From 439fc76c8d321d10018aad3a9a5d9562906c58ad Mon Sep 17 00:00:00 2001 From: Peter Kjellerstedt Date: Wed, 9 Feb 2005 08:42:13 +0000 Subject: Implement _start completely in assembler. Otherwise the compiler will push the frame pointer when DO_DEBUG is enabled (and thus incorrect argc, argv and envp will be passed to the program). --- libc/sysdeps/linux/cris/crt0.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) (limited to 'libc/sysdeps/linux/cris') diff --git a/libc/sysdeps/linux/cris/crt0.c b/libc/sysdeps/linux/cris/crt0.c index 166d30b60..a676ee908 100644 --- a/libc/sysdeps/linux/cris/crt0.c +++ b/libc/sysdeps/linux/cris/crt0.c @@ -8,22 +8,26 @@ static void start1 (int argc, char **argv) __attribute__ ((used, noreturn)); /* * It is important that this be the first function. * This file is the first thing in the text section. + * This is implemented completely in assembler to avoid that the + * compiler pushes stuff on the stack (e.g. the frame pointer when + * debuging). */ -void -_start (void) -{ - /* - * On the stack we have argc. We can calculate argv/envp - * from that and the succeeding stack location, but fix so - * we get the right calling convention (regs in r10/r11). - * - * Please view linux/fs/binfmt_elf.c for a complete - * understanding of this. - */ - __asm__ volatile("pop $r10"); - __asm__ volatile("move.d $sp, $r11"); - __asm__ volatile("jump start1"); -} + +/* + * On the stack we have argc. We can calculate argv/envp + * from that and the succeeding stack location, but fix so + * we get the right calling convention (regs in r10/r11). + * + * Please view linux/fs/binfmt_elf.c for a complete + * understanding of this. + */ +__asm__ ( \ + ".text\n\t" \ + ".global _start\n\t" \ + "_start:\n\t" \ + "pop $r10\n\t" \ + "move.d $sp, $r11\n\t" \ + "jump start1\n\t"); #include -- cgit v1.2.3