diff options
| author | Julien Thierry <julien.thierry@arm.com> | 2019-01-31 14:59:01 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2019-02-06 10:06:31 +0000 |
| commit | 1234ad686fb1bde5a9c2447fc4c9df8430358763 (patch) | |
| tree | a0ccfcd8724cc240966a7b15c12dc9856dc359b9 /arch/arm64 | |
| parent | 7d31464adf20fb8c075a3a3dfe2002a195566510 (diff) | |
| download | linux-0-day-1234ad686fb1bde5a9c2447fc4c9df8430358763.tar.gz linux-0-day-1234ad686fb1bde5a9c2447fc4c9df8430358763.tar.xz | |
arm64: Skip preemption when exiting an NMI
Handling of an NMI should not set any TIF flags. For NMIs received from
EL0 the current exit path is safe to use.
However, an NMI received at EL1 could have interrupted some task context
that has set the TIF_NEED_RESCHED flag. Preempting a task should not
happen as a result of an NMI.
Skip preemption after handling an NMI from EL1.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 02f809a5c8233..35ed484695065 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -624,7 +624,15 @@ el1_irq: #ifdef CONFIG_PREEMPT ldr x24, [tsk, #TSK_TI_PREEMPT] // get preempt count - cbnz x24, 1f // preempt count != 0 +alternative_if ARM64_HAS_IRQ_PRIO_MASKING + /* + * DA_F were cleared at start of handling. If anything is set in DAIF, + * we come back from an NMI, so skip preemption + */ + mrs x0, daif + orr x24, x24, x0 +alternative_else_nop_endif + cbnz x24, 1f // preempt count != 0 || NMI return path bl preempt_schedule_irq // irq en/disable is done inside 1: #endif |