Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
 "There's the usual summary below, but the highlights are support for
  the Armv8.6 timer extensions, KASAN support for asymmetric MTE, the
  ability to kexec() with the MMU enabled and a second attempt at
  switching to the generic pfn_valid() implementation.

  Summary:

   - Support for the Arm8.6 timer extensions, including a
     self-synchronising view of the system registers to elide some
     expensive ISB instructions.

   - Exception table cleanup and rework so that the fixup handlers
     appear correctly in backtraces.

   - A handful of miscellaneous changes, the main one being selection of
     CONFIG_HAVE_POSIX_CPU_TIMERS_TASK_WORK.

   - More mm and pgtable cleanups.

   - KASAN support for "asymmetric" MTE, where tag faults are reported
     synchronously for loads (via an exception) and asynchronously for
     stores (via a register).

   - Support for leaving the MMU enabled during kexec relocation, which
     significantly speeds up the operation.

   - Minor improvements to our perf PMU drivers.

   - Improvements to the compat vDSO build system, particularly when
     building with LLVM=1.

   - Preparatory work for handling some Coresight TRBE tracing errata.

   - Cleanup and refactoring of the SVE code to pave the way for SME
     support in future.

   - Ensure SCS pages are unpoisoned immediately prior to freeing them
     when KASAN is enabled for the vmalloc area.

   - Try moving to the generic pfn_valid() implementation again now that
     the DMA mapping issue from last time has been resolved.

   - Numerous improvements and additions to our FPSIMD and SVE
     selftests"

[ armv8.6 timer updates were in a shared branch and already came in
  through -tip in the timer pull  - Linus ]

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (85 commits)
  arm64: Select POSIX_CPU_TIMERS_TASK_WORK
  arm64: Document boot requirements for FEAT_SME_FA64
  arm64/sve: Fix warnings when SVE is disabled
  arm64/sve: Add stub for sve_max_virtualisable_vl()
  arm64: errata: Add detection for TRBE write to out-of-range
  arm64: errata: Add workaround for TSB flush failures
  arm64: errata: Add detection for TRBE overwrite in FILL mode
  arm64: Add Neoverse-N2, Cortex-A710 CPU part definition
  selftests: arm64: Factor out utility functions for assembly FP tests
  arm64: vmlinux.lds.S: remove `.fixup` section
  arm64: extable: add load_unaligned_zeropad() handler
  arm64: extable: add a dedicated uaccess handler
  arm64: extable: add `type` and `data` fields
  arm64: extable: use `ex` for `exception_table_entry`
  arm64: extable: make fixup_exception() return bool
  arm64: extable: consolidate definitions
  arm64: gpr-num: support W registers
  arm64: factor out GPR numbering helpers
  arm64: kvm: use kvm_exception_table_entry
  arm64: lib: __arch_copy_to_user(): fold fixups into body
  ...

3 files changed, 46 insertions, 17 deletions

diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 05d1e9460e2e..dc892119e88f 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -29,6 +29,7 @@ enum kasan_arg_mode {
 	KASAN_ARG_MODE_DEFAULT,
 	KASAN_ARG_MODE_SYNC,
 	KASAN_ARG_MODE_ASYNC,
+	KASAN_ARG_MODE_ASYMM,
 };
 
 enum kasan_arg_stacktrace {
@@ -45,9 +46,9 @@ static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init;
 DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled);
 EXPORT_SYMBOL(kasan_flag_enabled);
 
-/* Whether the asynchronous mode is enabled. */
-bool kasan_flag_async __ro_after_init;
-EXPORT_SYMBOL_GPL(kasan_flag_async);
+/* Whether the selected mode is synchronous/asynchronous/asymmetric.*/
+enum kasan_mode kasan_mode __ro_after_init;
+EXPORT_SYMBOL_GPL(kasan_mode);
 
 /* Whether to collect alloc/free stack traces. */
 DEFINE_STATIC_KEY_FALSE(kasan_flag_stacktrace);
@@ -69,7 +70,7 @@ static int __init early_kasan_flag(char *arg)
 }
 early_param("kasan", early_kasan_flag);
 
-/* kasan.mode=sync/async */
+/* kasan.mode=sync/async/asymm */
 static int __init early_kasan_mode(char *arg)
 {
 	if (!arg)
@@ -79,6 +80,8 @@ static int __init early_kasan_mode(char *arg)
 		kasan_arg_mode = KASAN_ARG_MODE_SYNC;
 	else if (!strcmp(arg, "async"))
 		kasan_arg_mode = KASAN_ARG_MODE_ASYNC;
+	else if (!strcmp(arg, "asymm"))
+		kasan_arg_mode = KASAN_ARG_MODE_ASYMM;
 	else
 		return -EINVAL;
 
