Revert "FROMGIT: kasan, arm64: allow using KUnit tests with HW_TAGS mode"

This reverts commit a599a4e3b9.

The upstream version of this patch has been updated. Revert the FROMGIT
version before applying the UPSTREAM one.

Bug: 172318110
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Change-Id: I423a68e2a3e55b97b04180fedd7160c704ae0972

arch/arm64/include/asm/memory.h

@@ -233,7 +233,6 @@ static inline const void *__tag_set(const void *addr, u8 tag)
 
 #ifdef CONFIG_KASAN_HW_TAGS
 #define arch_enable_tagging()			mte_enable_kernel()
-#define arch_set_tagging_report_once(state)	mte_set_report_once(state)
 #define arch_init_tags(max_tag)			mte_init_tags(max_tag)
 #define arch_get_random_tag()			mte_get_random_tag()
 #define arch_get_mem_tag(addr)			mte_get_mem_tag(addr)

arch/arm64/include/asm/mte-kasan.h

@@ -80,9 +80,6 @@ static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
 void mte_enable_kernel(void);
 void mte_init_tags(u64 max_tag);
 
-void mte_set_report_once(bool state);
-bool mte_report_once(void);
-
 #else /* CONFIG_ARM64_MTE */
 
 static inline u8 mte_get_ptr_tag(void *ptr)
@@ -112,15 +109,6 @@ static inline void mte_init_tags(u64 max_tag)
 {
 }
 
-static inline void mte_set_report_once(bool state)
-{
-}
-
-static inline bool mte_report_once(void)
-{
-	return false;
-}
-
 #endif /* CONFIG_ARM64_MTE */
 
 #endif /* __ASSEMBLY__ */

arch/arm64/kernel/mte.c

@@ -24,8 +24,6 @@
 
 u64 gcr_kernel_excl __ro_after_init;
 
-static bool report_fault_once = true;
-
 static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap)
 {
 	pte_t old_pte = READ_ONCE(*ptep);
@@ -114,16 +112,6 @@ void mte_enable_kernel(void)
 	isb();
 }
 
-void mte_set_report_once(bool state)
-{
-	WRITE_ONCE(report_fault_once, state);
-}
-
-bool mte_report_once(void)
-{
-	return READ_ONCE(report_fault_once);
-}
-
 static void update_sctlr_el1_tcf0(u64 tcf0)
 {
 	/* ISB required for the kernel uaccess routines */

arch/arm64/mm/fault.c

@@ -306,24 +306,12 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
 static void report_tag_fault(unsigned long addr, unsigned int esr,
 			     struct pt_regs *regs)
 {
-	static bool reported;
+	bool is_write  = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
-	bool is_write;
-
-	if (READ_ONCE(reported))
-		return;
-
-	/*
-	 * This is used for KASAN tests and assumes that no MTE faults
-	 * happened before running the tests.
-	 */
-	if (mte_report_once())
-		WRITE_ONCE(reported, true);
 
 	/*
 	 * SAS bits aren't set for all faults reported in EL1, so we can't
 	 * find out access size.
 	 */
-	is_write = !!(esr & ESR_ELx_WNR);
 	kasan_report(addr, 0, is_write, regs->pc);
 }
 #else
@@ -335,8 +323,12 @@ static inline void report_tag_fault(unsigned long addr, unsigned int esr,
 static void do_tag_recovery(unsigned long addr, unsigned int esr,
 			   struct pt_regs *regs)
 {
+	static bool reported;
 
+	if (!READ_ONCE(reported)) {
 		report_tag_fault(addr, esr, regs);
+		WRITE_ONCE(reported, true);
+	}
 
 	/*
 	 * Disable MTE Tag Checking on the local CPU for the current EL.

lib/Kconfig.kasan

@@ -199,11 +199,11 @@ config KASAN_KUNIT_TEST
 	  kernel debugging features like KASAN.
 
