| Message ID | 1403041357-11740-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 39f89fb..88c6bab 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -132,6 +132,10 @@ orrne r5, V7M_xPSR_FRAMEPTRALIGN biceq r5, V7M_xPSR_FRAMEPTRALIGN + @ ensure bit 0 is cleared in the PC, otherwise behaviour is + @ unpredictable + bic r4, #1 + @ write basic exception frame stmdb r2!, {r1, r3-r5} ldmia sp, {r1, r3-r5}
This is a note to let you know that I have just added a patch titled ARM: 8064/1: fix v7-M signal return to the linux-3.13.y-queue branch of the 3.13.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-3.13.y-queue This patch is scheduled to be released in version 3.13.11.4. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From d7e2eb195e1d4712a891c00008c06fd64c3b8524 Mon Sep 17 00:00:00 2001 From: Rabin Vincent <rabin@rab.in> Date: Sat, 24 May 2014 17:38:01 +0100 Subject: ARM: 8064/1: fix v7-M signal return MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 483a6c9d447f625b991fa04a1530493d893984db upstream. According to the ARM ARM, the behaviour is UNPREDICTABLE if the PC read from the exception return stack is not half word aligned. See the pseudo code for ExceptionReturn() and PopStack(). The signal handler's address has the bit 0 set, and setup_return() directly writes this to regs->ARM_pc. Current hardware happens to discard this bit, but QEMU's emulation doesn't and this makes processes crash. Mask out bit 0 before the exception return in order to get predictable behaviour. Fixes: 19c4d593f0b4 ("ARM: ARMv7-M: Add support for exception handling") Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/arm/kernel/entry-header.S | 4 ++++ 1 file changed, 4 insertions(+) -- 1.9.1