On Wed, Apr 23, 2008 at 04:03:58PM +0200, Jes Sorensen wrote:
> Isaku Yamahata wrote:
> >>I'd rather have PARAVIRT_NR_IRQ set from Kconfig if possible given that
> >>all of these are constants anyway. If we cannot do that, then it would
> >>be better to do the #if FOO_NR_IRQ > PARAVIRT_NR_IRQ in the various
> >>header files for Xen/KVM/lguest so we don't get the clutter in the main
> >>makefile.
> >
> >Unfotunately Kconfig doesn't support arithmetic comparison.
> >So do you want something like the followings?
>
> IMHO, that would be better.
How about this?
Eventually I found another way which doesn't use #undef trick.
ASM_OFFSET_C is somewhat tricky, but much better, I suppose.
>From 8b13a7498112d2f3f1d8eb58543209956ffc5417 Mon Sep 17 00:00:00 2001
From: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Date: Thu, 24 Apr 2008 19:53:50 +0900
Subject: ia64/pv_ops: paravirtualize NR_IRQS
Make NR_IRQ overridable by each pv instances.
Pv instance may need each own number of irqs so that
NR_IRQS should be the maximum number of nr_irqs each
pv instances need.
Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
---
arch/ia64/kernel/asm-offsets.c | 18 ++++++++++++++++++
include/asm-ia64/hardirq.h | 4 +++-
include/asm-ia64/irq.h | 13 +++++++++++--
3 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c
index 230a6f9..dff6403 100644
--- a/arch/ia64/kernel/asm-offsets.c
+++ b/arch/ia64/kernel/asm-offsets.c
@@ -10,6 +10,7 @@
#include <linux/pid.h>
#include <linux/clocksource.h>
+#include <asm-ia64/irq.h>
#include <asm-ia64/processor.h>
#include <asm-ia64/ptrace.h>
#include <asm-ia64/siginfo.h>
@@ -291,4 +292,21 @@ void foo(void)
offsetof (struct itc_jitter_data_t, itc_jitter));
DEFINE(IA64_ITC_LASTCYCLE_OFFSET,
offsetof (struct itc_jitter_data_t, itc_lastcycle));
+ BLANK();
+
+ {
+ /*
+ * calculate
+ * max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, FOO_NR_IRQS...)
+ * depending on config.
+ */
+ union paravirt_nr_irqs_max {
+ char ia64_native_nr_irqs[IA64_NATIVE_NR_IRQS];
+#ifdef CONFIG_XEN
+ char xen_nr_irqs[XEN_NR_IRQS];
+#endif
+ };
+
+ DEFINE(PARAVIRT_NR_IRQS, sizeof (union paravirt_nr_irqs_max));
+ }
}
diff --git a/include/asm-ia64/hardirq.h b/include/asm-ia64/hardirq.h
index 140e495..7ee7626 100644
--- a/include/asm-ia64/hardirq.h
+++ b/include/asm-ia64/hardirq.h
@@ -8,7 +8,9 @@
#include <linux/threads.h>
+#ifndef ASM_OFFSETS_C
#include <linux/irq.h>
+#endif
#include <asm/processor.h>
@@ -26,7 +28,7 @@
* The hardirq mask has to be large enough to have space for potentially all IRQ sources
* in the system nesting on a single CPU:
*/
-#if (1 << HARDIRQ_BITS) < NR_IRQS
+#if !defined (ASM_OFFSETS_C) && ((1 << HARDIRQ_BITS) < NR_IRQS)
# error HARDIRQ_BITS is too low!
#endif
diff --git a/include/asm-ia64/irq.h b/include/asm-ia64/irq.h
index a66d268..5208318 100644
--- a/include/asm-ia64/irq.h
+++ b/include/asm-ia64/irq.h
@@ -17,9 +17,18 @@
#define NR_VECTORS 256
#if (NR_VECTORS + 32 * NR_CPUS) < 1024
-#define NR_IRQS (NR_VECTORS + 32 * NR_CPUS)
+#define IA64_NATIVE_NR_IRQS (NR_VECTORS + 32 * NR_CPUS)
#else
-#define NR_IRQS 1024
+#define IA64_NATIVE_NR_IRQS 1024
+#endif
+
+/*
+ * PARAVIRT_NR_IRQS is defined by asm-offsets.c as
+ * max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, ...) depending on config.
+ */
+#ifndef ASM_OFFSETS_C
+#include <asm/asm-offsets.h>
+#define NR_IRQS PARAVIRT_NR_IRQS
#endif
static __inline__ int
--
1.5.3
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