 	  For more information on KUnit and unit tests in general, please refer
-	  to the KUnit documentation in Documentation/dev-tools/kunit.
+	  to the KUnit documentation in Documentation/dev-tools/kunit
 
 config KASAN_MODULE_TEST
 	tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
-	depends on m && KASAN && !KASAN_HW_TAGS
+	depends on m && KASAN
 	help
 	  This is a part of the KASAN test suite that is incompatible with
 	  KUnit. Currently includes tests that do bad copy_from/to_user

lib/test_kasan.c

@@ -41,9 +41,7 @@ static bool multishot;
 
 /*
  * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the
- * first detected bug and panic the kernel if panic_on_warn is enabled. For
+ * first detected bug and panic the kernel if panic_on_warn is enabled.
- * hardware tag-based KASAN also allow tag checking to be reenabled for each
- * test, see the comment for KUNIT_EXPECT_KASAN_FAIL().
  */
 static int kasan_test_init(struct kunit *test)
 {
@@ -53,13 +51,11 @@ static int kasan_test_init(struct kunit *test)
 	}
 
 	multishot = kasan_save_enable_multi_shot();
-	hw_set_tagging_report_once(false);
 	return 0;
 }
 
 static void kasan_test_exit(struct kunit *test)
 {
-	hw_set_tagging_report_once(true);
 	kasan_restore_multi_shot(multishot);
 }
 
@@ -69,19 +65,12 @@ static void kasan_test_exit(struct kunit *test)
  * resource named "kasan_data". Do not use this name for KUnit resources
  * outside of KASAN tests.
  *
- * For hardware tag-based KASAN, when a tag fault happens, tag checking is
- * normally auto-disabled. When this happens, this test handler reenables
- * tag checking. As tag checking can be only disabled or enabled per CPU, this
- * handler disables migration (preemption).
- *
  * Since the compiler doesn't see that the expression can change the fail_data
  * fields, it can reorder or optimize away the accesses to those fields.
  * Use READ/WRITE_ONCE() for the accesses and compiler barriers around the
  * expression to prevent that.
  */
 #define KUNIT_EXPECT_KASAN_FAIL(test, expression) do {		\
-	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS))			\
-		migrate_disable();				\
 	WRITE_ONCE(fail_data.report_expected, true);		\
 	WRITE_ONCE(fail_data.report_found, false);		\
 	kunit_add_named_resource(test,				\
@@ -95,11 +84,6 @@ static void kasan_test_exit(struct kunit *test)
 	KUNIT_EXPECT_EQ(test,					\
 			READ_ONCE(fail_data.report_expected),	\
 			READ_ONCE(fail_data.report_found));	\
-	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) {			\
-		if (READ_ONCE(fail_data.report_found))		\
-			hw_enable_tagging();			\
-		migrate_enable();				\
-	}							\
 } while (0)
 
 #define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do {			\

mm/kasan/kasan.h

@@ -281,9 +281,6 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 #ifndef arch_init_tags
 #define arch_init_tags(max_tag)
 #endif
-#ifndef arch_set_tagging_report_once
-#define arch_set_tagging_report_once(state)
-#endif
 #ifndef arch_get_random_tag
 #define arch_get_random_tag()	(0xFF)
 #endif
@@ -296,16 +293,10 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 
 #define hw_enable_tagging()			arch_enable_tagging()
 #define hw_init_tags(max_tag)			arch_init_tags(max_tag)
-#define hw_set_tagging_report_once(state)	arch_set_tagging_report_once(state)
 #define hw_get_random_tag()			arch_get_random_tag()
 #define hw_get_mem_tag(addr)			arch_get_mem_tag(addr)
 #define hw_set_mem_tag_range(addr, size, tag)	arch_set_mem_tag_range((addr), (size), (tag))
 
-#else /* CONFIG_KASAN_HW_TAGS */
-
-#define hw_enable_tagging()
-#define hw_set_tagging_report_once(state)
-
 #endif /* CONFIG_KASAN_HW_TAGS */
 
 #ifdef CONFIG_KASAN_SW_TAGS