diff options
Diffstat (limited to 'tools/testing/selftests/powerpc/context_switch')
3 files changed, 121 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/context_switch/.gitignore b/tools/testing/selftests/powerpc/context_switch/.gitignore new file mode 100644 index 000000000000..c1431af7b51c --- /dev/null +++ b/tools/testing/selftests/powerpc/context_switch/.gitignore @@ -0,0 +1 @@ +cp_abort diff --git a/tools/testing/selftests/powerpc/context_switch/Makefile b/tools/testing/selftests/powerpc/context_switch/Makefile new file mode 100644 index 000000000000..e164d1466466 --- /dev/null +++ b/tools/testing/selftests/powerpc/context_switch/Makefile @@ -0,0 +1,10 @@ +TEST_PROGS := cp_abort + +all: $(TEST_PROGS) + +$(TEST_PROGS): ../harness.c ../utils.c + +include ../../lib.mk + +clean: + rm -f $(TEST_PROGS) diff --git a/tools/testing/selftests/powerpc/context_switch/cp_abort.c b/tools/testing/selftests/powerpc/context_switch/cp_abort.c new file mode 100644 index 000000000000..5a5b55afda0e --- /dev/null +++ b/tools/testing/selftests/powerpc/context_switch/cp_abort.c @@ -0,0 +1,110 @@ +/* + * Adapted from Anton Blanchard's context switch microbenchmark. + * + * Copyright 2009, Anton Blanchard, IBM Corporation. + * Copyright 2016, Mikey Neuling, Chris Smart, IBM Corporation. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * This program tests the copy paste abort functionality of a P9 + * (or later) by setting up two processes on the same CPU, one + * which executes the copy instruction and the other which + * executes paste. + * + * The paste instruction should never succeed, as the cp_abort + * instruction is called by the kernel during a context switch. + * + */ + +#define _GNU_SOURCE + +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include "utils.h" +#include <sched.h> + +#define READ_FD 0 +#define WRITE_FD 1 + +#define NUM_LOOPS 1000 + +/* This defines the "paste" instruction from Power ISA 3.0 Book II, section 4.4. */ +#define PASTE(RA, RB, L, RC) \ + .long (0x7c00070c | (RA) << (31-15) | (RB) << (31-20) | (L) << (31-10) | (RC) << (31-31)) + +int paste(void *i) +{ + int cr; + + asm volatile(str(PASTE(0, %1, 1, 1))";" + "mfcr %0;" + : "=r" (cr) + : "b" (i) + : "memory" + ); + return cr; +} + +/* This defines the "copy" instruction from Power ISA 3.0 Book II, section 4.4. */ +#define COPY(RA, RB, L) \ + .long (0x7c00060c | (RA) << (31-15) | (RB) << (31-20) | (L) << (31-10)) + +void copy(void *i) +{ + asm volatile(str(COPY(0, %0, 1))";" + : + : "b" (i) + : "memory" + ); +} + +int test_cp_abort(void) +{ + /* 128 bytes for a full cache line */ + char buf[128] __cacheline_aligned; + cpu_set_t cpuset; + int fd1[2], fd2[2], pid; + char c; + + /* only run this test on a P9 or later */ + SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_3_00)); + + /* + * Run both processes on the same CPU, so that copy is more likely + * to leak into a paste. + */ + CPU_ZERO(&cpuset); + CPU_SET(pick_online_cpu(), &cpuset); + FAIL_IF(sched_setaffinity(0, sizeof(cpuset), &cpuset)); + + FAIL_IF(pipe(fd1) || pipe(fd2)); + + pid = fork(); + FAIL_IF(pid < 0); + + if (!pid) { + for (int i = 0; i < NUM_LOOPS; i++) { + FAIL_IF((write(fd1[WRITE_FD], &c, 1)) != 1); + FAIL_IF((read(fd2[READ_FD], &c, 1)) != 1); + /* A paste succeeds if CR0 EQ bit is set */ + FAIL_IF(paste(buf) & 0x20000000); + } + } else { + for (int i = 0; i < NUM_LOOPS; i++) { + FAIL_IF((read(fd1[READ_FD], &c, 1)) != 1); + copy(buf); + FAIL_IF((write(fd2[WRITE_FD], &c, 1) != 1)); + } + } + return 0; + +} + +int main(int argc, char *argv[]) +{ + return test_harness(test_cp_abort, "cp_abort"); +} |