Commit 998f5bbe authored Jun 17, 2020 by Vasily Gorbik Committed by Heiko Carstens Jun 23, 2020

s390/kasan: fix early pgm check handler execution



Currently if early_pgm_check_handler is called it ends up in pgm check
loop. The problem is that early_pgm_check_handler is instrumented by
KASAN but executed without DAT flag enabled which leads to addressing
exception when KASAN checks try to access shadow memory.

Fix that by executing early handlers with DAT flag on under KASAN as
expected.

Reported-and-tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

parent e64a1618

arch/s390/kernel/early.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -170,6 +170,8 @@ static noinline __init void setup_lowcore_early(void)
		psw_t psw;

		psw.mask = PSW_MASK_BASE \| PSW_DEFAULT_KEY \| PSW_MASK_EA \| PSW_MASK_BA;
		if (IS_ENABLED(CONFIG_KASAN))
		psw.mask \|= PSW_MASK_DAT;
		psw.addr = (unsigned long) s390_base_ext_handler;
		S390_lowcore.external_new_psw = psw;
		psw.addr = (unsigned long) s390_base_pgm_handler;

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