kasan, arm64: implement HW_TAGS runtime

Provide implementation of KASAN functions required for the hardware
tag-based mode.  Those include core functions for memory and pointer
tagging (tags_hw.c) and bug reporting (report_tags_hw.c).  Also adapt
common KASAN code to support the new mode.

Link: https://lkml.kernel.org/r/cfd0fbede579a6b66755c98c88c108e54f9c56bf.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c
new file mode 100644
index 000000000000..da543eb832cd
--- /dev/null
+++ b/mm/kasan/report_hw_tags.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains hardware tag-based KASAN specific error reporting code.
+ *
+ * Copyright (c) 2020 Google, Inc.
+ * Author: Andrey Konovalov <andreyknvl@google.com>
+ */
+
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "kasan.h"
+
+const char *get_bug_type(struct kasan_access_info *info)
+{
+	return "invalid-access";
+}
+
+void *find_first_bad_addr(void *addr, size_t size)
+{
+	return reset_tag(addr);
+}
+
+void metadata_fetch_row(char *buffer, void *row)
+{
+	int i;
+
+	for (i = 0; i < META_BYTES_PER_ROW; i++)
+		buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
+}
+
+void print_tags(u8 addr_tag, const void *addr)
+{
+	u8 memory_tag = hw_get_mem_tag((void *)addr);
+
+	pr_err("Pointer tag: [%02x], memory tag: [%02x]\n",
+		addr_tag, memory_tag);
+}