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Subject[PATCH 2/3] arm64: vdso: put read only/mostly objects into proper sections
Date
vdso_pages and vdso_spec are initialized by vdso_init(), thereafter are
mostly read during vdso special mapping handling.

vectors_page is initialized by alloc_vectors_page(), thereafter is
mostly read during aarch32 vectors special mapping handling.

The fact that they are mostly read and not written to makes them
candidates for __read_mostly declarations.

The vm_special_mapping spec is never modified, so mark it as const.

This patch also removes global vdso_pagelist.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
arch/arm64/kernel/vdso.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index e320e8f..e62da76 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -37,8 +37,7 @@
#include <asm/vdso_datapage.h>

extern char vdso_start, vdso_end;
-static unsigned long vdso_pages;
-static struct page **vdso_pagelist;
+static unsigned long vdso_pages __read_mostly;

/*
* The vDSO data page.
@@ -53,7 +52,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
/*
* Create and map the vectors page for AArch32 tasks.
*/
-static struct page *vectors_page[1];
+static struct page *vectors_page[1] __read_mostly;

static int __init alloc_vectors_page(void)
{
@@ -88,7 +87,7 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
unsigned long addr = AARCH32_VECTORS_BASE;
- static struct vm_special_mapping spec = {
+ static const struct vm_special_mapping spec = {
.name = "[vectors]",
.pages = vectors_page,

@@ -110,11 +109,19 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
}
#endif /* CONFIG_COMPAT */

-static struct vm_special_mapping vdso_spec[2];
+static struct vm_special_mapping vdso_spec[2] __read_mostly = {
+ {
+ .name = "[vvar]",
+ },
+ {
+ .name = "[vdso]",
+ },
+};

static int __init vdso_init(void)
{
int i;
+ struct page **vdso_pagelist;

if (memcmp(&vdso_start, "\177ELF", 4)) {
pr_err("vDSO is not a valid ELF object!\n");
@@ -138,16 +145,8 @@ static int __init vdso_init(void)
for (i = 0; i < vdso_pages; i++)
vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa(&vdso_start)) + i);

- /* Populate the special mapping structures */
- vdso_spec[0] = (struct vm_special_mapping) {
- .name = "[vvar]",
- .pages = vdso_pagelist,
- };
-
- vdso_spec[1] = (struct vm_special_mapping) {
- .name = "[vdso]",
- .pages = &vdso_pagelist[1],
- };
+ vdso_spec[0].pages = vdso_pagelist;
+ vdso_spec[1].pages = &vdso_pagelist[1];

return 0;
}
--
2.8.1
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