The existing hook from KDB in the IPI code is really just a hook for the
NMI vector. We rename the vector thusly and then it's up to the
debugger to handle things from do_default_nmi().
---
linux-2.6.13-trini/arch/x86_64/kernel/i8259.c | 3 +--
linux-2.6.13-trini/arch/x86_64/kernel/smp.c | 2 +-
linux-2.6.13-trini/arch/x86_64/kernel/traps.c | 2 +-
linux-2.6.13-trini/include/asm-x86_64/hw_irq.h | 2 +-
linux-2.6.13-trini/include/asm-x86_64/ipi.h | 2 +-
5 files changed, 5 insertions(+), 6 deletions(-)
diff -puN arch/x86_64/kernel/i8259.c~x86_64-rename_kdb_vector arch/x86_64/kernel/i8259.c
--- linux-2.6.13/arch/x86_64/kernel/i8259.c~x86_64-rename_kdb_vector 2005-09-01 12:00:42.000000000 -0700
+++ linux-2.6.13-trini/arch/x86_64/kernel/i8259.c 2005-09-01 12:00:42.000000000 -0700
@@ -544,10 +544,9 @@ void __init init_IRQ(void)
int vector = FIRST_EXTERNAL_VECTOR + i;
if (i >= NR_IRQS)
break;
- if (vector != IA32_SYSCALL_VECTOR && vector != KDB_VECTOR) {
+ if (vector != IA32_SYSCALL_VECTOR && vector != NMI_VECTOR)
set_intr_gate(vector, interrupt[i]);
}
- }
#ifdef CONFIG_SMP
/*
diff -puN arch/x86_64/kernel/smp.c~x86_64-rename_kdb_vector arch/x86_64/kernel/smp.c
--- linux-2.6.13/arch/x86_64/kernel/smp.c~x86_64-rename_kdb_vector 2005-09-01 12:00:42.000000000 -0700
+++ linux-2.6.13-trini/arch/x86_64/kernel/smp.c 2005-09-01 12:00:42.000000000 -0700
@@ -252,7 +252,7 @@ void flush_tlb_all(void)
void smp_kdb_stop(void)
{
- send_IPI_allbutself(KDB_VECTOR);
+ send_IPI_allbutself(NMI_VECTOR);
}
/*
diff -puN arch/x86_64/kernel/traps.c~x86_64-rename_kdb_vector arch/x86_64/kernel/traps.c
--- linux-2.6.13/arch/x86_64/kernel/traps.c~x86_64-rename_kdb_vector 2005-09-01 12:00:42.000000000 -0700
+++ linux-2.6.13-trini/arch/x86_64/kernel/traps.c 2005-09-01 12:00:56.000000000 -0700
@@ -931,7 +931,7 @@ void __init trap_init(void)
set_system_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
#endif
- set_intr_gate(KDB_VECTOR, call_debug);
+ set_intr_gate(NMI_VECTOR, call_debug);
/*
* Should be a barrier for any external CPU state.
diff -puN include/asm-x86_64/hw_irq.h~x86_64-rename_kdb_vector include/asm-x86_64/hw_irq.h
--- linux-2.6.13/include/asm-x86_64/hw_irq.h~x86_64-rename_kdb_vector 2005-09-01 12:00:42.000000000 -0700
+++ linux-2.6.13-trini/include/asm-x86_64/hw_irq.h 2005-09-01 12:00:42.000000000 -0700
@@ -54,7 +54,7 @@ struct hw_interrupt_type;
#define RESCHEDULE_VECTOR 0xfc
#define TASK_MIGRATION_VECTOR 0xfb
#define CALL_FUNCTION_VECTOR 0xfa
-#define KDB_VECTOR 0xf9
+#define NMI_VECTOR 0xf9
#define THERMAL_APIC_VECTOR 0xf0
diff -puN include/asm-x86_64/ipi.h~x86_64-rename_kdb_vector include/asm-x86_64/ipi.h
--- linux-2.6.13/include/asm-x86_64/ipi.h~x86_64-rename_kdb_vector 2005-09-01 12:00:42.000000000 -0700
+++ linux-2.6.13-trini/include/asm-x86_64/ipi.h 2005-09-01 12:00:42.000000000 -0700
@@ -32,7 +32,7 @@
static inline unsigned int __prepare_ICR (unsigned int shortcut, int vector, unsigned int dest)
{
unsigned int icr = APIC_DM_FIXED | shortcut | vector | dest;
- if (vector == KDB_VECTOR)
+ if (vector == NMI_VECTOR)
icr = (icr & (~APIC_VECTOR_MASK)) | APIC_DM_NMI;
return icr;
}
--
Tom Rini
http://gate.crashing.org/~trini/
On Thursday 08 September 2005 18:39, Tom Rini wrote:
> The existing hook from KDB in the IPI code is really just a hook for the
> NMI vector. We rename the vector thusly and then it's up to the
> debugger to handle things from do_default_nmi().
Jan Beulich pointed out some problems with this:
- First NMI vector is always 2 in the x86 architecture, so calling
another vector NMI_VECTOR is misleading.
- And when an NMI is forced in ICR the x86 architecture specifies
that the interrupt is delivered to vector 2.
Intel IA32 vol 3 8-23:
>>
100 (NMI) Delivers an NMI interrupt to the target processor
or processors. The vector information is ignored.
<<
So how did this ever work? I suspect you just got reentered
via the hooks in the NMI handler, but never through this vector.
I think I'll just remove this unless someone can explain how
it is supposed to work.
Thanks,
-Andi