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authorWaldemar Brodkorb <wbx@uclibc-ng.org>2018-02-04 15:34:18 +0000
committerWaldemar Brodkorb <wbx@uclibc-ng.org>2018-03-12 20:11:14 +0100
commit490e84f5e146485a26dea2f41279a4ff13aaca05 (patch)
tree03b9eab7297c5ad571b548b5ed916f17be78bf48 /libc/sysdeps/linux/tile/crt1.S
parent6e627523ee4b3fc00c30dcff74c2adf93e2b6840 (diff)
tile: add basic support for tilegx
This adds basic support for tile architecture. Only static binaries, no ld.so or threading support. Tested with qemu-tilegx only.
Diffstat (limited to 'libc/sysdeps/linux/tile/crt1.S')
-rw-r--r--libc/sysdeps/linux/tile/crt1.S182
1 files changed, 182 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/tile/crt1.S b/libc/sysdeps/linux/tile/crt1.S
new file mode 100644
index 000000000..4a7c1d76d
--- /dev/null
+++ b/libc/sysdeps/linux/tile/crt1.S
@@ -0,0 +1,182 @@
+/* Copyright (C) 2011-2018 Free Software Foundation, Inc.
+
+ 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/>. */
+
+/* This is the canonical entry point, usually the first thing in the text
+ segment. The ELF standard tells us that the stack is set up like this on
+ entry (the left side is the offset from "sp"), in units of
+ __SIZEOF_POINTER__ entries:
+
+ +0 argc
+ +1 argv[0]
+ ...
+ +(argc+1) NULL
+ +(argc+2) envp[0]
+ ...
+ NULL
+ ... ElfInfo
+
+ The ElfInfo is pairs of key/value long words following the envp
+ pointers and terminated by a zero-valued key.
+
+ Although not mandated by the standard, it happens to be the case
+ that we store the actual argv and envp strings immediately after
+ the ElfInfo data on the stack.
+
+ On entry r0 points to the shared library termination function, or 0
+ if there isn't one.
+*/
+
+#include <features.h>
+#include <sysdep.h>
+#include <arch/abi.h>
+
+/* Just create no-ops if we don't support PC-relative PLT relocations. */
+#ifdef NO_PLT_PCREL
+# define hw2_last_plt(x) 0
+# define hw1_plt(x) 0
+# define hw0_plt(x) 0
+#endif
+
+ .text
+ .global _start
+ .type _start,@function
+ .align 8
+_start:
+ /* Linux starts us with sp pointing at the conventional Elf layout,
+ but we need to allow two "caller" words for our ABI convention. */
+ {
+ /* Load argc (stored as a "long", equivalent to a pointer type). */
+ LD_PTR r1, sp
+
+ /* Save incoming 'sp', which points to the Elf argument block. */
+ move r52, sp
+ }
+
+ {
+ /* Allocate stack frame callee space for __libc_start_main. */
+ ADDI_PTR r12, sp, -(2 * REGSIZE)
+ }
+
+ {
+ /* Get our PC. */
+ lnk r13
+
+ /* sp is not necessarily properly aligned on startup because
+ of the way ld.so pops off leading argv elements. So align it. */
+ andi sp, r12, -8
+ }
+.Lmy_pc:
+
+ {
+ /* Pass the address of the shared library termination function. */
+ move r5, r0
+
+ /* Compute location where __libc_start_main's caller is supposed to
+ store its frame pointer. */
+ ADDI_PTR r12, sp, REGSIZE
+
+ /* Zero out callee space for return address. Unnecessary but free.
+ This is just paranoia to help backtracing not go awry. */
+ st sp, zero
+ }
+ {
+ /* Zero out our frame pointer for __libc_start_main. */
+ st r12, zero
+
+ /* Zero out lr to make __libc_start_main the end of backtrace. */
+ move lr, zero
+
+ /* Compute a pointer to argv. envp will be determined
+ later in __libc_start_main. We set up the first argument
+ (the address of main) below. */
+ ADDI_PTR r2, r52, __SIZEOF_POINTER__
+ }
+ {
+ /* Pass the highest stack address to user code. */
+ ADDI_PTR r6, sp, (2 * REGSIZE)
+
+ /* Pass address of main() in r0, and of our own entry
+ points to .fini and .init in r3 and r4. */
+ moveli r0, hw2_last(main - .Lmy_pc)
+ }
+ {
+ shl16insli r0, r0, hw1(main - .Lmy_pc)
+ moveli r3, hw2_last(_init - .Lmy_pc)
+ }
+ {
+ shl16insli r0, r0, hw0(main - .Lmy_pc)
+ shl16insli r3, r3, hw1(_init - .Lmy_pc)
+ }
+ {
+ ADD_PTR r0, r0, r13
+ shl16insli r3, r3, hw0(_init - .Lmy_pc)
+ }
+ {
+ moveli r12, hw2_last_plt(__uClibc_main - .Lmy_pc)
+ ADD_PTR r3, r3, r13
+ }
+ {
+ shl16insli r12, r12, hw1_plt(__uClibc_main - .Lmy_pc)
+ moveli r4, hw2_last(_fini - .Lmy_pc)
+ }
+ {
+ shl16insli r12, r12, hw0_plt(__uClibc_main - .Lmy_pc)
+ shl16insli r4, r4, hw1(_fini - .Lmy_pc)
+ }
+ {
+ ADD_PTR r12, r12, r13
+ shl16insli r4, r4, hw0(_fini - .Lmy_pc)
+ }
+ {
+ ADD_PTR r4, r4, r13
+#ifdef NO_PLT_PCREL
+ j plt(__uClibc_main)
+#else
+ jr r12
+#endif
+ }
+
+ {
+ /* Tell backtracer to give up (_start has no caller). */
+ info INFO_OP_CANNOT_BACKTRACE
+ }
+.size _start, .-_start
+
+/* Define a symbol for the first piece of initialized data. */
+ .data
+ .global __data_start
+ .align 8
+__data_start:
+ .long 0
+ .weak data_start
+ data_start = __data_start