[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190922190103.4906-10-sashal@kernel.org>
Date: Sun, 22 Sep 2019 15:00:28 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.4 10/44] x86/apic: Soft disable APIC before initializing it
From: Thomas Gleixner <tglx@...utronix.de>
[ 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@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20190722105219.068290579@linutronix.de
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
arch/x86/kernel/apic/apic.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 834d1b5b43557..be3d4dcf3a10a 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) {
--
2.20.1
Powered by blists - more mailing lists