls arch_kasan_reset_tag(), this is a
macro (and its callees are either macros or __always_inline), so there
is not a risk of transient instrumentation.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20221114144042.3001140-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch/arm64/include/asm/processor.h