[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>
diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index acee4bc..5a1c0a3 100644
--- a/arch/x86_64/kernel/smp.c
+++ b/arch/x86_64/kernel/smp.c
@@ -135,10 +135,10 @@
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))
