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| author | D Scott Phillips <scott@os.amperecomputing.com> | 2022-11-02 09:01:06 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-26 09:24:36 +0100 |
| commit | 530e987a02263a1651cc72f09f504ff1890ba8c3 (patch) | |
| tree | 422872fb9effd8e86619f8ef43d966cc5b3b2bba /drivers | |
| parent | d4944497827a3d14bc5a26dbcfb7433eb5a956c0 (diff) | |
| download | linux-stable-530e987a02263a1651cc72f09f504ff1890ba8c3.tar.gz linux-stable-530e987a02263a1651cc72f09f504ff1890ba8c3.tar.bz2 linux-stable-530e987a02263a1651cc72f09f504ff1890ba8c3.zip | |
arm64: Fix bit-shifting UB in the MIDR_CPU_MODEL() macro
[ Upstream commit 8ec8490a1950efeccb00967698cf7cb2fcd25ca7 ]
CONFIG_UBSAN_SHIFT with gcc-5 complains that the shifting of
ARM_CPU_IMP_AMPERE (0xC0) into bits [31:24] by MIDR_CPU_MODEL() is
undefined behavior. Well, sort of, it actually spells the error as:
arch/arm64/kernel/proton-pack.c: In function 'spectre_bhb_loop_affected':
arch/arm64/include/asm/cputype.h:44:2: error: initializer element is not constant
(((imp) << MIDR_IMPLEMENTOR_SHIFT) | \
^
This isn't an issue for other Implementor codes, as all the other codes
have zero in the top bit and so are representable as a signed int.
Cast the implementor code to unsigned in MIDR_CPU_MODEL to remove the
undefined behavior.
Fixes: 0e5d5ae837c8 ("arm64: Add AMPERE1 to the Spectre-BHB affected list")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20221102160106.1096948-1-scott@os.amperecomputing.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
0 files changed, 0 insertions, 0 deletions