1 files changed, 356 insertions, 0 deletions
diff --git a/tools/testing/selftests/arm64/fp/za-ptrace.c b/tools/testing/selftests/arm64/fp/za-ptrace.c
new file mode 100644
index 000000000000..bf6158654056
--- /dev/null
+++ b/tools/testing/selftests/arm64/fp/za-ptrace.c
@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 ARM Limited.
+ */
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+#include <sys/prctl.h>
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+#include <asm/sigcontext.h>
+#include <asm/ptrace.h>
+
+#include "../../kselftest.h"
+
+/* <linux/elf.h> and <sys/auxv.h> don't like each other, so: */
+#ifndef NT_ARM_ZA
+#define NT_ARM_ZA 0x40c
+#endif
+
+#define EXPECTED_TESTS (((SVE_VQ_MAX - SVE_VQ_MIN) + 1) * 3)
+
+static void fill_buf(char *buf, size_t size)
+{
+	int i;
+
+	for (i = 0; i < size; i++)
+		buf[i] = random();
+}
+
+static int do_child(void)
+{
+	if (ptrace(PTRACE_TRACEME, -1, NULL, NULL))
+		ksft_exit_fail_msg("PTRACE_TRACEME", strerror(errno));
+
+	if (raise(SIGSTOP))
+		ksft_exit_fail_msg("raise(SIGSTOP)", strerror(errno));
+
+	return EXIT_SUCCESS;
+}
+
+static struct user_za_header *get_za(pid_t pid, void **buf, size_t *size)
+{
+	struct user_za_header *za;
+	void *p;
+	size_t sz = sizeof(*za);
+	struct iovec iov;
+
+	while (1) {
+		if (*size < sz) {
+			p = realloc(*buf, sz);
+			if (!p) {
+				errno = ENOMEM;
+				goto error;
+			}
+
+			*buf = p;
+			*size = sz;
+		}
+
+		iov.iov_base = *buf;
+		iov.iov_len = sz;
+		if (ptrace(PTRACE_GETREGSET, pid, NT_ARM_ZA, &iov))
+			goto error;
+
+		za = *buf;
+		if (za->size <= sz)
+			break;
+
+		sz = za->size;
+	}
+
+	return za;
+
+error:
+	return NULL;
+}
+
+static int set_za(pid_t pid, const struct user_za_header *za)
+{
+	struct iovec iov;
+
+	iov.iov_base = (void *)za;
+	iov.iov_len = za->size;
+	return ptrace(PTRACE_SETREGSET, pid, NT_ARM_ZA, &iov);
+}
+
+/* Validate attempting to set the specfied VL via ptrace */
+static void ptrace_set_get_vl(pid_t child, unsigned int vl, bool *supported)
+{
+	struct user_za_header za;
+	struct user_za_header *new_za = NULL;
+	size_t new_za_size = 0;
+	int ret, prctl_vl;
+
+	*supported = false;
+
+	/* Check if the VL is supported in this process */
+	prctl_vl = prctl(PR_SME_SET_VL, vl);
+	if (prctl_vl == -1)
+		ksft_exit_fail_msg("prctl(PR_SME_SET_VL) failed: %s (%d)\n",
+				   strerror(errno), errno);
+
+	/* If the VL is not supported then a supported VL will be returned */
+	*supported = (prctl_vl == vl);
+
+	/* Set the VL by doing a set with no register payload */
+	memset(&za, 0, sizeof(za));
+	za.size = sizeof(za);
+	za.vl = vl;
+	ret = set_za(child, &za);
+	if (ret != 0) {
+		ksft_test_result_fail("Failed to set VL %u\n", vl);
+		return;
+	}
+
+	/*
+	 * Read back the new register state and verify that we have the
+	 * same VL that we got from prctl() on ourselves.
