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Commit dc5882b2 authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

[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: 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 7d91d531

arch/x86_64/ia32/syscall32.c

+13 −46
Original line number Diff line number Diff line
@@ -18,69 +18,35 @@ 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))) {

	/* 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);

		kmem_cache_free(vm_area_cachep, vma);

	return ret;

}

	mm->total_vm += npages;

	up_write(&mm->mmap_sem);

	return 0;

}



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);

include/asm-x86_64/proto.h

+0 −1
Original line number Diff line number Diff line
@@ -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);