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Re: [PATCH 1/2] S390: Save and restore fprs/vrs while resolving symbols.
- From: Stefan Liebler <stli at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Date: Wed, 6 Apr 2016 15:45:53 +0200
- Subject: Re: [PATCH 1/2] S390: Save and restore fprs/vrs while resolving symbols.
- Authentication-results: sourceware.org; auth=none
- References: <1458645925-28632-1-git-send-email-stli at linux dot vnet dot ibm dot com> <5704F951 dot 6050906 at redhat dot com>
On 04/06/2016 01:56 PM, Florian Weimer wrote:
On 03/22/2016 12:25 PM, Stefan Liebler wrote:
On s390, no fpr/vrs were saved while resolving a symbol
According to the abi, the fpr-arguments are defined as call clobbered.
In leaf-functions, gcc 4.9 and newer can use fprs for saving/restoring gprs
instead of saving them to the stack.
If gcc do this in one of the resolver-functions, then the floating point
arguments of a library-function are invalid for the first library-function-call.
Thus, this patch saves/restores the fprs around the resolving code.
I think this bug is end-user-visible because it is due to an incorrect
implementation of the original ABI. Can you file a bug to track this
and add the number to the ChangeLog retroactively?
(The other patch, “Extend structs La_s390_regs / La_s390_retval” seems
different in this regard; I believe applications would have to check
that glibc supports the new ABI before they use the new features.)
Okay. Done. Here is the bugzilla 19916: