diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/kernel-features.h | 59 |
2 files changed, 64 insertions, 0 deletions
@@ -1,3 +1,8 @@ +2019-09-04 Lukasz Majewski <lukma@denx.de> + + * sysdeps/unix/sysv/linux/kernel-features.h + (__ASSUME_TIME64_SYSCALLS): New macro. + 2019-09-04 Zack Weinberg <zackw@panix.com> [BZ #24959] diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h index 1518bb5228..179df79433 100644 --- a/sysdeps/unix/sysv/linux/kernel-features.h +++ b/sysdeps/unix/sysv/linux/kernel-features.h @@ -20,6 +20,11 @@ /* This file must not contain any C code. At least it must be protected to allow using the file also in assembler files. */ +#ifndef _LINUX_KERNEL_FEATURES_H +#define _LINUX_KERNEL_FEATURES_H 1 + +#include <bits/wordsize.h> + #ifndef __LINUX_KERNEL_VERSION /* We assume the worst; all kernels should be supported. */ # define __LINUX_KERNEL_VERSION 0 @@ -139,3 +144,57 @@ */ #define __ASSUME_CLONE_DEFAULT 1 + +/* Support for 64-bit time_t in the system call interface. When this + flag is set, the kernel provides a version of each of these system + calls that accepts 64-bit time_t: + + clock_adjtime(64) + clock_gettime(64) + clock_settime(64) + clock_getres(_time64) + clock_nanosleep(_time64) + futex(_time64) + mq_timedreceive(_time64) + mq_timedsend(_time64) + ppoll(_time64) + pselect6(_time64) + rt_sigtimedwait(_time64) + sched_rr_get_interval(_time64) + timer_gettime(64) + timer_settime(64) + timerfd_gettime(64) + timerfd_settime(64) + utimensat(_time64) + + On architectures where time_t has historically been 64 bits, + only the 64-bit version of each system call exists, and there + are no suffixes on the __NR_ constants. + + On architectures where time_t has historically been 32 bits, + both 32-bit and 64-bit versions of each system call may exist, + depending on the kernel version. When the 64-bit version exists, + there is a '64' or '_time64' suffix on the name of its __NR_ + constant, as shown above. + + This flag is always set for Linux 5.1 and later. Prior to that + version, it is set only for some CPU architectures and ABIs: + + - __WORDSIZE == 64 - all supported architectures where pointers + are 64 bits also have always had 64-bit time_t. + + - __WORDSIZE == 32 && __SYSCALL_WORDSIZE == 64 - this describes + only one supported configuration, x86's 'x32' subarchitecture, + where pointers are 32 bits but time_t has always been 64 bits. + + __ASSUME_TIME64_SYSCALLS being set does not mean __TIMESIZE is 64, + and __TIMESIZE equal to 64 does not mean __ASSUME_TIME64_SYSCALLS + is set. All four cases are possible. */ + +#if __LINUX_KERNEL_VERSION >= 0x050100 \ + || __WORDSIZE == 64 \ + || (defined __SYSCALL_WORDSIZE && __SYSCALL_WORDSIZE == 64) +# define __ASSUME_TIME64_SYSCALLS 1 +#endif + +#endif /* kernel-features.h */ |