Re: [PATCH v3 4/9] livepatch: Add klp-convert annotation helpers

[Miroslav Benes]

On Wed, 10 Apr 2019, Joe Lawrence wrote:

> On Wed, Apr 10, 2019 at 11:50:53AM -0400, Joe Lawrence wrote:
> > From: Josh Poimboeuf 
> > 
> > Define macros KLP_MODULE_RELOC and KLP_SYMPOS in
> > include/linux/livepatch.h to improve user-friendliness of the
> > livepatch annotation process.
> > 
> > Signed-off-by: Josh Poimboeuf 
> > Signed-off-by: Joao Moreira 
> > Signed-off-by: Joe Lawrence 
> > ---
> >  include/linux/livepatch.h | 12 
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
> > index 16b48e8b29a2..947cfc2d1980 100644
> > --- a/include/linux/livepatch.h
> > +++ b/include/linux/livepatch.h
> > @@ -236,6 +236,18 @@ void *klp_shadow_get_or_alloc(void *obj, unsigned long 
> > id,
> >  void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor);
> >  void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor);
> >  
> > +/* Used to annotate symbol relocations in livepatches */
> > +#define KLP_MODULE_RELOC(obj)  
> > \
> > +   struct klp_module_reloc \
> > +   __attribute__((__section__(".klp.module_relocs." #obj)))\
> > +   __attribute__((aligned (4)))
> > +
> > +#define KLP_SYMPOS(symbol, pos)
> > \
> > +   {   \
> > +   .sym = , \
> > +   .sympos = pos,  \
> > +   },
> ^^
> nit: if we dropped the trailing array comma delimiter from KLP_SYMPOS
> macro, the invocations would look more intuitively like an array.  For
> example:
> 
>   KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = {
>   KLP_SYMPOS(driver_name, 0),
>   KLP_SYMPOS(homonym_string, 2),
>   KLP_SYMPOS(get_homonym_string, 2),
>   };
> 
> But I could not figure out a good regex to reference if other such
> kernel preprocessor macros include or exclude the delimiter.  Are there
> reasons to include it?

No, I don't think so. We should change it. Good catch.

Miroslav

Re: [PATCH v3 4/9] livepatch: Add klp-convert annotation helpers

[Joe Lawrence]

On Wed, Apr 10, 2019 at 11:50:53AM -0400, Joe Lawrence wrote:
> From: Josh Poimboeuf 
> 
> Define macros KLP_MODULE_RELOC and KLP_SYMPOS in
> include/linux/livepatch.h to improve user-friendliness of the
> livepatch annotation process.
> 
> Signed-off-by: Josh Poimboeuf 
> Signed-off-by: Joao Moreira 
> Signed-off-by: Joe Lawrence 
> ---
>  include/linux/livepatch.h | 12 
>  1 file changed, 12 insertions(+)
> 
> diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
> index 16b48e8b29a2..947cfc2d1980 100644
> --- a/include/linux/livepatch.h
> +++ b/include/linux/livepatch.h
> @@ -236,6 +236,18 @@ void *klp_shadow_get_or_alloc(void *obj, unsigned long 
> id,
>  void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor);
>  void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor);
>  
> +/* Used to annotate symbol relocations in livepatches */
> +#define KLP_MODULE_RELOC(obj)
> \
> + struct klp_module_reloc \
> + __attribute__((__section__(".klp.module_relocs." #obj)))\
> + __attribute__((aligned (4)))
> +
> +#define KLP_SYMPOS(symbol, pos)  
> \
> + {   \
> + .sym = , \
> + .sympos = pos,  \
> + },
^^
nit: if we dropped the trailing array comma delimiter from KLP_SYMPOS
macro, the invocations would look more intuitively like an array.  For
example:

  KLP_MODULE_RELOC(test_klp_convert_mod) test_klp_convert_mod_relocs_a[] = {
KLP_SYMPOS(driver_name, 0),
KLP_SYMPOS(homonym_string, 2),
KLP_SYMPOS(get_homonym_string, 2),
  };

But I could not figure out a good regex to reference if other such
kernel preprocessor macros include or exclude the delimiter.  Are there
reasons to include it?

-- Joe

[PATCH v3 4/9] livepatch: Add klp-convert annotation helpers

[Joe Lawrence]

From: Josh Poimboeuf 

Define macros KLP_MODULE_RELOC and KLP_SYMPOS in
include/linux/livepatch.h to improve user-friendliness of the
livepatch annotation process.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Joao Moreira 
Signed-off-by: Joe Lawrence 
---
 include/linux/livepatch.h | 12 
 1 file changed, 12 insertions(+)

diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 16b48e8b29a2..947cfc2d1980 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -236,6 +236,18 @@ void *klp_shadow_get_or_alloc(void *obj, unsigned long id,
 void klp_shadow_free(void *obj, unsigned long id, klp_shadow_dtor_t dtor);
 void klp_shadow_free_all(unsigned long id, klp_shadow_dtor_t dtor);
 
+/* Used to annotate symbol relocations in livepatches */
+#define KLP_MODULE_RELOC(obj)  \
+   struct klp_module_reloc \
+   __attribute__((__section__(".klp.module_relocs." #obj)))\
+   __attribute__((aligned (4)))
+
+#define KLP_SYMPOS(symbol, pos)
\
+   {   \
+   .sym = , \
+   .sympos = pos,  \
+   },
+
 #else /* !CONFIG_LIVEPATCH */
 
 static inline int klp_module_coming(struct module *mod) { return 0; }
-- 
2.20.1