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PATCH: Add 64-bit preadv.c and pwritev.c
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 18 May 2012 13:08:12 -0700
- Subject: PATCH: Add 64-bit preadv.c and pwritev.c
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Hi,
The curent preadv/pwritev on x86-64 has
a: 49 89 ca mov %rcx,%r10
d: 85 c0 test %eax,%eax
f: 75 1d jne 2e <preadv+0x2e>
11: 45 31 c0 xor %r8d,%r8d
14: 48 63 d2 movslq %edx,%rdx
17: 48 63 ff movslq %edi,%rdi
1a: b8 27 01 00 00 mov $0x127,%eax
1f: 0f 05 syscall
There is uselss:
11: 45 31 c0 xor %r8d,%r8d
It is generated by
#define LO_HI_LONG(val) \
(off_t) val, \
(off_t) ((((uint64_t) (val)) >> (sizeof (long) * 4)) >> (sizeof (long) * 4))
It isn't needed for 64-bit archs. Here is a patch to add 64-bit
preadv.c and pwritev.c. Now we have
1ce: 49 89 ca mov %rcx,%r10
1d1: 48 63 d2 movslq %edx,%rdx
1d4: 48 63 ff movslq %edi,%rdi
1d7: b8 27 01 00 00 mov $0x127,%eax
1dc: 0f 05 syscall
They will also be used by x32. Tested on Linux/x86-64. OK
to install?
Thanks.
H.J.
* sysdeps/unix/sysv/linux/wordsize-64/preadv.c: New file.
* sysdeps/unix/sysv/linux/wordsize-64/pwritev.c: Likewise.
diff --git a/sysdeps/unix/sysv/linux/wordsize-64/preadv.c b/sysdeps/unix/sysv/linux/wordsize-64/preadv.c
new file mode 100644
index 0000000..600af13
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/wordsize-64/preadv.c
@@ -0,0 +1,73 @@
+/* 64-bit preadv.
+ 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 <errno.h>
+#include <stddef.h>
+#include <sys/param.h>
+/* Hide the preadv64 declaration. */
+#define preadv64 __redirect_preadv64
+#include <sys/uio.h>
+
+#include <sysdep-cancel.h>
+#include <sys/syscall.h>
+#include <kernel-features.h>
+
+#ifndef __ASSUME_PREADV
+static ssize_t __atomic_preadv_replacement (int, const struct iovec *,
+ int, off_t) internal_function;
+#endif
+
+ssize_t
+preadv (int fd, const struct iovec *vector, int count, off_t offset)
+{
+#ifdef __NR_preadv
+ ssize_t result;
+
+ if (SINGLE_THREAD_P)
+ result = INLINE_SYSCALL (preadv, 4, fd, vector, count, offset);
+ else
+ {
+ int oldtype = LIBC_CANCEL_ASYNC ();
+
+ result = INLINE_SYSCALL (preadv, 4, fd, vector, count, offset);
+
+ LIBC_CANCEL_RESET (oldtype);
+ }
+# ifdef __ASSUME_PREADV
+ return result;
+# endif
+#endif
+
+#ifndef __ASSUME_PREADV
+# ifdef __NR_preadv
+ if (result >= 0 || errno != ENOSYS)
+ return result;
+# endif
+
+ return __atomic_preadv_replacement (fd, vector, count, offset);
+#endif
+}
+#undef preadv64
+strong_alias (preadv, preadv64)
+
+#ifndef __ASSUME_PREADV
+# define PREADV static internal_function __atomic_preadv_replacement
+# define PREAD __pread
+# define OFF_T off_t
+# include <sysdeps/posix/preadv.c>
+#endif
diff --git a/sysdeps/unix/sysv/linux/wordsize-64/pwritev.c b/sysdeps/unix/sysv/linux/wordsize-64/pwritev.c
new file mode 100644
index 0000000..f2dee8f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/wordsize-64/pwritev.c
@@ -0,0 +1,73 @@
+/* 64-bi pwritev.
+ 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 <errno.h>
+#include <stddef.h>
+#include <sys/param.h>
+/* Hide the pwritev64 declaration. */
+#define pwritev64 __redirect_pwritev64
+#include <sys/uio.h>
+
+#include <sysdep-cancel.h>
+#include <sys/syscall.h>
+#include <kernel-features.h>
+
+#ifndef __ASSUME_PWRITEV
+static ssize_t __atomic_pwritev_replacement (int, const struct iovec *,
+ int, off_t) internal_function;
+#endif
+
+ssize_t
+pwritev (int fd, const struct iovec *vector, int count, off_t offset)
+{
+#ifdef __NR_pwritev
+ ssize_t result;
+
+ if (SINGLE_THREAD_P)
+ result = INLINE_SYSCALL (pwritev, 4, fd, vector, count, offset);
+ else
+ {
+ int oldtype = LIBC_CANCEL_ASYNC ();
+
+ result = INLINE_SYSCALL (pwritev, 4, fd, vector, count, offset);
+
+ LIBC_CANCEL_RESET (oldtype);
+ }
+# ifdef __ASSUME_PWRITEV
+ return result;
+# endif
+#endif
+
+#ifndef __ASSUME_PWRITEV
+# ifdef __NR_pwritev
+ if (result >= 0 || errno != ENOSYS)
+ return result;
+# endif
+
+ return __atomic_pwritev_replacement (fd, vector, count, offset);
+#endif
+}
+#undef pwritev64
+strong_alias (pwritev, pwritev64)
+
+#ifndef __ASSUME_PWRITEV
+# define PWRITE __pwrite
+# define PWRITEV static internal_function __atomic_pwritev_replacement
+# define OFF_T off_t
+# include <sysdeps/posix/pwritev.c>
+#endif