Re: [U-Boot] [PATCH] ARM: Fix __bss_start and __bss_end in linker scripts

On Friday, April 5, 2013 1:05:53 AM, Benoît Thébaudeau wrote:

Hi Albert,

On Friday, April 5, 2013 12:13:53 AM, Albert ARIBAUD wrote:

...

Subject: [PATCH] ARM: Fix __bss_start and __bss_end in linker scripts

Commit 3ebd1cbc introduced compiler-generated __bss_start and __bss_end__ and commit c23561e7 rewrote all __bss_end__ as __bss_end. Their merge caused silent and harmless but potentially bug-inducing clashes between compiler- and linker- enerated __bss_end symbols.

Make __bss_end and __bss_start compiler-only, and create __bss_base and __bss_limit for linker-only use.

Reported-by: Benoît Thébaudeau benoit.thebaudeau@advansee.com Signed-off-by: Albert ARIBAUD albert.u.boot@aribaud.net

---

arch/arm/cpu/ixp/u-boot.lds | 14 ++++++++++---- arch/arm/cpu/u-boot.lds | 14 ++++++++++---- board/actux1/u-boot.lds | 14 ++++++++++---- board/actux2/u-boot.lds | 14 ++++++++++---- board/actux3/u-boot.lds | 14 ++++++++++---- board/dvlhost/u-boot.lds | 14 ++++++++++---- board/freescale/mx31ads/u-boot.lds | 14 ++++++++++---- 7 files changed, 70 insertions(+), 28 deletions(-)

diff --git a/arch/arm/cpu/ixp/u-boot.lds b/arch/arm/cpu/ixp/u-boot.lds index 8345b55..c999829 100644 --- a/arch/arm/cpu/ixp/u-boot.lds +++ b/arch/arm/cpu/ixp/u-boot.lds @@ -67,17 +67,23 @@ SECTIONS

_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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

•  HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.dynstr*) }

diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds index 3a1083d..0543b06 100644 --- a/arch/arm/cpu/u-boot.lds +++ b/arch/arm/cpu/u-boot.lds @@ -81,18 +81,24 @@ 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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

•  HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.dynstr*) }

diff --git a/board/actux1/u-boot.lds b/board/actux1/u-boot.lds index c76728a..7e5c4d8 100644 --- a/board/actux1/u-boot.lds +++ b/board/actux1/u-boot.lds @@ -74,17 +74,23 @@ SECTIONS

_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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

•  HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.dynstr*) }

diff --git a/board/actux2/u-boot.lds b/board/actux2/u-boot.lds index 984f70e..ce1b7c9 100644 --- a/board/actux2/u-boot.lds +++ b/board/actux2/u-boot.lds @@ -74,17 +74,23 @@ SECTIONS

_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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

•  HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.dynstr*) }

diff --git a/board/actux3/u-boot.lds b/board/actux3/u-boot.lds index fc48cf0..3e091dd 100644 --- a/board/actux3/u-boot.lds +++ b/board/actux3/u-boot.lds @@ -74,17 +74,23 @@ SECTIONS

_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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

• HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.dynstr*) }

diff --git a/board/dvlhost/u-boot.lds b/board/dvlhost/u-boot.lds index b13d3e1..fe3c21b 100644 --- a/board/dvlhost/u-boot.lds +++ b/board/dvlhost/u-boot.lds @@ -74,17 +74,23 @@ SECTIONS

_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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

•  HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.dynstr*) }

diff --git a/board/freescale/mx31ads/u-boot.lds b/board/freescale/mx31ads/u-boot.lds index 264c4e8..e6885a5 100644 --- a/board/freescale/mx31ads/u-boot.lds +++ b/board/freescale/mx31ads/u-boot.lds @@ -80,17 +80,23 @@ SECTIONS

_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));

• HIDDEN(__bss_base = .);
  

  }

• .bss __bss_start (OVERLAY) : {

• .bss __bss_base (OVERLAY) : { *(.bss*) . = ALIGN(4);

•  __bss_end = .;
  

•  HIDDEN(__bss_limit = .);
  

  }

• .bss_end __bss_end (OVERLAY) : {

• KEEP(*(__bss_end));
  

• .bss_end __bss_limit (OVERLAY) : {

• KEEP(*(.__bss_end));
  

  }

  /DISCARD/ : { *(.bss*) }

-- 1.7.10.4

Looks good, but what about the __bss_end in ASSERT(__bss_end < (CONFIG_SPL_TEXT_BASE + CONFIG_SPL_MAX_SIZE), "SPL image too big"); ?

Shouldn't it be replaced with __bss_limit, or even better, with __image_copy_end (why should BSS be taken into account for SPL image size?)?

I meant __bss_base, not __image_copy_end.

Best regards, Benoît