diff options
| author | Heiko Carstens <hca@linux.ibm.com> | 2023-12-08 15:03:15 +0100 |
|---|---|---|
| committer | Alexander Gordeev <agordeev@linux.ibm.com> | 2023-12-18 10:53:41 +0100 |
| commit | e6b2dab41888332bf83f592131e7ea07756770a4 (patch) | |
| tree | 8fb7fa4708c5839b06eb46b10f69fa35f43c8c38 /arch/s390 | |
| parent | b1a6a1a77f0666a5a6dc0893ab6ec8fcae46f24c (diff) | |
| download | lwn-e6b2dab41888332bf83f592131e7ea07756770a4.tar.gz lwn-e6b2dab41888332bf83f592131e7ea07756770a4.zip | |
s390/vx: fix save/restore of fpu kernel context
The KERNEL_FPR mask only contains a flag for the first eight vector
registers. However floating point registers overlay parts of the first
sixteen vector registers.
This could lead to vector register corruption if a kernel fpu context uses
any of the vector registers 8 to 15 and is interrupted or calls a
KERNEL_FPR context. If that context uses also vector registers 8 to 15,
their contents will be corrupted on return.
Luckily this is currently not a real bug, since the kernel has only one
KERNEL_FPR user with s390_adjust_jiffies() and it is only using floating
point registers 0 to 2.
Fix this by using the correct bits for KERNEL_FPR.
Fixes: 7f79695cc1b6 ("s390/fpu: improve kernel_fpu_[begin|end]")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/fpu/api.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/include/asm/fpu/api.h b/arch/s390/include/asm/fpu/api.h index b714ed0ef688..9acf48e53a87 100644 --- a/arch/s390/include/asm/fpu/api.h +++ b/arch/s390/include/asm/fpu/api.h @@ -79,7 +79,7 @@ static inline int test_fp_ctl(u32 fpc) #define KERNEL_VXR_HIGH (KERNEL_VXR_V16V23|KERNEL_VXR_V24V31) #define KERNEL_VXR (KERNEL_VXR_LOW|KERNEL_VXR_HIGH) -#define KERNEL_FPR (KERNEL_FPC|KERNEL_VXR_V0V7) +#define KERNEL_FPR (KERNEL_FPC|KERNEL_VXR_LOW) struct kernel_fpu; |