[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>

[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>
Roland McGrath · Linus Torvalds
1 parent 7f6ee1adc7
Showing 5 changed files with 13 additions and 4 deletions Side-by-side Diff
arch/i386/kernel/entry.S
arch/i386/kernel/sysenter.c
include/asm-i386/elf.h
include/asm-i386/fixmap.h
include/asm-i386/page.h
@@ -302,12 +302,16 @@
 	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
  
@@ -100,6 +100,7 @@
 	return 0;
 }
  
+#ifndef CONFIG_COMPAT_VDSO
 static struct page *syscall_nopage(struct vm_area_struct *vma,
 				unsigned long adr, int *type)
 {
@@ -187,4 +188,5 @@
 {
 	return 0;
 }
+#endif
@@ -143,12 +143,9 @@
 # define VDSO_PRELINK		0
 #endif
  
-#define VDSO_COMPAT_SYM(x) \
+#define VDSO_SYM(x) \
 		(VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
  
-#define VDSO_SYM(x) \
-		(VDSO_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 @@
  
 #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;
  
@@ -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__
@@ -143,7 +143,9 @@
 #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 */
...	...	@@ -302,12 +302,16 @@
302	302	pushl $(__USER_CS)
303	303	CFI_ADJUST_CFA_OFFSET 4
304	304	/CFI_REL_OFFSET cs, 0/
	305	+#ifndef CONFIG_COMPAT_VDSO
305	306	/*
306	307	* Push current_thread_info()->sysenter_return to the stack.
307	308	* A tiny bit of offset fixup is necessary - 4*4 means the 4 words
308	309	* pushed above; +8 corresponds to copy_thread's esp0 setting.
309	310	*/
310	311	pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
	312	+#else
	313	+ pushl $SYSENTER_RETURN
	314	+#endif
311	315	CFI_ADJUST_CFA_OFFSET 4
312	316	CFI_REL_OFFSET eip, 0
313	317
...	...	@@ -100,6 +100,7 @@
100	100	return 0;
101	101	}
102	102
	103	+#ifndef CONFIG_COMPAT_VDSO
103	104	static struct page syscall_nopage(struct vm_area_struct vma,
104	105	unsigned long adr, int *type)
105	106	{
...	...	@@ -187,4 +188,5 @@
187	188	{
188	189	return 0;
189	190	}
	191	+#endif
...	...	@@ -143,12 +143,9 @@
143	143	# define VDSO_PRELINK 0
144	144	#endif
145	145
146		-#define VDSO_COMPAT_SYM(x) \
	146	+#define VDSO_SYM(x) \
147	147	(VDSO_COMPAT_BASE + (unsigned long)(x) - VDSO_PRELINK)
148	148
149		-#define VDSO_SYM(x) \
150		- (VDSO_BASE + (unsigned long)(x) - VDSO_PRELINK)
151		-
152	149	#define VDSO_HIGH_EHDR ((const struct elfhdr *) VDSO_HIGH_BASE)
153	150	#define VDSO_EHDR ((const struct elfhdr *) VDSO_COMPAT_BASE)
154	151
155	152
...	...	@@ -156,10 +153,12 @@
156	153
157	154	#define VDSO_ENTRY VDSO_SYM(&__kernel_vsyscall)
158	155
	156	+#ifndef CONFIG_COMPAT_VDSO
159	157	#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
160	158	struct linux_binprm;
161	159	extern int arch_setup_additional_pages(struct linux_binprm *bprm,
162	160	int executable_stack);
	161	+#endif
163	162
164	163	extern unsigned int vdso_enabled;
165	164
...	...	@@ -23,6 +23,8 @@
23	23	extern unsigned long __FIXADDR_TOP;
24	24	#else
25	25	#define __FIXADDR_TOP 0xfffff000
	26	+#define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
	27	+#define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
26	28	#endif
27	29
28	30	#ifndef __ASSEMBLY__
...	...	@@ -143,7 +143,9 @@
143	143	#include <asm-generic/memory_model.h>
144	144	#include <asm-generic/page.h>
145	145
	146	+#ifndef CONFIG_COMPAT_VDSO
146	147	#define __HAVE_ARCH_GATE_AREA 1
	148	+#endif
147	149	#endif /* __KERNEL__ */
148	150
149	151	#endif /* _I386_PAGE_H */