[PATCH v4 6/6] RISC-V: selftests: Add CBO tests
Andrew Jones
ajones at ventanamicro.com
Mon Sep 18 06:15:25 PDT 2023
Add hwprobe test for Zicboz and its block size. Also, when Zicboz is
present, test that cbo.zero may be issued and works. Additionally
provide a command line option that enables testing that the Zicbom
instructions cause SIGILL and also that cbo.zero causes SIGILL when
Zicboz it's not present. The SIGILL tests require "opt-in" with a
command line option because the RISC-V ISA does not require
unimplemented standard opcodes to issue illegal-instruction
exceptions (but hopefully most platforms do).
Pinning the test to a subset of cpus with taskset will also restrict
the hwprobe calls to that set.
Signed-off-by: Andrew Jones <ajones at ventanamicro.com>
---
.../testing/selftests/riscv/hwprobe/Makefile | 7 +-
tools/testing/selftests/riscv/hwprobe/cbo.c | 228 ++++++++++++++++++
.../testing/selftests/riscv/hwprobe/hwprobe.c | 12 +-
.../testing/selftests/riscv/hwprobe/hwprobe.h | 15 ++
4 files changed, 250 insertions(+), 12 deletions(-)
create mode 100644 tools/testing/selftests/riscv/hwprobe/cbo.c
create mode 100644 tools/testing/selftests/riscv/hwprobe/hwprobe.h
diff --git a/tools/testing/selftests/riscv/hwprobe/Makefile b/tools/testing/selftests/riscv/hwprobe/Makefile
index 5f614c3ba598..f224b84591fb 100644
--- a/tools/testing/selftests/riscv/hwprobe/Makefile
+++ b/tools/testing/selftests/riscv/hwprobe/Makefile
@@ -2,9 +2,14 @@
# Copyright (C) 2021 ARM Limited
# Originally tools/testing/arm64/abi/Makefile
-TEST_GEN_PROGS := hwprobe
+CFLAGS += -I$(top_srcdir)/tools/include
+
+TEST_GEN_PROGS := hwprobe cbo
include ../../lib.mk
$(OUTPUT)/hwprobe: hwprobe.c sys_hwprobe.S
$(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
+
+$(OUTPUT)/cbo: cbo.c sys_hwprobe.S
+ $(CC) -static -o$@ $(CFLAGS) $(LDFLAGS) $^
diff --git a/tools/testing/selftests/riscv/hwprobe/cbo.c b/tools/testing/selftests/riscv/hwprobe/cbo.c
new file mode 100644
index 000000000000..50a2cc8aef38
--- /dev/null
+++ b/tools/testing/selftests/riscv/hwprobe/cbo.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ *
+ * Run with 'taskset -c <cpu-list> cbo' to only execute hwprobe on a
+ * subset of cpus, as well as only executing the tests on those cpus.
+ */
+#define _GNU_SOURCE
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <sched.h>
+#include <signal.h>
+#include <assert.h>
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <asm/ucontext.h>
+
+#include "hwprobe.h"
+#include "../../kselftest.h"
+
+#define MK_CBO(fn) cpu_to_le32((fn) << 20 | 10 << 15 | 2 << 12 | 0 << 7 | 15)
+
+static char mem[4096] __aligned(4096) = { [0 ... 4095] = 0xa5 };
+
+static bool illegal_insn;
+
+static void sigill_handler(int sig, siginfo_t *info, void *context)
+{
+ unsigned long *regs = (unsigned long *)&((ucontext_t *)context)->uc_mcontext;
+ uint32_t insn = *(uint32_t *)regs[0];
+
+ assert(insn == MK_CBO(regs[11]));
+
+ illegal_insn = true;
+ regs[0] += 4;
+}
+
+static void cbo_insn(char *base, int fn)
+{
+ uint32_t insn = MK_CBO(fn);
+
+ asm volatile(
+ "mv a0, %0\n"
+ "li a1, %1\n"
