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Subject[RFC PATCH V2 07/10] arm64: Handle TRAP_BRKPT for user mode as well
Date
uprobe is registered at break_hook with a unique ESR code. So, when a
TRAP_BRKPT occurs, call_break_hook checks if it was for uprobe. If not,
then send a SIGTRAP to user.

Signed-off-by: Pratyush Anand <panand@redhat.com>
---
arch/arm64/kernel/debug-monitors.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 7eb13dcf09fa..1fe912e77f62 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -311,8 +311,18 @@ static int brk_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
siginfo_t info;
+ bool handler_found = false;
+
+#ifdef CONFIG_KPROBES
+ if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) {
+ if (kprobe_breakpoint_handler(regs, esr) == DBG_HOOK_HANDLED)
+ handler_found = true;
+ }
+#endif
+ if (!handler_found && call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
+ handler_found = true;

- if (user_mode(regs)) {
+ if (!handler_found && user_mode(regs)) {
info = (siginfo_t) {
.si_signo = SIGTRAP,
.si_errno = 0,
@@ -321,15 +331,8 @@ static int brk_handler(unsigned long addr, unsigned int esr,
};

force_sig_info(SIGTRAP, &info, current);
- }
-#ifdef CONFIG_KPROBES
- else if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) {
- if (kprobe_breakpoint_handler(regs, esr) != DBG_HOOK_HANDLED)
- return -EFAULT;
- }
-#endif
- else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) {
- pr_warn("Unexpected kernel BRK exception at EL1\n");
+ } else if (!handler_found) {
+ pr_warning("Unexpected kernel BRK exception at EL1\n");
return -EFAULT;
}

--
2.1.0


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