diff options
Diffstat (limited to '')
9 files changed, 544 insertions, 85 deletions
diff --git a/tools/testing/selftests/powerpc/security/.gitignore b/tools/testing/selftests/powerpc/security/.gitignore index f795e06f5ae3..9357b186b13c 100644 --- a/tools/testing/selftests/powerpc/security/.gitignore +++ b/tools/testing/selftests/powerpc/security/.gitignore @@ -1,2 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only rfi_flush +entry_flush +spectre_v2 +uaccess_flush diff --git a/tools/testing/selftests/powerpc/security/Makefile b/tools/testing/selftests/powerpc/security/Makefile index eadbbff50be6..e0d979ab0204 100644 --- a/tools/testing/selftests/powerpc/security/Makefile +++ b/tools/testing/selftests/powerpc/security/Makefile @@ -1,9 +1,11 @@ # SPDX-License-Identifier: GPL-2.0+ -TEST_GEN_PROGS := rfi_flush spectre_v2 +TEST_GEN_PROGS := rfi_flush entry_flush uaccess_flush spectre_v2 +TEST_PROGS := mitigation-patching.sh + top_srcdir = ../../../../.. -CFLAGS += -I../../../../../usr/include +CFLAGS += $(KHDR_INCLUDES) include ../../lib.mk @@ -11,3 +13,6 @@ $(TEST_GEN_PROGS): ../harness.c ../utils.c $(OUTPUT)/spectre_v2: CFLAGS += -m64 $(OUTPUT)/spectre_v2: ../pmu/event.c branch_loops.S +$(OUTPUT)/rfi_flush: flush_utils.c +$(OUTPUT)/entry_flush: flush_utils.c +$(OUTPUT)/uaccess_flush: flush_utils.c diff --git a/tools/testing/selftests/powerpc/security/entry_flush.c b/tools/testing/selftests/powerpc/security/entry_flush.c new file mode 100644 index 000000000000..e01c573deadd --- /dev/null +++ b/tools/testing/selftests/powerpc/security/entry_flush.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * Copyright 2018 IBM Corporation. + */ + +#define __SANE_USERSPACE_TYPES__ + +#include <sys/types.h> +#include <stdint.h> +#include <malloc.h> +#include <unistd.h> +#include <signal.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include "utils.h" +#include "flush_utils.h" + +int entry_flush_test(void) +{ + char *p; + int repetitions = 10; + int fd, passes = 0, iter, rc = 0; + struct perf_event_read v; + __u64 l1d_misses_total = 0; + unsigned long iterations = 100000, zero_size = 24 * 1024; + unsigned long l1d_misses_expected; + int rfi_flush_orig; + int entry_flush, entry_flush_orig; + + SKIP_IF(geteuid() != 0); + + // The PMU event we use only works on Power7 or later + SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06)); + + if (read_debugfs_int("powerpc/rfi_flush", &rfi_flush_orig) < 0) { + perror("Unable to read powerpc/rfi_flush debugfs file"); + SKIP_IF(1); + } + + if (read_debugfs_int("powerpc/entry_flush", &entry_flush_orig) < 0) { + perror("Unable to read powerpc/entry_flush debugfs file"); + SKIP_IF(1); + } + + if (rfi_flush_orig != 0) { + if (write_debugfs_int("powerpc/rfi_flush", 0) < 0) { + perror("error writing to powerpc/rfi_flush debugfs file"); + FAIL_IF(1); + } + } + + entry_flush = entry_flush_orig; + + fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1); + FAIL_IF(fd < 0); + + p = (char *)memalign(zero_size, CACHELINE_SIZE); + + FAIL_IF(perf_event_enable(fd)); + + // disable L1 prefetching + set_dscr(1); + + iter = repetitions; + + /* + * We expect to see l1d miss for each cacheline access when entry_flush + * is set. Allow a small variation on this. + */ + l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2); + +again: + FAIL_IF(perf_event_reset(fd)); + + syscall_loop(p, iterations, zero_size); + + FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v)); + + if (entry_flush && v.l1d_misses >= l1d_misses_expected) + passes++; + else if (!entry_flush && v.l1d_misses < (l1d_misses_expected / 2)) + passes++; + + l1d_misses_total += v.l1d_misses; + + while (--iter) + goto again; + + if (passes < repetitions) { + printf("FAIL (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d failures]\n", + entry_flush, l1d_misses_total, entry_flush ? '<' : '>', + entry_flush ? repetitions * l1d_misses_expected : + repetitions * l1d_misses_expected / 2, + repetitions - passes, repetitions); + rc = 1; + } else { + printf("PASS (L1D misses with entry_flush=%d: %llu %c %lu) [%d/%d pass]\n", + entry_flush, l1d_misses_total, entry_flush ? '>' : '<', + entry_flush ? repetitions * l1d_misses_expected : + repetitions * l1d_misses_expected / 2, + passes, repetitions); + } + + if (entry_flush == entry_flush_orig) { + entry_flush = !entry_flush_orig; + if (write_debugfs_int("powerpc/entry_flush", entry_flush) < 0) { + perror("error writing to powerpc/entry_flush debugfs file"); + return 1; + } + iter = repetitions; + l1d_misses_total = 0; + passes = 0; + goto again; + } + + perf_event_disable(fd); + close(fd); + + set_dscr(0); + + if (write_debugfs_int("powerpc/rfi_flush", rfi_flush_orig) < 0) { + perror("unable to restore original value of powerpc/rfi_flush debugfs file"); + return 1; + } + + if (write_debugfs_int("powerpc/entry_flush", entry_flush_orig) < 0) { + perror("unable to restore original value of powerpc/entry_flush debugfs file"); + return 1; + } + + return rc; +} + +int main(int argc, char *argv[]) +{ + return test_harness(entry_flush_test, "entry_flush_test"); +} diff --git a/tools/testing/selftests/powerpc/security/flush_utils.c b/tools/testing/selftests/powerpc/security/flush_utils.c new file mode 100644 index 000000000000..9c5c00e04f63 --- /dev/null +++ b/tools/testing/selftests/powerpc/security/flush_utils.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * Copyright 2018 IBM Corporation. + */ + +#define __SANE_USERSPACE_TYPES__ + +#include <sys/types.h> +#include <stdint.h> +#include <unistd.h> +#include <signal.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <sys/utsname.h> +#include "reg.h" +#include "utils.h" +#include "flush_utils.h" + +static inline __u64 load(void *addr) +{ + __u64 tmp; + + asm volatile("ld %0,0(%1)" : "=r"(tmp) : "b"(addr)); + + return tmp; +} + +void syscall_loop(char *p, unsigned long iterations, + unsigned long zero_size) +{ + for (unsigned long i = 0; i < iterations; i++) { + for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE) + load(p + j); + getppid(); + } +} + +void syscall_loop_uaccess(char *p, unsigned long iterations, + unsigned long zero_size) +{ + struct utsname utsname; + + for (unsigned long i = 0; i < iterations; i++) { + for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE) + load(p + j); + uname(&utsname); + } +} + +static void sigill_handler(int signr, siginfo_t *info, void *unused) +{ + static int warned; + ucontext_t *ctx = (ucontext_t *)unused; + unsigned long *pc = &UCONTEXT_NIA(ctx); + + /* mtspr 3,RS to check for move to DSCR below */ + if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) { + 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; + 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; + } + + mtspr(SPRN_DSCR, val); +} diff --git a/tools/testing/selftests/powerpc/security/flush_utils.h b/tools/testing/selftests/powerpc/security/flush_utils.h new file mode 100644 index 000000000000..e1e68281f7ac --- /dev/null +++ b/tools/testing/selftests/powerpc/security/flush_utils.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +/* + * Copyright 2018 IBM Corporation. + */ + +#ifndef _SELFTESTS_POWERPC_SECURITY_FLUSH_UTILS_H +#define _SELFTESTS_POWERPC_SECURITY_FLUSH_UTILS_H + +#define CACHELINE_SIZE 128 + +#define PERF_L1D_READ_MISS_CONFIG ((PERF_COUNT_HW_CACHE_L1D) | \ + (PERF_COUNT_HW_CACHE_OP_READ << 8) | \ + (PERF_COUNT_HW_CACHE_RESULT_MISS << 16)) + +void syscall_loop(char *p, unsigned long iterations, + unsigned long zero_size); + +void syscall_loop_uaccess(char *p, unsigned long iterations, + unsigned long zero_size); + +void set_dscr(unsigned long val); + +#endif /* _SELFTESTS_POWERPC_SECURITY_FLUSH_UTILS_H */ diff --git a/tools/testing/selftests/powerpc/security/mitigation-patching.sh b/tools/testing/selftests/powerpc/security/mitigation-patching.sh new file mode 100755 index 000000000000..f43aa4b77fba --- /dev/null +++ b/tools/testing/selftests/powerpc/security/mitigation-patching.sh @@ -0,0 +1,78 @@ +#!