From: Vasily Gorbik Date: Mon, 25 Nov 2019 12:34:59 +0000 (+0100) Subject: s390: fix register clobbering in CALL_ON_STACK X-Git-Tag: v5.5-rc1~59^2~9 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=4ac24c092b4eef69b2436ee4d478500dc886e8b5;p=linux-block.git s390: fix register clobbering in CALL_ON_STACK CALL_ON_STACK defines and initializes register variables. Inline assembly which follows might trigger compiler to generate memory access for "stack" argument (e.g. in case of S390_lowcore.nodat_stack). This memory access produces a function call under kasan with outline instrumentation which clobbers registers. Switch "stack" argument in CALL_ON_STACK helper to use memory reference constraint and perform load instead. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h index 4725315a9cb1..ee056f4a4fa3 100644 --- a/arch/s390/include/asm/stacktrace.h +++ b/arch/s390/include/asm/stacktrace.h @@ -112,12 +112,12 @@ struct stack_frame { \ asm volatile( \ " la %[_prev],0(15)\n" \ - " la 15,0(%[_stack])\n" \ + " lg 15,%[_stack]\n" \ " stg %[_frame],%[_bc](15)\n" \ " brasl 14,%[_fn]\n" \ " la 15,0(%[_prev])\n" \ : [_prev] "=&a" (prev), CALL_FMT_##nr \ - [_stack] "a" (stack), \ + [_stack] "R" (stack), \ [_bc] "i" (offsetof(struct stack_frame, back_chain)), \ [_frame] "d" (frame), \ [_fn] "X" (fn) : CALL_CLOBBER_##nr); \