1 files changed, 41 insertions, 13 deletions

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 1a7e92ab69eb..a30818ed9c60 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -148,7 +148,7 @@ static inline bool is_ttbr1_addr(unsigned long addr)
 /*
  * Dump out the page tables associated with 'addr' in the currently active mm.
  */
-void show_pte(unsigned long addr)
+static void show_pte(unsigned long addr)
 {
 	struct mm_struct *mm;
 	pgd_t *pgdp;
@@ -171,9 +171,10 @@ void show_pte(unsigned long addr)
 		return;
 	}
 
-	pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgdp = %p\n",
+	pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgdp=%016lx\n",
 		 mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K,
-		 mm == &init_mm ? VA_BITS : (int) vabits_user, mm->pgd);
+		 mm == &init_mm ? VA_BITS : (int)vabits_user,
+		 (unsigned long)virt_to_phys(mm->pgd));
 	pgdp = pgd_offset(mm, addr);
 	pgd = READ_ONCE(*pgdp);
 	pr_alert("[%016lx] pgd=%016llx", addr, pgd_val(pgd));
@@ -810,13 +811,45 @@ void __init hook_debug_fault_code(int nr,
 	debug_fault_info[nr].name	= name;
 }
 
-asmlinkage int __exception do_debug_exception(unsigned long addr_if_watchpoint,
-					      unsigned int esr,
-					      struct pt_regs *regs)
+#ifdef CONFIG_ARM64_ERRATUM_1463225
+DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
+
+static int __exception
+cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+	if (user_mode(regs))
+		return 0;
+
+	if (!__this_cpu_read(__in_cortex_a76_erratum_1463225_wa))
+		return 0;
+
+	/*
+	 * We've taken a dummy step exception from the kernel to ensure
+	 * that interrupts are re-enabled on the syscall path. Return back
+	 * to cortex_a76_erratum_1463225_svc_handler() with debug exceptions
+	 * masked so that we can safely restore the mdscr and get on with
+	 * handling the syscall.
+	 */
+	regs->pstate |= PSR_D_BIT;
+	return 1;
+}
+#else
+static int __exception
+cortex_a76_erratum_1463225_debug_handler(struct pt_regs *regs)
+{
+	return 0;
+}
+#endif /* CONFIG_ARM64_ERRATUM_1463225 */
+
+asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint,
+					       unsigned int esr,
+					       struct pt_regs *regs)
 {
 	const struct fault_info *inf = esr_to_debug_fault_info(esr);
 	unsigned long pc = instruction_pointer(regs);
-	int rv;
+
+	if (cortex_a76_erratum_1463225_debug_handler(regs))
+		return;
 
 	/*
 	 * Tell lockdep we disabled irqs in entry.S. Do nothing if they were
@@ -828,17 +861,12 @@ asmlinkage int __exception do_debug_exception(unsigned long addr_if_watchpoint,
 	if (user_mode(regs) && !is_ttbr0_addr(pc))
 		arm64_apply_bp_hardening();
 
-	if (!inf->fn(addr_if_watchpoint, esr, regs)) {
-		rv = 1;
-	} else {
+	if (inf->fn(addr_if_watchpoint, esr, regs)) {
 		arm64_notify_die(inf->name, regs,
 				 inf->sig, inf->code, (void __user *)pc, esr);
-		rv = 0;
 	}
 
 	if (interrupts_enabled(regs))
 		trace_hardirqs_on();
-
-	return rv;
 }
 NOKPROBE_SYMBOL(do_debug_exception);