glibc/sysdeps/riscv/start.S

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/* Startup code compliant to the ELF RISC-V ABI.
Copyright (C) 1995-2021 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
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 05:40:42 +00:00
<https://www.gnu.org/licenses/>. */
#define __ASSEMBLY__ 1
#include <entry.h>
#include <sysdep.h>
#include <sys/asm.h>
/* The entry point's job is to call __libc_start_main. Per the ABI,
a0 contains the address of a function to be passed to atexit.
__libc_start_main wants this in a5. */
ENTRY (ENTRY_POINT)
/* Terminate call stack by noting ra is undefined. Use a dummy
.cfi_label to force starting the FDE. */
.cfi_label .Ldummy
cfi_undefined (ra)
call load_gp
mv a5, a0 /* rtld_fini. */
/* main may be in a shared library. */
la a0, main
REG_L a1, 0(sp) /* argc. */
addi a2, sp, SZREG /* argv. */
andi sp, sp, ALMASK /* Align stack. */
li a3, 0 /* Used to be init. */
li a4, 0 /* Used to be fini. */
mv a6, sp /* stack_end. */
call __libc_start_main@plt
ebreak
END (ENTRY_POINT)
/* Dynamic links need the global pointer to be initialized prior to calling
any shared library's initializers, so we use preinit_array to load it.
This doesn't cut it for static links, though, since the global pointer
needs to be initialized before calling __libc_start_main in that case.
So we redundantly initialize it at the beginning of _start. */
load_gp:
.option push
.option norelax
lla gp, __global_pointer$
.option pop
ret
.section .preinit_array,"aw"
.dc.a load_gp
/* Define a symbol for the first piece of initialized data. */
.data
.globl __data_start
__data_start:
.weak data_start
data_start = __data_start