This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH] Fix localplt check for GNU_IFUNC
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>, libc-alpha at sourceware dot org
- Date: Tue, 25 Mar 2014 14:13:18 -0400
- Subject: Re: [PATCH] Fix localplt check for GNU_IFUNC
- Authentication-results: sourceware.org; auth=none
- References: <531B63DE dot 5090803 at linux dot vnet dot ibm dot com> <5329E65A dot 5010703 at redhat dot com> <5329F9F2 dot 6060900 at linux dot vnet dot ibm dot com> <20140321203357 dot 40883744AC at topped-with-meat dot com> <5331C60E dot 3020605 at linux dot vnet dot ibm dot com>
On 03/25/2014 02:08 PM, Adhemerval Zanella wrote:
> On 21-03-2014 17:33, Roland McGrath wrote:
>> You need to double-check back to the oldest binutils version that we
>> support for building libc (>=2.20) that had STT_GNU_IFUNC support (from
>> NEWS looks like 2.20 itself did have it) to ensure that the script handles
>> the output from the readelf in all the intervening binutils releases.
>> If it's verified that the modified script works with all those versions of
>> readelf, then it looks fine.
>>
> I just check against 2.20.1.20101209, 2.21.1.20110925, 2.22.0.20120801, 2.23.2.20130919,
> and 2.24.0.20140325 'readelf -W -S -d -r' against a x86_64 and PowerPC64 build by generating
> the jmprel files and all generate the same output for both archs.
>
> I also check with wrong IFUNC usage code change on both archs to see if the script is now
> capable to detect them:
>
> * PowerPC64:
>
> diff --git a/sysdeps/powerpc/powerpc64/power7/strncat.S b/sysdeps/powerpc/powerpc64/power7/strncat.S
> index 1a1a95e..23861f6 100644
> --- a/sysdeps/powerpc/powerpc64/power7/strncat.S
> +++ b/sysdeps/powerpc/powerpc64/power7/strncat.S
> @@ -69,7 +69,7 @@ EALIGN(STRNCAT, 4, 0)
> beq cr0,L(done)
>
> mr r31, r4 /* Save "s2" in r31 from r4. */
> - bl STRLEN /* Call optimized strlen on s1; goto
> + bl strlen /* Call optimized strlen on s1; goto
> end of s1. */
> nop
> cmpldi cr7, r29, 7 /* If s2 is <=7 process
>
> * X86_64:
>
> diff --git a/sysdeps/x86_64/multiarch/strcat-ssse3.S b/sysdeps/x86_64/multiarch/strcat-ssse3.S
> index fde7b90..98fd69c 100644
> --- a/sysdeps/x86_64/multiarch/strcat-ssse3.S
> +++ b/sysdeps/x86_64/multiarch/strcat-ssse3.S
> @@ -37,6 +37,8 @@ ENTRY (STRCAT)
> /* Inline corresponding strlen file, temporary until new strcpy
> implementation gets merged. */
>
> + call strstr
> +
> xor %eax, %eax
> cmpb $0, (%rdi)
> jz L(exit_tail0)
>
> And both cases all readelf test correctly shows the wrong PLT cases. Ok to commit?
Looks good to me. Thanks for the additional manual testing.
Cheers,
Carlos.