[PATCH] i386: Relocate VDSO ELF headers to match mapped location with COMPAT_VDSO
Some versions of libc can't deal with a VDSO which doesn't have its
ELF headers matching its mapped address. COMPAT_VDSO maps the VDSO at
a specific system-wide fixed address. Previously this was all done at
build time, on the grounds that the fixed VDSO address is always at
the top of the address space. However, a hypervisor may reserve some
of that address space, pushing the fixmap address down.
This patch does the adjustment dynamically at runtime, depending on
the runtime location of the VDSO fixmap.
[ Patch has been through several hands: Jan Beulich wrote the orignal
version; Zach reworked it, and Jeremy converted it to relocate phdrs
as well as sections. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Cc: "Jan Beulich" <JBeulich@novell.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h
index 952b3ee..d304ab4 100644
--- a/include/asm-i386/elf.h
+++ b/include/asm-i386/elf.h
@@ -133,39 +133,31 @@
#define ELF_CORE_COPY_XFPREGS(tsk, elf_xfpregs) dump_task_extended_fpu(tsk, elf_xfpregs)
#define VDSO_HIGH_BASE (__fix_to_virt(FIX_VDSO))
-#define VDSO_BASE ((unsigned long)current->mm->context.vdso)
-
-#ifdef CONFIG_COMPAT_VDSO
-# define VDSO_COMPAT_BASE VDSO_HIGH_BASE
-# define VDSO_PRELINK VDSO_HIGH_BASE
-#else
-# define VDSO_COMPAT_BASE VDSO_BASE
-# define VDSO_PRELINK 0
-#endif
+#define VDSO_CURRENT_BASE ((unsigned long)current->mm->context.vdso)
+#define VDSO_PRELINK 0
#define VDSO_SYM(x) \
- (VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
+ (VDSO_CURRENT_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)
+#define VDSO_EHDR ((const struct elfhdr *) VDSO_CURRENT_BASE)
extern void __kernel_vsyscall;
#define VDSO_ENTRY VDSO_SYM(&__kernel_vsyscall)
-#ifndef CONFIG_COMPAT_VDSO
-#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
struct linux_binprm;
+
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack);
-#endif
extern unsigned int vdso_enabled;
-#define ARCH_DLINFO \
-do if (vdso_enabled) { \
- NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
- NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_COMPAT_BASE); \
+#define ARCH_DLINFO \
+do if (vdso_enabled) { \
+ NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
} while (0)
#endif
diff --git a/include/asm-i386/fixmap.h b/include/asm-i386/fixmap.h
index 3e9f610..e5651b2 100644
--- a/include/asm-i386/fixmap.h
+++ b/include/asm-i386/fixmap.h
@@ -19,13 +19,9 @@
* Leave one empty page between vmalloc'ed areas and
* the start of the fixmap.
*/
-#ifndef CONFIG_COMPAT_VDSO
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
+#define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
+#define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
#ifndef __ASSEMBLY__
#include <linux/kernel.h>