s390/facility: Disable compile time optimization for decompressor code

[ 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>
This commit is contained in:
Heiko Carstens 2024-09-04 11:39:24 +02:00 committed by Greg Kroah-Hartman
parent 029aa36ba3
commit 1cd197813e

View File

@ -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);
}