5.4-stable review patch. If anyone has any objections, please let me know.
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From: Sven Schnelle svens@linux.ibm.com
[ Upstream commit 7278a8fb8d032dfdc03d9b5d17e0bc451cdc1492 ]
Without __unitialized, the following code is generated when INIT_STACK_ALL_ZERO is enabled:
86: d7 0f f0 a0 f0 a0 xc 160(16,%r15), 160(%r15) 8c: e3 40 f0 a0 00 24 stg %r4, 160(%r15) 92: c0 10 00 00 00 08 larl %r1, 0xa2 98: e3 10 f0 a8 00 24 stg %r1, 168(%r15) 9e: b2 b2 f0 a0 lpswe 160(%r15)
The xc is not adding any security because psw is fully initialized with the following instructions. Add __unitialized to the psw definitiation to avoid the superfluous clearing of psw.
Reviewed-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sven Schnelle svens@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/include/asm/processor.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h index 48d6ccdef5f77..00bb2d287f740 100644 --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -256,8 +256,8 @@ static inline void __load_psw(psw_t psw) */ static __always_inline void __load_psw_mask(unsigned long mask) { + psw_t psw __uninitialized; unsigned long addr; - psw_t psw;
psw.mask = mask;