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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-07-22 20:47:08 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-25 16:11:56 +0200 |
| commit | 2640da4cccf5cc613bf26f0998b9e340f4b5f69c (patch) | |
| tree | fd9339f9760a29c0c0cc4beab2bb5ca702ea1c3a /arch/x86/kernel/apic | |
| parent | x86/apic: Invoke perf_events_lapic_init() after enabling APIC (diff) | |
| download | linux-2640da4cccf5cc613bf26f0998b9e340f4b5f69c.tar.xz linux-2640da4cccf5cc613bf26f0998b9e340f4b5f69c.zip | |
x86/apic: Soft disable APIC before initializing it
If the APIC was already enabled on entry of setup_local_APIC() then
disabling it soft via the SPIV register makes a lot of sense.
That masks all LVT entries and brings it into a well defined state.
Otherwise previously enabled LVTs which are not touched in the setup
function stay unmasked and might surprise the just booting kernel.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105219.068290579@linutronix.de
Diffstat (limited to 'arch/x86/kernel/apic')
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index fa0846d4e000..621992de49ee 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1522,6 +1522,14 @@ static void setup_local_APIC(void) return; } + /* + * If this comes from kexec/kcrash the APIC might be enabled in + * SPIV. Soft disable it before doing further initialization. + */ + value = apic_read(APIC_SPIV); + value &= ~APIC_SPIV_APIC_ENABLED; + apic_write(APIC_SPIV, value); + #ifdef CONFIG_X86_32 /* Pound the ESR really hard over the head with a big hammer - mbligh */ if (lapic_is_integrated() && apic->disable_esr) { |