From 704fc59e1d056de80beaf30174bc8e0b1682efbb Mon Sep 17 00:00:00 2001 From: "Siddha, Suresh B" Date: Mon, 26 Jun 2006 13:59:53 +0200 Subject: [PATCH] x86_64: fix apic error on bootup Appended patch fixes the "APIC error on CPUX: 00(40)" observed during bootup. From SDM Vol-3A "Valid Interrupt Vectors" section: "When an illegal vector value (0-15) is written to an LVT entry and the delivery mode is Fixed, the APIC may signal an illegal vector error, with out regard to whether the mask bit is set or whether an interrupt is actually seen on input." Signed-off-by: Suresh Siddha Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/apic.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/x86_64') diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c index 396e125cb21..b2ead91df21 100644 --- a/arch/x86_64/kernel/apic.c +++ b/arch/x86_64/kernel/apic.c @@ -100,7 +100,7 @@ void clear_local_APIC(void) maxlvt = get_maxlvt(); /* - * Masking an LVT entry on a P6 can trigger a local APIC error + * Masking an LVT entry can trigger a local APIC error * if the vector is zero. Mask LVTERR first to prevent this. */ if (maxlvt >= 3) { @@ -851,7 +851,18 @@ void disable_APIC_timer(void) unsigned long v; v = apic_read(APIC_LVTT); - apic_write(APIC_LVTT, v | APIC_LVT_MASKED); + /* + * When an illegal vector value (0-15) is written to an LVT + * entry and delivery mode is Fixed, the APIC may signal an + * illegal vector error, with out regard to whether the mask + * bit is set or whether an interrupt is actually seen on input. + * + * Boot sequence might call this function when the LVTT has + * '0' vector value. So make sure vector field is set to + * valid value. + */ + v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR); + apic_write(APIC_LVTT, v); } } -- cgit v1.2.3