From d2bf793237b3aa9c4275a466eef3893eef593691 Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Mon, 21 May 2018 20:43:57 +0530 Subject: selftests/powerpc: Add test to verify rfi flush across a system call This adds a test to verify proper functioning of the rfi flush capability implemented to mitigate meltdown. The test works by measuring the number of L1d cache misses encountered while loading data from memory. Across a system call, since the L1d cache is flushed when rfi_flush is enabled, the number of cache misses is expected to be relative to the number of cachelines corresponding to the data being loaded. The current system setting is reflected via powerpc/rfi_flush under debugfs (assumed to be /sys/kernel/debug/). This test verifies the expected result with rfi_flush enabled as well as when it is disabled. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman Signed-off-by: Naveen N. Rao [mpe: Add SPDX tags, clang format, skip if the debugfs is missing, use __u64 and SANE_USERSPACE_TYPES to avoid printf() build errors.] Signed-off-by: Michael Ellerman --- tools/testing/selftests/powerpc/utils.c | 152 ++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) (limited to 'tools/testing/selftests/powerpc/utils.c') diff --git a/tools/testing/selftests/powerpc/utils.c b/tools/testing/selftests/powerpc/utils.c index aa8fc1e6365b..43c342845be0 100644 --- a/tools/testing/selftests/powerpc/utils.c +++ b/tools/testing/selftests/powerpc/utils.c @@ -10,16 +10,22 @@ #include #include #include +#include #include +#include #include +#include #include #include #include #include +#include +#include #include "utils.h" static char auxv[4096]; +extern unsigned int dscr_insn[]; int read_auxv(char *buf, ssize_t buf_size) { @@ -121,3 +127,149 @@ bool is_ppc64le(void) return strcmp(uts.machine, "ppc64le") == 0; } + +int read_debugfs_file(char *debugfs_file, int *result) +{ + int rc = -1, fd; + char path[PATH_MAX]; + char value[16]; + + strcpy(path, "/sys/kernel/debug/"); + strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1); + + if ((fd = open(path, O_RDONLY)) < 0) + return rc; + + if ((rc = read(fd, value, sizeof(value))) < 0) + return rc; + + value[15] = 0; + *result = atoi(value); + close(fd); + + return 0; +} + +int write_debugfs_file(char *debugfs_file, int result) +{ + int rc = -1, fd; + char path[PATH_MAX]; + char value[16]; + + strcpy(path, "/sys/kernel/debug/"); + strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1); + + if ((fd = open(path, O_WRONLY)) < 0) + return rc; + + snprintf(value, 16, "%d", result); + + if ((rc = write(fd, value, strlen(value))) < 0) + return rc; + + close(fd); + + return 0; +} + +static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid, + int cpu, int group_fd, unsigned long flags) +{ + return syscall(__NR_perf_event_open, hw_event, pid, cpu, + group_fd, flags); +} + +static void perf_event_attr_init(struct perf_event_attr *event_attr, + unsigned int type, + unsigned long config) +{ + memset(event_attr, 0, sizeof(*event_attr)); + + event_attr->type = type; + event_attr->size = sizeof(struct perf_event_attr); + event_attr->config = config; + event_attr->read_format = PERF_FORMAT_GROUP; + event_attr->disabled = 1; + event_attr->exclude_kernel = 1; + event_attr->exclude_hv = 1; + event_attr->exclude_guest = 1; +} + +int perf_event_open_counter(unsigned int type, + unsigned long config, int group_fd) +{ + int fd; + struct perf_event_attr event_attr; + + perf_event_attr_init(&event_attr, type, config); + + fd = perf_event_open(&event_attr, 0, -1, group_fd, 0); + + if (fd < 0) + perror("perf_event_open() failed"); + + return fd; +} + +int perf_event_enable(int fd) +{ + if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) { + perror("error while enabling perf events"); + return -1; + } + + return 0; +} + +int perf_event_disable(int fd) +{ + if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) { + perror("error disabling perf events"); + return -1; + } + + return 0; +} + +int perf_event_reset(int fd) +{ + if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) { + perror("error resetting perf events"); + return -1; + } + + return 0; +} + +static void sigill_handler(int signr, siginfo_t *info, void *unused) +{ + static int warned = 0; + ucontext_t *ctx = (ucontext_t *)unused; + unsigned long *pc = &UCONTEXT_NIA(ctx); + + if (*pc == (unsigned long)&dscr_insn) { + if (!warned++) + printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n"); + *pc += 4; + } else { + printf("SIGILL at %p\n", pc); + abort(); + } +} + +void set_dscr(unsigned long val) +{ + static int init = 0; + struct sigaction sa; + + if (!init) { + memset(&sa, 0, sizeof(sa)); + sa.sa_sigaction = sigill_handler; + sa.sa_flags = SA_SIGINFO; + if (sigaction(SIGILL, &sa, NULL)) + perror("sigill_handler"); + init = 1; + } + + asm volatile("dscr_insn: mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR)); +} -- cgit v1.2.3-59-g8ed1b