diff options
| author | Zack Weinberg <zackw@panix.com> | 2018-03-18 17:12:42 -0400 |
|---|---|---|
| committer | Zack Weinberg <zackw@panix.com> | 2018-03-26 08:27:47 -0400 |
| commit | 65a7c4c9272f1b14a2b87733bf4dbb564c3dd1d2 (patch) | |
| tree | 4071e1a9510db7601199bd81d045374a94ab044c /io/posix_fallocate64.c | |
| parent | 3dfd23eb4bdc7707048b115548e2238dacef064e (diff) | |
| download | glibc-65a7c4c9272f1b14a2b87733bf4dbb564c3dd1d2.tar.gz glibc-65a7c4c9272f1b14a2b87733bf4dbb564c3dd1d2.tar.xz glibc-65a7c4c9272f1b14a2b87733bf4dbb564c3dd1d2.zip | |
RFC: Introduce pt-compat-stubs and use it to replace pt-vfork.
I am looking into the possibility of eliminating all of the duplicate function definitions from libpthread, replacing them with properly-tagged weak compatibility symbols that just call the definition in libc. Because one of the duplicated functions is vfork, the calls to libc absolutely must reuse the stack frame (a "sibcall" in GCC internals jargon), and on several important targets, GCC does not implement sibcalls, or only implements them for intra-module calls. But we only need to implement a single special case, sibcalling a function with exactly the same signature, from immediately after the caller's own entry point; so doing it by hand in assembly language is not a crazy notion. I believe I have managed to turn the trick for all currently-supported targets. This patch just converts the existing vfork stub, so that review can focus on the new sysdep.h SIBCALL macros. * sysdeps/generic/pt-compat-stubs.S: New file. * nptl/Makefile (libpthread-routines): Remove pt-vfork, add pt-compat-stubs. (libpthread-shared-only-routines): Add pt-compat-stubs. * posix/vfork.c: Define __libc_vfork as well as __vfork and vfork. * sysdeps/generic/sysdep.h (SIBCALL): New macro to perform sibling calls; the generic definition errors out if used. * sysdeps/aarch64/sysdep.h, sysdeps/arm/sysdep.h * sysdeps/hppa/sysdep.h, sysdeps/ia64/sysdep.h * sysdeps/m68k/sysdep.h, sysdeps/microblaze/sysdep.h * sysdeps/nios2/sysdep.h, sysdeps/powerpc/powerpc32/sysdep.h * sysdeps/powerpc/powerpc64/sysdep.h, sysdeps/s390/s390-32/sysdep.h * sysdeps/s390/s390-64/sysdep.h, sysdeps/tile/sysdep.h * sysdeps/unix/alpha/sysdep.h, sysdeps/unix/mips/mips32/sysdep.h * sysdeps/unix/mips/mips64/n32/sysdep.h * sysdeps/unix/mips/mips64/n64/sysdep.h * sysdeps/unix/sysv/linux/riscv/sysdep.h * sysdeps/x86/sysdep.h Provide appropriate architecture-specific definitions of SIBCALL and, if necessary, SIBCALL_ENTRY. * nptl/pt-vfork.c * sysdeps/unix/sysv/linux/aarch64/pt-vfork.c * sysdeps/unix/sysv/linux/m68k/pt-vfork.c * sysdeps/unix/sysv/linux/tile/pt-vfork.c * sysdeps/unix/sysv/linux/alpha/pt-vfork.S * sysdeps/unix/sysv/linux/hppa/pt-vfork.S * sysdeps/unix/sysv/linux/ia64/pt-vfork.S * sysdeps/unix/sysv/linux/microblaze/pt-vfork.S * sysdeps/unix/sysv/linux/mips/pt-vfork.S * sysdeps/unix/sysv/linux/riscv/pt-vfork.S * sysdeps/unix/sysv/linux/s390/pt-vfork.S * sysdeps/unix/sysv/linux/sh/pt-vfork.S * sysdeps/unix/sysv/linux/sparc/pt-vfork.S Remove file.
Diffstat (limited to 'io/posix_fallocate64.c')
0 files changed, 0 insertions, 0 deletions