| /* Copyright (C) 2011-2016 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011. |
| |
| 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> |
| |
| /* Get address of "sym" in "reg" assuming r51 holds ".Llink". */ |
| .macro pic_addr reg, sym |
| #ifdef __tilegx__ |
| moveli \reg, hw1_last(\sym - .Llink) |
| shl16insli \reg, \reg, hw0(\sym - .Llink) |
| ADD_PTR \reg, r51, \reg |
| #else |
| ADDLI_PTR \reg, r51, lo16(\sym - .Llink) |
| auli \reg, \reg, ha16(\sym - .Llink) |
| #endif |
| .endm |
| |
| .text |
| ENTRY (_start) |
| /* Linux starts us with sp pointing at the conventional Elf layout, |
| but we need to allow two 'caller' words for our ABI convention. */ |
| { |
| move r52, sp |
| andi sp, sp, -8 |
| } |
| cfi_def_cfa_register (r52) |
| { |
| /* Point sp at base of ABI area; point r4 to the caller-sp word. */ |
| ADDI_PTR sp, sp, -(2 * REGSIZE) |
| ADDI_PTR r4, sp, -REGSIZE |
| } |
| { |
| /* Save zero for caller sp in our 'caller' save area, and make |
| sure lr has a zero value, to limit backtraces. */ |
| move lr, zero |
| ST r4, zero |
| } |
| { |
| move r0, r52 |
| jal _dl_start |
| } |
| /* Save returned start of user program address for later. */ |
| move r50, r0 |
| |
| /* See if we were invoked explicitly with the dynamic loader, |
| in which case we have to adjust the argument vector. */ |
| lnk r51; .Llink: |
| pic_addr r4, _dl_skip_args |
| LD4U r4, r4 |
| BEQZT r4, .Lno_skip |
| |
| /* Load the argc word at the initial sp and adjust it. |
| We basically jump "sp" up over the first few argv entries |
| and write "argc" a little higher up in memory, to be the |
| base of the new kernel-initialized stack area. */ |
| LD_PTR r0, r52 |
| { |
| sub r0, r0, r4 |
| SHL_PTR_ADD r52, r4, r52 |
| } |
| { |
| ST_PTR r52, r0 |
| SHL_PTR_ADD sp, r4, sp |
| } |
| andi sp, sp, -8 |
| |
| .Lno_skip: |
| /* Call_dl_init (_dl_loaded, argc, argv, envp). See elf/start.s |
| for the layout of memory here; r52 is pointing to "+0". */ |
| pic_addr r0, _rtld_local |
| { |
| LD_PTR r1, r52 /* load argc in r1 */ |
| ADDLI_PTR r2, r52, __SIZEOF_POINTER__ /* point r2 at argv */ |
| } |
| { |
| LD_PTR r0, r0 /* yields _rtld_global._ns_loaded */ |
| addi r3, r1, 1 |
| move lr, zero |
| } |
| { |
| SHL_PTR_ADD r3, r3, r2 /* point r3 at envp */ |
| jal _dl_init |
| } |
| |
| /* Call user program whose address we saved in r50. |
| We invoke it just like a static binary, but with _dl_fini |
| in r0 so we can distinguish. */ |
| |
| pic_addr r0, _dl_fini |
| move lr, zero |
| { |
| move sp, r52 |
| jr r50 |
| } |
| |
| /* Tell backtracer to give up (_start has no caller). */ |
| info 2 /* INFO_OP_CANNOT_BACKTRACE */ |
| |
| END (_start) |