[PATCH] x86_64 ia32 vDSO: use install_special_mapping

This patch uses install_special_mapping for the ia32 vDSO setup, consolidating
duplicated code.

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@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c
index 59f1fa1559151029d99f077d0861cd6bfd17392d..568ff0df89e7800412017c349e3e138aba5218fb 100644 (file)
--- a/arch/x86_64/ia32/syscall32.c
+++ b/arch/x86_64/ia32/syscall32.c
@@ -18,68 +18,34 @@ extern unsigned char syscall32_syscall[], syscall32_syscall_end[];
 extern unsigned char syscall32_sysenter[], syscall32_sysenter_end[];
 extern int sysctl_vsyscall32;
 
-char *syscall32_page; 
+static struct page *syscall32_pages[1];
 static int use_sysenter = -1;
 
-static struct page *
-syscall32_nopage(struct vm_area_struct *vma, unsigned long adr, int *type)
-{
-       struct page *p = virt_to_page(adr - vma->vm_start + syscall32_page);
-       get_page(p);
-       return p;
-}
-
-/* Prevent VMA merging */
-static void syscall32_vma_close(struct vm_area_struct *vma)
-{
-}
-
-static struct vm_operations_struct syscall32_vm_ops = {
-       .close = syscall32_vma_close,
-       .nopage = syscall32_nopage,
-};
-
 struct linux_binprm;
 
 /* Setup a VMA at program startup for the vsyscall page */
 int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
 {
-       int npages = (VSYSCALL32_END - VSYSCALL32_BASE) >> PAGE_SHIFT;
-       struct vm_area_struct *vma;
        struct mm_struct *mm = current->mm;
        int ret;
 
-       vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
-       if (!vma)
-               return -ENOMEM;
-
-       memset(vma, 0, sizeof(struct vm_area_struct));
-       /* Could randomize here */
-       vma->vm_start = VSYSCALL32_BASE;
-       vma->vm_end = VSYSCALL32_END;
-       /* MAYWRITE to allow gdb to COW and set breakpoints */
-       vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
+       down_write(&mm->mmap_sem);
        /*
+        * MAYWRITE to allow gdb to COW and set breakpoints
+        *
         * Make sure the vDSO gets into every core dump.
         * Dumping its contents makes post-mortem fully interpretable later
         * without matching up the same kernel and hardware config to see
         * what PC values meant.
         */
-       vma->vm_flags |= VM_ALWAYSDUMP;
-       vma->vm_flags |= mm->def_flags;
-       vma->vm_page_prot = protection_map[vma->vm_flags & 7];
-       vma->vm_ops = &syscall32_vm_ops;
-       vma->vm_mm = mm;
-
-       down_write(&mm->mmap_sem);
-       if ((ret = insert_vm_struct(mm, vma))) {
-               up_write(&mm->mmap_sem);
-               kmem_cache_free(vm_area_cachep, vma);
-               return ret;
-       }
-       mm->total_vm += npages;
+       /* Could randomize here */
+       ret = install_special_mapping(mm, VSYSCALL32_BASE, PAGE_SIZE,
+                                     VM_READ|VM_EXEC|
+                                     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
+                                     VM_ALWAYSDUMP,
+                                     syscall32_pages);
        up_write(&mm->mmap_sem);
-       return 0;
+       return ret;
 }
 
 const char *arch_vma_name(struct vm_area_struct *vma)
@@ -92,9 +58,10 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 
 static int __init init_syscall32(void)
 { 
-       syscall32_page = (void *)get_zeroed_page(GFP_KERNEL); 
+       char *syscall32_page = (void *)get_zeroed_page(GFP_KERNEL);
        if (!syscall32_page) 
                panic("Cannot allocate syscall32 page"); 
+       syscall32_pages[0] = virt_to_page(syscall32_page);
        if (use_sysenter > 0) {
                memcpy(syscall32_page, syscall32_sysenter,
                       syscall32_sysenter_end - syscall32_sysenter);

diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h
index 6d324b83897207f56f9e348bc6ef6feae8c553ef..a6d2ff5c69b76ea2a5941740dd2206cf45f03726 100644 (file)
--- a/include/asm-x86_64/proto.h
+++ b/include/asm-x86_64/proto.h
@@ -81,7 +81,6 @@ extern void swap_low_mappings(void);
 extern void __show_regs(struct pt_regs * regs);
 extern void show_regs(struct pt_regs * regs);
 
-extern char *syscall32_page;
 extern void syscall32_cpu_init(void);
 
 extern void setup_node_bootmem(int nodeid, unsigned long start, unsigned long end);