Mercurial > sdl-ios-xcode
view src/timer/mint/SDL_vbltimer.S @ 1176:dd2a8deeb26d
Date: Mon, 17 Oct 2005 20:09:03 -0400
From: Mark Schreiber <mark7@alumni.cmu.edu>
To: ryan@clutteredmind.org
Subject: [PATCH]SDL mprotect() crash fix
(I'm going to throw this patch your way at the suggestion of #SDL --
for some reason, I had some difficulty sending it to the main list
last time, and I go bonkers subscribing to send each email or
patch...)
Currently, when I run SDL applications as non-root using
SDL_VIDEODRIVER=dga, the fbdev fallback mprotect()s read/write the
proper size of mmapped /dev/fb0 (7.5MB), but on framebuffer release
mprotect()s read-only the range by the entire size of my video memory
(128MB), which causes a segfault:
#0 0x002a9a27 in ?? () from /lib/libc.so.6
#1 0x04a63eb6 in SDL_XDGAUnmapFramebuffer (screen=3D0) at XF86DGA2.c:978
#2 0x04a63efc in SDL_XDGACloseFramebuffer (dpy=3D0x9d3f008, screen=3D0)
at XF86DGA2.c:268
#3 0x04a68b57 in DGA_Available () at SDL_dgavideo.c:98
#4 0x04a53677 in SDL_VideoInit (driver_name=3D0xbfb0bfc7 "dga", flags=3D0)
at SDL_video.c:180
#5 0x04a2613f in SDL_InitSubSystem (flags=3D32) at SDL.c:74
#6 0x04a2617c in SDL_Init (flags=3D32) at SDL.c:166
#7 0x08049722 in main (argc=3D1, argv=3D0x0) at testwin.c:32
This is SDL 1.2.8 on Fedora Core 4, radeon driver for a Radeon 9250,
xorg-x11-6.8.2-37.
I've attached a one-line patch against SDL CVS that updates the size
of the framebuffer at framebuffer map time so that the mprotect() on
unmap will be the same size. I'm not sure if this is the best
approach (i.e. one might want to retain the original value), but it
does make my SDL applications work without segfaulting.
-- Best of luck, Mark Schreiber
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Sat, 19 Nov 2005 18:57:00 +0000 |
| parents | f6ffac90895c |
| children | c9b51268668f |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Sam Lantinga slouken@libsdl.org */ #ifdef SAVE_RCSID static char rcsid = "@(#) $Id$"; #endif /* * VBL queue routine * * Patrice Mandin */ #define _vbl_queue 0x456 .text .globl _SDL_AtariVblInstall .globl _SDL_AtariVblUninstall /*--- Vector installer ---*/ _SDL_AtariVblInstall: movel sp@(4),my_vector lea _my_vbl,a0 clrw vbl_mutex /* Stop interrupts */ movew #0x2700,sr /* Read vbl_queue pointer */ movel _vbl_queue.w,a1 /* Search a free place */ moveq #7,d0 bcl_search_place: movel (a1),d1 beqs place_found addql #4,a1 dbra d0,bcl_search_place /* Not found */ moveq #1,d0 bras exit_vbl_queue /* Then install ourselves */ place_found: movel a0,(a1) moveq #0,d0 exit_vbl_queue: /* Restart interrupts */ movew #0x2300,sr rts /*--- Vector uninstaller ---*/ _SDL_AtariVblUninstall: movel sp@(4),d0 cmpl my_vector,d0 bnes badvector movel #_my_vbl,d0 /* Stop interrupts */ movew #0x2700,sr /* Read vbl_queue pointer */ movel _vbl_queue.w,a1 /* Search where we are */ moveq #7,d1 bcl2_search_place: cmpl (a1),d0 bnes next_place clrl (a1) moveq #0,d1 next_place: addql #4,a1 dbra d1,bcl2_search_place /* Restart interrupts */ movew #0x2300,sr badvector: rts /*--- Our vbl ---*/ _my_vbl: /* Verify if this is not already running */ tstw vbl_mutex bnes vbl_end notw vbl_mutex moveml d0-d7/a0-a6,sp@- movel my_vector,a0 jsr a0@ moveml sp@+,d0-d7/a0-a6 clrw vbl_mutex vbl_end: rts .data .even .comm vbl_mutex,2*1 .even .comm my_vector,4*1