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From: Pratyush Anand <panand@redhat.com>
To: linux-arm-kernel@lists.infradead.org, linux@arm.linux.org.uk,
	catalin.marinas@arm.com, will.deacon@arm.com
Cc: linux-kernel@vger.kernel.org, wcohen@redhat.com, oleg@redhat.com,
	dave.long@linaro.org, steve.capper@linaro.org,
	srikar@linux.vnet.ibm.com, vijaya.kumar@caviumnetworks.com,
	Pratyush Anand <panand@redhat.com>,
	Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Yang Shi <yang.shi@linaro.org>
Subject: [PATCH 4/5] arm64: Handle TRAP_BRKPT for user mode as well
Date: Tue,  2 Aug 2016 11:00:08 +0530	[thread overview]
Message-ID: <9737ec351e2f9f2e7472d8d7133568f7915f20aa.1470114993.git.panand@redhat.com> (raw)
In-Reply-To: <cover.1470114993.git.panand@redhat.com>
In-Reply-To: <cover.1470114993.git.panand@redhat.com>

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 | 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

  parent reply	other threads:[~2016-08-02  5:32 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-02  5:30 [PATCH 0/5] ARM64: Uprobe support added Pratyush Anand
2016-08-02  5:30 ` [PATCH 1/5] arm64: kprobe: protect/rename few definitions to be reused by uprobe Pratyush Anand
2016-08-02  5:30 ` [PATCH 2/5] arm64: kgdb_step_brk_fn: ignore other's exception Pratyush Anand
2016-08-02  5:30 ` [PATCH 3/5] arm64: Handle TRAP_HWBRKPT for user mode as well Pratyush Anand
2016-09-06 16:11   ` Catalin Marinas
2016-09-06 21:36     ` David Long
2016-09-07  4:47       ` Pratyush Anand
2016-09-07 13:41       ` Catalin Marinas
2016-08-02  5:30 ` Pratyush Anand [this message]
2016-09-06 16:34   ` [PATCH 4/5] arm64: Handle TRAP_BRKPT " Catalin Marinas
2016-08-02  5:30 ` [PATCH 5/5] arm64: Add uprobe support Pratyush Anand
2016-08-09 18:49   ` Oleg Nesterov
2016-08-24  7:13     ` Pratyush Anand
2016-08-24 15:47       ` Oleg Nesterov
2016-08-24 15:56         ` Will Deacon
2016-08-25 13:33           ` Oleg Nesterov
2016-09-20 16:59   ` Catalin Marinas
2016-09-21 11:00     ` Pratyush Anand
2016-09-21 17:04       ` Catalin Marinas
2016-09-22  3:23         ` Pratyush Anand
2016-09-22 16:50           ` Catalin Marinas
2016-09-23  4:12             ` Pratyush Anand
2016-09-23 13:05               ` Catalin Marinas
2016-09-25 17:02                 ` Pratyush Anand
2016-09-26 11:01                   ` Catalin Marinas
2016-09-26 13:03                     ` Pratyush Anand
2016-09-27 13:51                       ` Catalin Marinas
2016-09-27 15:03                         ` Pratyush Anand
2016-09-28 17:12                           ` Catalin Marinas
2016-08-24  7:26 ` [PATCH 0/5] ARM64: Uprobe support added Pratyush Anand
2016-09-20  2:51   ` Pratyush Anand

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