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Commit 7d91d531 authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

[PATCH] i386 vDSO: use install_special_mapping 



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

Signed-off-by: default avatarRoland 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fa5dc22f

arch/i386/kernel/sysenter.c

+11 −42
Original line number Diff line number Diff line
@@ -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 linux_binprm *bprm, int exstack) 
		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;