* [PATCH v3] ARM: VDSO: put RO and RO after init objects into proper sections
@ 2016-08-12 8:12 Jisheng Zhang
2016-08-12 18:06 ` Kees Cook
0 siblings, 1 reply; 3+ messages in thread
From: Jisheng Zhang @ 2016-08-12 8:12 UTC (permalink / raw)
To: linux, nathan_lynch, keescook, arnd
Cc: linux-arm-kernel, linux-kernel, Jisheng Zhang
vdso_data_mapping is never modified, so mark it as const.
vdso_total_pages, vdso_data_page, vdso_text_mapping and cntvct_ok are
initialized by vdso_init(), thereafter are read only.
The fact that they are read only after init makes them candidates for
__ro_after_init declarations.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
Since v2:
- include <linux/cache.h> explicitly for __ro_after_init
Since v1:
- use __ro_after_init instead of __read_mostly
- apply __ro_after_init for vdso_total_pages and cntvct_ok as well
arch/arm/kernel/vdso.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 994e971..bbbffe94 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -17,6 +17,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/cache.h>
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/kernel.h>
@@ -39,7 +40,7 @@
static struct page **vdso_text_pagelist;
/* Total number of pages needed for the data and text portions of the VDSO. */
-unsigned int vdso_total_pages __read_mostly;
+unsigned int vdso_total_pages __ro_after_init;
/*
* The VDSO data page.
@@ -47,13 +48,13 @@ unsigned int vdso_total_pages __read_mostly;
static union vdso_data_store vdso_data_store __page_aligned_data;
static struct vdso_data *vdso_data = &vdso_data_store.data;
-static struct page *vdso_data_page;
-static struct vm_special_mapping vdso_data_mapping = {
+static struct page *vdso_data_page __ro_after_init;
+static const struct vm_special_mapping vdso_data_mapping = {
.name = "[vvar]",
.pages = &vdso_data_page,
};
-static struct vm_special_mapping vdso_text_mapping = {
+static struct vm_special_mapping vdso_text_mapping __ro_after_init = {
.name = "[vdso]",
};
@@ -67,7 +68,7 @@ struct elfinfo {
/* Cached result of boot-time check for whether the arch timer exists,
* and if so, whether the virtual counter is useable.
*/
-static bool cntvct_ok __read_mostly;
+static bool cntvct_ok __ro_after_init;
static bool __init cntvct_functional(void)
{
--
2.8.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v3] ARM: VDSO: put RO and RO after init objects into proper sections
2016-08-12 8:12 [PATCH v3] ARM: VDSO: put RO and RO after init objects into proper sections Jisheng Zhang
@ 2016-08-12 18:06 ` Kees Cook
2016-08-12 18:40 ` Nathan Lynch
0 siblings, 1 reply; 3+ messages in thread
From: Kees Cook @ 2016-08-12 18:06 UTC (permalink / raw)
To: Jisheng Zhang
Cc: Russell King, Nathan Lynch, Arnd Bergmann, linux-arm-kernel, LKML
On Fri, Aug 12, 2016 at 1:12 AM, Jisheng Zhang <jszhang@marvell.com> wrote:
> vdso_data_mapping is never modified, so mark it as const.
>
> vdso_total_pages, vdso_data_page, vdso_text_mapping and cntvct_ok are
> initialized by vdso_init(), thereafter are read only.
>
> The fact that they are read only after init makes them candidates for
> __ro_after_init declarations.
>
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Looks great; thanks for keeping __ro_after_init in mind. :)
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
>
> Since v2:
> - include <linux/cache.h> explicitly for __ro_after_init
>
> Since v1:
> - use __ro_after_init instead of __read_mostly
> - apply __ro_after_init for vdso_total_pages and cntvct_ok as well
>
> arch/arm/kernel/vdso.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
> index 994e971..bbbffe94 100644
> --- a/arch/arm/kernel/vdso.c
> +++ b/arch/arm/kernel/vdso.c
> @@ -17,6 +17,7 @@
> * along with this program. If not, see <http://www.gnu.org/licenses/>.
> */
>
> +#include <linux/cache.h>
> #include <linux/elf.h>
> #include <linux/err.h>
> #include <linux/kernel.h>
> @@ -39,7 +40,7 @@
> static struct page **vdso_text_pagelist;
>
> /* Total number of pages needed for the data and text portions of the VDSO. */
> -unsigned int vdso_total_pages __read_mostly;
> +unsigned int vdso_total_pages __ro_after_init;
>
> /*
> * The VDSO data page.
> @@ -47,13 +48,13 @@ unsigned int vdso_total_pages __read_mostly;
> static union vdso_data_store vdso_data_store __page_aligned_data;
> static struct vdso_data *vdso_data = &vdso_data_store.data;
>
> -static struct page *vdso_data_page;
> -static struct vm_special_mapping vdso_data_mapping = {
> +static struct page *vdso_data_page __ro_after_init;
> +static const struct vm_special_mapping vdso_data_mapping = {
> .name = "[vvar]",
> .pages = &vdso_data_page,
> };
>
> -static struct vm_special_mapping vdso_text_mapping = {
> +static struct vm_special_mapping vdso_text_mapping __ro_after_init = {
> .name = "[vdso]",
> };
>
> @@ -67,7 +68,7 @@ struct elfinfo {
> /* Cached result of boot-time check for whether the arch timer exists,
> * and if so, whether the virtual counter is useable.
> */
> -static bool cntvct_ok __read_mostly;
> +static bool cntvct_ok __ro_after_init;
>
> static bool __init cntvct_functional(void)
> {
> --
> 2.8.1
>
--
Kees Cook
Nexus Security
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] ARM: VDSO: put RO and RO after init objects into proper sections
2016-08-12 18:06 ` Kees Cook
@ 2016-08-12 18:40 ` Nathan Lynch
0 siblings, 0 replies; 3+ messages in thread
From: Nathan Lynch @ 2016-08-12 18:40 UTC (permalink / raw)
To: Kees Cook
Cc: Jisheng Zhang, Russell King, Arnd Bergmann, linux-arm-kernel, LKML
On 08/12/2016 01:06 PM, Kees Cook wrote:
> On Fri, Aug 12, 2016 at 1:12 AM, Jisheng Zhang <jszhang@marvell.com> wrote:
>> vdso_data_mapping is never modified, so mark it as const.
>>
>> vdso_total_pages, vdso_data_page, vdso_text_mapping and cntvct_ok are
>> initialized by vdso_init(), thereafter are read only.
>>
>> The fact that they are read only after init makes them candidates for
>> __ro_after_init declarations.
>>
>> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
>
> Looks great; thanks for keeping __ro_after_init in mind. :)
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
Looks fine and nothing goes wrong with my vdso tests. Please send it
through Russell.
Acked-by: Nathan Lynch <nathan_lynch@mentor.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-08-12 18:40 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-12 8:12 [PATCH v3] ARM: VDSO: put RO and RO after init objects into proper sections Jisheng Zhang
2016-08-12 18:06 ` Kees Cook
2016-08-12 18:40 ` Nathan Lynch
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).