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-rw-r--r--arch/arm64/mm/fault.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 0cb0e09995e1..9a84a4071561 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -810,6 +810,36 @@ void __init hook_debug_fault_code(int nr,
debug_fault_info[nr].name = name;
}
+#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)
@@ -817,6 +847,9 @@ asmlinkage void __exception do_debug_exception(unsigned long addr_if_watchpoint,
const struct fault_info *inf = esr_to_debug_fault_info(esr);
unsigned long pc = instruction_pointer(regs);
+ if (cortex_a76_erratum_1463225_debug_handler(regs))
+ return;
+
/*
* Tell lockdep we disabled irqs in entry.S. Do nothing if they were
* already disabled to preserve the last enabled/disabled addresses.