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[PATCH] Fix CONFIG_COMPAT_VDSO 

I wouldn't mind if CONFIG_COMPAT_VDSO went away entirely.  But if it's there,
it should work properly.  Currently it's quite haphazard: both real vma and
fixmap are mapped, both are put in the two different AT_* slots, sysenter
returns to the vma address rather than the fixmap address, and core dumps yet
are another story.

This patch makes CONFIG_COMPAT_VDSO disable the real vma and use the fixmap
area consistently.  This makes it actually compatible with what the old vdso
implementation did.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roland McGrath 2007-01-26 00:56:46 -08:00 committed by Linus Torvalds
parent 7f6ee1adc7
commit a1f3bb9ae4
5 changed files with 13 additions and 4 deletions
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4
arch/i386/kernel/entry.S
View File

@ -302,12 +302,16 @@ sysenter_past_esp:
pushl $(__USER_CS)
CFI_ADJUST_CFA_OFFSET 4
/*CFI_REL_OFFSET cs, 0*/
#ifndef CONFIG_COMPAT_VDSO
/*
* Push current_thread_info()->sysenter_return to the stack.
* A tiny bit of offset fixup is necessary - 4*4 means the 4 words
* pushed above; +8 corresponds to copy_thread's esp0 setting.
*/
pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
#else
pushl $SYSENTER_RETURN
#endif
CFI_ADJUST_CFA_OFFSET 4
CFI_REL_OFFSET eip, 0

2
arch/i386/kernel/sysenter.c
View File

@ -100,6 +100,7 @@ int __init sysenter_setup(void)
return 0;
}
#ifndef CONFIG_COMPAT_VDSO
static struct page *syscall_nopage(struct vm_area_struct *vma,
unsigned long adr, int *type)
{
@ -187,3 +188,4 @@ int in_gate_area_no_task(unsigned long addr)
{
return 0;
}
#endif

7
include/asm-i386/elf.h
View File

@ -143,11 +143,8 @@ extern int dump_task_extended_fpu (struct task_struct *, struct user_fxsr_struct
# define VDSO_PRELINK 0
#endif
#define VDSO_COMPAT_SYM(x) \
(VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
#define VDSO_SYM(x) \
(VDSO_BASE + (unsigned long)(x) - VDSO_PRELINK)
(VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
#define VDSO_HIGH_EHDR ((const struct elfhdr *) VDSO_HIGH_BASE)
#define VDSO_EHDR ((const struct elfhdr *) VDSO_COMPAT_BASE)
@ -156,10 +153,12 @@ extern void __kernel_vsyscall;
#define VDSO_ENTRY VDSO_SYM(&__kernel_vsyscall)
#ifndef CONFIG_COMPAT_VDSO
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
struct linux_binprm;
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack);
#endif
extern unsigned int vdso_enabled;

2
include/asm-i386/fixmap.h
View File

@ -23,6 +23,8 @@
extern unsigned long __FIXADDR_TOP;
#else
#define __FIXADDR_TOP 0xfffff000
#define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
#define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
#endif
#ifndef __ASSEMBLY__

2
include/asm-i386/page.h
View File

@ -143,7 +143,9 @@ extern int page_is_ram(unsigned long pagenr);
#include <asm-generic/memory_model.h>
#include <asm-generic/page.h>
#ifndef CONFIG_COMPAT_VDSO
#define __HAVE_ARCH_GATE_AREA 1
#endif
#endif /* __KERNEL__ */
#endif /* _I386_PAGE_H */