Commit 744c6c37 authored by James Morse's avatar James Morse Committed by Catalin Marinas

arm64: kernel: Fix unmasked debug exceptions when restoring mdscr_el1

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: default avatarLorenzo Pieralisi <>
Fixes: cabe1c81 ("arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va")
Cc: <> # 4.7+
Signed-off-by: default avatarJames Morse <>
Acked-by: default avatarWill Deacon <>
Signed-off-by: default avatarCatalin Marinas <>
parent 63fb0a95
......@@ -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.
msr mdscr_el1, x10
msr sctlr_el1, x12
* Restore oslsr_el1 by writing oslar_el1
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