ARC: Linux Startup and Dynamic Loading

A big shoutout to Cupertino Miranda <cmiranda@synopsys.com> for his
valuable contribution in initial bringup and debugging on Linux and
later in solving pesky unwinding/cancelation failures in testsuite.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Vineet Gupta 2018-10-23 14:58:39 -07:00
parent e5ccf113cd
commit c86a9483f4
2 changed files with 116 additions and 0 deletions

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/* Variable initialization. ARC version.
Copyright (C) 2020 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
<https://www.gnu.org/licenses/>. */
#include <ldsodefs.h>
#ifdef SHARED
void
_dl_var_init (void *array[])
{
/* It has to match "variables" below. */
enum
{
DL_PAGESIZE = 0
};
GLRO(dl_pagesize) = *((size_t *) array[DL_PAGESIZE]);
}
#else
static void *variables[] =
{
&GLRO(dl_pagesize)
};
static void
_dl_unprotect_relro (struct link_map *l)
{
ElfW(Addr) start = ((l->l_addr + l->l_relro_addr)
& ~(GLRO(dl_pagesize) - 1));
ElfW(Addr) end = ((l->l_addr + l->l_relro_addr + l->l_relro_size)
& ~(GLRO(dl_pagesize) - 1));
if (start != end)
__mprotect ((void *) start, end - start, PROT_READ | PROT_WRITE);
}
void
_dl_static_init (struct link_map *l)
{
struct link_map *rtld_map = l;
struct r_scope_elem **scope;
const ElfW(Sym) *ref = NULL;
lookup_t loadbase;
void (*f) (void *[]);
size_t i;
loadbase = _dl_lookup_symbol_x ("_dl_var_init", l, &ref, l->l_local_scope,
NULL, 0, 1, NULL);
for (scope = l->l_local_scope; *scope != NULL; scope++)
for (i = 0; i < (*scope)->r_nlist; i++)
if ((*scope)->r_list[i] == loadbase)
{
rtld_map = (*scope)->r_list[i];
break;
}
if (ref != NULL)
{
f = (void (*) (void *[])) DL_SYMBOL_ADDRESS (loadbase, ref);
_dl_unprotect_relro (rtld_map);
f (variables);
_dl_protect_relro (rtld_map);
}
}
#endif

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/* Run-time dynamic linker data structures for loaded ELF shared objects. ARC
Copyright (C) 2020 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
<https://www.gnu.org/licenses/>. */
#ifndef _LDSODEFS_H
/* Get the real definitions. */
#include_next <ldsodefs.h>
/* Now define our stuff. */
/* We need special support to initialize DSO loaded for statically linked
binaries. */
extern void _dl_static_init (struct link_map *map);
#undef DL_STATIC_INIT
#define DL_STATIC_INIT(map) _dl_static_init (map)
#endif /* ldsodefs.h */