On Wed, Jul 25, 2007 at 08:31:32PM +0200, Sam Ravnborg wrote:
> In include/linux/mm.h arch_vma_name() is declared __weak.
> This hide the fact that x86_64 has 2 implementations of
> said function.
>
> In arch/x86_64/mm/init.c:
> const char *arch_vma_name(struct vm_area_struct *vma)
> {
> if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
> return "[vdso]";
> if (vma == &gate_vma)
> return "[vsyscall]";
> return NULL;
> }
>
> And in arch/x86_64/ia32/syscall32.c:
> const char *arch_vma_name(struct vm_area_struct *vma)
> {
> if (vma->vm_start == VSYSCALL32_BASE &&
> vma->vm_mm && vma->vm_mm->task_size == IA32_PAGE_OFFSET)
> return "[vdso]";
> return NULL;
> }
>
> As no comment were preceeding the fucntions this seems not to be on
> purpose.
> If I am correct which one should die?
>
> The reason why this popped up is that the __weak definition in mm.h
> causes problems on at least powerpc (trigger a binutils bug).
> A similar bug is present at ia64 - but I have not confirmed if the
> same fix is needed.
I cooked up following patch - but I do not claim I understand this
code. It was done only by merging the functionality into one function.
I need this patch or a similar one to be added so the weak declaration
of arch_vma_name in mm.h can be made a normal prototype.
Sam
[PATCH] x86_64: merge two identical named funtion into one
The function arch_vma_name() is declared weak and thus it was
not noticed that x86_64 had two almost identical implementations.
It was introduced in syscall32.c by: c633090e3105e779c97d4978e5e3d7d66b291cfb
It was introduced in mm/init.c by: 2aae950b21e4bc789d1fc6668faf67e8748300b7
Signed-off-by: Sam Ravnborg <[email protected]>
Cc: Roland McGrath <[email protected]>
---
diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c
index fc4419f..15013ba 100644
--- a/arch/x86_64/ia32/syscall32.c
+++ b/arch/x86_64/ia32/syscall32.c
@@ -49,14 +49,6 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
return ret;
}
-const char *arch_vma_name(struct vm_area_struct *vma)
-{
- if (vma->vm_start == VSYSCALL32_BASE &&
- vma->vm_mm && vma->vm_mm->task_size == IA32_PAGE_OFFSET)
- return "[vdso]";
- return NULL;
-}
-
static int __init init_syscall32(void)
{
char *syscall32_page = (void *)get_zeroed_page(GFP_KERNEL);
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 38f5d63..6f608d8 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -43,6 +43,7 @@
#include <asm/proto.h>
#include <asm/smp.h>
#include <asm/sections.h>
+#include <asm/vsyscall32.h>
#ifndef Dprintk
#define Dprintk(x...)
@@ -734,6 +735,9 @@ const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
return "[vdso]";
+ if (vma->vm_mm && vma->vm_start == VSYSCALL32_BASE &&
+ vma->vm_mm->task_size == IA32_PAGE_OFFSET)
+ return "[vdso]";
if (vma == &gate_vma)
return "[vsyscall]";
return NULL;
-
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