| From foo@baz Mon Apr 9 17:09:24 CEST 2018 |
| From: Michael Ellerman <mpe@ellerman.id.au> |
| Date: Fri, 19 May 2017 11:29:04 +1000 |
| Subject: selftests/powerpc: Fix TM resched DSCR test with some compilers |
| |
| From: Michael Ellerman <mpe@ellerman.id.au> |
| |
| |
| [ Upstream commit fe06fe860250a4f01d0eaf70a2563b1997174a74 ] |
| |
| 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 <mpe@ellerman.id.au> |
| Acked-by: Michael Neuling <mikey@neuling.org> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| tools/testing/selftests/powerpc/tm/tm-resched-dscr.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- 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;" |
