From e5d00aaac651a69b8016d355123438387bfd37be Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 29 Nov 2023 00:27:45 +1100 Subject: selftests/powerpc: Check all FPRs in fpu_preempt There's a selftest that checks FPRs aren't corrupted by preemption, or just process scheduling. However it only checks the non-volatile FPRs, meaning corruption of the volatile FPRs could go undetected. The check_fpu function it calls is used by several other tests, so for now add a new routine to check all the FPRs. Increase the size of the array of FPRs to 32, and initialise them all with random values. Signed-off-by: Michael Ellerman Link: https://msgid.link/20231128132748.1990179-2-mpe@ellerman.id.au --- tools/testing/selftests/powerpc/math/fpu_asm.S | 41 +++++++++++++++++++--- tools/testing/selftests/powerpc/math/fpu_preempt.c | 15 ++++---- 2 files changed, 43 insertions(+), 13 deletions(-) (limited to 'tools/testing/selftests/powerpc') diff --git a/tools/testing/selftests/powerpc/math/fpu_asm.S b/tools/testing/selftests/powerpc/math/fpu_asm.S index 9dc0c158f871..051392ad3ce7 100644 --- a/tools/testing/selftests/powerpc/math/fpu_asm.S +++ b/tools/testing/selftests/powerpc/math/fpu_asm.S @@ -66,6 +66,40 @@ FUNC_START(check_fpu) li r3,0 # Success!!! 1: blr + +// int check_all_fprs(double darray[32]) +FUNC_START(check_all_fprs) + PUSH_BASIC_STACK(8) + mr r4, r3 // r4 = darray + li r3, 1 // prepare for failure + + stfd f31, STACK_FRAME_LOCAL(0, 0)(sp) // backup f31 + + // Check regs f0-f30, using f31 as scratch + .set i, 0 + .rept 31 + lfd f31, (8 * i)(r4) // load expected value + fcmpu cr0, i, f31 // compare + bne cr0, 1f // bail if mismatch + .set i, i + 1 + .endr + + lfd f31, STACK_FRAME_LOCAL(0, 0)(sp) // reload f31 + stfd f30, STACK_FRAME_LOCAL(0, 0)(sp) // backup f30 + + lfd f30, (8 * 31)(r4) // load expected value of f31 + fcmpu cr0, f30, f31 // compare + bne cr0, 1f // bail if mismatch + + lfd f30, STACK_FRAME_LOCAL(0, 0)(sp) // reload f30 + + // Success + li r3, 0 + +1: POP_BASIC_STACK(8) + blr +FUNC_END(check_all_fprs) + FUNC_START(test_fpu) # r3 holds pointer to where to put the result of fork # r4 holds pointer to the pid @@ -104,8 +138,8 @@ FUNC_START(preempt_fpu) std r4,STACK_FRAME_PARAM(1)(sp) # int *threads_starting std r5,STACK_FRAME_PARAM(2)(sp) # int *running - bl load_fpu - nop + // Load FPRs with expected values + OP_REGS lfd, 8, 0, 31, r3 sync # Atomic DEC @@ -116,8 +150,7 @@ FUNC_START(preempt_fpu) bne- 1b 2: ld r3,STACK_FRAME_PARAM(0)(sp) - bl check_fpu - nop + bl check_all_fprs cmpdi r3,0 bne 3f ld r4,STACK_FRAME_PARAM(2)(sp) diff --git a/tools/testing/selftests/powerpc/math/fpu_preempt.c b/tools/testing/selftests/powerpc/math/fpu_preempt.c index 3e5b5663d244..24b5abacccdc 100644 --- a/tools/testing/selftests/powerpc/math/fpu_preempt.c +++ b/tools/testing/selftests/powerpc/math/fpu_preempt.c @@ -1,13 +1,12 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright 2015, Cyril Bur, IBM Corp. + * Copyright 2023, Michael Ellerman, IBM Corp. * * This test attempts to see if the FPU registers change across preemption. - * Two things should be noted here a) The check_fpu function in asm only checks - * the non volatile registers as it is reused from the syscall test b) There is - * no way to be sure preemption happened so this test just uses many threads - * and a long wait. As such, a successful test doesn't mean much but a failure - * is bad. + * There is no way to be sure preemption happened so this test just uses many + * threads and a long wait. As such, a successful test doesn't mean much but + * a failure is bad. */ #include @@ -30,9 +29,7 @@ #define THREAD_FACTOR 8 -__thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, - 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, - 2.1}; +__thread double darray[32]; int threads_starting; int running; @@ -45,7 +42,7 @@ void *preempt_fpu_c(void *p) int i; srand(pthread_self()); - for (i = 0; i < 21; i++) + for (i = 0; i < ARRAY_SIZE(darray); i++) darray[i] = rand(); rc = preempt_fpu(darray, &threads_starting, &running); -- cgit v1.2.3