/usr/bin/env bash + +set -euo pipefail + +TIMEOUT=10 + +function do_one +{ + local mitigation="$1" + local orig + local start + local now + + orig=$(cat "$mitigation") + + start=$(date +%s) + now=$start + + while [[ $((now-start)) -lt "$TIMEOUT" ]] + do + echo 0 > "$mitigation" + echo 1 > "$mitigation" + + now=$(date +%s) + done + + echo "$orig" > "$mitigation" +} + +rc=0 +cd /sys/kernel/debug/powerpc || rc=1 +if [[ "$rc" -ne 0 ]]; then + echo "Error: couldn't cd to /sys/kernel/debug/powerpc" >&2 + exit 1 +fi + +tainted=$(cat /proc/sys/kernel/tainted) +if [[ "$tainted" -ne 0 ]]; then + echo "Error: kernel already tainted!" >&2 + exit 1 +fi + +mitigations="barrier_nospec stf_barrier count_cache_flush rfi_flush entry_flush uaccess_flush" + +for m in $mitigations +do + if [[ -f /sys/kernel/debug/powerpc/$m ]] + then + do_one "$m" & + fi +done + +echo "Spawned threads enabling/disabling mitigations ..." + +if stress-ng > /dev/null 2>&1; then + stress="stress-ng" +elif stress > /dev/null 2>&1; then + stress="stress" +else + stress="" +fi + +if [[ -n "$stress" ]]; then + "$stress" -m "$(nproc)" -t "$TIMEOUT" & + echo "Spawned VM stressors ..." +fi + +echo "Waiting for timeout ..." +wait + +tainted=$(cat /proc/sys/kernel/tainted) +if [[ "$tainted" -ne 0 ]]; then + echo "Error: kernel became tainted!" >&2 + exit 1 +fi + +echo "OK" +exit 0 diff --git a/tools/testing/selftests/powerpc/security/rfi_flush.c b/tools/testing/selftests/powerpc/security/rfi_flush.c index 93a65bd1f231..6bedc86443a6 100644 --- a/tools/testing/selftests/powerpc/security/rfi_flush.c +++ b/tools/testing/selftests/powerpc/security/rfi_flush.c @@ -10,71 +10,12 @@ #include <stdint.h> #include <malloc.h> #include <unistd.h> -#include <signal.h> #include <stdlib.h> #include <string.h> #include <stdio.h> #include "utils.h" +#include "flush_utils.h" -#define CACHELINE_SIZE 128 - -struct perf_event_read { - __u64 nr; - __u64 l1d_misses; -}; - -static inline __u64 load(void *addr) -{ - __u64 tmp; - - asm volatile("ld %0,0(%1)" : "=r"(tmp) : "b"(addr)); - - return tmp; -} - -static void syscall_loop(char *p, unsigned long iterations, - unsigned long zero_size) -{ - for (unsigned long i = 0; i < iterations; i++) { - for (unsigned long j = 0; j < zero_size; j += CACHELINE_SIZE) - load(p + j); - getppid(); - } -} - -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); - - /* mtspr 3,RS to check for move to DSCR below */ - if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) { - 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(); - } -} - -static 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("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR)); -} int rfi_flush_test(void) { @@ -85,27 +26,42 @@ int rfi_flush_test(void) __u64 l1d_misses_total = 0; unsigned long iterations = 100000, zero_size = 24 * 1024; unsigned long l1d_misses_expected; - int rfi_flush_org, rfi_flush; + int rfi_flush_orig, rfi_flush; + int have_entry_flush, entry_flush_orig; SKIP_IF(geteuid() != 0); // The PMU event we use only works on Power7 or later SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06)); - if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) { + if (read_debugfs_int("powerpc/rfi_flush", &rfi_flush_orig) < 0) { perror("Unable to read powerpc/rfi_flush debugfs file"); SKIP_IF(1); } - rfi_flush = rfi_flush_org; + if (read_debugfs_int("powerpc/entry_flush", &entry_flush_orig) < 0) { + have_entry_flush = 0; + } else { + have_entry_flush = 1; + + if (entry_flush_orig != 0) { + if (write_debugfs_int("powerpc/entry_flush", 0) < 0) { + perror("error writing to powerpc/entry_flush debugfs file"); + return 1; + } + } + } + + rfi_flush = rfi_flush_orig; - fd = perf_event_open_counter(PERF_TYPE_RAW, /* L1d miss */ 0x400f0, -1); + fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1); FAIL_IF(fd < 0); p = (char *)memalign(zero_size, CACHELINE_SIZE); FAIL_IF(perf_event_enable(fd)); + // disable L1 prefetching