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Re: [RFC 2.0] Implementing hwcap2
- From: "Ryan S. Arnold" <ryan dot arnold at gmail dot com>
- To: Richard Henderson <rth at twiddle dot net>
- Cc: "Ryan S. Arnold" <rsa at us dot ibm dot com>, libc-alpha <libc-alpha at sourceware dot org>
- Date: Thu, 28 Mar 2013 16:21:02 -0500
- Subject: Re: [RFC 2.0] Implementing hwcap2
- References: <1364493171 dot 3473 dot 23 dot camel at localhost dot localdomain> <515486A9 dot 5080202 at twiddle dot net>
On Thu, Mar 28, 2013 at 1:06 PM, Richard Henderson <rth@twiddle.net> wrote:
> On 03/28/2013 10:52 AM, Ryan Arnold wrote:
>> +++ b/sysdeps/s390/s390-32/multiarch/ifunc-resolve.c
>> @@ -19,6 +19,7 @@
>>
>> #include <unistd.h>
>> #include <dl-procinfo.h>
>> +#include <stdint.h>
>>
>> #define STFLE_BITS_Z10 34 /* General instructions extension */
>> #define STFLE_BITS_Z196 45 /* Distinct operands, pop ... */
>> @@ -38,7 +39,7 @@
>> extern void *FUNC##_z10 attribute_hidden; \
>> extern void *FUNC##_g5 attribute_hidden; \
>> \
>> - void *resolve_##FUNC (unsigned long int dl_hwcap) \
>> + void *resolve_##FUNC (uint64_t dl_hwcap) \
>
> This is an abi change for 32-bit big-endian systems.
A uint64_t hwcap is already the default storage type for hwcap for all
architectures.
>From ldsodefs.h:
/* Mask for hardware capabilities that are available. */
EXTERN uint64_t _dl_hwcap;
Am I not understanding what you mean by 'abi change'? Can you throw
me a bone and describe a problematic use case where my suggestion
breaks something?
> There probably aren't many^Wany ifunc users outside glibc for these
> systems, but just so we're 100% clear on this.
The implication of leaving this as-is.. would be that resolvers
wouldn't have access to bits in HWCAP2 to make their selections.
What's the alternative?
Ryan