[RFC PATCH 2/6] arm: clean up v7 and v8 linker scripts for bss_start/end
Ilias Apalodimas
ilias.apalodimas at linaro.org
Fri Mar 1 14:10:24 CET 2024
Thanks for testing Caleb,
On Thu, 29 Feb 2024 at 15:49, Caleb Connolly <caleb.connolly at linaro.org> wrote:
>
>
>
> On 28/02/2024 10:48, Ilias Apalodimas wrote:
> > commit 3ebd1cbc49f0 ("arm: make __bss_start and __bss_end__ compiler-generated")
> > and
> > commit f84a7b8f54db ("ARM: Fix __bss_start and __bss_end in linker scripts")
> > were moving the bss_start/end on c generated variables that were
> > injected in their own sections. The reason was that we needed relative
> > relocations for position independent code.
> >
> > However, the linker documentation pages states that symbols that are
> > defined within a section definition will create a relocatable
> > type with the value being a fixed offset from the base of a section.
> >
> > So let's start cleaning this up starting with the bss_start and bss_end
> > variables. Convert them into symbols within the .bss section definition.
> >
> > [0] https://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_mono/ld.html#SEC13
> >
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> Tested-by: Caleb Connolly <caleb.connolly at linaro.org> # Qualcomm sdm845
>
> This patch and a few others in this series conflict with my patch [1]
> which drops the dragonboard820c linker script. My patch doesn't have any
> external dependencies, so would it be easier for you to take it along
> with this series? Or how best should we avoid the merge conflicts here?
Yes, I can carry the snapdragon lds removal. Rebasing on top is of it
is pretty easy
/Ilias
>
> [1]:
> https://lore.kernel.org/u-boot/20240226-b4-qcom-common-target-v5-19-10c8e078befb@linaro.org/
>
> Thanks and regards,
> > ---
> > arch/arm/cpu/armv8/u-boot-spl.lds | 14 +++-----------
> > arch/arm/cpu/armv8/u-boot.lds | 15 +++------------
> > arch/arm/cpu/u-boot.lds | 22 ++++------------------
> > arch/arm/lib/sections.c | 2 --
> > arch/arm/mach-rockchip/u-boot-tpl-v8.lds | 14 +++-----------
> > arch/arm/mach-zynq/u-boot.lds | 21 +++------------------
> > board/qualcomm/dragonboard820c/u-boot.lds | 15 +++------------
> > 7 files changed, 19 insertions(+), 84 deletions(-)
> >
> > diff --git a/arch/arm/cpu/armv8/u-boot-spl.lds b/arch/arm/cpu/armv8/u-boot-spl.lds
> > index 7cb9d731246d..16fddb46e9cb 100644
> > --- a/arch/arm/cpu/armv8/u-boot-spl.lds
> > +++ b/arch/arm/cpu/armv8/u-boot-spl.lds
> > @@ -63,18 +63,10 @@ SECTIONS
> >
> > _image_binary_end = .;
> >
> > - .bss_start (NOLOAD) : {
> > - . = ALIGN(8);
> > - KEEP(*(.__bss_start));
> > - } >.sdram
> > -
> > - .bss (NOLOAD) : {
> > + .bss : {
> > + __bss_start = .;
> > *(.bss*)
> > - . = ALIGN(8);
> > - } >.sdram
> > -
> > - .bss_end (NOLOAD) : {
> > - KEEP(*(.__bss_end));
> > + __bss_end = .;
> > } >.sdram
> >
> > /DISCARD/ : { *(.rela*) }
> > diff --git a/arch/arm/cpu/armv8/u-boot.lds b/arch/arm/cpu/armv8/u-boot.lds
> > index fb6a30c922f7..c4ee10ebc3ff 100644
> > --- a/arch/arm/cpu/armv8/u-boot.lds
> > +++ b/arch/arm/cpu/armv8/u-boot.lds
> > @@ -149,19 +149,10 @@ SECTIONS
> >
> > _end = .;
> >
> > - . = ALIGN(8);
> > -
> > - .bss_start : {
> > - KEEP(*(.__bss_start));
> > - }
> > -
> > - .bss : {
> > + .bss ALIGN(8): {
> > + __bss_start = .;
> > *(.bss*)
> > - . = ALIGN(8);
> > - }
> > -
> > - .bss_end : {
> > - KEEP(*(.__bss_end));
> > + __bss_end = .;
> > }
> >
> > /DISCARD/ : { *(.dynsym) }
> > diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
> > index 7724c9332c3b..90d329b1ebe0 100644
> > --- a/arch/arm/cpu/u-boot.lds
> > +++ b/arch/arm/cpu/u-boot.lds
> > @@ -206,27 +206,13 @@ SECTIONS
> > *(.mmutable)
> > }
> >
> > -/*
> > - * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
> > - * __bss_base and __bss_limit are for linker only (overlay ordering)
> > - */
> > -
> > - .bss_start __rel_dyn_start (OVERLAY) : {
> > - KEEP(*(.__bss_start));
> > - __bss_base = .;
> > - }
> > -
> > - .bss __bss_base (OVERLAY) : {
> > + .bss ALIGN(4): {
> > + __bss_start = .;
> > *(.bss*)
> > - . = ALIGN(4);
> > - __bss_limit = .;
> > - }
> > -
> > - .bss_end __bss_limit (OVERLAY) : {
> > - KEEP(*(.__bss_end));
> > + __bss_end = .;
> > }
> >
> > - .dynsym _image_binary_end : { *(.dynsym) }
> > + .dynsym : { *(.dynsym) }
> > .dynbss : { *(.dynbss) }
> > .dynstr : { *(.dynstr*) }
> > .dynamic : { *(.dynamic*) }
> > diff --git a/arch/arm/lib/sections.c b/arch/arm/lib/sections.c
> > index 857879711c6a..8e8bd5797e16 100644
> > --- a/arch/arm/lib/sections.c
> > +++ b/arch/arm/lib/sections.c
> > @@ -19,8 +19,6 @@
> > * aliasing warnings.