@@ -116,11 +119,13 @@ void kasan_init_hw_tags_cpu(void)
 		return;
 
 	/*
-	 * Enable async mode only when explicitly requested through
-	 * the command line.
+	 * Enable async or asymm modes only when explicitly requested
+	 * through the command line.
 	 */
 	if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC)
 		hw_enable_tagging_async();
+	else if (kasan_arg_mode == KASAN_ARG_MODE_ASYMM)
+		hw_enable_tagging_asymm();
 	else
 		hw_enable_tagging_sync();
 }
@@ -143,15 +148,19 @@ void __init kasan_init_hw_tags(void)
 	case KASAN_ARG_MODE_DEFAULT:
 		/*
 		 * Default to sync mode.
-		 * Do nothing, kasan_flag_async keeps its default value.
 		 */
-		break;
+		fallthrough;
 	case KASAN_ARG_MODE_SYNC:
-		/* Do nothing, kasan_flag_async keeps its default value. */
+		/* Sync mode enabled. */
+		kasan_mode = KASAN_MODE_SYNC;
 		break;
 	case KASAN_ARG_MODE_ASYNC:
 		/* Async mode enabled. */
-		kasan_flag_async = true;
+		kasan_mode = KASAN_MODE_ASYNC;
+		break;
+	case KASAN_ARG_MODE_ASYMM:
+		/* Asymm mode enabled. */
+		kasan_mode = KASAN_MODE_ASYMM;
 		break;
 	}
 
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 8bf568a80eb8..b495e17445ad 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -13,16 +13,28 @@
 #include "../slab.h"
 
 DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace);
-extern bool kasan_flag_async __ro_after_init;
+
+enum kasan_mode {
+	KASAN_MODE_SYNC,
+	KASAN_MODE_ASYNC,
+	KASAN_MODE_ASYMM,
+};
+
+extern enum kasan_mode kasan_mode __ro_after_init;
 
 static inline bool kasan_stack_collection_enabled(void)
 {
 	return static_branch_unlikely(&kasan_flag_stacktrace);
 }
 
-static inline bool kasan_async_mode_enabled(void)
+static inline bool kasan_async_fault_possible(void)
+{
+	return kasan_mode == KASAN_MODE_ASYNC || kasan_mode == KASAN_MODE_ASYMM;
+}
+
+static inline bool kasan_sync_fault_possible(void)
 {
-	return kasan_flag_async;
+	return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM;
 }
 #else
 
@@ -31,14 +43,17 @@ static inline bool kasan_stack_collection_enabled(void)
 	return true;
 }
 
-static inline bool kasan_async_mode_enabled(void)
+static inline bool kasan_async_fault_possible(void)
 {
 	return false;
 }
 
-#endif
+static inline bool kasan_sync_fault_possible(void)
+{
+	return true;
+}
 
-extern bool kasan_flag_async __ro_after_init;
+#endif
 
 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 #define KASAN_GRANULE_SIZE	(1UL << KASAN_SHADOW_SCALE_SHIFT)
@@ -289,6 +304,9 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 #ifndef arch_enable_tagging_async
 #define arch_enable_tagging_async()
 #endif
+#ifndef arch_enable_tagging_asymm
+#define arch_enable_tagging_asymm()
+#endif
 #ifndef arch_force_async_tag_fault
 #define arch_force_async_tag_fault()
 #endif
@@ -304,6 +322,7 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 
 #define hw_enable_tagging_sync()		arch_enable_tagging_sync()
 #define hw_enable_tagging_async()		arch_enable_tagging_async()
+#define hw_enable_tagging_asymm()		arch_enable_tagging_asymm()
 #define hw_force_async_tag_fault()		arch_force_async_tag_fault()
 #define hw_get_random_tag()			arch_get_random_tag()
 #define hw_get_mem_tag(addr)			arch_get_mem_tag(addr)
@@ -314,6 +333,7 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 
 #define hw_enable_tagging_sync()
 #define hw_enable_tagging_async()
+#define hw_enable_tagging_asymm()
 
 #endif /* CONFIG_KASAN_HW_TAGS */
 
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 884a950c7026..9da071ad930c 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -112,7 +112,7 @@ static void start_report(unsigned long *flags)
 
 static void end_report(unsigned long *flags, unsigned long addr)
 {
-	if (!kasan_async_mode_enabled())
+	if (!kasan_async_fault_possible())
 		trace_error_report_end(ERROR_DETECTOR_KASAN, addr);
 	pr_err("==================================================================\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);