This is the mail archive of the
mailing list for the GCC project.
Re: [patch] Allow -mcmodel=large for x86-64 target
- From: Jason R Thorpe <thorpej at wasabisystems dot com>
- To: Jan Hubicka <jh at suse dot cz>
- Cc: gcc-patches at gcc dot gnu dot org, fvdl at wasabisystems dot com
- Date: Sat, 29 Dec 2001 13:32:57 -0800
- Subject: Re: [patch] Allow -mcmodel=large for x86-64 target
- Organization: Wasabi Systems, Inc.
- References: <20011229120140.E2892@dr-evil.shagadelic.org> <20011229215910.F7122@atrey.karlin.mff.cuni.cz>
- Reply-to: thorpej at wasabisystems dot com
On Sat, Dec 29, 2001 at 09:59:10PM +0100, Jan Hubicka wrote:
> It does not work - at least not fully.
> Large code model specifies no limitations for the code size so the
> jumps needs not to be relative that are limited to 32bit. THis is tricky
> and expensive to implement.
Ah, I see.
> What exactly do you need? Why medium is not enought?
The kernel VM layout for NetBSD/x86_64 is larger than will fit in either
kernel or medium models. The issue is the amount of VM required for 2
recursive linear PTE mappings (one for the current process, one for the
"alternate" PTE spaced used to operate the page tables of a non-current
The kernel does not link unless large is used ("relocation truncted" errors).
-- Jason R. Thorpe <firstname.lastname@example.org>