video/logo: prevent use of logos after they have been freed
[cascardo/linux.git] / drivers / video / logo / logo.c
1
2 /*
3  *  Linux logo to be displayed on boot
4  *
5  *  Copyright (C) 1996 Larry Ewing (lewing@isc.tamu.edu)
6  *  Copyright (C) 1996,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
7  *  Copyright (C) 2001 Greg Banks <gnb@alphalink.com.au>
8  *  Copyright (C) 2001 Jan-Benedict Glaw <jbglaw@lug-owl.de>
9  *  Copyright (C) 2003 Geert Uytterhoeven <geert@linux-m68k.org>
10  */
11
12 #include <linux/linux_logo.h>
13 #include <linux/stddef.h>
14 #include <linux/module.h>
15
16 #ifdef CONFIG_M68K
17 #include <asm/setup.h>
18 #endif
19
20 static bool nologo;
21 module_param(nologo, bool, 0);
22 MODULE_PARM_DESC(nologo, "Disables startup logo");
23
24 /*
25  * Logos are located in the initdata, and will be freed in kernel_init.
26  * Use late_init to mark the logos as freed to prevent any further use.
27  */
28
29 static bool logos_freed;
30
31 static int __init fb_logo_late_init(void)
32 {
33         logos_freed = true;
34         return 0;
35 }
36
37 late_initcall(fb_logo_late_init);
38
39 /* logo's are marked __initdata. Use __init_refok to tell
40  * modpost that it is intended that this function uses data
41  * marked __initdata.
42  */
43 const struct linux_logo * __init_refok fb_find_logo(int depth)
44 {
45         const struct linux_logo *logo = NULL;
46
47         if (nologo || logos_freed)
48                 return NULL;
49
50         if (depth >= 1) {
51 #ifdef CONFIG_LOGO_LINUX_MONO
52                 /* Generic Linux logo */
53                 logo = &logo_linux_mono;
54 #endif
55 #ifdef CONFIG_LOGO_SUPERH_MONO
56                 /* SuperH Linux logo */
57                 logo = &logo_superh_mono;
58 #endif
59         }
60         
61         if (depth >= 4) {
62 #ifdef CONFIG_LOGO_LINUX_VGA16
63                 /* Generic Linux logo */
64                 logo = &logo_linux_vga16;
65 #endif
66 #ifdef CONFIG_LOGO_BLACKFIN_VGA16
67                 /* Blackfin processor logo */
68                 logo = &logo_blackfin_vga16;
69 #endif
70 #ifdef CONFIG_LOGO_SUPERH_VGA16
71                 /* SuperH Linux logo */
72                 logo = &logo_superh_vga16;
73 #endif
74         }
75         
76         if (depth >= 8) {
77 #ifdef CONFIG_LOGO_LINUX_CLUT224
78                 /* Generic Linux logo */
79                 logo = &logo_linux_clut224;
80 #endif
81 #ifdef CONFIG_LOGO_BLACKFIN_CLUT224
82                 /* Blackfin Linux logo */
83                 logo = &logo_blackfin_clut224;
84 #endif
85 #ifdef CONFIG_LOGO_DEC_CLUT224
86                 /* DEC Linux logo on MIPS/MIPS64 or ALPHA */
87                 logo = &logo_dec_clut224;
88 #endif
89 #ifdef CONFIG_LOGO_MAC_CLUT224
90                 /* Macintosh Linux logo on m68k */
91                 if (MACH_IS_MAC)
92                         logo = &logo_mac_clut224;
93 #endif
94 #ifdef CONFIG_LOGO_PARISC_CLUT224
95                 /* PA-RISC Linux logo */
96                 logo = &logo_parisc_clut224;
97 #endif
98 #ifdef CONFIG_LOGO_SGI_CLUT224
99                 /* SGI Linux logo on MIPS/MIPS64 */
100                 logo = &logo_sgi_clut224;
101 #endif
102 #ifdef CONFIG_LOGO_SUN_CLUT224
103                 /* Sun Linux logo */
104                 logo = &logo_sun_clut224;
105 #endif
106 #ifdef CONFIG_LOGO_SUPERH_CLUT224
107                 /* SuperH Linux logo */
108                 logo = &logo_superh_clut224;
109 #endif
110 #ifdef CONFIG_LOGO_M32R_CLUT224
111                 /* M32R Linux logo */
112                 logo = &logo_m32r_clut224;
113 #endif
114         }
115         return logo;
116 }
117 EXPORT_SYMBOL_GPL(fb_find_logo);