5.4-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit 0147addc4fb72a39448b8873d8acdf3a0f29aa65 ]
Disable compile time optimizations of test_facility() for the decompressor. The decompressor should not contain any optimized code depending on the architecture level set the kernel image is compiled for to avoid unexpected operation exceptions.
Add a __DECOMPRESSOR check to test_facility() to enforce that facilities are always checked during runtime for the decompressor.
Reviewed-by: Sven Schnelle svens@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/include/asm/facility.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/s390/include/asm/facility.h b/arch/s390/include/asm/facility.h index 68c476b20b57e..c7031d9ada293 100644 --- a/arch/s390/include/asm/facility.h +++ b/arch/s390/include/asm/facility.h @@ -53,8 +53,10 @@ static inline int test_facility(unsigned long nr) unsigned long facilities_als[] = { FACILITIES_ALS };
if (__builtin_constant_p(nr) && nr < sizeof(facilities_als) * 8) { - if (__test_facility(nr, &facilities_als)) - return 1; + if (__test_facility(nr, &facilities_als)) { + if (!__is_defined(__DECOMPRESSOR)) + return 1; + } } return __test_facility(nr, &S390_lowcore.stfle_fac_list); }