glibc/sysdeps/powerpc/powerpc64/crtn.S

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/* Special .init and .fini section support for PowerPC64.
Copyright (C) 2012-2017 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.
In addition to the permissions in the GNU Lesser General Public
License, the Free Software Foundation gives you unlimited
permission to link the compiled version of this file with other
programs, and to distribute those programs without any restriction
coming from the use of this file. (The GNU Lesser General Public
License restrictions do apply in other respects; for example, they
cover modification of the file, and distribution when not linked
into another program.)
Note that people who make modified versions of this file are not
obligated to grant this special exception for their modified
versions; it is their choice whether to do so. The GNU Lesser
General Public License gives permission to release a modified
version without this exception; this exception also makes it
possible to release a modified version which carries forward this
exception.
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/>. */
/* crtn.S puts function epilogues in the .init and .fini sections
corresponding to the prologues in crti.S. */
#include <sysdep.h>
.section .init,"ax",@progbits
PowerPC64 ELFv2 ABI 4/6: Stack frame layout changes This updates glibc for the changes in the ELFv2 relating to the stack frame layout. These are described in more detail here: http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01149.html http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01146.html Specifically, the "compiler and linker doublewords" were removed, which has the effect that the save slot for the TOC register is now at offset 24 rather than 40 to the stack pointer. In addition, a function may now no longer necessarily assume that its caller has set up a 64-byte register save area its use. To address the first change, the patch goes through all assembler files and replaces immediate offsets in instructions accessing the ABI-defined stack slots by symbolic offsets. Those already were defined in ucontext_i.sym and used in some of the context routines, but that doesn't really seem like the right place for those defines. The patch instead defines those symbolic offsets in sysdeps.h, in two variants for the old and new ABI, and uses them systematically in all assembler files, not just the context routines. The second change only affected a few assembler files that used the save area to temporarily store some registers. In those cases where this happens within a leaf function, this patch changes the code to store those registers to the "red zone" below the stack pointer. Otherwise, the functions already allocate a stack frame, and the patch changes them to add extra space in these frames as temporary space for the ELFv2 ABI.
2013-12-04 12:55:03 +00:00
addi r1, r1, FRAME_MIN_SIZE_PARM
ld r0, FRAME_LR_SAVE(r1)
mtlr r0
blr
.section .fini,"ax",@progbits
PowerPC64 ELFv2 ABI 4/6: Stack frame layout changes This updates glibc for the changes in the ELFv2 relating to the stack frame layout. These are described in more detail here: http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01149.html http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01146.html Specifically, the "compiler and linker doublewords" were removed, which has the effect that the save slot for the TOC register is now at offset 24 rather than 40 to the stack pointer. In addition, a function may now no longer necessarily assume that its caller has set up a 64-byte register save area its use. To address the first change, the patch goes through all assembler files and replaces immediate offsets in instructions accessing the ABI-defined stack slots by symbolic offsets. Those already were defined in ucontext_i.sym and used in some of the context routines, but that doesn't really seem like the right place for those defines. The patch instead defines those symbolic offsets in sysdeps.h, in two variants for the old and new ABI, and uses them systematically in all assembler files, not just the context routines. The second change only affected a few assembler files that used the save area to temporarily store some registers. In those cases where this happens within a leaf function, this patch changes the code to store those registers to the "red zone" below the stack pointer. Otherwise, the functions already allocate a stack frame, and the patch changes them to add extra space in these frames as temporary space for the ELFv2 ABI.
2013-12-04 12:55:03 +00:00
addi r1, r1, FRAME_MIN_SIZE_PARM
ld r0, FRAME_LR_SAVE(r1)
mtlr r0
blr