3 files changed, 17 insertions, 11 deletions
diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index 0278a58abe69..19713d0f013b 100644
--- a/arch/arm64/include/asm/exception.h
+++ b/arch/arm64/include/asm/exception.h
@@ -71,6 +71,7 @@ void do_sysinstr(unsigned long esr, struct pt_regs *regs);
 void do_sp_pc_abort(unsigned long addr, unsigned long esr, struct pt_regs *regs);
 void bad_el0_sync(struct pt_regs *regs, int reason, unsigned long esr);
 void do_cp15instr(unsigned long esr, struct pt_regs *regs);
+int do_compat_alignment_fixup(unsigned long addr, struct pt_regs *regs);
 void do_el0_svc(struct pt_regs *regs);
 void do_el0_svc_compat(struct pt_regs *regs);
 void do_el0_fpac(struct pt_regs *regs, unsigned long esr);
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
index aa523591a44e..760c62f8e22f 100644
--- a/arch/arm64/include/asm/mte.h
+++ b/arch/arm64/include/asm/mte.h
@@ -42,7 +42,9 @@ void mte_sync_tags(pte_t old_pte, pte_t pte);
 void mte_copy_page_tags(void *kto, const void *kfrom);
 void mte_thread_init_user(void);
 void mte_thread_switch(struct task_struct *next);
+void mte_cpu_setup(void);
 void mte_suspend_enter(void);
+void mte_suspend_exit(void);
 long set_mte_ctrl(struct task_struct *task, unsigned long arg);
 long get_mte_ctrl(struct task_struct *task);
 int mte_ptrace_copy_tags(struct task_struct *child, long request,
@@ -72,6 +74,9 @@ static inline void mte_thread_switch(struct task_struct *next)
 static inline void mte_suspend_enter(void)
 {
 }
+static inline void mte_suspend_exit(void)
+{
+}
 static inline long set_mte_ctrl(struct task_struct *task, unsigned long arg)
 {
 	return 0;
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 2fc9f0861769..5c7b2f9d5913 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -203,9 +203,11 @@ static inline void uaccess_enable_privileged(void)
 }
 
 /*
- * Sanitise a uaccess pointer such that it becomes NULL if above the maximum
- * user address. In case the pointer is tagged (has the top byte set), untag
- * the pointer before checking.
+ * Sanitize a uaccess pointer such that it cannot reach any kernel address.
+ *
+ * Clearing bit 55 ensures the pointer cannot address any portion of the TTBR1
+ * address range (i.e. any kernel address), and either the pointer falls within
+ * the TTBR0 address range or must cause a fault.
  */
 #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
 static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
@@ -213,14 +215,12 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
 	void __user *safe_ptr;
 
 	asm volatile(
-	"	bics	xzr, %3, %2\n"
-	"	csel	%0, %1, xzr, eq\n"
-	: "=&r" (safe_ptr)
-	: "r" (ptr), "r" (TASK_SIZE_MAX - 1),
-	  "r" (untagged_addr(ptr))
-	: "cc");
-
-	csdb();
+	"	bic	%0, %1, %2\n"
+	: "=r" (safe_ptr)
+	: "r" (ptr),
+	  "i" (BIT(55))
+	);
+
 	return safe_ptr;
 }