2022-11-12 00:10:22

by Jim Cromie

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

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 <[email protected]>
---
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

2022-11-12 00:15:22

by Jim Cromie

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

crap, missed something. lemme fix and resend.

On Fri, Nov 11, 2022 at 4:53 PM Jim Cromie <[email protected]> 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 <[email protected]>
> ---
> 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
>