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Message-Id: <9737ec351e2f9f2e7472d8d7133568f7915f20aa.1470114993.git.panand@redhat.com>
Date: Tue, 2 Aug 2016 11:00:08 +0530
From: Pratyush Anand <panand@...hat.com>
To: linux-arm-kernel@...ts.infradead.org, linux@....linux.org.uk,
catalin.marinas@....com, will.deacon@....com
Cc: linux-kernel@...r.kernel.org, wcohen@...hat.com, oleg@...hat.com,
dave.long@...aro.org, steve.capper@...aro.org,
srikar@...ux.vnet.ibm.com, vijaya.kumar@...iumnetworks.com,
Pratyush Anand <panand@...hat.com>,
Sandeepa Prabhu <sandeepa.s.prabhu@...il.com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Yang Shi <yang.shi@...aro.org>
Subject: [PATCH 4/5] arm64: Handle TRAP_BRKPT for user mode as well
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@...hat.com>
---
arch/arm64/kernel/debug-monitors.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index fae2f57a92b7..466d199498b5 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -326,16 +326,20 @@ NOKPROBE_SYMBOL(call_break_hook);
static int brk_handler(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
- if (user_mode(regs)) {
- send_user_sigtrap(TRAP_BRKPT);
- }
+ bool handler_found = false;
+
#ifdef CONFIG_KPROBES
- else if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) {
- if (kprobe_breakpoint_handler(regs, esr) != DBG_HOOK_HANDLED)
- return -EFAULT;
+ if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) {
+ if (kprobe_breakpoint_handler(regs, esr) == DBG_HOOK_HANDLED)
+ handler_found = true;
}
#endif
- else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) {
+ if (!handler_found && call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
+ handler_found = true;
+
+ if (!handler_found && user_mode(regs)) {
+ send_user_sigtrap(TRAP_BRKPT);
+ } else if (!handler_found) {
pr_warn("Unexpected kernel BRK exception at EL1\n");
return -EFAULT;
}
--
2.5.5
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