+ ".4byte %2\n"
+ : : "r" (base), "i" (fn), "i" (insn) : "a0", "a1", "memory");
+}
+
+static void cbo_inval(char *base) { cbo_insn(base, 0); }
+static void cbo_clean(char *base) { cbo_insn(base, 1); }
+static void cbo_flush(char *base) { cbo_insn(base, 2); }
+static void cbo_zero(char *base) { cbo_insn(base, 4); }
+
+static void test_no_zicbom(void *arg)
+{
+ ksft_print_msg("Testing Zicbom instructions remain privileged\n");
+
+ illegal_insn = false;
+ cbo_clean(&mem[0]);
+ ksft_test_result(illegal_insn, "No cbo.clean\n");
+
+ illegal_insn = false;
+ cbo_flush(&mem[0]);
+ ksft_test_result(illegal_insn, "No cbo.flush\n");
+
+ illegal_insn = false;
+ cbo_inval(&mem[0]);
+ ksft_test_result(illegal_insn, "No cbo.inval\n");
+}
+
+static void test_no_zicboz(void *arg)
+{
+ ksft_print_msg("No Zicboz, testing cbo.zero remains privileged\n");
+
+ illegal_insn = false;
+ cbo_zero(&mem[0]);
+ ksft_test_result(illegal_insn, "No cbo.zero\n");
+}
+
+static bool is_power_of_2(__u64 n)
+{
+ return n != 0 && (n & (n - 1)) == 0;
+}
+
+static void test_zicboz(void *arg)
+{
+ struct riscv_hwprobe pair = {
+ .key = RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE,
+ };
+ cpu_set_t *cpus = (cpu_set_t *)arg;
+ __u64 block_size;
+ int i, j;
+ long rc;
+
+ rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)cpus, 0);
+ block_size = pair.value;
+ ksft_test_result(rc == 0 && pair.key == RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE &&
+ is_power_of_2(block_size), "Zicboz block size\n");
+ ksft_print_msg("Zicboz block size: %ld\n", block_size);
+
+ illegal_insn = false;
+ cbo_zero(&mem[block_size]);
+ ksft_test_result(!illegal_insn, "cbo.zero\n");
+
+ if (illegal_insn || !is_power_of_2(block_size)) {
+ ksft_test_result_skip("cbo.zero check\n");
+ return;
+ }
+
+ assert(block_size <= 1024);
+
+ for (i = 0; i < 4096 / block_size; ++i) {
+ if (i % 2)
+ cbo_zero(&mem[i * block_size]);
+ }
+
+ for (i = 0; i < 4096 / block_size; ++i) {
+ char expected = i % 2 ? 0x0 : 0xa5;
+
+ for (j = 0; j < block_size; ++j) {
+ if (mem[i * block_size + j] != expected) {
+ ksft_test_result_fail("cbo.zero check\n");
+ ksft_print_msg("cbo.zero check: mem[%d] != 0x%x\n",
+ i * block_size + j, expected);
+ return;
+ }
+ }
+ }
+
+ ksft_test_result_pass("cbo.zero check\n");
+}
+
+static void check_no_zicboz_cpus(cpu_set_t *cpus)
+{
+ struct riscv_hwprobe pair = {
+ .key = RISCV_HWPROBE_KEY_IMA_EXT_0,
+ };
+ cpu_set_t one_cpu;
+ int i = 0, c = 0;
+ long rc;
+
+ while (i++ < CPU_COUNT(cpus)) {
+ while (!CPU_ISSET(c, cpus))
+ ++c;
+
+ CPU_ZERO(&one_cpu);
+ CPU_SET(c, &one_cpu);
+
+ rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)&one_cpu, 0);
+ assert(rc == 0 && pair.key == RISCV_HWPROBE_KEY_IMA_EXT_0);
+
+ if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ)
+ ksft_exit_fail_msg("Zicboz is only present on a subset of harts.\n"
+ "Use taskset to select a set of harts where Zicboz\n"
+ "presence (present or not) is consistent for each hart\n");
+ ++c;
+ }
+}
+
+enum {
+ TEST_ZICBOZ,
+ TEST_NO_ZICBOZ,
+ TEST_NO_ZICBOM,
+};
+
+static struct test_info {
