1 files changed, 16 insertions, 6 deletions

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index a5ca15daeb8a..96482a1412c6 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -288,7 +288,9 @@ static void flush_gcs(void)
 	if (!system_supports_gcs())
 		return;
 
-	gcs_free(current);
+	current->thread.gcspr_el0 = 0;
+	current->thread.gcs_base = 0;
+	current->thread.gcs_size = 0;
 	current->thread.gcs_el0_mode = 0;
 	write_sysreg_s(GCSCRE0_EL1_nTR, SYS_GCSCRE0_EL1);
 	write_sysreg_s(0, SYS_GCSPR_EL0);
@@ -305,13 +307,13 @@ static int copy_thread_gcs(struct task_struct *p,
 	p->thread.gcs_base = 0;
 	p->thread.gcs_size = 0;
 
+	p->thread.gcs_el0_mode = current->thread.gcs_el0_mode;
+	p->thread.gcs_el0_locked = current->thread.gcs_el0_locked;
+
 	gcs = gcs_alloc_thread_stack(p, args);
 	if (IS_ERR_VALUE(gcs))
 		return PTR_ERR((void *)gcs);
 
-	p->thread.gcs_el0_mode = current->thread.gcs_el0_mode;
-	p->thread.gcs_el0_locked = current->thread.gcs_el0_locked;
-
 	return 0;
 }
 
@@ -339,7 +341,6 @@ void flush_thread(void)
 void arch_release_task_struct(struct task_struct *tsk)
 {
 	fpsimd_release_task(tsk);
-	gcs_free(tsk);
 }
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
@@ -671,6 +672,11 @@ static void permission_overlay_switch(struct task_struct *next)
 	current->thread.por_el0 = read_sysreg_s(SYS_POR_EL0);
 	if (current->thread.por_el0 != next->thread.por_el0) {
 		write_sysreg_s(next->thread.por_el0, SYS_POR_EL0);
+		/*
+		 * No ISB required as we can tolerate spurious Overlay faults -
+		 * the fault handler will check again based on the new value
+		 * of POR_EL0.
+		 */
 	}
 }
 
@@ -849,10 +855,14 @@ long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg)
 	if (is_compat_thread(ti))
 		return -EINVAL;
 
-	if (system_supports_mte())
+	if (system_supports_mte()) {
 		valid_mask |= PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC \
 			| PR_MTE_TAG_MASK;
 
+		if (cpus_have_cap(ARM64_MTE_STORE_ONLY))
+			valid_mask |= PR_MTE_STORE_ONLY;
+	}
+
 	if (arg & ~valid_mask)
 		return -EINVAL;