[PATCH 14/24] arm64: Add mte_{enter,exit}_*_{kernel,user}_mode()

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

Abstract away and consolidate MTE switching code by aligning with the
concepts and naming from entry-common.c, similarly to the SME routines.

Define the helpers in entry-common.c, conveniently grouped for more
straightforward enter-exit logic pair evaluation.

Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
---
 arch/arm64/kernel/entry-common.c | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 11d3f888fcd8..fbf9bafc6962 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -25,6 +25,7 @@
 #include <asm/irq_regs.h>
 #include <asm/kprobes.h>
 #include <asm/mmu.h>
+#include <asm/mte.h>
 #include <asm/percpu.h>
 #include <asm/processor.h>
 #include <asm/sdei.h>
@@ -68,6 +69,27 @@ static __always_inline void irqentry_exit_pcpu_adjust(struct pt_regs *regs)
 	pt_regs_write_reg(regs, reg_addr, addr);
 }
 
+static __always_inline void mte_enter_from_kernel_mode(void)
+{
+	mte_check_tfsr_entry();
+	mte_disable_tco_entry(current);
+}
+
+static __always_inline void mte_exit_to_kernel_mode(void)
+{
+	mte_check_tfsr_exit();
+}
+
+static __always_inline void mte_enter_from_user_mode(void)
+{
+	mte_disable_tco_entry(current);
+}
+
+static __always_inline void mte_exit_to_user_mode(void)
+{
+	mte_check_tfsr_exit();
+}
+
 /*
  * Handle IRQ/context state management when entering from kernel mode.
  * Before this function is called it is not safe to call regular kernel code,
@@ -78,8 +100,7 @@ static noinstr irqentry_state_t arm64_enter_from_kernel_mode(struct pt_regs *reg
 	irqentry_state_t state;
 
 	state = irqentry_enter_from_kernel_mode(regs);
-	mte_check_tfsr_entry();
-	mte_disable_tco_entry(current);
+	mte_enter_from_kernel_mode();
 
 	return state;
 }
@@ -94,7 +115,7 @@ static void noinstr __arm64_exit_to_kernel_mode(struct pt_regs *regs,
 {
 	local_daif_mask();
 	irqentry_exit_pcpu_adjust(regs);
-	mte_check_tfsr_exit();
+	mte_exit_to_kernel_mode();
 	irqentry_exit_to_kernel_mode_after_preempt(regs, state);
 }
 
@@ -123,7 +144,7 @@ static void noinstr arm64_exit_to_kernel_mode(struct pt_regs *regs,
 static __always_inline void arm64_syscall_enter_from_user_mode(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);
-	mte_disable_tco_entry(current);
+	mte_enter_from_user_mode();
 	sme_enter_from_user_mode();
 }
 
@@ -136,7 +157,7 @@ static __always_inline void arm64_enter_from_user_mode(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);
 	rseq_note_user_irq_entry();
-	mte_disable_tco_entry(current);
+	mte_enter_from_user_mode();
 	sme_enter_from_user_mode();
 }
 
@@ -146,7 +167,7 @@ static __always_inline void arm64_syscall_exit_to_user_mode(struct pt_regs *regs
 	syscall_exit_to_user_mode_prepare(regs);
 	local_daif_mask();
 	sme_exit_to_user_mode();
-	mte_check_tfsr_exit();
+	mte_exit_to_user_mode();
 	exit_to_user_mode();
 }
 
@@ -161,7 +182,7 @@ static __always_inline void arm64_exit_to_user_mode(struct pt_regs *regs)
 	irqentry_exit_to_user_mode_prepare(regs);
 	local_daif_mask();
 	sme_exit_to_user_mode();
-	mte_check_tfsr_exit();
+	mte_exit_to_user_mode();
 	exit_to_user_mode();
 }
 

-- 
2.56.0.455.g6c5a503b38-goog