set_dscr(1); iter = repetitions; @@ -147,9 +103,9 @@ again: repetitions * l1d_misses_expected / 2, passes, repetitions); - if (rfi_flush == rfi_flush_org) { - rfi_flush = !rfi_flush_org; - if (write_debugfs_file("powerpc/rfi_flush", rfi_flush) < 0) { + if (rfi_flush == rfi_flush_orig) { + rfi_flush = !rfi_flush_orig; + if (write_debugfs_int("powerpc/rfi_flush", rfi_flush) < 0) { perror("error writing to powerpc/rfi_flush debugfs file"); return 1; } @@ -164,11 +120,19 @@ again: set_dscr(0); - if (write_debugfs_file("powerpc/rfi_flush", rfi_flush_org) < 0) { + if (write_debugfs_int("powerpc/rfi_flush", rfi_flush_orig) < 0) { perror("unable to restore original value of powerpc/rfi_flush debugfs file"); return 1; } + if (have_entry_flush) { + if (write_debugfs_int("powerpc/entry_flush", entry_flush_orig) < 0) { + perror("unable to restore original value of powerpc/entry_flush " + "debugfs file"); + return 1; + } + } + return rc; } diff --git a/tools/testing/selftests/powerpc/security/spectre_v2.c b/tools/testing/selftests/powerpc/security/spectre_v2.c index adc2b7294e5f..5b2abb719ef2 100644 --- a/tools/testing/selftests/powerpc/security/spectre_v2.c +++ b/tools/testing/selftests/powerpc/security/spectre_v2.c @@ -125,8 +125,6 @@ static enum spectre_v2_state get_sysfs_state(void) #define PM_BR_PRED_PCACHE 0x048a0 // P9 only #define PM_BR_MPRED_PCACHE 0x048b0 // P9 only -#define SPRN_PVR 287 - int spectre_v2_test(void) { enum spectre_v2_state state; @@ -184,17 +182,23 @@ int spectre_v2_test(void) case COUNT_CACHE_FLUSH_HW: // These should all not affect userspace branch prediction if (miss_percent > 15) { - printf("Branch misses > 15%% unexpected in this configuration!\n"); - printf("Possible mis-match between reported & actual mitigation\n"); - /* - * Such a mismatch may be caused by a guest system - * reporting as vulnerable when the host is mitigated. - * Return skip code to avoid detecting this as an error. - * We are not vulnerable and reporting otherwise, so - * missing such a mismatch is safe. - */ - if (state == VULNERABLE) + if (miss_percent > 95) { + /* + * Such a mismatch may be caused by a system being unaware + * the count cache is disabled. This may be to enable + * guest migration between hosts with different settings. + * Return skip code to avoid detecting this as an error. + * We are not vulnerable and reporting otherwise, so + * missing such a mismatch is safe. + */ + printf("Branch misses > 95%% unexpected in this configuration.\n"); + printf("Count cache likely disabled without Linux knowing.\n"); + if (state == COUNT_CACHE_FLUSH_SW) + printf("WARNING: Kernel performing unnecessary flushes.\n"); return 4; + } + printf("Branch misses > 15%% unexpected in this configuration!\n"); + printf("Possible mismatch between reported & actual mitigation\n"); return 1; } @@ -203,14 +207,14 @@ int spectre_v2_test(void) // This seems to affect userspace branch prediction a bit? if (miss_percent > 25) { printf("Branch misses > 25%% unexpected in this configuration!\n"); - printf("Possible mis-match between reported & actual mitigation\n"); + printf("Possible mismatch between reported & actual mitigation\n"); return 1; } break; case COUNT_CACHE_DISABLED: if (miss_percent < 95) { - printf("Branch misses < 20%% unexpected in this configuration!\n"); - printf("Possible mis-match between reported & actual mitigation\n"); + printf("Branch misses < 95%% unexpected in this configuration!\n"); + printf("Possible mismatch between reported & actual mitigation\n"); return 1; } break; diff --git a/tools/testing/selftests/powerpc/security/uaccess_flush.c b/tools/testing/selftests/powerpc/security/uaccess_flush.c new file mode 100644 index 000000000000..fcf23ea9b183 --- /dev/null +++ b/tools/testing/selftests/powerpc/security/uaccess_flush.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * Copyright 2018 IBM Corporation. + * Copyright 2020 Canonical Ltd. + */ + +#define __SANE_USERSPACE_TYPES__ + +#include <sys/types.h> +#include <stdint.h> +#include <malloc.h> +#include <unistd.h> +#include <signal.