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Re: question on sparc SHMLBA helper function
From: Roland McGrath <roland@hack.frob.com>
Date: Fri, 16 Mar 2012 16:16:31 -0700 (PDT)
>> It just seems to be a very poor way to detect an error return value.
>
> Ok, that's what I kind of thought, but it looked so strange I could't
> really tell.
>
> Perhaps you can verify the safety of a change like that and then do it?
>
>> All the INTERNAL_SYSCALL_ERROR_P bits should take care of things these
>> days, and then the only return value we have to check for from
>> INTERNAL_SYSCALL is "-1".
>
> Seems cleaner to use INTERNAL_SYSCALL* directly.
Ok, here is what I'm doing final testing on an will commit:
--------------------
Fix SHMLBA on sparc.
[BZ #6471]
* sysdeps/unix/sysv/linux/shmat.c (shmat): Test for syscall errors
properly.
* sysdeps/unix/sysv/linux/sparc/getshmlba.c: New file.
* sysdeps/unix/sysv/linux/sparc/Makefile: Add getshmlba to
sysdep_routines when subdir is sysvipc.
* sysdeps/unix/sysv/linux/sparc/bits/shm.h (SHMLBA): Use new
__getshmlba helper.
---
ChangeLog | 9 ++++++
NEWS | 12 ++++----
sysdeps/unix/sysv/linux/shmat.c | 22 +++++++++------
sysdeps/unix/sysv/linux/sparc/Makefile | 4 +++
sysdeps/unix/sysv/linux/sparc/bits/shm.h | 4 +-
sysdeps/unix/sysv/linux/sparc/getshmlba.c | 40 +++++++++++++++++++++++++++++
6 files changed, 74 insertions(+), 17 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/sparc/getshmlba.c
diff --git a/ChangeLog b/ChangeLog
index 4b3981f..df662af 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
2012-03-16 David S. Miller <davem@davemloft.net>
+ [BZ #6471]
+ * sysdeps/unix/sysv/linux/shmat.c (shmat): Test for syscall errors
+ properly.
+ * sysdeps/unix/sysv/linux/sparc/getshmlba.c: New file.
+ * sysdeps/unix/sysv/linux/sparc/Makefile: Add getshmlba to
+ sysdep_routines when subdir is sysvipc.
+ * sysdeps/unix/sysv/linux/sparc/bits/shm.h (SHMLBA): Use new
+ __getshmlba helper.
+
* sysdeps/sparc/fpu/libm-test/ulps: Update.
2012-03-16 H.J. Lu <hongjiu.lu@intel.com>
diff --git a/NEWS b/NEWS
index cc897db..5af4f68 100644
--- a/NEWS
+++ b/NEWS
@@ -11,12 +11,12 @@ Version 2.16
174, 350, 411, 2541, 2547, 2548, 2551, 2552, 2553, 2554, 2562, 2563, 2565,
2566, 2576, 3335, 3976, 3992, 4026, 4108, 4596, 4822, 5077, 5461, 5805,
- 5993, 6884, 6907, 6911, 9739, 9902, 10110, 10135, 10140, 10210, 10545,
- 10716, 11174, 11322, 11365, 11494, 12047, 13058, 13525, 13526, 13527,
- 13528, 13529, 13530, 13531, 13532, 13533, 13547, 13551, 13552, 13553,
- 13555, 13559, 13566, 13583, 13618, 13637, 13656, 13658, 13673, 13695,
- 13704, 13706, 13726, 13738, 13786, 13792, 13806, 13840, 13841, 13844,
- 13846, 13851, 13852, 13854
+ 5993, 6471, 6884, 6907, 6911, 9739, 9902, 10110, 10135, 10140, 10210,
+ 10545, 10716, 11174, 11322, 11365, 11494, 12047, 13058, 13525, 13526,
+ 13527, 13528, 13529, 13530, 13531, 13532, 13533, 13547, 13551, 13552,
