glibc/sysdeps/unix/sysv/linux/i386/libc-do-syscall.S
Joseph Myers a9fe4c5aa8 Support six-argument syscalls from C for 32-bit x86, use generic lowlevellock-futex.h (bug 18138).
This patch follows the approach outlined in
<https://sourceware.org/ml/libc-alpha/2015-03/msg00656.html> to
support six-argument syscalls from INTERNAL_SYSCALL for 32-bit x86,
making them call a function __libc_do_syscall that takes the syscall
number and three syscall arguments in the registers in which the
kernel expects them, along with a pointer to a structure containing
the other three arguments.

In turn, this allows the generic lowlevellock-futex.h to be used on
32-bit x86, so supporting lll_futex_timed_wait_bitset (and so allowing
FUTEX_CLOCK_REALTIME to be used in various cases, so fixing bug 18138
for 32-bit x86 and leaving hppa as the only architecture missing
lll_futex_timed_wait_bitset).  The change to lowlevellock.h's
definition of SYS_futex is because the generic lowlevelloc-futex.h
ends up bringing in bits/syscall.h which defines SYS_futex to
__NR_futex, so resulting in redefinition errors.  The revised
definition in lowlevellock.h is in line with what the x86_64 version
does.

__libc_do_syscall is only needed in libpthread at present (meaning
nothing special needs to be done to make it shared-only in most
libraries containing it, static in libc only, as on ARM).

Tested for 32-bit x86, with the glibc testsuite and with the test in
bug 18138.  The failures seen

FAIL: nptl/tst-cleanupx4
FAIL: rt/tst-cpuclock2

are pre-existing.

	[BZ #18138]
	* sysdeps/unix/sysv/linux/i386/sysdep.h (struct
	libc_do_syscall_args): New structure.
	(INTERNAL_SYSCALL_MAIN_0): New macro.
	(INTERNAL_SYSCALL_MAIN_1): Likewise.
	(INTERNAL_SYSCALL_MAIN_2): Likewise.
	(INTERNAL_SYSCALL_MAIN_3): Likewise.
	(INTERNAL_SYSCALL_MAIN_4): Likewise.
	(INTERNAL_SYSCALL_MAIN_5): Likewise.
	(INTERNAL_SYSCALL_MAIN_6): Likewise.  Call __libc_do_syscall.
	(INTERNAL_SYSCALL): Define to use INTERNAL_SYSCALL_MAIN_##nr.
	Replace conditional definitions by conditional definitions of ....
	(INTERNAL_SYSCALL_MAIN_INLINE): ... this.  New macro.
	* sysdeps/unix/sysv/linux/i386/libc-do-syscall.S: New file.
	* sysdeps/unix/sysv/linux/i386/Makefile [$(subdir) = nptl]
	(libpthread-sysdep_routines): Add libc-do-syscall.
	* sysdeps/unix/sysv/linux/i386/lowlevellock-futex.h: Remove file.
	* sysdeps/unix/sysv/linux/i386/lowlevellock.h (SYS_futex): Define
	to __NR_futex not 240.
2015-03-25 15:17:54 +00:00

51 lines
1.5 KiB
ArmAsm

/* Out-of-line syscall stub for six-argument syscalls from C.
Copyright (C) 2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* %eax, %ecx, %edx and %esi contain the values expected by the kernel.
%edi points to a structure with the values of %ebx, %edi and %ebp. */
.hidden __libc_do_syscall
ENTRY (__libc_do_syscall)
pushl %ebx
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebx, 0)
pushl %edi
cfi_adjust_cfa_offset (4)
cfi_rel_offset (edi, 0)
pushl %ebp
cfi_adjust_cfa_offset (4)
cfi_rel_offset (ebp, 0)
movl 0(%edi), %ebx
movl 8(%edi), %ebp
movl 4(%edi), %edi
ENTER_KERNEL
popl %ebp
cfi_adjust_cfa_offset (-4)
cfi_restore (ebp)
popl %edi
cfi_adjust_cfa_offset (-4)
cfi_restore (edi)
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
ret
END (__libc_do_syscall)