Remove the limit of 256 interrupt vectors by changing the value
stored in orig_{e,r}ax to be the negated 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 <[email protected]>
Signed-off-by: Christian Limpach <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
arch/i386/kernel/entry.S | 4 ++--
arch/i386/kernel/irq.c | 4 ++--
arch/x86_64/kernel/entry.S | 2 +-
arch/x86_64/kernel/irq.c | 4 ++--
arch/x86_64/kernel/smp.c | 4 ++--
include/asm-x86_64/hw_irq.h | 2 +-
6 files changed, 10 insertions(+), 10 deletions(-)
--- linus-2.6.orig/arch/i386/kernel/entry.S
+++ linus-2.6/arch/i386/kernel/entry.S
@@ -464,7 +464,7 @@ vector=0
ENTRY(irq_entries_start)
.rept NR_IRQS
ALIGN
-1: pushl $vector-256
+1: pushl $~(vector)
jmp common_interrupt
.data
.long 1b
@@ -481,7 +481,7 @@ common_interrupt:
#define BUILD_INTERRUPT(name, nr) \
ENTRY(name) \
- pushl $nr-256; \
+ pushl $~(nr); \
SAVE_ALL \
movl %esp,%eax; \
call smp_/**/name; \
--- linus-2.6.orig/arch/i386/kernel/irq.c
+++ linus-2.6/arch/i386/kernel/irq.c
@@ -53,8 +53,8 @@ static union irq_ctx *softirq_ctx[NR_CPU
*/
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;
--- linus-2.6.orig/arch/x86_64/kernel/entry.S
+++ linus-2.6/arch/x86_64/kernel/entry.S
@@ -601,7 +601,7 @@ retint_kernel:
*/
.macro apicinterrupt num,func
INTR_FRAME
- pushq $\num-256
+ pushq $~(\num)
CFI_ADJUST_CFA_OFFSET 8
interrupt \func
jmp ret_from_intr
--- linus-2.6.orig/arch/x86_64/kernel/irq.c
+++ linus-2.6/arch/x86_64/kernel/irq.c
@@ -91,8 +91,8 @@ 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();
--- linus-2.6.orig/arch/x86_64/kernel/smp.c
+++ linus-2.6/arch/x86_64/kernel/smp.c
@@ -135,10 +135,10 @@ asmlinkage void smp_invalidate_interrupt
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))
--- linus-2.6.orig/include/asm-x86_64/hw_irq.h
+++ linus-2.6/include/asm-x86_64/hw_irq.h
@@ -127,7 +127,7 @@ 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)
--
In-Reply-To: <[email protected]>
On Tue, 09 May 2006 00:00:23 -0700, Chris Wright wrote:
> Remove the limit of 256 interrupt vectors by changing the value
> stored in orig_{e,r}ax to be the negated 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 <[email protected]>
> Signed-off-by: Christian Limpach <[email protected]>
> Signed-off-by: Chris Wright <[email protected]>
> ---
AFAIC this could go in anytime. It's simple, self-contained and makes
sense even without Xen.
One minor nit: the IRQ value isn't negated, it's complemented. The
comments need to be fixed.
Original patch:
arch/i386/kernel/entry.S | 4 ++--
arch/i386/kernel/irq.c | 4 ++--
arch/x86_64/kernel/entry.S | 2 +-
arch/x86_64/kernel/irq.c | 4 ++--
arch/x86_64/kernel/smp.c | 4 ++--
include/asm-x86_64/hw_irq.h | 2 +-
6 files changed, 10 insertions(+), 10 deletions(-)
--- linus-2.6.orig/arch/i386/kernel/entry.S
+++ linus-2.6/arch/i386/kernel/entry.S
@@ -464,7 +464,7 @@ vector=0
ENTRY(irq_entries_start)
.rept NR_IRQS
ALIGN
-1: pushl $vector-256
+1: pushl $~(vector)
jmp common_interrupt
.data
.long 1b
@@ -481,7 +481,7 @@ common_interrupt:
#define BUILD_INTERRUPT(name, nr) \
ENTRY(name) \
- pushl $nr-256; \
+ pushl $~(nr); \
SAVE_ALL \
movl %esp,%eax; \
call smp_/**/name; \
--- linus-2.6.orig/arch/i386/kernel/irq.c
+++ linus-2.6/arch/i386/kernel/irq.c
@@ -53,8 +53,8 @@ static union irq_ctx *softirq_ctx[NR_CPU
*/
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;
--- linus-2.6.orig/arch/x86_64/kernel/entry.S
+++ linus-2.6/arch/x86_64/kernel/entry.S
@@ -601,7 +601,7 @@ retint_kernel:
*/
.macro apicinterrupt num,func
INTR_FRAME
- pushq $\num-256
+ pushq $~(\num)
CFI_ADJUST_CFA_OFFSET 8
interrupt \func
jmp ret_from_intr
--- linus-2.6.orig/arch/x86_64/kernel/irq.c
+++ linus-2.6/arch/x86_64/kernel/irq.c
@@ -91,8 +91,8 @@ 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();
--- linus-2.6.orig/arch/x86_64/kernel/smp.c
+++ linus-2.6/arch/x86_64/kernel/smp.c
@@ -135,10 +135,10 @@ asmlinkage void smp_invalidate_interrupt
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))
--- linus-2.6.orig/include/asm-x86_64/hw_irq.h
+++ linus-2.6/include/asm-x86_64/hw_irq.h
@@ -127,7 +127,7 @@ 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)
--
Chuck
"The x86 isn't all that complex -- it just doesn't make a lot of sense."
-- Mike Johnson
On 13 May 2006, at 18:44, Chuck Ebbert wrote:
> AFAIC this could go in anytime. It's simple, self-contained and makes
> sense even without Xen.
>
> One minor nit: the IRQ value isn't negated, it's complemented. The
> comments need to be fixed.
If we really want it disambiguated then we should call it something
like 'bitwise-negated' or 'ones-complemented'. 'Complemented' alone is
worse than 'negated' imo, since negation is at least the usual name for
the tilde operator in C while complementation is an ambiguous term
unless you know the base/radix.
-- Keir
On Sunday, 14. May 2006 09:52, Keir Fraser wrote:
> If we really want it disambiguated then we should call it something
> like 'bitwise-negated' or 'ones-complemented'. 'Complemented' alone is
> worse than 'negated' imo, since negation is at least the usual name for
> the tilde operator in C while complementation is an ambiguous term
> unless you know the base/radix.
Not really.
I've seen "negate" only be used to mean "twos complement"
and "invert" only be seen with "ones complement".
So if you like to be clear, just use "negate" vs. "invert".
Regards
Ingo Oeser
* Chuck Ebbert ([email protected]) wrote:
> In-Reply-To: <[email protected]>
>
> On Tue, 09 May 2006 00:00:23 -0700, Chris Wright wrote:
>
> > Remove the limit of 256 interrupt vectors by changing the value
> > stored in orig_{e,r}ax to be the negated 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 <[email protected]>
> > Signed-off-by: Christian Limpach <[email protected]>
> > Signed-off-by: Chris Wright <[email protected]>
> > ---
>
> AFAIC this could go in anytime. It's simple, self-contained and makes
> sense even without Xen.
The plan is to split out things like this and push them ahead of the
rest of the batch.
> One minor nit: the IRQ value isn't negated, it's complemented. The
> comments need to be fixed.
OK, bitwise negated.
thanks,
-chris