freebsd-dev/lib/libc/amd64/sys/sbrk.S
Jilles Tjoelker 5ac7ffcc38 libc/amd64: Do not export .cerror.
For some reason, libc exports the symbol .cerror (HIDENAME(cerror)), albeit
in the FBSDprivate_1.0 version. It looks like there is no reason for this
since it is not used from other libraries. Given that it cannot be accessed
from C and its strange calling convention, it is rather unlikely that other
things rely on it. Perhaps it is from a time when symbols could not be
hidden.

Most of the amd64 assembler code jumps to .cerror using the GOT. It can jump
to it directly now, as in non-PIC mode.

There are also some minor size optimizations to instructions but they yield
virtually no benefit in the size of libc.so.7 due to padding.

Reviewed by:	kib
2012-09-06 20:59:49 +00:00

86 lines
2.5 KiB
ArmAsm

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(SYSLIBC_SCCS) && !defined(lint)
.asciz "@(#)sbrk.s 5.1 (Berkeley) 4/23/90"
#endif /* SYSLIBC_SCCS and not lint */
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#include "SYS.h"
.globl CNAME(_end)
.globl HIDENAME(minbrk)
.globl HIDENAME(curbrk)
.data
HIDENAME(minbrk): .quad CNAME(_end)
HIDENAME(curbrk): .quad CNAME(_end)
.text
ENTRY(sbrk)
pushq %rdi
movq %rdi,%rcx
#ifdef PIC
movq PIC_GOT(HIDENAME(curbrk)),%rdx
movq (%rdx),%rax
#else
movq HIDENAME(curbrk)(%rip),%rax
#endif
testq %rcx,%rcx
jz back
addq %rax,%rdi
mov $SYS_break,%eax
KERNCALL
jb err
#ifdef PIC
movq PIC_GOT(HIDENAME(curbrk)),%rdx
movq (%rdx),%rax
#else
movq HIDENAME(curbrk)(%rip),%rax
#endif
movq 0(%rsp), %rcx
#ifdef PIC
addq %rcx,(%rdx)
#else
addq %rcx,HIDENAME(curbrk)(%rip)
#endif
back:
addq $8, %rsp
ret
err:
addq $8, %rsp
jmp HIDENAME(cerror)
END(sbrk)
.section .note.GNU-stack,"",%progbits