2015-05-22 06:07:18

by Minfei Huang

Subject: [PATCH] livepatch: Let compiler put module initialized function to section ".init.text"

From: Minfei Huang <[email protected]>

Usually we prefer to let compiler put the module initialized function to
section ".init.text". Thus this text in memory will be freed in future.

Once we add the "__init" preceding function name, we can use following
command to find it in specfied section.

$ objdump -t -j .init.text built-in.o

built-in.o: file format elf64-x86-64

SYMBOL TABLE:
0000000000000000 l d .init.text 0000000000000000 .init.text
0000000000000000 l F .init.text 000000000000004e klp_init

Signed-off-by: Minfei Huang <[email protected]>
---
kernel/livepatch/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 284e269..86e40b9 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -973,7 +973,7 @@ static struct notifier_block klp_module_nb = {
.priority = INT_MIN+1, /* called late but before ftrace notifier */
};

-static int klp_init(void)
+static int __init klp_init(void)
{
int ret;

--
2.2.2

2015-05-22 13:25:33

by Josh Poimboeuf

Subject: Re: [PATCH] livepatch: Let compiler put module initialized function to section ".init.text"

On Fri, May 22, 2015 at 02:10:32PM +0800, Minfei Huang wrote:
> From: Minfei Huang <[email protected]>
>
> Usually we prefer to let compiler put the module initialized function to
> section ".init.text". Thus this text in memory will be freed in future.
>
> Once we add the "__init" preceding function name, we can use following
> command to find it in specfied section.
>
> $ objdump -t -j .init.text built-in.o
>
> built-in.o: file format elf64-x86-64
>
> SYMBOL TABLE:
> 0000000000000000 l d .init.text 0000000000000000 .init.text
> 0000000000000000 l F .init.text 000000000000004e klp_init
>
> Signed-off-by: Minfei Huang <[email protected]>

The patch looks good but can you make the subject more concise? Maybe
something like:

livepatch: annotate klp_init() with __init

Thanks.

--
Josh

2015-05-22 14:03:13

by Minfei Huang

Subject: Re: [PATCH] livepatch: Let compiler put module initialized function to section ".init.text"

On 05/22/15 at 08:25P, Josh Poimboeuf wrote:
> On Fri, May 22, 2015 at 02:10:32PM +0800, Minfei Huang wrote:
> > From: Minfei Huang <[email protected]>
> >
> > Usually we prefer to let compiler put the module initialized function to
> > section ".init.text". Thus this text in memory will be freed in future.
> >
> > Once we add the "__init" preceding function name, we can use following
> > command to find it in specfied section.
> >
> > $ objdump -t -j .init.text built-in.o
> >
> > built-in.o: file format elf64-x86-64
> >
> > SYMBOL TABLE:
> > 0000000000000000 l d .init.text 0000000000000000 .init.text
> > 0000000000000000 l F .init.text 000000000000004e klp_init
> >
> > Signed-off-by: Minfei Huang <[email protected]>
>
> The patch looks good but can you make the subject more concise? Maybe
> something like:
>
> livepatch: annotate klp_init() with __init

Sure. Will modify the subject.

Thanks
Minfei

>
> Thanks.
>
> --
> Josh