kselftest/arm64: Add utilities and a test to validate mte memory

This test checks that the memory tag is present after mte allocation and
the memory is accessible with those tags. This testcase verifies all
sync, async and none mte error reporting mode. The allocated mte buffers
are verified for Allocated range (no error expected while accessing
buffer), Underflow range, and Overflow range.

Different test scenarios covered here are,
* Verify that mte memory are accessible at byte/block level.
* Force underflow and overflow to occur and check the data consistency.
* Check to/from between tagged and untagged memory.
* Check that initial allocated memory to have 0 tag.

This change also creates the necessary infrastructure to add mte test
cases. MTE kselftests can use the several utility functions provided here
to add wide variety of mte test scenarios.

GCC compiler need flag '-march=armv8.5-a+memtag' so those flags are
verified before compilation.

The mte testcases can be launched with kselftest framework as,

make TARGETS=arm64 ARM64_SUBTARGETS=mte kselftest

or compiled as,

make -C tools/testing/selftests TARGETS=arm64 ARM64_SUBTARGETS=mte CC='compiler'

Co-developed-by: Gabor Kertesz <gabor.kertesz@arm.com>
Signed-off-by: Gabor Kertesz <gabor.kertesz@arm.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201002115630.24683-2-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 341 insertions, 0 deletions

