[PATCH v3 18/23] arm64: mte: Restore the GCR_EL1 register after a suspend

[Catalin Marinas <catalin.marinas@arm.com>]

The CPU resume/suspend routines only take care of the common system
registers. Restore GCR_EL1 in addition via the __cpu_suspend_exit()
function.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
---

Notes:
    New in v3.

 arch/arm64/include/asm/mte.h | 4 ++++
 arch/arm64/kernel/mte.c      | 8 ++++++++
 arch/arm64/kernel/suspend.c  | 4 ++++
 3 files changed, 16 insertions(+)

diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
index 3dc0a7977124..22eb3e06f311 100644
--- a/arch/arm64/include/asm/mte.h
+++ b/arch/arm64/include/asm/mte.h
@@ -12,6 +12,7 @@ int mte_memcmp_pages(const void *page1_addr, const void *page2_addr);
 #ifdef CONFIG_ARM64_MTE
 void flush_mte_state(void);
 void mte_thread_switch(struct task_struct *next);
+void mte_suspend_exit(void);
 long set_mte_ctrl(unsigned long arg);
 long get_mte_ctrl(void);
 #else
@@ -21,6 +22,9 @@ static inline void flush_mte_state(void)
 static inline void mte_thread_switch(struct task_struct *next)
 {
 }
+static inline void mte_suspend_exit(void)
+{
+}
 static inline long set_mte_ctrl(unsigned long arg)
 {
 	return 0;
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index 212b9fac294d..fa4a4196b248 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -76,6 +76,14 @@ void mte_thread_switch(struct task_struct *next)
 	update_gcr_el1_excl(next->thread.gcr_incl);
 }
 
+void mte_suspend_exit(void)
+{
+	if (!system_supports_mte())
+		return;
+
+	update_gcr_el1_excl(current->thread.gcr_incl);
+}
+
 long set_mte_ctrl(unsigned long arg)
 {
 	u64 tcf0;
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index 9405d1b7f4b0..1d405b73d009 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -9,6 +9,7 @@
 #include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
 #include <asm/exec.h>
+#include <asm/mte.h>
 #include <asm/pgtable.h>
 #include <asm/memory.h>
 #include <asm/mmu_context.h>
@@ -74,6 +75,9 @@ void notrace __cpu_suspend_exit(void)
 	 */
 	if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE)
 		arm64_set_ssbd_mitigation(false);
+
+	/* Restore additional MTE-specific configuration */
+	mte_suspend_exit();
 }
 
 /*