linux-kernel - [RFC 6/8] ARM64: Handle TRAP_HWBRKPT for user mode as well

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Message-Id: <1e0a9e778669bb2a2e40bf101eff8ae85110ce54.1420038188.git.panand@redhat.com>
Date:	Wed, 31 Dec 2014 20:51:22 +0530
From:	Pratyush Anand <panand@...hat.com>
To:	linux-arm-kernel@...ts.infradead.org, linux@....linux.org.uk
Cc:	tixy@...aro.org, ananth@...ibm.com, sandeepa.prabhu@...aro.org,
	catalin.marinas@....com, will.deacon@....com,
	linux-kernel@...r.kernel.org, anil.s.keshavamurthy@...el.com,
	masami.hiramatsu.pt@...achi.com, wcohen@...hat.com,
	oleg@...hat.com, Pratyush Anand <panand@...hat.com>
Subject: [RFC 6/8] ARM64: Handle TRAP_HWBRKPT for user mode as well

uprobe registers a handler at step_hook. So, single_step_handler now
checks for user mode as well if there is a valid hook.

Signed-off-by: Pratyush Anand <panand@...hat.com>
---
 arch/arm64/kernel/debug-monitors.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index b056369fd47d..2676b8655241 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -236,6 +236,9 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
 	if (!reinstall_suspended_bps(regs))
 		return 0;
 
+	if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
+		return 0;
+
 	if (user_mode(regs)) {
 		info.si_signo = SIGTRAP;
 		info.si_errno = 0;
@@ -251,9 +254,6 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
 		 */
 		user_rewind_single_step(current);
 	} else {
-		if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
-			return 0;
-
 		pr_warning("Unexpected kernel single-step exception at EL1\n");
 		/*
 		 * Re-enable stepping since we know that we will be
-- 
2.1.0

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