Commit 19eadf98 authored by Rusty Russell's avatar Rusty Russell Committed by Linus Torvalds
Browse files

[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: default avatarIan Pratt <ian.pratt@xensource.com>
Signed-off-by: default avatarChristian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bd9e0b74

arch/i386/kernel/entry.S

+2 −2
Original line number Diff line number Diff line
@@ -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;			\

arch/i386/kernel/irq.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

arch/x86_64/kernel/entry.S

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86_64/kernel/irq.c

+2 −2
Original line number Diff line number Diff line
@@ -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();

arch/x86_64/kernel/smp.c

+2 −2
Original line number Diff line number Diff line
@@ -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))

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