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Subject[PATCH 1/11] Fix CONFIG_COMPAT_VDSO
Date

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>
---
arch/i386/kernel/entry.S | 4 ++++
arch/i386/kernel/sysenter.c | 2 ++
include/asm-i386/elf.h | 7 +++----
include/asm-i386/fixmap.h | 2 ++
include/asm-i386/page.h | 2 ++
5 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 06461b8..5e47683 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -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

diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c
index 7de9117..454d12d 100644
--- a/arch/i386/kernel/sysenter.c
+++ b/arch/i386/kernel/sysenter.c
@@ -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 a
{
return 0;
}
+#endif
diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h
index 45d21a0..0515d61 100644
--- a/include/asm-i386/elf.h
+++ b/include/asm-i386/elf.h
@@ -143,11 +143,8 @@ extern int dump_task_extended_fpu (struc
# 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;

diff --git a/include/asm-i386/fixmap.h b/include/asm-i386/fixmap.h
index 02428cb..3e9f610 100644
--- a/include/asm-i386/fixmap.h
+++ b/include/asm-i386/fixmap.h
@@ -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__
diff --git a/include/asm-i386/page.h b/include/asm-i386/page.h
index fd3f64a..7b19f45 100644
--- a/include/asm-i386/page.h
+++ b/include/asm-i386/page.h
@@ -143,7 +143,9 @@ extern int page_is_ram(unsigned long pag
#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 */
-
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