* Pekka Enberg <penberg@xxxxxxxxxx> wrote:
> > asm/system.h is one of the messier kernel headers, so i'm not surprised it
> > has assymetric requirements on 64-bit and 32-bit systems.
>
> So does including <asm/bitsperlong.h> before <asm/system.h> fix the problem
> on 32-bit boxes? [...]
No, it's more complex than that.
> [...] If so, I'd prefer we fix it like that for now.
The patch below sorts out the dependencies and makes it build on both 64-bit
and 32-bit systems. (I have not runtime tested the result though.)
I'm not entirely happy about how it has added dependent includes to virtio.c
but that's a property of this messy header file. Might be worth adding a
comment about that.
Thanks,
Ingo
----------------->
>From 51cb9390753c0bb333896fbc951cc53bcae2723d Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@xxxxxxx>
Date: Thu, 5 May 2011 10:00:45 +0200
Subject: [PATCH] kvm: Fix 32-bit build of the asm/system.h include
Provide wrappers and other environmental dependencies that the asm/system.h
header file from hell needs to build fine in user-space.
Sidenote: right now alternative() defaults to the compatible, slightly slower
barrier instructions that work on all x86 systems.
If this ever shows up in profiles then kvm could provide an alternatives
patching machinery as well. Right now those instructions are emitted into
special sections and then discarded by the linker harmlessly.
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
tools/kvm/include/asm/hweight.h | 8 ++++++++
tools/kvm/include/linux/bitops.h | 33 +++++++++++++++++++++++++++++++++
tools/kvm/virtio.c | 5 +++++
3 files changed, 46 insertions(+), 0 deletions(-)
diff --git a/tools/kvm/include/asm/hweight.h b/tools/kvm/include/asm/hweight.h
new file mode 100644
index 0000000..36cf26d
--- /dev/null
+++ b/tools/kvm/include/asm/hweight.h
@@ -0,0 +1,8 @@
+#ifndef PERF_HWEIGHT_H
+#define PERF_HWEIGHT_H
+
+#include <linux/types.h>
+unsigned int hweight32(unsigned int w);
+unsigned long hweight64(__u64 w);
+
+#endif /* PERF_HWEIGHT_H */
diff --git a/tools/kvm/include/linux/bitops.h b/tools/kvm/include/linux/bitops.h
new file mode 100644
index 0000000..305c848
--- /dev/null
+++ b/tools/kvm/include/linux/bitops.h
@@ -0,0 +1,33 @@
+#ifndef _PERF_LINUX_BITOPS_H_
+#define _PERF_LINUX_BITOPS_H_
+
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <asm/hweight.h>
+
+#define BITS_PER_LONG __WORDSIZE
+#define BITS_PER_BYTE 8
+#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
+
+static inline void set_bit(int nr, unsigned long *addr)
+{
+ addr[nr / BITS_PER_LONG] |= 1UL << (nr % BITS_PER_LONG);
+}
+
+static inline void clear_bit(int nr, unsigned long *addr)
+{
+ addr[nr / BITS_PER_LONG] &= ~(1UL << (nr % BITS_PER_LONG));
+}
+
+static __always_inline int test_bit(unsigned int nr, const unsigned long *addr)
+{
+ return ((1UL << (nr % BITS_PER_LONG)) &
+ (((unsigned long *)addr)[nr / BITS_PER_LONG])) != 0;
+}
+
+static inline unsigned long hweight_long(unsigned long w)
+{
+ return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
+}
+
+#endif
diff --git a/tools/kvm/virtio.c b/tools/kvm/virtio.c
index 266a1b6..3a4b1c9 100644
--- a/tools/kvm/virtio.c
+++ b/tools/kvm/virtio.c
@@ -1,7 +1,12 @@
#include <linux/virtio_ring.h>
#include <stdint.h>
#include <sys/uio.h>
+
+#include <linux/stringify.h>
+#include <linux/bitops.h>
+#include <asm/alternative.h>
#include <asm/system.h>
+
#include "kvm/kvm.h"
#include "kvm/virtio.h"
--
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