Date: Thu, 02 Dec 1999 12:28:39 +0100 From: Marcel Moolenaar <marcel@scc.nl> To: Ville-Pertti Keinonen <will@iki.fi> Cc: current@freebsd.org, dillon@apollo.backplane.com, bde@zeta.org.au Subject: Re: kernel: -mpreferred-stack-boundary=2 ?? Message-ID: <384657E7.B3E461D5@scc.nl> References: <19991202094037.4079.qmail@ns.demophon.com>
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Ville-Pertti Keinonen wrote:
> +++ crt1.c 1999/12/02 09:02:05
> @@ -92,7 +92,17 @@
> monstartup(&eprol, &etext);
> #endif
> _init();
> - exit( main(argc, argv, env) );
> + asm volatile("andl $~15,%%esp;"
> + "addl $4,%%esp;"
> + "pushl %2;"
> + "pushl %1;"
> + "pushl %0;"
> + "call main;"
> + "movl %%eax,(%%esp);"
> + "call exit"
> + : : "rm" (argc), "rm" (argv), "rm" (env));
AFAICT, it's enough to just align the stack before doing anything else.
In this case it means aligning the stack somewhere before
(exit(main(...)). gcc maintains proper alignment on an aligned stack.
Maybe alignment can even be done in the kernel...
--
Marcel Moolenaar mailto:marcel@scc.nl
SCC Internetworking & Databases http://www.scc.nl/
The FreeBSD project mailto:marcel@FreeBSD.org
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