From: Jordan Niethe Date: Thu, 29 Jul 2021 04:13:16 +0000 (+1000) Subject: selftests/powerpc: Add missing clobbered register to to ptrace TM tests X-Git-Tag: v5.15-rc1~100^2~36 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c95278a0534449efc64ac8169382bce217963be2;p=thirdparty%2Fkernel%2Flinux.git selftests/powerpc: Add missing clobbered register to to ptrace TM tests ISA v3.1 removes TM but includes a synthetic implementation for backwards compatibility. With this implementation, the tests ptrace-tm-spd-gpr and ptrace-tm-gpr should never be able to make any forward progress and eventually should be killed by the timeout. Instead on a P10 running in P9 mode, ptrace_tm_gpr fails like so: test: ptrace_tm_gpr tags: git_version:unknown Starting the child ... ... GPR[27]: 1 Expected: 2 GPR[28]: 1 Expected: 2 GPR[29]: 1 Expected: 2 GPR[30]: 1 Expected: 2 GPR[31]: 1 Expected: 2 [FAIL] Test FAILED on line 98 failure: ptrace_tm_gpr selftests: ptrace-tm-gpr [FAIL] The problem is in the inline assembly of the child. r0 is loaded with a value in the child's transaction abort handler but this register is not included in the clobbers list. This means it is possible that this statement: cptr[1] = 0; which is meant to signal the parent to wait may actually use the value placed into r0 by the inline assembly incorrectly signal the parent to continue. By inspection the same problem is present in ptrace-tm-spd-gpr. Adding r0 to the clobbbers list makes the test fail correctly via a timeout on a P10 running in P8/P9 compatibility mode. Suggested-by: Michael Neuling Signed-off-by: Jordan Niethe Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210729041317.366612-1-jniethe5@gmail.com --- diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c index 82f7bdc2e5e6f..7df7100a29beb 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-gpr.c @@ -57,7 +57,7 @@ trans: : [gpr_1]"i"(GPR_1), [gpr_2]"i"(GPR_2), [sprn_texasr] "i" (SPRN_TEXASR), [flt_1] "b" (&a), [flt_2] "b" (&b), [cptr1] "b" (&cptr[1]) - : "memory", "r7", "r8", "r9", "r10", + : "memory", "r0", "r7", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23", "r24", "r25", "r26", "r27", "r28", diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c index ad65be6e8e85b..8706bea5d015f 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-tm-spd-gpr.c @@ -65,7 +65,7 @@ trans: : [gpr_1]"i"(GPR_1), [gpr_2]"i"(GPR_2), [gpr_4]"i"(GPR_4), [sprn_texasr] "i" (SPRN_TEXASR), [flt_1] "b" (&a), [flt_4] "b" (&d) - : "memory", "r5", "r6", "r7", + : "memory", "r0", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23", "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31"