3 files changed, 53 insertions, 1 deletions

diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h
index 5747a8baa413..8bb66bca2e3e 100644
--- a/arch/arm/include/asm/elf.h
+++ b/arch/arm/include/asm/elf.h
@@ -127,4 +127,8 @@ struct mm_struct;
 extern unsigned long arch_randomize_brk(struct mm_struct *mm);
 #define arch_randomize_brk arch_randomize_brk
 
+extern int vectors_user_mapping(void);
+#define arch_setup_additional_pages(bprm, uses_interp) vectors_user_mapping()
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
+
 #endif
diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h
index a0b3cac0547c..71605d9f8e42 100644
--- a/arch/arm/include/asm/mmu_context.h
+++ b/arch/arm/include/asm/mmu_context.h
@@ -18,7 +18,6 @@
 #include <asm/cacheflush.h>
 #include <asm/cachetype.h>
 #include <asm/proc-fns.h>
-#include <asm-generic/mm_hooks.h>
 
 void __check_kvm_seq(struct mm_struct *mm);
 
@@ -134,4 +133,32 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
 #define deactivate_mm(tsk,mm)   do { } while (0)
 #define activate_mm(prev,next)  switch_mm(prev, next, NULL)
 
+/*
+ * We are inserting a "fake" vma for the user-accessible vector page so
+ * gdb and friends can get to it through ptrace and /proc/<pid>/mem.
+ * But we also want to remove it before the generic code gets to see it
+ * during process exit or the unmapping of it would  cause total havoc.
+ * (the macro is used as remove_vma() is static to mm/mmap.c)
+ */
+#define arch_exit_mmap(mm) \
+do { \
+        struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \
+        if (high_vma) { \
+                BUG_ON(high_vma->vm_next);  /* it should be last */ \
+                if (high_vma->vm_prev) \
+                        high_vma->vm_prev->vm_next = NULL; \
+                else \
+                        mm->mmap = NULL; \
+                rb_erase(&high_vma->vm_rb, &mm->mm_rb); \
+                mm->mmap_cache = NULL; \
+                mm->map_count--; \
+                remove_vma(high_vma); \
+        } \
+} while (0)
+
+static inline void arch_dup_mmap(struct mm_struct *oldmm,
+                                 struct mm_struct *mm)
+{
+}
+
 #endif
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 401e38be1f78..66ac9c926200 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -458,3 +458,24 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
         unsigned long range_end = mm->brk + 0x02000000;
         return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
 }
+
+/*
+ * The vectors page is always readable from user space for the
+ * atomic helpers and the signal restart code.  Let's declare a mapping
+ * for it so it is visible through ptrace and /proc/<pid>/mem.
+ */
+
+int vectors_user_mapping(void)
+{
+        struct mm_struct *mm = current->mm;
+        return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
+                                       VM_READ | VM_EXEC |
+                                       VM_MAYREAD | VM_MAYEXEC |
+                                       VM_ALWAYSDUMP | VM_RESERVED,
+                                       NULL);
+}
+
+const char *arch_vma_name(struct vm_area_struct *vma)
+{
+        return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
+}