+ bool enabled;
+ unsigned int nr_tests;
+ void (*test_fn)(void *arg);
+} tests[] = {
+ [TEST_ZICBOZ] = { .nr_tests = 3, test_zicboz },
+ [TEST_NO_ZICBOZ] = { .nr_tests = 1, test_no_zicboz },
+ [TEST_NO_ZICBOM] = { .nr_tests = 3, test_no_zicbom },
+};
+
+int main(int argc, char **argv)
+{
+ struct sigaction act = {
+ .sa_sigaction = &sigill_handler,
+ .sa_flags = SA_SIGINFO,
+ };
+ struct riscv_hwprobe pair;
+ unsigned int plan = 0;
+ cpu_set_t cpus;
+ long rc;
+ int i;
+
+ if (argc > 1 && !strcmp(argv[1], "--sigill")) {
+ rc = sigaction(SIGILL, &act, NULL);
+ assert(rc == 0);
+ tests[TEST_NO_ZICBOZ].enabled = true;
+ tests[TEST_NO_ZICBOM].enabled = true;
+ }
+
+ rc = sched_getaffinity(0, sizeof(cpu_set_t), &cpus);
+ assert(rc == 0);
+
+ ksft_print_header();
+
+ pair.key = RISCV_HWPROBE_KEY_IMA_EXT_0;
+ rc = riscv_hwprobe(&pair, 1, sizeof(cpu_set_t), (unsigned long *)&cpus, 0);
+ if (rc < 0)
+ ksft_exit_fail_msg("hwprobe() failed with %d\n", rc);
+ assert(rc == 0 && pair.key == RISCV_HWPROBE_KEY_IMA_EXT_0);
+
+ if (pair.value & RISCV_HWPROBE_EXT_ZICBOZ) {
+ tests[TEST_ZICBOZ].enabled = true;
+ tests[TEST_NO_ZICBOZ].enabled = false;
+ } else {
+ check_no_zicboz_cpus(&cpus);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(tests); ++i)
+ plan += tests[i].enabled ? tests[i].nr_tests : 0;
+
+ if (plan == 0)
+ ksft_print_msg("No tests enabled.\n");
+ else
+ ksft_set_plan(plan);
+
+ for (i = 0; i < ARRAY_SIZE(tests); ++i) {
+ if (tests[i].enabled)
+ tests[i].test_fn(&cpus);
+ }
+
+ ksft_finished();
+}
diff --git a/tools/testing/selftests/riscv/hwprobe/hwprobe.c b/tools/testing/selftests/riscv/hwprobe/hwprobe.c
index 4f15f1f3b4c3..c474891df307 100644
--- a/tools/testing/selftests/riscv/hwprobe/hwprobe.c
+++ b/tools/testing/selftests/riscv/hwprobe/hwprobe.c
@@ -1,17 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
-#include <stddef.h>
-#include <asm/hwprobe.h>
-
+#include "hwprobe.h"
#include "../../kselftest.h"
-/*
- * Rather than relying on having a new enough libc to define this, just do it
- * ourselves. This way we don't need to be coupled to a new-enough libc to
- * contain the call.
- */
-long riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
- size_t cpu_count, unsigned long *cpus, unsigned int flags);
-
int main(int argc, char **argv)
{
struct riscv_hwprobe pairs[8];
diff --git a/tools/testing/selftests/riscv/hwprobe/hwprobe.h b/tools/testing/selftests/riscv/hwprobe/hwprobe.h
new file mode 100644
index 000000000000..721b0ce73a56
--- /dev/null
+++ b/tools/testing/selftests/riscv/hwprobe/hwprobe.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_RISCV_HWPROBE_H
+#define SELFTEST_RISCV_HWPROBE_H
+#include <stddef.h>
+#include <asm/hwprobe.h>
+
+/*
+ * Rather than relying on having a new enough libc to define this, just do it
+ * ourselves. This way we don't need to be coupled to a new-enough libc to
+ * contain the call.
+ */
+long riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count,
+ size_t cpu_count, unsigned long *cpus, unsigned int flags);
+
+#endif
--
2.41.0
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