From 4e66aee3711050ae863076542cf94a6e6367c665 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 21 Aug 2015 14:46:05 -0700
Subject: [PATCH 3/6] Avoid reading errno in syscall implementations
Reading errno is expensive for x86 PIC. With INTERNAL_SYSCALL,
INTERNAL_SYSCALL_ERROR_P, INTERNAL_SYSCALL_ERRNO and
INLINE_SYSCALL_ERROR_RETURN_VALUE, we can avoid reading errno.
* sysdeps/unix/sysv/linux/eventfd.c (eventfd): Use
INTERNAL_SYSCALL, INTERNAL_SYSCALL_ERROR_P and
INTERNAL_SYSCALL_ERRNO to avoid reading errno.
* sysdeps/unix/sysv/linux/fstatfs64.c (__fstatfs64): Likewise.
* sysdeps/unix/sysv/linux/getrlimit64.c (__getrlimit64):
Likewise.
* sysdeps/unix/sysv/linux/setrlimit64.c (setrlimit64):
Likewise.
* sysdeps/unix/sysv/linux/signalfd.c (signalfd): Likewise.
* sysdeps/unix/sysv/linux/statfs64.c (__statfs64): Likewise.
---
sysdeps/unix/sysv/linux/eventfd.c | 10 +++++++---
sysdeps/unix/sysv/linux/fstatfs64.c | 12 ++++++++----
sysdeps/unix/sysv/linux/getrlimit64.c | 7 +++++--
sysdeps/unix/sysv/linux/lxstat64.c | 7 +++++--
sysdeps/unix/sysv/linux/setrlimit64.c | 7 +++++--
sysdeps/unix/sysv/linux/signalfd.c | 11 ++++++++---
sysdeps/unix/sysv/linux/statfs64.c | 13 +++++++++----
7 files changed, 47 insertions(+), 20 deletions(-)
@@ -25,11 +25,15 @@ int
eventfd (unsigned int count, int flags)
{
#ifdef __NR_eventfd2
- int res = INLINE_SYSCALL (eventfd2, 2, count, flags);
# ifndef __ASSUME_EVENTFD2
- if (res != -1 || errno != ENOSYS)
-# endif
+ INTERNAL_SYSCALL_DECL (err);
+ int res = INTERNAL_SYSCALL (eventfd2, err, 2, count, flags);
+ if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))
+ || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS)
return res;
+# else
+ return INLINE_SYSCALL (eventfd2, 2, count, flags);
+# endif
#endif
#ifndef __ASSUME_EVENTFD2
@@ -35,12 +35,16 @@ __fstatfs64 (int fd, struct statfs64 *buf)
if (! __no_statfs64)
# endif
{
- int result = INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf);
-
# if __ASSUME_STATFS64 == 0
- if (result == 0 || errno != ENOSYS)
-# endif
+ INTERNAL_SYSCALL_DECL (err);
+ int result = INTERNAL_SYSCALL (fstatfs64, err, 3, fd,
+ sizeof (*buf), buf);
+ if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err))
+ || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
return result;
+# else
+ return INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf);
+# endif
# if __ASSUME_STATFS64 == 0
__no_statfs64 = 1;
@@ -30,8 +30,11 @@ __getrlimit64 (enum __rlimit_resource resource, struct rlimit64 *rlimits)
return INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits);
#else
# ifdef __NR_prlimit64
- int res = INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits);
- if (res == 0 || errno != ENOSYS)
+ INTERNAL_SYSCALL_DECL (err);
+ int res = INTERNAL_SYSCALL (prlimit64, err, 4, 0, resource, NULL,
+ rlimits);
+ if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))
+ || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS)
return res;
# endif
struct rlimit rlimits32;
@@ -30,8 +30,11 @@
int
___lxstat64 (int vers, const char *name, struct stat64 *buf)
{
- int result;
- result = INLINE_SYSCALL (lstat64, 2, name, buf);
+ INTERNAL_SYSCALL_DECL (err);
+ int result = INTERNAL_SYSCALL (lstat64, err, 2, name, buf);
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
+ return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result,
+ err));
#if defined _HAVE_STAT64___ST_INO && __ASSUME_ST_INO_64_BIT == 0
if (__builtin_expect (!result, 1) && buf->__st_ino != (__ino_t) buf->st_ino)
buf->st_ino = buf->__st_ino;
@@ -33,8 +33,11 @@ setrlimit64 (resource, rlimits)
return INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL);
#else
# ifdef __NR_prlimit64
- int res = INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL);
- if (res == 0 || errno != ENOSYS)
+ INTERNAL_SYSCALL_DECL (err);
+ int res = INTERNAL_SYSCALL (prlimit64, err, 4, 0, resource, rlimits,
+ NULL);
+ if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))
+ || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS)
return res;
# endif
struct rlimit rlimits32;
@@ -26,11 +26,16 @@ int
signalfd (int fd, const sigset_t *mask, int flags)
{
#ifdef __NR_signalfd4
- int res = INLINE_SYSCALL (signalfd4, 4, fd, mask, _NSIG / 8, flags);
# ifndef __ASSUME_SIGNALFD4
- if (res != -1 || errno != ENOSYS)
-# endif
+ INTERNAL_SYSCALL_DECL (err);
+ int res = INTERNAL_SYSCALL (signalfd4, err, 4, fd, mask, _NSIG / 8,
+ flags);
+ if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))
+ || INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS)
return res;
+# else
+ return INLINE_SYSCALL (signalfd4, 4, fd, mask, _NSIG / 8, flags);
+# endif
#endif
#ifndef __ASSUME_SIGNALFD4
@@ -37,12 +37,17 @@ __statfs64 (const char *file, struct statfs64 *buf)
if (! __no_statfs64)
# endif
{
- int result = INLINE_SYSCALL (statfs64, 3, file, sizeof (*buf), buf);
-
# if __ASSUME_STATFS64 == 0
- if (result == 0 || errno != ENOSYS)
-# endif
+ INTERNAL_SYSCALL_DECL (err);
+ int result = INTERNAL_SYSCALL (statfs64, err, 3, file,
+ sizeof (*buf), buf);
+
+ if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err))
+ || INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
return result;
+# else
+ return INLINE_SYSCALL (statfs64, 3, file, sizeof (*buf), buf);
+# endif
# if __ASSUME_STATFS64 == 0
__no_statfs64 = 1;
--
2.4.3