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Subject[PATCH 9/11] i386 vDSO: use install_special_mapping
Date

This patch uses install_special_mapping for the i386 vDSO setup,
consolidating duplicated code.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
arch/i386/kernel/sysenter.c | 53 +++++++++----------------------------------
1 files changed, 11 insertions(+), 42 deletions(-)
diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c
index 5da7442..bc882a2 100644
--- a/arch/i386/kernel/sysenter.c
+++ b/arch/i386/kernel/sysenter.c
@@ -70,11 +70,12 @@ void enable_sep_cpu(void)
*/
extern const char vsyscall_int80_start, vsyscall_int80_end;
extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
-static void *syscall_page;
+static struct page *syscall_pages[1];

int __init sysenter_setup(void)
{
- syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
+ void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
+ syscall_pages[0] = virt_to_page(syscall_page);

#ifdef CONFIG_COMPAT_VDSO
__set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_READONLY);
@@ -96,31 +97,12 @@ int __init sysenter_setup(void)
}

#ifndef CONFIG_COMPAT_VDSO
-static struct page *syscall_nopage(struct vm_area_struct *vma,
- unsigned long adr, int *type)
-{
- struct page *p = virt_to_page(adr - vma->vm_start + syscall_page);
- get_page(p);
- return p;
-}
-
-/* Prevent VMA merging */
-static void syscall_vma_close(struct vm_area_struct *vma)
-{
-}
-
-static struct vm_operations_struct syscall_vm_ops = {
- .close = syscall_vma_close,
- .nopage = syscall_nopage,
-};
-
/* Defined in vsyscall-sysenter.S */
extern void SYSENTER_RETURN;

/* Setup a VMA at program startup for the vsyscall page */
int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack)
{
- struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr;
int ret;
@@ -132,38 +114,25 @@ int arch_setup_additional_pages(struct l
goto up_fail;
}

- vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
- if (!vma) {
- ret = -ENOMEM;
- goto up_fail;
- }
-
- vma->vm_start = addr;
- vma->vm_end = addr + PAGE_SIZE;
- /* MAYWRITE to allow gdb to COW and set breakpoints */
- vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
/*
+ * 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 = &syscall_vm_ops;
- vma->vm_mm = mm;
-
- ret = insert_vm_struct(mm, vma);
- if (unlikely(ret)) {
- kmem_cache_free(vm_area_cachep, vma);
+ ret = install_special_mapping(mm, addr, PAGE_SIZE,
+ VM_READ|VM_EXEC|
+ VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
+ VM_ALWAYSDUMP,
+ syscall_pages);
+ if (ret)
goto up_fail;
- }

current->mm->context.vdso = (void *)addr;
current_thread_info()->sysenter_return =
(void *)VDSO_SYM(&SYSENTER_RETURN);
- mm->total_vm++;
up_fail:
up_write(&mm->mmap_sem);
return ret;
-
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