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Commit aafade24 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by H. Peter Anvin
Browse files

x86-64, vdso: Do not allocate memory for the vDSO 



We can map the vDSO straight from kernel data, saving a few page
allocations.  As an added bonus, the deleted code contained a memory
leak.

Signed-off-by: default avatarAndy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/2c4ed5c2c2e93603790229e0c3403ae506ccc0cb.1311277573.git.luto@mit.edu


Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent ae7bd11b

arch/x86/vdso/vdso.S

+13 −2
Original line number Original line Diff line number Diff line 
#include <asm/page_types.h>

#include <linux/linkage.h>

#include <linux/init.h>

#include <linux/init.h>





__INITDATA

__PAGE_ALIGNED_DATA





	.globl vdso_start, vdso_end

	.globl vdso_start, vdso_end

	.align PAGE_SIZE

vdso_start:

vdso_start:

	.incbin "arch/x86/vdso/vdso.so"

	.incbin "arch/x86/vdso/vdso.so"

vdso_end:

vdso_end:





__FINIT
 
.previous



	.globl vdso_pages

	.bss

	.align 8

	.type vdso_pages, @object

vdso_pages:

	.zero (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE * 8

	.size vdso_pages, .-vdso_pages

arch/x86/vdso/vma.c

+6 −19
Original line number Original line Diff line number Diff line
@@ -14,13 +14,14 @@ 
#include <asm/vgtod.h>

#include <asm/vgtod.h>

#include <asm/proto.h>

#include <asm/proto.h>

#include <asm/vdso.h>

#include <asm/vdso.h>

#include <asm/page.h>





unsigned int __read_mostly vdso_enabled = 1;

unsigned int __read_mostly vdso_enabled = 1;





extern char vdso_start[], vdso_end[];

extern char vdso_start[], vdso_end[];

extern unsigned short vdso_sync_cpuid;

extern unsigned short vdso_sync_cpuid;





static struct page **vdso_pages;

extern struct page *vdso_pages[];

static unsigned vdso_size;

static unsigned vdso_size;





static void __init patch_vdso(void *vdso, size_t len)

static void __init patch_vdso(void *vdso, size_t len)
@@ -54,7 +55,7 @@ static void __init patch_vdso(void *vdso, size_t len) 
	apply_alternatives(alt_data, alt_data + alt_sec->sh_size);

	apply_alternatives(alt_data, alt_data + alt_sec->sh_size);

}

}





static int __init init_vdso_vars(void)

static int __init init_vdso(void)

{

{

	int npages = (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE;

	int npages = (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE;

	int i;

	int i;
@@ -62,26 +63,12 @@ static int __init init_vdso_vars(void) 
	patch_vdso(vdso_start, vdso_end - vdso_start);

	patch_vdso(vdso_start, vdso_end - vdso_start);





	vdso_size = npages << PAGE_SHIFT;

	vdso_size = npages << PAGE_SHIFT;

	vdso_pages = kmalloc(sizeof(struct page *) * npages, GFP_KERNEL);

	for (i = 0; i < npages; i++)

	if (!vdso_pages)

		vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE);

		goto oom;

	for (i = 0; i < npages; i++) {

		struct page *p;

		p = alloc_page(GFP_KERNEL);

		if (!p)

			goto oom;

		vdso_pages[i] = p;

		copy_page(page_address(p), vdso_start + i*PAGE_SIZE);

	}





	return 0;

	return 0;



 oom:

	printk("Cannot allocate vdso\n");

	vdso_enabled = 0;

	return -ENOMEM;

}

}

subsys_initcall(init_vdso_vars);

subsys_initcall(init_vdso);





struct linux_binprm;

struct linux_binprm;