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| author | James Morse <james.morse@arm.com> | 2016-08-26 16:03:42 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-07 08:34:49 +0200 |
| commit | d066c41d10f0b2c6f8c6fb477e7d3152fdf5a8d8 (patch) | |
| tree | be6593cbbeee369a28b8e612a65beec8f2c056ce /arch/arm64 | |
| parent | 02d7cb95e7e45aee58bb3228b0e8f3c3f9d75473 (diff) | |
| download | lwn-d066c41d10f0b2c6f8c6fb477e7d3152fdf5a8d8.tar.gz lwn-d066c41d10f0b2c6f8c6fb477e7d3152fdf5a8d8.zip | |
arm64: kernel: Fix unmasked debug exceptions when restoring mdscr_el1
commit 744c6c37cc18705d19e179622f927f5b781fe9cc upstream.
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")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/mm/proc.S | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 5bb61de23201..9d37e967fa19 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 |