From fe06fe860250a4f01d0eaf70a2563b1997174a74 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 19 May 2017 11:29:04 +1000 Subject: [PATCH] selftests/powerpc: Fix TM resched DSCR test with some compilers The tm-resched-dscr test has started failing sometimes, depending on what compiler it's built with, eg: test: tm_resched_dscr Check DSCR TM context switch: tm-resched-dscr: tm-resched-dscr.c:76: test_body: Assertion `rv' failed. !! child died by signal 6 When it fails we see that the compiler doesn't initialise rv to 1 before entering the inline asm block. Although that's counter intuitive, it is allowed because we tell the compiler that the inline asm will write to rv (using "=r"), meaning the original value is irrelevant. Marking it as a read/write parameter would presumably work, but it seems simpler to fix it by setting the initial value of rv in the inline asm. Fixes: 96d016108640 ("powerpc: Correct DSCR during TM context switch") Signed-off-by: Michael Ellerman Acked-by: Michael Neuling --- tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c index d9c49f4..e79ccd6 100644 --- a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c +++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c @@ -42,12 +42,12 @@ int test_body(void) printf("Check DSCR TM context switch: "); fflush(stdout); for (;;) { - rv = 1; asm __volatile__ ( /* set a known value into the DSCR */ "ld 3, %[dscr1];" "mtspr %[sprn_dscr], 3;" + "li %[rv], 1;" /* start and suspend a transaction */ "tbegin.;" "beq 1f;" -- 2.7.4