[ 3.8.y.z extended stable ] Patch "arm64: don't kill the kernel on a bad esr from el0" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    arm64: don't kill the kernel on a bad esr from el0

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From f1e6d26bd6aa5997534ea9e2e9be73d17253f9ed Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland at arm.com>
Date: Tue, 28 May 2013 15:54:15 +0100
Subject: arm64: don't kill the kernel on a bad esr from el0

commit 9955ac47f4ba1c95ecb6092aeaefb40a22e99268 upstream.

Rather than completely killing the kernel if we receive an esr value we
can't deal with in the el0 handlers, send the process a SIGILL and log
the esr value in the hope that we can debug it. If we receive a bad esr
from el1, we'll die() as before.

Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm64/kernel/traps.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 3883f84..18f8fa5 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -317,14 +317,20 @@ asmlinkage long do_ni_syscall(struct pt_regs *regs)
  */
 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 {
+	siginfo_t info;
+	void __user *pc = (void __user *)instruction_pointer(regs);
 	console_verbose();

 	pr_crit("Bad mode in %s handler detected, code 0x%08x\n",
 		handler[reason], esr);
+	__show_regs(regs);
+
+	info.si_signo = SIGILL;
+	info.si_errno = 0;
+	info.si_code  = ILL_ILLOPC;
+	info.si_addr  = pc;

-	die("Oops - bad mode", regs, 0);
-	local_irq_disable();
-	panic("bad mode");
+	arm64_notify_die("Oops - bad mode", regs, &info, 0);
 }

 void __pte_error(const char *file, int line, unsigned long val)
--
1.8.1.2