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[PATCH] x86_64: Standardize i386/x86_64 handling of NMI_VECTOR
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x86_64 and i386 behave inconsistently when sending an IPI on vector 2
(NMI_VECTOR).  Make both behave the same, so IPI 2 is sent as NMI.

The crash code was abusing send_IPI_allbutself() by passing a code
instead of a vector, it only worked because crash knew about the
internal code of send_IPI_allbutself().  Change crash to use NMI_VECTOR
instead, and remove the comment about how crash was abusing the function.

This patch is a pre-requisite for fixing the problem where sending an
IPI as NMI would reboot some Dell Xeon systems.  I cannot fix that
problem while crash continus to abuse send_IPI_allbutself().

It also removes the inconsistency between i386 and x86_64 for
NMI_VECTOR.  That will simplify all the RAS code that needs to bring
all the cpus to a clean stop, even when one or more cpus are spinning
disabled.

Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Keith Owens authored and Linus Torvalds committed Jun 26, 2006
1 parent 9c63f87 commit 45486f8
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Showing 4 changed files with 15 additions and 8 deletions.
7 changes: 1 addition & 6 deletions arch/i386/kernel/crash.c
Original file line number Diff line number Diff line change
Expand Up @@ -120,14 +120,9 @@ static int crash_nmi_callback(struct pt_regs *regs, int cpu)
return 1;
}

/*
* By using the NMI code instead of a vector we just sneak thru the
* word generator coming out with just what we want. AND it does
* not matter if clustered_apic_mode is set or not.
*/
static void smp_send_nmi_allbutself(void)
{
send_IPI_allbutself(APIC_DM_NMI);
send_IPI_allbutself(NMI_VECTOR);
}

static void nmi_shootdown_cpus(void)
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12 changes: 11 additions & 1 deletion arch/i386/kernel/smp.c
Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,17 @@ DEFINE_PER_CPU(struct tlb_state, cpu_tlbstate) ____cacheline_aligned = { &init_m

static inline int __prepare_ICR (unsigned int shortcut, int vector)
{
return APIC_DM_FIXED | shortcut | vector | APIC_DEST_LOGICAL;
unsigned int icr = shortcut | APIC_DEST_LOGICAL;

switch (vector) {
default:
icr |= APIC_DM_FIXED | vector;
break;
case NMI_VECTOR:
icr |= APIC_DM_NMI;
break;
}
return icr;
}

static inline int __prepare_ICR2 (unsigned int mask)
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2 changes: 1 addition & 1 deletion arch/x86_64/kernel/crash.c
Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,7 @@ static int crash_nmi_callback(struct pt_regs *regs, int cpu)

static void smp_send_nmi_allbutself(void)
{
send_IPI_allbutself(APIC_DM_NMI);
send_IPI_allbutself(NMI_VECTOR);
}

/*
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2 changes: 2 additions & 0 deletions include/asm-i386/hw_irq.h
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,8 @@

struct hw_interrupt_type;

#define NMI_VECTOR 0x02

/*
* Various low-level irq details needed by irq.c, process.c,
* time.c, io_apic.c and smp.c
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