> > */
> >
> > -char __bss_start[0] __section(".__bss_start");
> > -char __bss_end[0] __section(".__bss_end");
> > char __image_copy_start[0] __section(".__image_copy_start");
> > char __image_copy_end[0] __section(".__image_copy_end");
> > char __rel_dyn_start[0] __section(".__rel_dyn_start");
> > diff --git a/arch/arm/mach-rockchip/u-boot-tpl-v8.lds b/arch/arm/mach-rockchip/u-boot-tpl-v8.lds
> > index 74618eba591b..b7887194026e 100644
> > --- a/arch/arm/mach-rockchip/u-boot-tpl-v8.lds
> > +++ b/arch/arm/mach-rockchip/u-boot-tpl-v8.lds
> > @@ -56,18 +56,10 @@ SECTIONS
> >
> > _image_binary_end = .;
> >
> > - .bss_start (NOLOAD) : {
> > - . = ALIGN(8);
> > - KEEP(*(.__bss_start));
> > - }
> > -
> > - .bss (NOLOAD) : {
> > + .bss ALIGN(8) : {
> > + __bss_start = .;
> > *(.bss*)
> > - . = ALIGN(8);
> > - }
> > -
> > - .bss_end (NOLOAD) : {
> > - KEEP(*(.__bss_end));
> > + __bss_end = .;
> > }
> >
> > /DISCARD/ : { *(.dynsym) }
> > diff --git a/arch/arm/mach-zynq/u-boot.lds b/arch/arm/mach-zynq/u-boot.lds
> > index 3b7c9d515f8b..8d3259821719 100644
> > --- a/arch/arm/mach-zynq/u-boot.lds
> > +++ b/arch/arm/mach-zynq/u-boot.lds
> > @@ -102,26 +102,11 @@ SECTIONS
> >
> > _image_binary_end = .;
> >
> > -/*
> > - * Compiler-generated __bss_start and __bss_end, see arch/arm/lib/bss.c
> > - * __bss_base and __bss_limit are for linker only (overlay ordering)
> > - */
> > -
> > - .bss_start __rel_dyn_start (OVERLAY) : {
> > - KEEP(*(.__bss_start));
> > - __bss_base = .;
> > - }
> > -
> > - .bss __bss_base (OVERLAY) : {
> > + .bss ALIGN(4): {
> > + __bss_start = .;
> > *(.bss*)
> > - . = ALIGN(8);
> > - __bss_limit = .;
> > - }
> > -
> > - .bss_end __bss_limit (OVERLAY) : {
> > - KEEP(*(.__bss_end));
> > + __bss_end = .;
> > }
> > -
> > /*
> > * Zynq needs to discard these sections because the user
> > * is expected to pass this image on to tools for boot.bin
> > diff --git a/board/qualcomm/dragonboard820c/u-boot.lds b/board/qualcomm/dragonboard820c/u-boot.lds
> > index 5251b59fbe76..d3cc5278b610 100644
> > --- a/board/qualcomm/dragonboard820c/u-boot.lds
> > +++ b/board/qualcomm/dragonboard820c/u-boot.lds
> > @@ -87,19 +87,10 @@ SECTIONS
> >
> > _end = .;
> >
> > - . = ALIGN(8);
> > -
> > - .bss_start : {
> > - KEEP(*(.__bss_start));
> > - }
> > -
> > - .bss : {
> > + .bss ALIGN(8): {
> > + __bss_start = .;
> > *(.bss*)
> > - . = ALIGN(8);
> > - }
> > -
> > - .bss_end : {
> > - KEEP(*(.__bss_end));
> > + __bss_end = .;
> > }
> >
> > /DISCARD/ : { *(.dynsym) }
> > --
> > 2.37.2
> >
>
> --
> // Caleb (they/them)
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