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Re: [PATCH 02/56] S390: Use hwcap instead of dl_hwcap in ifunc-resolvers.
- From: Stefan Liebler <stli at linux dot ibm dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 3 Dec 2018 09:20:36 +0100
- Subject: Re: [PATCH 02/56] S390: Use hwcap instead of dl_hwcap in ifunc-resolvers.
- References: <1543593514-10251-1-git-send-email-stli@linux.ibm.com> <1543593514-10251-3-git-send-email-stli@linux.ibm.com> <87va4eqxgb.fsf@oldenburg.str.redhat.com>
On 11/30/2018 06:36 PM, Florian Weimer wrote:
* Stefan Liebler:
+ if (__glibc_likely((hwcap & HWCAP_S390_STFLE) \
Missing space before paren. Since HWCAP_S390_STFLE 4 is four, this
__glibc_likely is actually equivalent to __glibc_unlikely, so perhaps
you should drop it.
Thanks,
Florian
Hi Florian,
I've added the missing space.
The condition of __glibc_likely does not result in the value "4"
as the full condition is:
(hwcap & HWCAP_S390_STFLE)
&& (hwcap & HWCAP_S390_ZARCH)
&& (hwcap & HWCAP_S390_HIGH_GPRS)
If hwcap is e.g. 518, then the result is one and __glibc_likely is not
equivalent to __glibc_unlikely.
Note: here are the other HWCAP_S390 defines:
#define HWCAP_S390_STFLE 4
#define HWCAP_S390_ZARCH 2
#define HWCAP_S390_HIGH_GPRS 512
Thanks.
Stefan
>From faeb0c30779296d58baab460e4671bc5e60d2609 Mon Sep 17 00:00:00 2001
From: Stefan Liebler <stli@linux.ibm.com>
Date: Fri, 30 Nov 2018 15:42:58 +0100
Subject: [PATCH 02/56] S390: Use hwcap instead of dl_hwcap in ifunc-resolvers.
The renaming of hwcap arguments in ifunc-resolvers is needed
in order to prepare for further commits which refactors
ifunc handling for memset, memcmp, and memcpy. Now you are able
to use s390_libc_ifunc_init which stores the stfle bits
within the expression for an ifunc-resolver generated by
s390_libc_ifunc_expr.
ChangeLog:
* sysdeps/s390/multiarch/ifunc-resolve.h
(s390_libc_ifunc_init, s390_libc_ifunc,
s390_vx_libc_ifunc2_redirected): Use hwcap instead of dl_hwcap.
---
sysdeps/s390/multiarch/ifunc-resolve.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/sysdeps/s390/multiarch/ifunc-resolve.h b/sysdeps/s390/multiarch/ifunc-resolve.h
index b42ed922fd..b7e20abc59 100644
--- a/sysdeps/s390/multiarch/ifunc-resolve.h
+++ b/sysdeps/s390/multiarch/ifunc-resolve.h
@@ -42,9 +42,9 @@
: : "cc");
#define s390_libc_ifunc_init() \
unsigned long long stfle_bits = 0ULL; \
- if (__glibc_likely((dl_hwcap & HWCAP_S390_STFLE) \
- && (dl_hwcap & HWCAP_S390_ZARCH) \
- && (dl_hwcap & HWCAP_S390_HIGH_GPRS))) \
+ if (__glibc_likely ((hwcap & HWCAP_S390_STFLE) \
+ && (hwcap & HWCAP_S390_ZARCH) \
+ && (hwcap & HWCAP_S390_HIGH_GPRS))) \
{ \
S390_STORE_STFLE (stfle_bits); \
}
@@ -61,7 +61,7 @@
: __glibc_likely (S390_IS_Z10 (stfle_bits)) \
? RESOLVERFUNC##_z10 \
: RESOLVERFUNC##_default, \
- unsigned long int dl_hwcap, s390_libc_ifunc_init);
+ unsigned long int hwcap, s390_libc_ifunc_init);
#define s390_vx_libc_ifunc(FUNC) \
s390_vx_libc_ifunc2_redirected(FUNC, FUNC, FUNC)
@@ -79,10 +79,10 @@
extern __typeof (TYPE_FUNC) RESOLVERFUNC##_vx attribute_hidden; \
extern __typeof (TYPE_FUNC) RESOLVERFUNC##_c attribute_hidden; \
__ifunc (TYPE_FUNC, FUNC, \
- (dl_hwcap & HWCAP_S390_VX) \
+ (hwcap & HWCAP_S390_VX) \
? RESOLVERFUNC##_vx \
: RESOLVERFUNC##_c, \
- unsigned long int dl_hwcap, s390_vx_libc_ifunc_init);
+ unsigned long int hwcap, s390_vx_libc_ifunc_init);
#define s390_libc_ifunc_expr_init()
#define s390_libc_ifunc_expr(TYPE_FUNC, FUNC, EXPR) \
--
2.17.0