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

Catalin Marinas
2020-04-21T14:32:13Z

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();
}

/*