diff --git a/tools/testing/selftests/arm64/mte/mte_common_util.c b/tools/testing/selftests/arm64/mte/mte_common_util.c
new file mode 100644
index 000000000000..39f8908988ea
--- /dev/null
+++ b/tools/testing/selftests/arm64/mte/mte_common_util.c
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 ARM Limited
+
+#include <fcntl.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <linux/auxvec.h>
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+
+#include <asm/hwcap.h>
+
+#include "kselftest.h"
+#include "mte_common_util.h"
+#include "mte_def.h"
+
+#define INIT_BUFFER_SIZE       256
+
+struct mte_fault_cxt cur_mte_cxt;
+static unsigned int mte_cur_mode;
+static unsigned int mte_cur_pstate_tco;
+
+void mte_default_handler(int signum, siginfo_t *si, void *uc)
+{
+	unsigned long addr = (unsigned long)si->si_addr;
+
+	if (signum == SIGSEGV) {
+#ifdef DEBUG
+		ksft_print_msg("INFO: SIGSEGV signal at pc=%lx, fault addr=%lx, si_code=%lx\n",
+				((ucontext_t *)uc)->uc_mcontext.pc, addr, si->si_code);
+#endif
+		if (si->si_code == SEGV_MTEAERR) {
+			if (cur_mte_cxt.trig_si_code == si->si_code)
+				cur_mte_cxt.fault_valid = true;
+			return;
+		}
+		/* Compare the context for precise error */
+		else if (si->si_code == SEGV_MTESERR) {
+			if (cur_mte_cxt.trig_si_code == si->si_code &&
+			    ((cur_mte_cxt.trig_range >= 0 &&
+			      addr >= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
+			      addr <= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)) ||
+			     (cur_mte_cxt.trig_range < 0 &&
+			      addr <= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
+			      addr >= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)))) {
+				cur_mte_cxt.fault_valid = true;
+				/* Adjust the pc by 4 */
+				((ucontext_t *)uc)->uc_mcontext.pc += 4;
+			} else {
+				ksft_print_msg("Invalid MTE synchronous exception caught!\n");
+				exit(1);
+			}
+		} else {
+			ksft_print_msg("Unknown SIGSEGV exception caught!\n");
+			exit(1);
+		}
+	} else if (signum == SIGBUS) {
+		ksft_print_msg("INFO: SIGBUS signal at pc=%lx, fault addr=%lx, si_code=%lx\n",
+				((ucontext_t *)uc)->uc_mcontext.pc, addr, si->si_code);
+		if ((cur_mte_cxt.trig_range >= 0 &&
+		     addr >= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
+		     addr <= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range)) ||
+		    (cur_mte_cxt.trig_range < 0 &&
+		     addr <= MT_CLEAR_TAG(cur_mte_cxt.trig_addr) &&
+		     addr >= (MT_CLEAR_TAG(cur_mte_cxt.trig_addr) + cur_mte_cxt.trig_range))) {
+			cur_mte_cxt.fault_valid = true;
+			/* Adjust the pc by 4 */
+			((ucontext_t *)uc)->uc_mcontext.pc += 4;
+		}
+	}
+}
+
+void mte_register_signal(int signal, void (*handler)(int, siginfo_t *, void *))
+{
+	struct sigaction sa;
+
+	sa.sa_sigaction = handler;
+	sa.sa_flags = SA_SIGINFO;
+	sigemptyset(&sa.sa_mask);
+	sigaction(signal, &sa, NULL);
+}
+
+void mte_wait_after_trig(void)
+{
+	sched_yield();
+}
+
+void *mte_insert_tags(void *ptr, size_t size)
+{
+	void *tag_ptr;
+	int align_size;
+
+	if (!ptr || (unsigned long)(ptr) & MT_ALIGN_GRANULE) {
+		ksft_print_msg("FAIL: Addr=%lx: invalid\n", ptr);
+		return NULL;
+	}
+	align_size = MT_ALIGN_UP(size);
+	tag_ptr = mte_insert_random_tag(ptr);
+	mte_set_tag_address_range(tag_ptr, align_size);
+	return tag_ptr;
+}
+
+void mte_clear_tags(void *ptr, size_t size)
+{
+	if (!ptr || (unsigned long)(ptr) & MT_ALIGN_GRANULE) {
+		ksft_print_msg("FAIL: Addr=%lx: invalid\n", ptr);
+		return;
+	}
+	size = MT_ALIGN_UP(size);
+	ptr = (void *)MT_CLEAR_TAG((unsigned long)ptr);
+	mte_clear_tag_address_range(ptr, size);
+}
+
+static void *__mte_allocate_memory_range(size_t size, int mem_type, int mapping,
+					 size_t range_before, size_t range_after,
+					 bool tags, int fd)
+{
+	void *ptr;
+	int prot_flag, map_flag;
+	size_t entire_size = size + range_before + range_after;
+
+	if (mem_type != USE_MALLOC && mem_type != USE_MMAP &&
+	    mem_type != USE_MPROTECT) {
+		ksft_print_msg("FAIL: Invalid allocate request\n");
+		return NULL;
+	}
+	if (mem_type == USE_MALLOC)
+		return malloc(entire_size) + range_before;
+
+	prot_flag = PROT_READ | PROT_WRITE;
+	if (mem_type == USE_MMAP)
+		prot_flag |= PROT_MTE;
+
+	map_flag = mapping;
+	if (fd == -1)
+		map_flag = MAP_ANONYMOUS | map_flag;
+	if (!(mapping & MAP_SHARED))
+		map_flag |= MAP_PRIVATE;
+	ptr = mmap(NULL, entire_size, prot_flag, map_flag, fd, 0);
+	if (ptr == MAP_FAILED) {
+		ksft_print_msg("FAIL: mmap allocation\n");
+		return NULL;
+	}
+	if (mem_type == USE_MPROTECT) {
+		if (mprotect(ptr, entire_size, prot_flag | PROT_MTE)) {
+			munmap(ptr, size);
+			ksft_print_msg("FAIL: mprotect PROT_MTE property\n");
+			return NULL;
+		}
+	}
+	if (tags)
+		ptr = mte_insert_tags(ptr + range_before, size);
+	return ptr;
+}
+
+void *mte_allocate_memory_tag_range(size_t size, int mem_type, int mapping,
+				    size_t range_before, size_t range_after)
+{
+	return __mte_allocate_memory_range(size, mem_type, mapping, range_before,
+					   range_after, true, -1);
+}
+
+void *mte_allocate_memory(size_t size, int mem_type, int mapping, bool tags)
+{
