kselftest/arm64: Verify mte tag inclusion via prctl

This testcase verifies that the tag generated with "irg" instruction
contains only included tags. This is done via prtcl call.

This test covers 4 scenarios,
* At least one included tag.
* More than one included tags.
* All included.
* None included.
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/20201002115630.24683-3-amit.kachhap@arm.comSigned-off-by: Will Deacon <will@kernel.org>

tools/testing/selftests/arm64/mte/.gitignore

 check_buffer_fill
+check_tags_inclusion

tools/testing/selftests/arm64/mte/check_tags_inclusion.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 ARM Limited
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ucontext.h>
+#include <sys/wait.h>
+
+#include "kselftest.h"
+#include "mte_common_util.h"
+#include "mte_def.h"
+
+#define BUFFER_SIZE		(5 * MT_GRANULE_SIZE)
+#define RUNS			(MT_TAG_COUNT * 2)
+#define MTE_LAST_TAG_MASK	(0x7FFF)
+
+static int verify_mte_pointer_validity(char *ptr, int mode)
+{
+	mte_initialize_current_context(mode, (uintptr_t)ptr, BUFFER_SIZE);
+	/* Check the validity of the tagged pointer */
+	memset((void *)ptr, '1', BUFFER_SIZE);
+	mte_wait_after_trig();
+	if (cur_mte_cxt.fault_valid)
+		return KSFT_FAIL;
+	/* Proceed further for nonzero tags */
+	if (!MT_FETCH_TAG((uintptr_t)ptr))
+		return KSFT_PASS;
+	mte_initialize_current_context(mode, (uintptr_t)ptr, BUFFER_SIZE + 1);
+	/* Check the validity outside the range */
+	ptr[BUFFER_SIZE] = '2';
+	mte_wait_after_trig();
+	if (!cur_mte_cxt.fault_valid)
+		return KSFT_FAIL;
+	else
+		return KSFT_PASS;
+}
+
+static int check_single_included_tags(int mem_type, int mode)
+{
+	char *ptr;
+	int tag, run, result = KSFT_PASS;
+
+	ptr = (char *)mte_allocate_memory(BUFFER_SIZE + MT_GRANULE_SIZE, mem_type, 0, false);
+	if (check_allocated_memory(ptr, BUFFER_SIZE + MT_GRANULE_SIZE,
+				   mem_type, false) != KSFT_PASS)
+		return KSFT_FAIL;
+
+	for (tag = 0; (tag < MT_TAG_COUNT) && (result == KSFT_PASS); tag++) {
+		mte_switch_mode(mode, MT_INCLUDE_VALID_TAG(tag));
+		/* Try to catch a excluded tag by a number of tries. */
+		for (run = 0; (run < RUNS) && (result == KSFT_PASS); run++) {
+			ptr = (char *)mte_insert_tags(ptr, BUFFER_SIZE);
+			/* Check tag value */
+			if (MT_FETCH_TAG((uintptr_t)ptr) == tag) {
+				ksft_print_msg("FAIL: wrong tag = 0x%x with include mask=0x%x\n",
+					       MT_FETCH_TAG((uintptr_t)ptr),
+					       MT_INCLUDE_VALID_TAG(tag));
+				result = KSFT_FAIL;
+				break;
+			}
+			result = verify_mte_pointer_validity(ptr, mode);
+		}
+	}
+	mte_free_memory_tag_range((void *)ptr, BUFFER_SIZE, mem_type, 0, MT_GRANULE_SIZE);
+	return result;
+}
+
+static int check_multiple_included_tags(int mem_type, int mode)
+{
+	char *ptr;
+	int tag, run, result = KSFT_PASS;
+	unsigned long excl_mask = 0;
+
+	ptr = (char *)mte_allocate_memory(BUFFER_SIZE + MT_GRANULE_SIZE, mem_type, 0, false);
+	if (check_allocated_memory(ptr, BUFFER_SIZE + MT_GRANULE_SIZE,
+				   mem_type, false) != KSFT_PASS)
+		return KSFT_FAIL;
+
+	for (tag = 0; (tag < MT_TAG_COUNT - 1) && (result == KSFT_PASS); tag++) {
+		excl_mask |= 1 << tag;
+		mte_switch_mode(mode, MT_INCLUDE_VALID_TAGS(excl_mask));
+		/* Try to catch a excluded tag by a number of tries. */
+		for (run = 0; (run < RUNS) && (result == KSFT_PASS); run++) {
