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[PATCH] x86: increase interrupt vector range 

Remove the limit of 256 interrupt vectors by changing the value stored in
orig_{e,r}ax to be the complemented interrupt vector.  The orig_{e,r}ax
needs to be < 0 to allow the signal code to distinguish between return from
interrupt and return from syscall.  With this change applied, NR_IRQS can
be > 256.

Xen extends the IRQ numbering space to include room for dynamically
allocated virtual interrupts (in the range 256-511), which requires a more
permissive interface to do_IRQ.

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Rusty Russell 2006-06-27 02:53:44 -07:00 committed by Linus Torvalds
parent bd9e0b74f5
commit 19eadf98c8
6 changed files with 10 additions and 10 deletions
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4
arch/i386/kernel/entry.S
View File

@ -515,7 +515,7 @@ ENTRY(irq_entries_start)
.if vector
CFI_ADJUST_CFA_OFFSET -4
.endif
1: pushl $vector-256
1: pushl $~(vector)
CFI_ADJUST_CFA_OFFSET 4
jmp common_interrupt
.data
@ -535,7 +535,7 @@ common_interrupt:
#define BUILD_INTERRUPT(name, nr) \
ENTRY(name) \
RING0_INT_FRAME; \
pushl $nr-256; \
pushl $~(nr); \
CFI_ADJUST_CFA_OFFSET 4; \
SAVE_ALL; \
movl %esp,%eax; \

4
arch/i386/kernel/irq.c
View File

@ -53,8 +53,8 @@ static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
*/
fastcall unsigned int do_IRQ(struct pt_regs *regs)
{
/* high bits used in ret_from_ code */
int irq = regs->orig_eax & 0xff;
/* high bit used in ret_from_ code */
int irq = ~regs->orig_eax;
#ifdef CONFIG_4KSTACKS
union irq_ctx *curctx, *irqctx;
u32 *isp;

2
arch/x86_64/kernel/entry.S
View File

@ -588,7 +588,7 @@ END(common_interrupt)
*/
.macro apicinterrupt num,func
INTR_FRAME
pushq $\num-256
pushq $~(\num)
CFI_ADJUST_CFA_OFFSET 8
interrupt \func
jmp ret_from_intr

4
arch/x86_64/kernel/irq.c
View File

@ -115,8 +115,8 @@ skip:
*/
asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
{
/* high bits used in ret_from_ code */
unsigned irq = regs->orig_rax & 0xff;
/* high bit used in ret_from_ code */
unsigned irq = ~regs->orig_rax;
exit_idle();
irq_enter();

4
arch/x86_64/kernel/smp.c
View File

@ -135,10 +135,10 @@ asmlinkage void smp_invalidate_interrupt(struct pt_regs *regs)
cpu = smp_processor_id();
/*
* orig_rax contains the interrupt vector - 256.
* orig_rax contains the negated interrupt vector.
* Use that to determine where the sender put the data.
*/
sender = regs->orig_rax + 256 - INVALIDATE_TLB_VECTOR_START;
sender = ~regs->orig_rax - INVALIDATE_TLB_VECTOR_START;
f = &per_cpu(flush_state, sender);
if (!cpu_isset(cpu, f->flush_cpumask))

2
include/asm-x86_64/hw_irq.h
View File

@ -124,7 +124,7 @@ asmlinkage void IRQ_NAME(nr); \
__asm__( \
"\n.p2align\n" \
"IRQ" #nr "_interrupt:\n\t" \
"push $" #nr "-256 ; " \
"push $~(" #nr ") ; " \
"jmp common_interrupt");
#if defined(CONFIG_X86_IO_APIC)