diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2019-07-22 20:47:08 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-05 12:27:45 +0200 |
| commit | 3b6cccf414ac23606aaa68e43392be52493eb279 (patch) | |
| tree | d5e772d88c563a595dc1977a2a2e7c618dbb6383 /arch/x86/kernel | |
| parent | 03b8c7430457993761da4b1f5e54a1a56cf7a4b0 (diff) | |
x86/apic: Soft disable APIC before initializing it
[ Upstream commit 2640da4cccf5cc613bf26f0998b9e340f4b5f69c ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/x86/kernel')
| -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 834d1b5b4355..be3d4dcf3a10 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1265,6 +1265,14 @@ 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) { |