From: Alexander Gordeev Date: Mon, 29 Mar 2021 16:35:07 +0000 (+0200) Subject: s390/cpcmd: fix inline assembly register clobbering X-Git-Tag: v4.4.267~20 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=68603455e61b4be988a3947c2e7b8b8cc193c891;p=thirdparty%2Fkernel%2Fstable.git s390/cpcmd: fix inline assembly register clobbering [ Upstream commit 7a2f91441b2c1d81b77c1cd816a4659f4abc9cbe ] Register variables initialized using arithmetic. That leads to kasan instrumentaton code corrupting the registers contents. Follow GCC guidlines and use temporary variables for assigning init values to register variables. Fixes: 94c12cc7d196 ("[S390] Inline assembly cleanup.") Signed-off-by: Alexander Gordeev Acked-by: Ilya Leoshkevich Link: https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Local-Register-Variables.html Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c index 7f768914fb4f9..c15546c6fb66d 100644 --- a/arch/s390/kernel/cpcmd.c +++ b/arch/s390/kernel/cpcmd.c @@ -37,10 +37,12 @@ static int diag8_noresponse(int cmdlen) static int diag8_response(int cmdlen, char *response, int *rlen) { + unsigned long _cmdlen = cmdlen | 0x40000000L; + unsigned long _rlen = *rlen; register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; register unsigned long reg3 asm ("3") = (addr_t) response; - register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L; - register unsigned long reg5 asm ("5") = *rlen; + register unsigned long reg4 asm ("4") = _cmdlen; + register unsigned long reg5 asm ("5") = _rlen; asm volatile( " sam31\n"