+			ptr = (char *)mte_insert_tags(ptr, BUFFER_SIZE);
+			/* Check tag value */
+			if (MT_FETCH_TAG((uintptr_t)ptr) < tag) {
+				ksft_print_msg("FAIL: wrong tag = 0x%x with include mask=0x%x\n",
+					       MT_FETCH_TAG((uintptr_t)ptr),
+					       MT_INCLUDE_VALID_TAGS(excl_mask));
+				result = KSFT_FAIL;
+				break;
+			}
+			result = verify_mte_pointer_validity(ptr, mode);
+		}
+	}
+	mte_free_memory_tag_range((void *)ptr, BUFFER_SIZE, mem_type, 0, MT_GRANULE_SIZE);
+	return result;
+}
+
+static int check_all_included_tags(int mem_type, int mode)
+{
+	char *ptr;
+	int run, result = KSFT_PASS;
+
+	ptr = (char *)mte_allocate_memory(BUFFER_SIZE + MT_GRANULE_SIZE, mem_type, 0, false);
+	if (check_allocated_memory(ptr, BUFFER_SIZE + MT_GRANULE_SIZE,
+				   mem_type, false) != KSFT_PASS)
+		return KSFT_FAIL;
+
+	mte_switch_mode(mode, MT_INCLUDE_TAG_MASK);
+	/* Try to catch a excluded tag by a number of tries. */
+	for (run = 0; (run < RUNS) && (result == KSFT_PASS); run++) {
+		ptr = (char *)mte_insert_tags(ptr, BUFFER_SIZE);
+		/*
+		 * Here tag byte can be between 0x0 to 0xF (full allowed range)
+		 * so no need to match so just verify if it is writable.
+		 */
+		result = verify_mte_pointer_validity(ptr, mode);
+	}
+	mte_free_memory_tag_range((void *)ptr, BUFFER_SIZE, mem_type, 0, MT_GRANULE_SIZE);
+	return result;
+}
+
+static int check_none_included_tags(int mem_type, int mode)
+{
+	char *ptr;
+	int run;
+
+	ptr = (char *)mte_allocate_memory(BUFFER_SIZE, mem_type, 0, false);
+	if (check_allocated_memory(ptr, BUFFER_SIZE, mem_type, false) != KSFT_PASS)
+		return KSFT_FAIL;
+
+	mte_switch_mode(mode, MT_EXCLUDE_TAG_MASK);
+	/* Try to catch a excluded tag by a number of tries. */
+	for (run = 0; run < RUNS; run++) {
+		ptr = (char *)mte_insert_tags(ptr, BUFFER_SIZE);
+		/* Here all tags exluded so tag value generated should be 0 */
+		if (MT_FETCH_TAG((uintptr_t)ptr)) {
+			ksft_print_msg("FAIL: included tag value found\n");
+			mte_free_memory((void *)ptr, BUFFER_SIZE, mem_type, true);
+			return KSFT_FAIL;
+		}
+		mte_initialize_current_context(mode, (uintptr_t)ptr, BUFFER_SIZE);
+		/* Check the write validity of the untagged pointer */
+		memset((void *)ptr, '1', BUFFER_SIZE);
+		mte_wait_after_trig();
+		if (cur_mte_cxt.fault_valid)
+			break;
+	}
+	mte_free_memory((void *)ptr, BUFFER_SIZE, mem_type, false);
+	if (cur_mte_cxt.fault_valid)
+		return KSFT_FAIL;
+	else
+		return KSFT_PASS;
+}
+
+int main(int argc, char *argv[])
+{
+	int err;
+
+	err = mte_default_setup();
+	if (err)
+		return err;
+
+	/* Register SIGSEGV handler */
+	mte_register_signal(SIGSEGV, mte_default_handler);
+
+	evaluate_test(check_single_included_tags(USE_MMAP, MTE_SYNC_ERR),
+		      "Check an included tag value with sync mode\n");
+	evaluate_test(check_multiple_included_tags(USE_MMAP, MTE_SYNC_ERR),
+		      "Check different included tags value with sync mode\n");
+	evaluate_test(check_none_included_tags(USE_MMAP, MTE_SYNC_ERR),
+		      "Check none included tags value with sync mode\n");
+	evaluate_test(check_all_included_tags(USE_MMAP, MTE_SYNC_ERR),
+		      "Check all included tags value with sync mode\n");
+
+	mte_restore_setup();
+	ksft_print_cnts();
+	return ksft_get_fail_cnt() == 0 ? KSFT_PASS : KSFT_FAIL;
+}