Re: [PATCH] arm/linux-crt0.c: New file

[Jeff Johnston <jjohnstn at redhat dot com>]

Shaun Jackman wrote:
> This patch replaces the arm/linux-crt0 assembler source file with a C
> source file. Some inline assembler is used to switch to Thumb mode.
> The purpose of this patch is to allow the compiler to generate the
> correct relocation for environ when compiling PIC code. As a bonus,
> the C source file is also shorter and easier to read. Alright to
> commit?

Yes.

-- Jeff J.

> Cheers,
> Shaun
>
> 2006-06-29  Shaun Jackman  <sjackman@gmail.com>
>
>     * arm/linux-crt0.S: Remove file.
>     * arm/linux-crt0.c: New file. Supports PIC code.
>
> --- /dev/null    2006-06-25 13:04:47.285393520 -0600
> +++ arm/linux-crt0.c    2006-06-29 11:43:50.000000000 -0600
> @@ -0,0 +1,39 @@
> +/** Linux startup code for the ARM processor.
> + * Written by Shaun Jackman <sjackman@gmail.com>.
> + * Copyright 2006 Pathway Connectivity
> + *
> + * Permission to use, copy, modify, and distribute this software
> + * is freely granted, provided that this notice is preserved.
> + */
> +
> +#include <stdlib.h>
> +#include <unistd.h>
> +
> +static int _main(int argc, char *argv[]) __attribute__((noreturn));
> +
> +#if __thumb__
> +asm("\n"
> +    ".code 32\n"
> +    ".global _start\n"
> +    ".type _start, %function\n"
> +    "_start:\n"
> +    "\tadr r0, _start_thumb+1\n"
> +    "\tbx r0\n"
> +    ".size _start, .-_start\n");
> +
> +__attribute__((naked, used))
> +static void _start_thumb(void)
> +#else
> +__attribute__((naked))
> +void _start(void)
> +#endif
> +{
> +    register int *sp asm("sp");
> +    _main(*sp, (char **)(sp + 1));
> +}
> +
> +static int _main(int argc, char *argv[])
> +{
> +    environ = argv + argc + 1;
> +    exit(main(argc, argv, environ));
> +}