From eeddfa91cbb1a619af135c7a9ac14251ec094b7a Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 21 Oct 2015 10:04:07 -0200 Subject: Consolidate off_t/off64_t syscall argument passing This patch add three new macros (SYSCALL_LL, SYSCALL_LL64, and __ASSUME_WORDSIZE64_ILP32) to use along with off_t and off64_t argument syscalls. The rationale for this change is: 1. Remove multiple implementations for the same syscall for different architectures (for instance, pread have 6 different implementations). 2. Also remove the requirement to use syscall wrappers for cancellable entrypoints. The macro usage should be used along __ALIGNMENT_ARG to follow ABI constrains for architecture where it applies. For instance, pread can be rewritten as: return SYSCALL_CANCEL (pread, fd, buf, count, __ALIGNMENT_ARG SYSCALL_LL (offset)); Another macro, SYSCALL_LL64, is provided for off64_t. The macro __ASSUME_WORDSIZE64_ILP32 is used by the ABI to define is uses 64-bit register even if ABI is ILP32 (for instance x32 and mips64-n32). The changes itself are not currently used in any implementation, so no code change is expected. * sysdeps/unix/sysv/linux/generic/sysdep.h (__ALIGNMENT_ARG): Move definition. (__ALIGNMENT_COUNT): Likewise. * sysdeps/unix/sysv/linux/sysdep.h (__ALIGNMENT_ARG): To here. (__ALIGNMENT_COUNT): Likewise. (SYSCALL_LL): New define. (SYSCALL_LL64): Likewise. * sysdeps/unix/sysv/linux/mips/kernel-features.h: [_MIPS_SIM == _ABIO32] (__ASSUME_WORDSIZE64_ILP32): Define. * sysdeps/unix/sysv/linux/x86_64/kernel-features.h: [ILP32] (__ASUME_WORDSIZE64_ILP32): Likewise. --- sysdeps/unix/sysv/linux/sysdep.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'sysdeps/unix/sysv/linux/sysdep.h') diff --git a/sysdeps/unix/sysv/linux/sysdep.h b/sysdeps/unix/sysv/linux/sysdep.h index c98fc3afcb..4ac4c00893 100644 --- a/sysdeps/unix/sysv/linux/sysdep.h +++ b/sysdeps/unix/sysv/linux/sysdep.h @@ -15,6 +15,8 @@ License along with the GNU C Library; if not, see . */ +#include + /* Set error number and return -1. A target may choose to return the internal function, __syscall_error, which sets errno and returns -1. We use -1l, instead of -1, so that it can be casted to (void *). */ @@ -23,3 +25,24 @@ __set_errno (err); \ -1l; \ }) + +/* Provide a dummy argument that can be used to force register + alignment for register pairs if required by the syscall ABI. */ +#ifdef __ASSUME_ALIGNED_REGISTER_PAIRS +#define __ALIGNMENT_ARG 0, +#define __ALIGNMENT_COUNT(a,b) b +#else +#define __ALIGNMENT_ARG +#define __ALIGNMENT_COUNT(a,b) a +#endif + +/* Provide a common macro to pass 64-bit value on syscalls. */ +#if __WORDSIZE == 64 || defined __ASSUME_WORDSIZE64_ILP32 +# define SYSCALL_LL(val) (val) +# define SYSCALL_LL64(val) (val) +#else +#define SYSCALL_LL(val) \ + __LONG_LONG_PAIR ((val) >> 31, (val)) +#define SYSCALL_LL64(val) \ + __LONG_LONG_PAIR ((long) ((val) >> 32), (long) ((val) & 0xffffffff)) +#endif -- cgit 1.4.1