[PATCH 13/24] arm64: Introduce set_pstate_tco() helper macro

["Pierre-Clément Tosi" <ptosi@google.com>]

Like other PSTATE bits, TCO deserves its own accessor.

Note that only HW KASAN common code now calls mte_{enable,disable}_tco()
so that their KASAN_HW_TAGS and ALTERNATIVE(ARM64_MTE) are superfluous.

Move the comment, as it now applies to them.

Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
---
 arch/arm64/include/asm/mte-kasan.h      | 24 +++++++++++-------------
 arch/arm64/include/asm/mte.h            |  2 +-
 arch/arm64/include/asm/sysreg.h         |  1 +
 arch/arm64/include/asm/uaccess.h        | 16 ++++++++--------
 arch/arm64/include/asm/word-at-a-time.h |  4 ++--
 5 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
index 17e4155781fc..9d00e9460b0f 100644
--- a/arch/arm64/include/asm/mte-kasan.h
+++ b/arch/arm64/include/asm/mte-kasan.h
@@ -13,6 +13,8 @@
 
 #include <linux/types.h>
 
+#include <asm/sysreg.h>
+
 #ifdef CONFIG_KASAN_HW_TAGS
 
 /* Whether the MTE asynchronous mode is enabled. */
@@ -34,27 +36,23 @@ static inline bool system_uses_mte_async_or_asymm_mode(void)
 
 #ifdef CONFIG_ARM64_MTE
 
+/*
+ * These functions are meant to be only used from KASAN runtime through
+ * the arch_*() interface defined in asm/memory.h.
+ * These functions don't include system_supports_mte() checks,
+ * as KASAN only calls them when MTE is supported and enabled.
+ */
+
 static inline void mte_disable_tco(void)
 {
-	if (!IS_ENABLED(CONFIG_KASAN_HW_TAGS))
-		return;
-	asm volatile(ALTERNATIVE("nop", SET_PSTATE_TCO(0), ARM64_MTE));
+	set_pstate_tco(0);
 }
 
 static inline void mte_enable_tco(void)
 {
-	if (!IS_ENABLED(CONFIG_KASAN_HW_TAGS))
-		return;
-	asm volatile(ALTERNATIVE("nop", SET_PSTATE_TCO(1), ARM64_MTE));
+	set_pstate_tco(1);
 }
 
-/*
- * These functions are meant to be only used from KASAN runtime through
- * the arch_*() interface defined in asm/memory.h.
- * These functions don't include system_supports_mte() checks,
- * as KASAN only calls them when MTE is supported and enabled.
- */
-
 static inline u8 mte_get_ptr_tag(void *ptr)
 {
 	/* Note: The format of KASAN tags is 0xF<x> */
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
index 614fff7dc35f..815843079eb9 100644
--- a/arch/arm64/include/asm/mte.h
+++ b/arch/arm64/include/asm/mte.h
@@ -271,7 +271,7 @@ static inline void mte_disable_tco_entry(struct task_struct *task)
 	 */
 	if (kasan_hw_tags_enabled() ||
 	    (task->thread.sctlr_user & (1UL << SCTLR_EL1_TCF0_SHIFT)))
-		asm volatile(SET_PSTATE_TCO(0));
+		set_pstate_tco(0);
 }
 
 #ifdef CONFIG_KASAN_HW_TAGS
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index e3b60ee03023..51c6a54d7146 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -105,6 +105,7 @@
 #define set_pstate_uao(x)		asm volatile(SET_PSTATE_UAO(x))
 #define set_pstate_ssbs(x)		asm volatile(SET_PSTATE_SSBS(x))
 #define set_pstate_dit(x)		asm volatile(SET_PSTATE_DIT(x))
+#define set_pstate_tco(x)		asm volatile(SET_PSTATE_TCO(x))
 
 /* Register-based PAN access, for save/restore purposes */
 #define SYS_PSTATE_PAN			sys_reg(3, 0, 4, 2, 3)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 9e3957ee3642..aac7676da531 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -140,13 +140,13 @@ static inline void __uaccess_disable_mte(void)
 	 * such that a bad user address tag could trigger a kernel MTE fault.
 	 */
 	if (kasan_hw_tags_enabled())
-		asm volatile(SET_PSTATE_TCO(1));
+		set_pstate_tco(1);
 }
 
 static inline void __uaccess_enable_mte(void)
 {
 	if (kasan_hw_tags_enabled())
-		asm volatile(SET_PSTATE_TCO(0));
+		set_pstate_tco(0);
 }
 
 static inline void uaccess_disable_privileged(void)
@@ -249,12 +249,12 @@ do {										\
 do {									\
 	__label__ __rgm_err;						\
 									\
-	asm volatile(SET_PSTATE_TCO(1));				\
+	set_pstate_tco(1);						\
 	__raw_get_mem(ldr, x, ptr, __rgm_err, type);			\
-	asm volatile(SET_PSTATE_TCO(0));				\
+	set_pstate_tco(0);						\
 	break;								\
 __rgm_err:								\
-	asm volatile(SET_PSTATE_TCO(0));				\
+	set_pstate_tco(0);						\
 	goto label;							\
 } while (0)
 
@@ -355,12 +355,12 @@ do {										\
 do {									\
 	__label__ __rpm_err;						\
 									\
-	asm volatile(SET_PSTATE_TCO(1));				\
+	set_pstate_tco(1);						\
 	__raw_put_mem(str, x, ptr, __rpm_err, type);			\
-	asm volatile(SET_PSTATE_TCO(0));				\
+	set_pstate_tco(0);						\
 	break;								\
 __rpm_err:								\
-	asm volatile(SET_PSTATE_TCO(0));				\
+	set_pstate_tco(0);						\
 	goto label;							\
 } while (0)
 
diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h
index ec72126210d1..430d5ab8f042 100644
--- a/arch/arm64/include/asm/word-at-a-time.h
+++ b/arch/arm64/include/asm/word-at-a-time.h
@@ -67,9 +67,9 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
 	if (!system_uses_mte_async_or_asymm_mode())
 		return __load_unaligned_zeropad(addr);
 
-	asm volatile(SET_PSTATE_TCO(1));
+	set_pstate_tco(1);
 	ret = __load_unaligned_zeropad(addr);
-	asm volatile(SET_PSTATE_TCO(0));
+	set_pstate_tco(0);
 
 	return ret;
 }

-- 
2.56.0.455.g6c5a503b38-goog