+	return __mte_allocate_memory_range(size, mem_type, mapping, 0, 0, tags, -1);
+}
+
+void *mte_allocate_file_memory(size_t size, int mem_type, int mapping, bool tags, int fd)
+{
+	int index;
+	char buffer[INIT_BUFFER_SIZE];
+
+	if (mem_type != USE_MPROTECT && mem_type != USE_MMAP) {
+		ksft_print_msg("FAIL: Invalid mmap file request\n");
+		return NULL;
+	}
+	/* Initialize the file for mappable size */
+	lseek(fd, 0, SEEK_SET);
+	for (index = INIT_BUFFER_SIZE; index < size; index += INIT_BUFFER_SIZE)
+		write(fd, buffer, INIT_BUFFER_SIZE);
+	index -= INIT_BUFFER_SIZE;
+	write(fd, buffer, size - index);
+	return __mte_allocate_memory_range(size, mem_type, mapping, 0, 0, tags, fd);
+}
+
+void *mte_allocate_file_memory_tag_range(size_t size, int mem_type, int mapping,
+					 size_t range_before, size_t range_after, int fd)
+{
+	int index;
+	char buffer[INIT_BUFFER_SIZE];
+	int map_size = size + range_before + range_after;
+
+	if (mem_type != USE_MPROTECT && mem_type != USE_MMAP) {
+		ksft_print_msg("FAIL: Invalid mmap file request\n");
+		return NULL;
+	}
+	/* Initialize the file for mappable size */
+	lseek(fd, 0, SEEK_SET);
+	for (index = INIT_BUFFER_SIZE; index < map_size; index += INIT_BUFFER_SIZE)
+		write(fd, buffer, INIT_BUFFER_SIZE);
+	index -= INIT_BUFFER_SIZE;
+	write(fd, buffer, map_size - index);
+	return __mte_allocate_memory_range(size, mem_type, mapping, range_before,
+					   range_after, true, fd);
+}
+
+static void __mte_free_memory_range(void *ptr, size_t size, int mem_type,
+				    size_t range_before, size_t range_after, bool tags)
+{
+	switch (mem_type) {
+	case USE_MALLOC:
+		free(ptr - range_before);
+		break;
+	case USE_MMAP:
+	case USE_MPROTECT:
+		if (tags)
+			mte_clear_tags(ptr, size);
+		munmap(ptr - range_before, size + range_before + range_after);
+		break;
+	default:
+		ksft_print_msg("FAIL: Invalid free request\n");
+		break;
+	}
+}
+
+void mte_free_memory_tag_range(void *ptr, size_t size, int mem_type,
+			       size_t range_before, size_t range_after)
+{
+	__mte_free_memory_range(ptr, size, mem_type, range_before, range_after, true);
+}
+
+void mte_free_memory(void *ptr, size_t size, int mem_type, bool tags)
+{
+	__mte_free_memory_range(ptr, size, mem_type, 0, 0, tags);
+}
+
+void mte_initialize_current_context(int mode, uintptr_t ptr, ssize_t range)
+{
+	cur_mte_cxt.fault_valid = false;
+	cur_mte_cxt.trig_addr = ptr;
+	cur_mte_cxt.trig_range = range;
+	if (mode == MTE_SYNC_ERR)
+		cur_mte_cxt.trig_si_code = SEGV_MTESERR;
+	else if (mode == MTE_ASYNC_ERR)
+		cur_mte_cxt.trig_si_code = SEGV_MTEAERR;
+	else
+		cur_mte_cxt.trig_si_code = 0;
+}
+
+int mte_switch_mode(int mte_option, unsigned long incl_mask)
+{
+	unsigned long en = 0;
+
+	if (!(mte_option == MTE_SYNC_ERR || mte_option == MTE_ASYNC_ERR ||
+	      mte_option == MTE_NONE_ERR || incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
+		ksft_print_msg("FAIL: Invalid mte config option\n");
+		return -EINVAL;
+	}
+	en = PR_TAGGED_ADDR_ENABLE;
+	if (mte_option == MTE_SYNC_ERR)
+		en |= PR_MTE_TCF_SYNC;
+	else if (mte_option == MTE_ASYNC_ERR)
+		en |= PR_MTE_TCF_ASYNC;
+	else if (mte_option == MTE_NONE_ERR)
+		en |= PR_MTE_TCF_NONE;
+
+	en |= (incl_mask << PR_MTE_TAG_SHIFT);
+	/* Enable address tagging ABI, mte error reporting mode and tag inclusion mask. */
+	if (!prctl(PR_SET_TAGGED_ADDR_CTRL, en, 0, 0, 0) == 0) {
+		ksft_print_msg("FAIL:prctl PR_SET_TAGGED_ADDR_CTRL for mte mode\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+#define ID_AA64PFR1_MTE_SHIFT		8
+#define ID_AA64PFR1_MTE			2
+
+int mte_default_setup(void)
+{
+	unsigned long hwcaps = getauxval(AT_HWCAP);
+	unsigned long en = 0;
+	int ret;
+
+	if (!(hwcaps & HWCAP_CPUID)) {
+		ksft_print_msg("FAIL: CPUID registers unavailable\n");
+		return KSFT_FAIL;
+	}
+	/* Read ID_AA64PFR1_EL1 register */
+	asm volatile("mrs %0, id_aa64pfr1_el1" : "=r"(hwcaps) : : "memory");
+	if (((hwcaps >> ID_AA64PFR1_MTE_SHIFT) & MT_TAG_MASK) != ID_AA64PFR1_MTE) {
+		ksft_print_msg("FAIL: MTE features unavailable\n");
+		return KSFT_SKIP;
+	}
+	/* Get current mte mode */
+	ret = prctl(PR_GET_TAGGED_ADDR_CTRL, en, 0, 0, 0);
+	if (ret < 0) {
+		ksft_print_msg("FAIL:prctl PR_GET_TAGGED_ADDR_CTRL with error =%d\n", ret);
+		return KSFT_FAIL;
+	}
+	if (ret & PR_MTE_TCF_SYNC)
+		mte_cur_mode = MTE_SYNC_ERR;
+	else if (ret & PR_MTE_TCF_ASYNC)
+		mte_cur_mode = MTE_ASYNC_ERR;
+	else if (ret & PR_MTE_TCF_NONE)
+		mte_cur_mode = MTE_NONE_ERR;
+
+	mte_cur_pstate_tco = mte_get_pstate_tco();
+	/* Disable PSTATE.TCO */
+	mte_disable_pstate_tco();
+	return 0;
+}
+
+void mte_restore_setup(void)
+{
+	mte_switch_mode(mte_cur_mode, MTE_ALLOW_NON_ZERO_TAG);
+	if (mte_cur_pstate_tco == MT_PSTATE_TCO_EN)
+		mte_enable_pstate_tco();
+	else if (mte_cur_pstate_tco == MT_PSTATE_TCO_DIS)
+		mte_disable_pstate_tco();
+}
+
+int create_temp_file(void)
+{
+	int fd;
+	char filename[] = "/dev/shm/tmp_XXXXXX";
+
+	/* Create a file in the tmpfs filesystem */
+	fd = mkstemp(&filename[0]);
+	if (fd == -1) {
+		ksft_print_msg("FAIL: Unable to open temporary file\n");
+		return 0;
+	}
+	unlink(&filename[0]);
+	return fd;
+}