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authorAndy Lutomirski <luto@amacapital.net>2014-05-19 15:58:33 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2014-05-20 11:38:42 -0700
commita62c34bd2a8a3f159945becd57401e478818d51c (patch)
tree8721aca251b468606e52376fc811dd0c8beeaeb8 /arch/x86
parent78d683e838a60ec4ba4591cca4364cba84a9e626 (diff)
downloadlinux-a62c34bd2a8a3f159945becd57401e478818d51c.tar.bz2
x86, mm: Improve _install_special_mapping and fix x86 vdso naming
Using arch_vma_name to give special mappings a name is awkward. x86 currently implements it by comparing the start address of the vma to the expected address of the vdso. This requires tracking the start address of special mappings and is probably buggy if a special vma is split or moved. Improve _install_special_mapping to just name the vma directly. Use it to give the x86 vvar area a name, which should make CRIU's life easier. As a side effect, the vvar area will show up in core dumps. This could be considered weird and is fixable. [hpa: I say we accept this as-is but be prepared to deal with knocking out the vvars from core dumps if this becomes a problem.] Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/276b39b6b645fb11e345457b503f17b83c2c6fd0.1400538962.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/vdso.h6
-rw-r--r--arch/x86/mm/init_64.c3
-rw-r--r--arch/x86/vdso/vdso2c.h5
-rw-r--r--arch/x86/vdso/vdso32-setup.c7
-rw-r--r--arch/x86/vdso/vma.c25
5 files changed, 25 insertions, 21 deletions
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index d0a2c909c72d..30be253dd283 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -7,10 +7,14 @@
#ifndef __ASSEMBLER__
+#include <linux/mm_types.h>
+
struct vdso_image {
void *data;
unsigned long size; /* Always a multiple of PAGE_SIZE */
- struct page **pages; /* Big enough for data/size page pointers */
+
+ /* text_mapping.pages is big enough for data/size page pointers */
+ struct vm_special_mapping text_mapping;
unsigned long alt, alt_len;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 6f881842116c..9deb59b0baea 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1223,9 +1223,6 @@ int in_gate_area_no_mm(unsigned long addr)
const char *arch_vma_name(struct vm_area_struct *vma)
{
- if (vma->vm_mm && vma->vm_start ==
- (long __force)vma->vm_mm->context.vdso)
- return "[vdso]";
if (vma == &gate_vma)
return "[vsyscall]";
return NULL;
diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h
index ed2e894e89ab..3dcc61e796e9 100644
--- a/arch/x86/vdso/vdso2c.h
+++ b/arch/x86/vdso/vdso2c.h
@@ -136,7 +136,10 @@ static int GOFUNC(void *addr, size_t len, FILE *outfile, const char *name)
fprintf(outfile, "const struct vdso_image %s = {\n", name);
fprintf(outfile, "\t.data = raw_data,\n");
fprintf(outfile, "\t.size = %lu,\n", data_size);
- fprintf(outfile, "\t.pages = pages,\n");
+ fprintf(outfile, "\t.text_mapping = {\n");
+ fprintf(outfile, "\t\t.name = \"[vdso]\",\n");
+ fprintf(outfile, "\t\t.pages = pages,\n");
+ fprintf(outfile, "\t},\n");
if (alt_sec) {
fprintf(outfile, "\t.alt = %lu,\n",
(unsigned long)alt_sec->sh_offset);
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index c3ed708e50f4..e4f7781ee162 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -119,13 +119,6 @@ __initcall(ia32_binfmt_init);
#else /* CONFIG_X86_32 */
-const char *arch_vma_name(struct vm_area_struct *vma)
-{
- if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
- return "[vdso]";
- return NULL;
-}
-
struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
return NULL;
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
index 8ad0081df7a8..e1513c47872a 100644
--- a/arch/x86/vdso/vma.c
+++ b/arch/x86/vdso/vma.c
@@ -30,7 +30,8 @@ void __init init_vdso_image(const struct vdso_image *image)
BUG_ON(image->size % PAGE_SIZE != 0);
for (i = 0; i < npages; i++)
- image->pages[i] = virt_to_page(image->data + i*PAGE_SIZE);
+ image->text_mapping.pages[i] =
+ virt_to_page(image->data + i*PAGE_SIZE);
apply_alternatives((struct alt_instr *)(image->data + image->alt),
(struct alt_instr *)(image->data + image->alt +
@@ -91,6 +92,10 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
unsigned long addr;
int ret = 0;
static struct page *no_pages[] = {NULL};
+ static struct vm_special_mapping vvar_mapping = {
+ .name = "[vvar]",
+ .pages = no_pages,
+ };
if (calculate_addr) {
addr = vdso_addr(current->mm->start_stack,
@@ -112,21 +117,23 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
/*
* MAYWRITE to allow gdb to COW and set breakpoints
*/
- ret = install_special_mapping(mm,
- addr,
- image->size,
- VM_READ|VM_EXEC|
- VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
- image->pages);
+ vma = _install_special_mapping(mm,
+ addr,
+ image->size,
+ VM_READ|VM_EXEC|
+ VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+ &image->text_mapping);
- if (ret)
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
goto up_fail;
+ }
vma = _install_special_mapping(mm,
addr + image->size,
image->sym_end_mapping - image->size,
VM_READ,
- no_pages);
+ &vvar_mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);