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Commit a1f3bb9a authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

[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: default avatarRoland 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7f6ee1ad

arch/i386/kernel/entry.S

+4 −0
Original line number Diff line number Diff line
@@ -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

arch/i386/kernel/sysenter.c

+2 −0
Original line number Diff line number Diff line
@@ -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

include/asm-i386/elf.h

+3 −4
Original line number Diff line number Diff line
@@ -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;

include/asm-i386/fixmap.h

+2 −0
Original line number Diff line number Diff line
@@ -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__

include/asm-i386/page.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */