From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, dja@axtens.net
Subject: [PATCH 5.9 05/14] selftests/powerpc: entry flush test
Date: Fri, 20 Nov 2020 12:03:43 +0100 [thread overview]
Message-ID: <20201120104541.433708552@linuxfoundation.org> (raw)
In-Reply-To: <20201120104541.168007611@linuxfoundation.org>
From: Daniel Axtens <dja@axtens.net>
commit 89a83a0c69c81a25ce91002b90ca27ed86132a0a upstream.
Add a test modelled on the RFI flush test which counts the number
of L1D misses doing a simple syscall with the entry flush on and off.
For simplicity of backporting, this test duplicates a lot of code from
rfi_flush. We clean that up in the next patch.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/testing/selftests/powerpc/security/.gitignore | 1
tools/testing/selftests/powerpc/security/Makefile | 2
tools/testing/selftests/powerpc/security/entry_flush.c | 198 +++++++++++++++++
3 files changed, 200 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/powerpc/security/entry_flush.c
--- a/tools/testing/selftests/powerpc/security/.gitignore
+++ b/tools/testing/selftests/powerpc/security/.gitignore
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
rfi_flush
+entry_flush
--- a/tools/testing/selftests/powerpc/security/Makefile
+++ b/tools/testing/selftests/powerpc/security/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0+
-TEST_GEN_PROGS := rfi_flush spectre_v2
+TEST_GEN_PROGS := rfi_flush entry_flush spectre_v2
top_srcdir = ../../../../..
CFLAGS += -I../../../../../usr/include
--- /dev/null
+++ b/tools/testing/selftests/powerpc/security/entry_flush.c
@@ -0,0 +1,198 @@
+// 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"
+
+#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;
+ 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;
+ 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 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_file("powerpc/rfi_flush", &rfi_flush_orig) < 0) {
+ perror("Unable to read powerpc/rfi_flush debugfs file");
+ SKIP_IF(1);
+ }
+
+ if (read_debugfs_file("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_file("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_RAW, /* L1d miss */ 0x400f0, -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_file("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_file("powerpc/rfi_flush", rfi_flush_orig) < 0) {
+ perror("unable to restore original value of powerpc/rfi_flush debugfs file");
+ return 1;
+ }
+
+ if (write_debugfs_file("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");
+}
next prev parent reply other threads:[~2020-11-20 11:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 11:03 [PATCH 5.9 00/14] 5.9.10-rc1 review Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 01/14] selftests/powerpc: rfi_flush: disable entry flush if present Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 02/14] powerpc/64s: flush L1D on kernel entry Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 03/14] powerpc/64s: flush L1D after user accesses Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 04/14] powerpc: Only include kup-radix.h for 64-bit Book3S Greg Kroah-Hartman
2020-11-20 11:03 ` Greg Kroah-Hartman [this message]
2020-11-20 11:03 ` [PATCH 5.9 06/14] leds: lm3697: Fix out-of-bound access Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 07/14] Input: sunkbd - avoid use-after-free in teardown paths Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 08/14] mac80211: always wind down STA state Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 09/14] can: proc: can_remove_proc(): silence remove_proc_entry warning Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 10/14] selftests/harness: prettify SKIP message whitespace again Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 11/14] powerpc/smp: Call rcu_cpu_starting() earlier Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 12/14] perf/x86/intel/uncore: Fix Add BW copypasta Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 13/14] KVM: x86: clflushopt should be treated as a no-op by emulation Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.9 14/14] ACPI: GED: fix -Wformat Greg Kroah-Hartman
2020-11-20 17:52 ` [PATCH 5.9 00/14] 5.9.10-rc1 review Jeffrin Jose T
2020-11-20 22:27 ` Shuah Khan
2020-11-22 9:18 ` Greg Kroah-Hartman
2020-11-21 11:12 ` Naresh Kamboju
2020-11-22 9:18 ` Greg Kroah-Hartman
[not found] ` <20201121183817.GG111877@roeck-us.net>
2020-11-22 9:19 ` Greg Kroah-Hartman
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