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| author | Adhemerval Zanella <adhemerval.zanella@linaro.com> | 2015-10-21 10:04:07 -0200 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2016-04-11 10:07:53 -0300 |
| commit | eeddfa91cbb1a619af135c7a9ac14251ec094b7a (patch) | |
| tree | 29e923a48e615c43a4fcaf45bdde3a50a0a5c51a /sysdeps/unix/sysv/linux/sysdep.h | |
| parent | 482b2f87a88d30fd5bc0277e6a3f75efeb1aff7f (diff) | |
| download | glibc-eeddfa91cbb1a619af135c7a9ac14251ec094b7a.zip glibc-eeddfa91cbb1a619af135c7a9ac14251ec094b7a.tar.gz glibc-eeddfa91cbb1a619af135c7a9ac14251ec094b7a.tar.bz2 | |
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.
Diffstat (limited to 'sysdeps/unix/sysv/linux/sysdep.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/sysdep.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/sysdep.h b/sysdeps/unix/sysv/linux/sysdep.h index c98fc3a..4ac4c00 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 <http://www.gnu.org/licenses/>. */ +#include <bits/wordsize.h> + /* 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 |