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authorWill Deacon <will.deacon@arm.com>2019-03-01 13:28:00 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-05 22:31:24 +0200
commit34cc16629523f361138731fc417c8e3c10b311b6 (patch)
tree3a3a61ed7589bb6cb341e86384a54879e99c5237 /arch/arm64/mm
parent80bf6c64d5cca26b4d2a94e38cbd89c2615a25c3 (diff)
arm64: debug: Don't propagate UNKNOWN FAR into si_code for debug signals
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>
Diffstat (limited to 'arch/arm64/mm')
-rw-r--r--arch/arm64/mm/fault.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 5edb706aacb0..465b90d7abf2 100644
--- 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_exception(unsigned long addr,
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;
}