+	 */
+	if (!get_za(child, (void **)&new_za, &new_za_size)) {
+		ksft_test_result_fail("Failed to read VL %u\n", vl);
+		return;
+	}
+
+	ksft_test_result(new_za->vl = prctl_vl, "Set VL %u\n", vl);
+
+	free(new_za);
+}
+
+/* Validate attempting to set no ZA data and read it back */
+static void ptrace_set_no_data(pid_t child, unsigned int vl)
+{
+	void *read_buf = NULL;
+	struct user_za_header write_za;
+	struct user_za_header *read_za;
+	size_t read_za_size = 0;
+	int ret;
+
+	/* Set up some data and write it out */
+	memset(&write_za, 0, sizeof(write_za));
+	write_za.size = ZA_PT_ZA_OFFSET;
+	write_za.vl = vl;
+
+	ret = set_za(child, &write_za);
+	if (ret != 0) {
+		ksft_test_result_fail("Failed to set VL %u no data\n", vl);
+		return;
+	}
+
+	/* Read the data back */
+	if (!get_za(child, (void **)&read_buf, &read_za_size)) {
+		ksft_test_result_fail("Failed to read VL %u no data\n", vl);
+		return;
+	}
+	read_za = read_buf;
+
+	/* We might read more data if there's extensions we don't know */
+	if (read_za->size < write_za.size) {
+		ksft_test_result_fail("VL %u wrote %d bytes, only read %d\n",
+				      vl, write_za.size, read_za->size);
+		goto out_read;
+	}
+
+	ksft_test_result(read_za->size == write_za.size,
+			 "Disabled ZA for VL %u\n", vl);
+
+out_read:
+	free(read_buf);
+}
+
+/* Validate attempting to set data and read it back */
+static void ptrace_set_get_data(pid_t child, unsigned int vl)
+{
+	void *write_buf;
+	void *read_buf = NULL;
+	struct user_za_header *write_za;
+	struct user_za_header *read_za;
+	size_t read_za_size = 0;
+	unsigned int vq = sve_vq_from_vl(vl);
+	int ret;
+	size_t data_size;
+
+	data_size = ZA_PT_SIZE(vq);
+	write_buf = malloc(data_size);
+	if (!write_buf) {
+		ksft_test_result_fail("Error allocating %d byte buffer for VL %u\n",
+				      data_size, vl);
+		return;
+	}
+	write_za = write_buf;
+
+	/* Set up some data and write it out */
+	memset(write_za, 0, data_size);
+	write_za->size = data_size;
+	write_za->vl = vl;
+
+	fill_buf(write_buf + ZA_PT_ZA_OFFSET, ZA_PT_ZA_SIZE(vq));
+
+	ret = set_za(child, write_za);
+	if (ret != 0) {
+		ksft_test_result_fail("Failed to set VL %u data\n", vl);
+		goto out;
+	}
+
+	/* Read the data back */
+	if (!get_za(child, (void **)&read_buf, &read_za_size)) {
+		ksft_test_result_fail("Failed to read VL %u data\n", vl);
+		goto out;
+	}
+	read_za = read_buf;
+
+	/* We might read more data if there's extensions we don't know */
+	if (read_za->size < write_za->size) {
+		ksft_test_result_fail("VL %u wrote %d bytes, only read %d\n",
+				      vl, write_za->size, read_za->size);
+		goto out_read;
+	}
+
+	ksft_test_result(memcmp(write_buf + ZA_PT_ZA_OFFSET,
+				read_buf + ZA_PT_ZA_OFFSET,
+				ZA_PT_ZA_SIZE(vq)) == 0,
+			 "Data match for VL %u\n", vl);
+
+out_read:
+	free(read_buf);
+out:
+	free(write_buf);
+}
+
+static int do_parent(pid_t child)
+{
+	int ret = EXIT_FAILURE;
+	pid_t pid;
+	int status;
+	siginfo_t si;
+	unsigned int vq, vl;
+	bool vl_supported;
+
+	/* Attach to the child */
+	while (1) {
+		int sig;
+
+		pid = wait(&status);
+		if (pid == -1) {
+			perror("wait");
+			goto error;
+		}
+
+		/*
+		 * This should never happen but it's hard to flag in
+		 * the framework.
+		 */
+		if (pid != child)
+			continue;
+
+		if (WIFEXITED(status) || WIFSIGNALED(status))
+			ksft_exit_fail_msg("Child died unexpectedly\n");
+
+		if (!WIFSTOPPED(status))
+			goto error;
+
+		sig = WSTOPSIG(status);
+
+		if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &si)) {
+			if (errno == ESRCH)
+				goto disappeared;
+
+			if (errno == EINVAL) {
+				sig = 0; /* bust group-stop */
+				goto cont;
+			}
+
+			ksft_test_result_fail("PTRACE_GETSIGINFO: %s\n",
+					      strerror(errno));
+			goto error;
+		}
+
+		if (sig == SIGSTOP && si.si_code == SI_TKILL &&
+		    si.si_pid == pid)
+			break;
+
+	cont:
+		if (ptrace(PTRACE_CONT, pid, NULL, sig)) {
+			if (errno == ESRCH)
+				goto disappeared;
+
+			ksft_test_result_fail("PTRACE_CONT: %s\n",
+					      strerror(errno));
+			goto error;
+		}
+	}
+
+	ksft_print_msg("Parent is %d, child is %d\n", getpid(), child);
+
+	/* Step through every possible VQ */
+	for (vq = SVE_VQ_MIN; vq <= SVE_VQ_MAX; vq++) {
+		vl = sve_vl_from_vq(vq);
+
+		/* First, try to set this vector length */
+		ptrace_set_get_vl(child, vl, &vl_supported);
+
+		/* If the VL is supported validate data set/get */
+		if (vl_supported) {
+			ptrace_set_no_data(child, vl);
+			ptrace_set_get_data(child, vl);
+		} else {
+			ksft_test_result_skip("Disabled ZA for VL %u\n", vl);
+			ksft_test_result_skip("Get and set data for VL %u\n",
+					      vl);
+		}
+	}
+
+	ret = EXIT_SUCCESS;
+
+error:
+	kill(child, SIGKILL);
+
+disappeared:
+	return ret;
+}
+
+int main(void)
+{
+	int ret = EXIT_SUCCESS;
+	pid_t child;
+
+	srandom(getpid());
+
+	ksft_print_header();
+
+	if (!(getauxval(AT_HWCAP2) & HWCAP2_SME)) {
+		ksft_set_plan(1);
+		ksft_exit_skip("SME not available\n");
+	}
+
+	ksft_set_plan(EXPECTED_TESTS);
+
+	child = fork();
+	if (!child)
+		return do_child();
+
+	if (do_parent(child))
+		ret = EXIT_FAILURE;
+
+	ksft_print_cnts();
+
+	return ret;
+}