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authorH.J. Lu <hjl.tools@gmail.com>2015-12-14 19:09:13 -0800
committerH.J. Lu <hjl.tools@gmail.com>2015-12-14 20:34:31 -0800
commit8a4f1e5889edc41f97c861af81d0f0354d0bc75a (patch)
treec2d52613c1f72bd6ac14887a261a2b7b350f7198
parenteed3e1eb79bcfa9b52609fd875fa2d522e2d6bce (diff)
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Use INTERNAL_SYSCALL_TIMES for Linux times
The Linux times function, which returns clock_t, is implemented with
INTERNAL_SYSCALL.  Since INTERNAL_SYSCALL returns 32-bit integer and
and clock_t is 64-bit on x32, this is a mismatch on x32.  times is the
only such function.  This patch replaces INTERNAL_SYSCALL in Linux
times.c with INTERNAL_SYSCALL_TIMES which is default to INTERNAL_SYSCALL
and provides x32 times.c with proper INTERNAL_SYSCALL_TIMES.

There is no code change on times for i686 nor x86-64.  For x32, before
this patch, there are

0000000 <__times>:
   0:	b8 64 00 00 40       	mov    $0x40000064,%eax
   5:	0f 05                	syscall
   7:	48 63 d0             	movslq %eax,%rdx
                                ^^^^^^^^^^ Incorrect signed extension
   a:	48 83 fa f2          	cmp    $0xfffffffffffffff2,%rdx
   e:	75 07                	jne    17 <__times+0x17>
  10:	3d 00 f0 ff ff       	cmp    $0xfffff000,%eax
  15:	77 11                	ja     28 <__times+0x28>
  17:	48 83 fa ff          	cmp    $0xffffffffffffffff,%rdx
  1b:	b8 00 00 00 00       	mov    $0x0,%eax
  20:	48 0f 45 c2          	cmovne %rdx,%rax
  24:	c3                   	retq

After this patch, there are

00000000 <__times>:
   0:	b8 64 00 00 40       	mov    $0x40000064,%eax
   5:	0f 05                	syscall
   7:	48 83 f8 f2          	cmp    $0xfffffffffffffff2,%rax
   b:	75 07                	jne    14 <__times+0x14>
   d:	3d 00 f0 ff ff       	cmp    $0xfffff000,%eax
  12:	77 14                	ja     28 <__times+0x28>
  14:	48 83 f8 ff          	cmp    $0xffffffffffffffff,%rax
  18:	ba 00 00 00 00       	mov    $0x0,%edx
  1d:	48 0f 44 c2          	cmove  %rdx,%rax
  21:	c3                   	retq

The incorrect signed extension is gone.

	[BZ #19363]
	* sysdeps/unix/sysv/linux/times.c (INTERNAL_SYSCALL_TIMES): New.
	(__times): Replace INTERNAL_SYSCALL with INTERNAL_SYSCALL_TIMES.
	* sysdeps/unix/sysv/linux/x86_64/x32/times.c: New file.

xxx
-rw-r--r--sysdeps/unix/sysv/linux/times.c6
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/x32/times.c31
2 files changed, 36 insertions, 1 deletions
diff --git a/sysdeps/unix/sysv/linux/times.c b/sysdeps/unix/sysv/linux/times.c
index 19b77cf1e0..9d3beed3b8 100644
--- a/sysdeps/unix/sysv/linux/times.c
+++ b/sysdeps/unix/sysv/linux/times.c
@@ -19,12 +19,16 @@
 #include <sys/times.h>
 #include <sysdep.h>
 
+#ifndef INTERNAL_SYSCALL_TIMES
+# define INTERNAL_SYSCALL_TIMES(err, buf) \
+  INTERNAL_SYSCALL (times, err, 1, buf)
+#endif
 
 clock_t
 __times (struct tms *buf)
 {
   INTERNAL_SYSCALL_DECL (err);
-  clock_t ret = INTERNAL_SYSCALL (times, err, 1, buf);
+  clock_t ret = INTERNAL_SYSCALL_TIMES (err, buf);
   if (INTERNAL_SYSCALL_ERROR_P (ret, err)
       && __builtin_expect (INTERNAL_SYSCALL_ERRNO (ret, err) == EFAULT, 0)
       && buf)
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/times.c b/sysdeps/unix/sysv/linux/x86_64/x32/times.c
new file mode 100644
index 0000000000..330315fed2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/times.c
@@ -0,0 +1,31 @@
+/* Linux times.  X32 version.
+   Copyright (C) 2015 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/>.  */
+
+/* Inline Linux times system call.  */
+#define INTERNAL_SYSCALL_TIMES(err, buf)				\
+  ({									\
+    unsigned long long int resultvar;					\
+    LOAD_ARGS_1 (buf)							\
+    LOAD_REGS_1								\
+    asm volatile (							\
+    "syscall\n\t"							\
+    : "=a" (resultvar)							\
+    : "0" (__NR_times) ASM_ARGS_1 : "memory", "cc", "r11", "cx");	\
+    (long long int) resultvar; })
+
+#include <sysdeps/unix/sysv/linux/times.c>