diff mbox series

[1/2] kprobes: Allow architectures to override optinsn page allocation

Message ID 472c597cc8cc8f74f037acf971f7799fb381a647.1620829724.git.christophe.leroy@csgroup.eu
State Superseded
Headers show
Series [1/2] kprobes: Allow architectures to override optinsn page allocation | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (1fab3666d738e4af3a7450c44441310e4d7a7e53)
snowpatch_ozlabs/checkpatch warning total: 0 errors, 1 warnings, 0 checks, 23 lines checked
snowpatch_ozlabs/needsstable success Patch has no Fixes tags

Commit Message

Christophe Leroy May 12, 2021, 2:29 p.m. UTC
Some architectures like powerpc require a non standard
allocation of optinsn page, because module pages are
too far from the kernel for direct branches.

Define weak alloc_optinsn_page() and free_optinsn_page(), that
fall back on alloc_insn_page() and free_insn_page() when not
overriden by the architecture.

Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 kernel/kprobes.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

Comments

kernel test robot May 12, 2021, 7:04 p.m. UTC | #1
Hi Christophe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on linus/master v5.13-rc1 next-20210512]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/kprobes-Allow-architectures-to-override-optinsn-page-allocation/20210512-223121
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: i386-randconfig-r012-20210512 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/2a1f135a9ce3c4d86d3bdefed561aa17760f430f
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christophe-Leroy/kprobes-Allow-architectures-to-override-optinsn-page-allocation/20210512-223121
        git checkout 2a1f135a9ce3c4d86d3bdefed561aa17760f430f
        # save the attached .config to linux build tree
        make W=1 W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> kernel/kprobes.c:324:14: warning: no previous prototype for 'alloc_optinsn_page' [-Wmissing-prototypes]
     324 | void __weak *alloc_optinsn_page(void)
         |              ^~~~~~~~~~~~~~~~~~
>> kernel/kprobes.c:329:13: warning: no previous prototype for 'free_optinsn_page' [-Wmissing-prototypes]
     329 | void __weak free_optinsn_page(void *page)
         |             ^~~~~~~~~~~~~~~~~


vim +/alloc_optinsn_page +324 kernel/kprobes.c

   322	
   323	#ifdef CONFIG_OPTPROBES
 > 324	void __weak *alloc_optinsn_page(void)
   325	{
   326		return alloc_insn_page();
   327	}
   328	
 > 329	void __weak free_optinsn_page(void *page)
   330	{
   331		free_insn_page(page);
   332	}
   333	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Masami Hiramatsu May 12, 2021, 11:43 p.m. UTC | #2
On Wed, 12 May 2021 14:29:26 +0000 (UTC)
Christophe Leroy <christophe.leroy@csgroup.eu> wrote:

> Some architectures like powerpc require a non standard
> allocation of optinsn page, because module pages are
> too far from the kernel for direct branches.
> 
> Define weak alloc_optinsn_page() and free_optinsn_page(), that
> fall back on alloc_insn_page() and free_insn_page() when not
> overriden by the architecture.
> 

Looks good to me :)

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

> Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
>  kernel/kprobes.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 745f08fdd7a6..8c0a6fdef771 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -321,11 +321,21 @@ int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
>  }
>  
>  #ifdef CONFIG_OPTPROBES
> +void __weak *alloc_optinsn_page(void)
> +{
> +	return alloc_insn_page();
> +}
> +
> +void __weak free_optinsn_page(void *page)
> +{
> +	free_insn_page(page);
> +}
> +
>  /* For optimized_kprobe buffer */
>  struct kprobe_insn_cache kprobe_optinsn_slots = {
>  	.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
> -	.alloc = alloc_insn_page,
> -	.free = free_insn_page,
> +	.alloc = alloc_optinsn_page,
> +	.free = free_optinsn_page,
>  	.sym = KPROBE_OPTINSN_PAGE_SYM,
>  	.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
>  	/* .insn_size is initialized later */
> -- 
> 2.25.0
>
Masami Hiramatsu May 13, 2021, 12:33 a.m. UTC | #3
On Thu, 13 May 2021 03:04:51 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Christophe,
> 
> I love your patch! Perhaps something to improve:
> 
> [auto build test WARNING on powerpc/next]
> [also build test WARNING on linus/master v5.13-rc1 next-20210512]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/kprobes-Allow-architectures-to-override-optinsn-page-allocation/20210512-223121
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
> config: i386-randconfig-r012-20210512 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
>         # https://github.com/0day-ci/linux/commit/2a1f135a9ce3c4d86d3bdefed561aa17760f430f
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Christophe-Leroy/kprobes-Allow-architectures-to-override-optinsn-page-allocation/20210512-223121
>         git checkout 2a1f135a9ce3c4d86d3bdefed561aa17760f430f
>         # save the attached .config to linux build tree
>         make W=1 W=1 ARCH=i386 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
> >> kernel/kprobes.c:324:14: warning: no previous prototype for 'alloc_optinsn_page' [-Wmissing-prototypes]
>      324 | void __weak *alloc_optinsn_page(void)
>          |              ^~~~~~~~~~~~~~~~~~
> >> kernel/kprobes.c:329:13: warning: no previous prototype for 'free_optinsn_page' [-Wmissing-prototypes]
>      329 | void __weak free_optinsn_page(void *page)
>          |             ^~~~~~~~~~~~~~~~~

Ah, we need a prototype for those in include/linux/kprobes.h
as same as alloc_insn_page() and free_insn_page().

Thank you,
diff mbox series

Patch

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 745f08fdd7a6..8c0a6fdef771 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -321,11 +321,21 @@  int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
 }
 
 #ifdef CONFIG_OPTPROBES
+void __weak *alloc_optinsn_page(void)
+{
+	return alloc_insn_page();
+}
+
+void __weak free_optinsn_page(void *page)
+{
+	free_insn_page(page);
+}
+
 /* For optimized_kprobe buffer */
 struct kprobe_insn_cache kprobe_optinsn_slots = {
 	.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
-	.alloc = alloc_insn_page,
-	.free = free_insn_page,
+	.alloc = alloc_optinsn_page,
+	.free = free_optinsn_page,
 	.sym = KPROBE_OPTINSN_PAGE_SYM,
 	.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
 	/* .insn_size is initialized later */