From: Ulrich Drepper <drepper@gmail.com>
Date: Tue, 6 Sep 2011 04:12:18 +0000 (-0400)
Subject: Prefer real syscalls instead of vsyscalls on x86-64 outside libc.so
X-Git-Tag: glibc-2.15~355
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ef60624956e93df1da329a48570776ed963b1916;p=thirdparty%2Fglibc.git

Prefer real syscalls instead of vsyscalls on x86-64 outside libc.so
---

diff --git a/ChangeLog b/ChangeLog
index 3f8a82174b0..0176dcf0f01 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-09-06  Ulrich Drepper  <drepper@gmail.com>
+
+	* sysdeps/unix/sysv/linux/kernel-features.h: Add entry for getcpu
+	syscall on x86-64.
+	* sysdeps/unix/sysv/linux/x86_64/gettimeofday.c [!SHARED]: Use real
+	syscall.
+	* sysdeps/unix/sysv/linux/x86_64/time.c: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S [!SHARED]: Use real
+	syscall if possible.
+
 2011-09-05  Ulrich Drepper  <drepper@gmail.com>
 
 	* elf/pldd.c (get_process_info): Don't read whole ELF header, just
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index d91f581a953..58f833e96a1 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -546,3 +546,8 @@
 #if __LINUX_KERNEL_VERSION >= 0x020627
 # define __ASSUME_SENDMMSG	1
 #endif
+
+/* getcpu is a syscall for x86-64 since 3.1.  */
+#if defined __x86_64__ && __LINUX_KERNEL_VERSION >= 0x030100
+# define __ASSUME_GETCPU_SYSCALL	1
+#endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
index 1a773d64127..56171bcfcae 100644
--- a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
@@ -37,11 +37,12 @@ gettimeofday_ifunc (void)
 __asm (".type __gettimeofday, %gnu_indirect_function");
 #else
 # include <sys/time.h>
+# include <sysdep.h>
 
 int
 __gettimeofday (struct timeval *tv, struct timezone *tz)
 {
-  return ((int (*) (struct timeval *, struct timezone *)) VSYSCALL_ADDR_vgettimeofday) (tv, tz);
+  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
 }
 #endif
 
diff --git a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
index 8ec7d3fcd25..246c9550422 100644
--- a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
+++ b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
@@ -20,6 +20,7 @@
 #include <tls.h>
 #define _ERRNO_H	1
 #include <bits/errno.h>
+#include <kernel-features.h>
 
 /* For the calculation see asm/vsyscall.h.  */
 #define VSYSCALL_ADDR_vgetcpu	0xffffffffff600800
@@ -38,10 +39,26 @@ ENTRY (sched_getcpu)
 #ifdef SHARED
 	movq	__vdso_getcpu(%rip), %rax
 	PTR_DEMANGLE (%rax)
+	callq	*%rax
 #else
+# ifdef __NR_getcpu
+	movl	$__NR_getcpu, %eax
+	syscall
+#  ifndef __ASSUME_GETCPU_SYSCALL
+	cmpq	$-ENOSYS, %rax
+	jne	1f
+#  endif
+# endif
+# ifndef __ASSUME_GETCPU_SYSCALL
 	movq	$VSYSCALL_ADDR_vgetcpu, %rax
-#endif
 	callq	*%rax
+1:
+# else
+#  ifndef __NR_getcpu
+#   error "cannot happen"
+#  endif
+# endif
+#endif
 
 	cmpq	$-4095, %rax
 	jae	SYSCALL_ERROR_LABEL
diff --git a/sysdeps/unix/sysv/linux/x86_64/time.c b/sysdeps/unix/sysv/linux/x86_64/time.c
index 698d56156c8..c1c1a7526f2 100644
--- a/sysdeps/unix/sysv/linux/x86_64/time.c
+++ b/sysdeps/unix/sysv/linux/x86_64/time.c
@@ -36,11 +36,13 @@ time_ifunc (void)
 __asm (".type time, %gnu_indirect_function");
 #else
 # include <time.h>
+# include <sysdep.h>
 
 time_t
 time (time_t *t)
 {
-  return ((time_t (*) (time_t *)) VSYSCALL_ADDR_vtime) (t);
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL (time, err, 1, t);
 }
 #endif