[PATCH 1/1] vmlinux.lds.h: improve BOUNDED_SECTION macros

[PATCH 1/1] vmlinux.lds.h: improve BOUNDED_SECTION macros

[Jim Cromie]

1- replace _s_ & _e_ with the more visibly obvious _BEGIN_ & _END_.

2- add a new _HDR_ linker symbol before the KEEP(*(.gnu.linkonce.##_sec_)).
   This gives the optional header record an extern'd name/address,
   which is "_hdr_", b4/after the _sec_/_label_.

3- move existing _BEGIN_ linker symbol after the KEEP.
   This insures the extern'd name always points at the data,
   independent of whether a header has been defined.

NOTE: if (start - hdr) { /* section has a header record */ }

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/vmlinux.lds.h | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index cfad4511cd68..c9b204b0364c 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -199,20 +199,22 @@
 # endif
 #endif
 
-#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _s_, _e_)		\
-	_s_##_label_ = .;						\
+#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
+	_HDR_##_label_ = .;						\
 	KEEP(*(.gnu.linkonce.##_sec_))					\
+	_BEGIN_##_label_ = .;						\
 	KEEP(*(_sec_))							\
-	_e_##_label_ = .;
+	_END_##_label_ = .;
 
-#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _s_, _e_)		\
-	_label_##_s_ = .;						\
+#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
+	_label_##_HDR_ = .;						\
 	KEEP(*(.gnu.linkonce.##_sec_))					\
+	_label_##_BEGIN_ = .;						\
 	KEEP(*(_sec_))							\
-	_label_##_e_ = .;
+	_label_##_END_ = .;
 
 #define BOUNDED_SECTION_BY(_sec_, _label_)				\
-	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
+	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop, _hdr_)
 
 #define BOUNDED_SECTION(_sec)	 BOUNDED_SECTION_BY(_sec, _sec)
 
-- 
2.38.1

Re: [PATCH 1/1] vmlinux.lds.h: improve BOUNDED_SECTION macros

[jim.cromie]

crap, missed something. lemme fix and resend.

On Fri, Nov 11, 2022 at 4:53 PM Jim Cromie <jim.cromie@gmail.com> wrote:
>
> 1- replace _s_ & _e_ with the more visibly obvious _BEGIN_ & _END_.
>
> 2- add a new _HDR_ linker symbol before the KEEP(*(.gnu.linkonce.##_sec_)).
>    This gives the optional header record an extern'd name/address,
>    which is "_hdr_", b4/after the _sec_/_label_.
>
> 3- move existing _BEGIN_ linker symbol after the KEEP.
>    This insures the extern'd name always points at the data,
>    independent of whether a header has been defined.
>
> NOTE: if (start - hdr) { /* section has a header record */ }
>
> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> ---
>  include/asm-generic/vmlinux.lds.h | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index cfad4511cd68..c9b204b0364c 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -199,20 +199,22 @@
>  # endif
>  #endif
>
> -#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _s_, _e_)            \
> -       _s_##_label_ = .;                                               \
> +#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
> +       _HDR_##_label_ = .;                                             \
>         KEEP(*(.gnu.linkonce.##_sec_))                                  \
> +       _BEGIN_##_label_ = .;                                           \
>         KEEP(*(_sec_))                                                  \
> -       _e_##_label_ = .;
> +       _END_##_label_ = .;
>
> -#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _s_, _e_)           \
> -       _label_##_s_ = .;                                               \
> +#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
> +       _label_##_HDR_ = .;                                             \
>         KEEP(*(.gnu.linkonce.##_sec_))                                  \
> +       _label_##_BEGIN_ = .;                                           \
>         KEEP(*(_sec_))                                                  \
> -       _label_##_e_ = .;
> +       _label_##_END_ = .;
>
>  #define BOUNDED_SECTION_BY(_sec_, _label_)                             \
> -       BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
> +       BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop, _hdr_)
>
>  #define BOUNDED_SECTION(_sec)   BOUNDED_SECTION_BY(_sec, _sec)
>
> --
> 2.38.1
>