From 6f6e3ee567cbff328df83dcf9ee0a5459746fce0 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Fri, 21 Aug 2015 14:46:05 -0700 Subject: 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. There are no code changes on x86-64. On i686, libc.so sizes in bytes show: text data bss dec after 1748495 11380 11132 1771007 before 1748403 11380 11132 1770915 * 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 | 11 ++++++++--- sysdeps/unix/sysv/linux/fstatfs64.c | 13 +++++++++---- sysdeps/unix/sysv/linux/getrlimit64.c | 8 ++++++-- sysdeps/unix/sysv/linux/lxstat64.c | 7 +++++-- sysdeps/unix/sysv/linux/setrlimit64.c | 8 ++++++-- sysdeps/unix/sysv/linux/signalfd.c | 12 +++++++++--- sysdeps/unix/sysv/linux/statfs64.c | 14 ++++++++++---- 7 files changed, 53 insertions(+), 20 deletions(-) diff --git a/sysdeps/unix/sysv/linux/eventfd.c b/sysdeps/unix/sysv/linux/eventfd.c index efce282617..3a9178183c 100644 --- a/sysdeps/unix/sysv/linux/eventfd.c +++ b/sysdeps/unix/sysv/linux/eventfd.c @@ -25,11 +25,16 @@ 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))) return res; + else if (INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (res, err)); +# else + return INLINE_SYSCALL (eventfd2, 2, count, flags); +# endif #endif #ifndef __ASSUME_EVENTFD2 diff --git a/sysdeps/unix/sysv/linux/fstatfs64.c b/sysdeps/unix/sysv/linux/fstatfs64.c index af8383010f..819b6238a5 100644 --- a/sysdeps/unix/sysv/linux/fstatfs64.c +++ b/sysdeps/unix/sysv/linux/fstatfs64.c @@ -35,12 +35,17 @@ __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))) return result; + else if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result, err)); +# else + return INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf); +# endif # if __ASSUME_STATFS64 == 0 __no_statfs64 = 1; diff --git a/sysdeps/unix/sysv/linux/getrlimit64.c b/sysdeps/unix/sysv/linux/getrlimit64.c index 100ba623e2..bc36c1466f 100644 --- a/sysdeps/unix/sysv/linux/getrlimit64.c +++ b/sysdeps/unix/sysv/linux/getrlimit64.c @@ -30,9 +30,13 @@ __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))) return res; + else if (INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (res, err)); # endif struct rlimit rlimits32; diff --git a/sysdeps/unix/sysv/linux/lxstat64.c b/sysdeps/unix/sysv/linux/lxstat64.c index 5d0c051aa1..63959cf93b 100644 --- a/sysdeps/unix/sysv/linux/lxstat64.c +++ b/sysdeps/unix/sysv/linux/lxstat64.c @@ -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; diff --git a/sysdeps/unix/sysv/linux/setrlimit64.c b/sysdeps/unix/sysv/linux/setrlimit64.c index 5b1f657c4f..b13014af35 100644 --- a/sysdeps/unix/sysv/linux/setrlimit64.c +++ b/sysdeps/unix/sysv/linux/setrlimit64.c @@ -31,9 +31,13 @@ setrlimit64 (enum __rlimit_resource resource, const struct rlimit64 *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))) return res; + else if (INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (res, err)); # endif struct rlimit rlimits32; diff --git a/sysdeps/unix/sysv/linux/signalfd.c b/sysdeps/unix/sysv/linux/signalfd.c index 8573450bd1..95a9707852 100644 --- a/sysdeps/unix/sysv/linux/signalfd.c +++ b/sysdeps/unix/sysv/linux/signalfd.c @@ -26,11 +26,17 @@ 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))) return res; + else if (INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (res, err)); +# else + return INLINE_SYSCALL (signalfd4, 4, fd, mask, _NSIG / 8, flags); +# endif #endif #ifndef __ASSUME_SIGNALFD4 diff --git a/sysdeps/unix/sysv/linux/statfs64.c b/sysdeps/unix/sysv/linux/statfs64.c index ac5c33fbf0..469eda1376 100644 --- a/sysdeps/unix/sysv/linux/statfs64.c +++ b/sysdeps/unix/sysv/linux/statfs64.c @@ -37,12 +37,18 @@ __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))) return result; + else if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result, err)); +# else + return INLINE_SYSCALL (statfs64, 3, file, sizeof (*buf), buf); +# endif # if __ASSUME_STATFS64 == 0 __no_statfs64 = 1; -- cgit 1.4.1