Re: [PATCH] BaseTools/Scripts: discard .gnu.hash section in GCC builds

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 21 May 2017 at 21:05, Gao, Liming <liming.gao@intel.com> wrote:
> Reviewed-by: Liming Gao <liming.gao@intel.com>
>

Thanks. Pushed as 00b00cc57bfe0fca54c904d4dd44a263e243c88b

>>-----Original Message-----
>>From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
>>Sent: Friday, May 19, 2017 6:48 PM
>>To: edk2-devel@lists.01.org
>>Cc: leif.lindholm@linaro.org; Zhu, Yonghong <yonghong.zhu@intel.com>; Gao,
>>Liming <liming.gao@intel.com>; Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>Subject: [PATCH] BaseTools/Scripts: discard .gnu.hash section in GCC builds
>>
>>Some builds of GCC/binutils will default to using the GNU flavor of
>>the symbol hash table, and will emit it into a section called .gnu.hash
>>rather than .hash. We have no use for its contents, and GenFw ignores
>>it anyway, so it shouldn't really matter what we do with it.
>>
>>However, due to a workaround for AARCH64 we have in GenFw to deal with
>>older GCCs that corrupt section-based relocations when merging sections
>>during the final link, we need the ELF and PE/COFF views of the binary
>>to be identical. Since we don't place the .gnu.hash section explicitly,
>>it may end up at the beginning of the ELF binary, causing other sections
>>to be shifted in the ELF view but not in the PE/COFF view.
>>
>>So let's add .gnu.hash to the GCC linker script. We don't care about its
>>contents so add it to the /DISCARD/ section.
>>
>>Contributed-under: TianoCore Contribution Agreement 1.0
>>Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>---
>> BaseTools/Scripts/GccBase.lds | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>>diff --git a/BaseTools/Scripts/GccBase.lds b/BaseTools/Scripts/GccBase.lds
>>index 41e5c0b4a769..a43e0072f2b4 100644
>>--- a/BaseTools/Scripts/GccBase.lds
>>+++ b/BaseTools/Scripts/GccBase.lds
>>@@ -78,7 +78,7 @@ SECTIONS {
>>     *(.dynsym)
>>     *(.dynstr)
>>     *(.dynamic)
>>-    *(.hash)
>>+    *(.hash .gnu.hash)
>>     *(.comment)
>>     *(COMMON)
>>   }
>>--
>>2.9.3
>