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authorJames Morse <james.morse@arm.com>2016-08-26 16:03:42 +0100
committerAlex Shi <alex.shi@linaro.org>2017-03-24 11:24:41 +0800
commit95bcc3e563748f65c9fc0eb1bbc3f99b76efd4b2 (patch)
tree46d3165ee51b97907c5e259ef7e99a39ef5e3c4c
parent18fc694578719686df59e31ae32dd862eb5f0ba8 (diff)
downloadlinux-linaro-stable-v4.4/topic/hibernate.tar.gz
arm64: kernel: Fix unmasked debug exceptions when restoring mdscr_el1v4.4/topic/hibernate
Changes to make the resume from cpu_suspend() code behave more like secondary boot caused debug exceptions to be unmasked early by __cpu_setup(). We then go on to restore mdscr_el1 in cpu_do_resume(), potentially taking break or watch points based on uninitialised registers. Mask debug exceptions in cpu_do_resume(), which is specific to resume from cpu_suspend(). Debug exceptions will be restored to their original state by local_dbg_restore() in cpu_suspend(), which runs after hw_breakpoint_restore() has re-initialised the other registers. Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Fixes: cabe1c81ea5b ("arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va") Cc: <stable@vger.kernel.org> # 4.7+ Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> (cherry picked from commit 744c6c37cc18705d19e179622f927f5b781fe9cc) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--arch/arm64/mm/proc.S9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 5bb61de..9d37e96 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -100,7 +100,16 @@ ENTRY(cpu_do_resume)
msr tcr_el1, x8
msr vbar_el1, x9
+
+ /*
+ * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
+ * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
+ * exception. Mask them until local_dbg_restore() in cpu_suspend()
+ * resets them.
+ */
+ disable_dbg
msr mdscr_el1, x10
+
msr sctlr_el1, x12
/*
* Restore oslsr_el1 by writing oslar_el1