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| author | Fuad Tabba <fuad.tabba@linux.dev> | 2026-09-22 19:14:30 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-09-23 12:34:30 +0000 |
| commit | 2bc6b218717b9d08f466f88209251d54bc09b207 (patch) | |
| tree | cb91c941eccb15f94cbec4e96aa3a9c8736b5d66 /include/uapi/asm-generic/bitsperlong.h | |
| download | linux-stable-2bc6b218717b9d08f466f88209251d54bc09b207.tar.gz linux-stable-2bc6b218717b9d08f466f88209251d54bc09b207.zip | |
arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted
__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.
Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.
Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'include/uapi/asm-generic/bitsperlong.h')
| -rw-r--r-- | include/uapi/asm-generic/bitsperlong.h | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/bitsperlong.h b/include/uapi/asm-generic/bitsperlong.h new file mode 100644 index 000000000..fadb3f857 --- /dev/null +++ b/include/uapi/asm-generic/bitsperlong.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI__ASM_GENERIC_BITS_PER_LONG +#define _UAPI__ASM_GENERIC_BITS_PER_LONG + +#ifndef __BITS_PER_LONG +/* + * In order to keep safe and avoid regression, only unify uapi + * bitsperlong.h for some archs which are using newer toolchains + * that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__. + * See the following link for more info: + * https://lore.kernel.org/linux-arch/b9624545-2c80-49a1-ac3c-39264a591f7b@app.fastmail.com/ + */ +#if defined(__CHAR_BIT__) && defined(__SIZEOF_LONG__) +#define __BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__) +#else +/* + * There seems to be no way of detecting this automatically from user + * space, so 64 bit architectures should override this in their + * bitsperlong.h. In particular, an architecture that supports + * both 32 and 64 bit user space must not rely on CONFIG_64BIT + * to decide it, but rather check a compiler provided macro. + */ +#define __BITS_PER_LONG 32 +#endif +#endif + +#ifndef __BITS_PER_LONG_LONG +#define __BITS_PER_LONG_LONG 64 +#endif + +#endif /* _UAPI__ASM_GENERIC_BITS_PER_LONG */ |