+ 13553, 13555, 13559, 13566, 13583, 13618, 13637, 13656, 13658, 13673,
+ 13695, 13704, 13706, 13726, 13738, 13786, 13792, 13806, 13840, 13841,
+ 13844, 13846, 13851, 13852, 13854
* ISO C11 support:
diff --git a/sysdeps/unix/sysv/linux/shmat.c b/sysdeps/unix/sysv/linux/shmat.c
index 2eec6a6..dd75491 100644
--- a/sysdeps/unix/sysv/linux/shmat.c
+++ b/sysdeps/unix/sysv/linux/shmat.c
@@ -35,7 +35,8 @@ shmat (shmid, shmaddr, shmflg)
const void *shmaddr;
int shmflg;
{
- void *__unbounded result;
+ INTERNAL_SYSCALL_DECL(err);
+ unsigned long resultvar;
void *__unbounded raddr;
#if __BOUNDED_POINTERS__
@@ -47,12 +48,15 @@ shmat (shmid, shmaddr, shmflg)
length = shmds.shm_segsz;
#endif
- result = (void *__unbounded) INLINE_SYSCALL (ipc, 5, IPCOP_shmat,
- shmid, shmflg,
- (long int) __ptrvalue (&raddr),
- __ptrvalue ((void *) shmaddr));
- if ((unsigned long) result <= -(unsigned long) SHMLBA)
- result = raddr;
-
- return BOUNDED_N (result, length);
+ resultvar = INTERNAL_SYSCALL (ipc, err, 5, IPCOP_shmat,
+ shmid, shmflg,
+ (long int) __ptrvalue (&raddr),
+ __ptrvalue ((void *) shmaddr));
+ if (INTERNAL_SYSCALL_ERROR_P (resultvar, err))
+ {
+ __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, err));
+ return (void *) -1;
+ }
+
+ return BOUNDED_N (raddr, length);
}
diff --git a/sysdeps/unix/sysv/linux/sparc/Makefile b/sysdeps/unix/sysv/linux/sparc/Makefile
index 96bf0bb..d769c48 100644
--- a/sysdeps/unix/sysv/linux/sparc/Makefile
+++ b/sysdeps/unix/sysv/linux/sparc/Makefile
@@ -7,3 +7,7 @@ syscall-list-64bit-condition := __WORDSIZE == 64
ifeq ($(subdir),rt)
librt-routines += rt-sysdep
endif
+
+ifeq ($(subdir),sysvipc)
+sysdep_routines += getshmlba
+endif
diff --git a/sysdeps/unix/sysv/linux/sparc/bits/shm.h b/sysdeps/unix/sysv/linux/sparc/bits/shm.h
index b0966d6..eb530de 100644
--- a/sysdeps/unix/sysv/linux/sparc/bits/shm.h
+++ b/sysdeps/unix/sysv/linux/sparc/bits/shm.h
@@ -40,8 +40,8 @@
__BEGIN_DECLS
/* Segment low boundary address multiple. */
-#define SHMLBA (__getpagesize ())
-extern int __getpagesize (void) __THROW __attribute__ ((__const__));
+#define SHMLBA (__getshmlba ())
+extern int __getshmlba (void) __attribute__ ((__const__));
/* Type to count number of attaches. */
diff --git a/sysdeps/unix/sysv/linux/sparc/getshmlba.c b/sysdeps/unix/sysv/linux/sparc/getshmlba.c
new file mode 100644
index 0000000..205bed2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/getshmlba.c
@@ -0,0 +1,40 @@
+/* Copyright (C) 2012
+ Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <unistd.h>
+#include <sys/shm.h>
+#include <ldsodefs.h>
+
+int
+__getshmlba (void)
+{
+ uint64_t hwcap = GLRO(dl_hwcap);
+ int pgsz = GLRO(dl_pagesize);
+
+ if (hwcap & HWCAP_SPARC_V9)
+ {
+ if (pgsz < (16 * 1024))
+ return 16 * 1024;
+ else
+ return pgsz;
+ }
+ else if (!(hwcap & HWCAP_SPARC_FLUSH))
+ return 64 * 1024;
+ else
+ return 256 * 1024;
+}
--
1.7.9.1