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include "utils.h" +#include "flush_utils.h" + +int uaccess_flush_test(void) +{ + char *p; + int repetitions = 10; + int fd, passes = 0, iter, rc = 0; + struct perf_event_read v; + __u64 l1d_misses_total = 0; + unsigned long iterations = 100000, zero_size = 24 * 1024; + unsigned long l1d_misses_expected; + int rfi_flush_orig; + int entry_flush_orig; + int uaccess_flush, uaccess_flush_orig; + + SKIP_IF(geteuid() != 0); + + // The PMU event we use only works on Power7 or later + SKIP_IF(!have_hwcap(PPC_FEATURE_ARCH_2_06)); + + if (read_debugfs_int("powerpc/rfi_flush", &rfi_flush_orig) < 0) { + perror("Unable to read powerpc/rfi_flush debugfs file"); + SKIP_IF(1); + } + + if (read_debugfs_int("powerpc/entry_flush", &entry_flush_orig) < 0) { + perror("Unable to read powerpc/entry_flush debugfs file"); + SKIP_IF(1); + } + + if (read_debugfs_int("powerpc/uaccess_flush", &uaccess_flush_orig) < 0) { + perror("Unable to read powerpc/entry_flush debugfs file"); + SKIP_IF(1); + } + + if (rfi_flush_orig != 0) { + if (write_debugfs_int("powerpc/rfi_flush", 0) < 0) { + perror("error writing to powerpc/rfi_flush debugfs file"); + FAIL_IF(1); + } + } + + if (entry_flush_orig != 0) { + if (write_debugfs_int("powerpc/entry_flush", 0) < 0) { + perror("error writing to powerpc/entry_flush debugfs file"); + FAIL_IF(1); + } + } + + uaccess_flush = uaccess_flush_orig; + + fd = perf_event_open_counter(PERF_TYPE_HW_CACHE, PERF_L1D_READ_MISS_CONFIG, -1); + FAIL_IF(fd < 0); + + p = (char *)memalign(zero_size, CACHELINE_SIZE); + + FAIL_IF(perf_event_enable(fd)); + + // disable L1 prefetching + set_dscr(1); + + iter = repetitions; + + /* + * We expect to see l1d miss for each cacheline access when entry_flush + * is set. Allow a small variation on this. + */ + l1d_misses_expected = iterations * (zero_size / CACHELINE_SIZE - 2); + +again: + FAIL_IF(perf_event_reset(fd)); + + syscall_loop_uaccess(p, iterations, zero_size); + + FAIL_IF(read(fd, &v, sizeof(v)) != sizeof(v)); + + if (uaccess_flush && v.l1d_misses >= l1d_misses_expected) + passes++; + else if (!uaccess_flush && v.l1d_misses < (l1d_misses_expected / 2)) + passes++; + + l1d_misses_total += v.l1d_misses; + + while (--iter) + goto again; + + if (passes < repetitions) { + printf("FAIL (L1D misses with uaccess_flush=%d: %llu %c %lu) [%d/%d failures]\n", + uaccess_flush, l1d_misses_total, uaccess_flush ? '<' : '>', + uaccess_flush ? repetitions * l1d_misses_expected : + repetitions * l1d_misses_expected / 2, + repetitions - passes, repetitions); + rc = 1; + } else { + printf("PASS (L1D misses with uaccess_flush=%d: %llu %c %lu) [%d/%d pass]\n", + uaccess_flush, l1d_misses_total, uaccess_flush ? '>' : '<', + uaccess_flush ? repetitions * l1d_misses_expected : + repetitions * l1d_misses_expected / 2, + passes, repetitions); + } + + if (uaccess_flush == uaccess_flush_orig) { + uaccess_flush = !uaccess_flush_orig; + if (write_debugfs_int("powerpc/uaccess_flush", uaccess_flush) < 0) { + perror("error writing to powerpc/uaccess_flush debugfs file"); + return 1; + } + iter = repetitions; + l1d_misses_total = 0; + passes = 0; + goto again; + } + + perf_event_disable(fd); + close(fd); + + set_dscr(0); + + if (write_debugfs_int("powerpc/rfi_flush", rfi_flush_orig) < 0) { + perror("unable to restore original value of powerpc/rfi_flush debugfs file"); + return 1; + } + + if (write_debugfs_int("powerpc/entry_flush", entry_flush_orig) < 0) { + perror("unable to restore original value of powerpc/entry_flush debugfs file"); + return 1; + } + + if (write_debugfs_int("powerpc/uaccess_flush", uaccess_flush_orig) < 0) { + perror("unable to restore original value of powerpc/uaccess_flush debugfs file"); + return 1; + } + + return rc; +} + +int main(int argc, char *argv[]) +{ + return test_harness(uaccess_flush_test, "uaccess_flush_test"); +} |