--- /dev/null
+From b9a4b9d084d978f80eb9210727c81804588b42ff Mon Sep 17 00:00:00 2001
+From: Will Deacon <will.deacon@arm.com>
+Date: Fri, 1 Mar 2019 13:28:00 +0000
+Subject: arm64: debug: Don't propagate UNKNOWN FAR into si_code for debug signals
+
+From: Will Deacon <will.deacon@arm.com>
+
+commit b9a4b9d084d978f80eb9210727c81804588b42ff upstream.
+
+FAR_EL1 is UNKNOWN for all debug exceptions other than those caused by
+taking a hardware watchpoint. Unfortunately, if a debug handler returns
+a non-zero value, then we will propagate the UNKNOWN FAR value to
+userspace via the si_addr field of the SIGTRAP siginfo_t.
+
+Instead, let's set si_addr to take on the PC of the faulting instruction,
+which we have available in the current pt_regs.
+
+Cc: <stable@vger.kernel.org>
+Reviewed-by: Mark Rutland <mark.rutland@arm.com>
+Signed-off-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+
+---
+ arch/arm64/mm/fault.c | 11 ++++++-----
+ 1 file changed, 6 insertions(+), 5 deletions(-)
+
+--- a/arch/arm64/mm/fault.c
++++ b/arch/arm64/mm/fault.c
+@@ -834,11 +834,12 @@ void __init hook_debug_fault_code(int nr
+ debug_fault_info[nr].name = name;
+ }
+
+-asmlinkage int __exception do_debug_exception(unsigned long addr,
++asmlinkage int __exception do_debug_exception(unsigned long addr_if_watchpoint,
+ unsigned int esr,
+ struct pt_regs *regs)
+ {
+ const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
++ unsigned long pc = instruction_pointer(regs);
+ struct siginfo info;
+ int rv;
+
+@@ -849,19 +850,19 @@ asmlinkage int __exception do_debug_exce
+ if (interrupts_enabled(regs))
+ trace_hardirqs_off();
+
+- if (user_mode(regs) && instruction_pointer(regs) > TASK_SIZE)
++ if (user_mode(regs) && pc > TASK_SIZE)
+ arm64_apply_bp_hardening();
+
+- if (!inf->fn(addr, esr, regs)) {
++ if (!inf->fn(addr_if_watchpoint, esr, regs)) {
+ rv = 1;
+ } else {
+ pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
+- inf->name, esr, addr);
++ inf->name, esr, pc);
+
+ info.si_signo = inf->sig;
+ info.si_errno = 0;
+ info.si_code = inf->code;
+- info.si_addr = (void __user *)addr;
++ info.si_addr = (void __user *)pc;
+ arm64_notify_die("", regs, &info, 0);
+ rv = 0;
+ }