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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * arch/um/kernel/elf_aux.c | |
3 | * | |
4 | * Scan the Elf auxiliary vector provided by the host to extract | |
5 | * information about vsyscall-page, etc. | |
6 | * | |
7 | * Copyright (C) 2004 Fujitsu Siemens Computers GmbH | |
8 | * Author: Bodo Stroesser (bodo.stroesser@fujitsu-siemens.com) | |
9 | */ | |
10 | #include <elf.h> | |
11 | #include <stddef.h> | |
12 | #include "init.h" | |
13 | #include "elf_user.h" | |
a502a359 | 14 | #include "mem_user.h" |
ecba97d4 | 15 | #include <kern_constants.h> |
1da177e4 | 16 | |
41c79dc3 PBG |
17 | /* Use the one from the kernel - the host may miss it, if having old headers. */ |
18 | #if UM_ELF_CLASS == UM_ELFCLASS32 | |
1da177e4 LT |
19 | typedef Elf32_auxv_t elf_auxv_t; |
20 | #else | |
21 | typedef Elf64_auxv_t elf_auxv_t; | |
22 | #endif | |
23 | ||
24 | char * elf_aux_platform; | |
25 | long elf_aux_hwcap; | |
26 | ||
27 | unsigned long vsyscall_ehdr; | |
28 | unsigned long vsyscall_end; | |
29 | ||
30 | unsigned long __kernel_vsyscall; | |
31 | ||
32 | __init void scan_elf_aux( char **envp) | |
33 | { | |
34 | long page_size = 0; | |
35 | elf_auxv_t * auxv; | |
36 | ||
37 | while ( *envp++ != NULL) ; | |
38 | ||
39 | for ( auxv = (elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) { | |
40 | switch ( auxv->a_type ) { | |
41 | case AT_SYSINFO: | |
42 | __kernel_vsyscall = auxv->a_un.a_val; | |
43 | break; | |
44 | case AT_SYSINFO_EHDR: | |
45 | vsyscall_ehdr = auxv->a_un.a_val; | |
a502a359 JD |
46 | /* See if the page is under TASK_SIZE */ |
47 | if (vsyscall_ehdr < (unsigned long) envp) | |
48 | vsyscall_ehdr = 0; | |
1da177e4 LT |
49 | break; |
50 | case AT_HWCAP: | |
51 | elf_aux_hwcap = auxv->a_un.a_val; | |
52 | break; | |
53 | case AT_PLATFORM: | |
da00d9a5 JD |
54 | /* elf.h removed the pointer elements from |
55 | * a_un, so we have to use a_val, which is | |
56 | * all that's left. | |
57 | */ | |
64b7673f JD |
58 | elf_aux_platform = |
59 | (char *) (long) auxv->a_un.a_val; | |
1da177e4 LT |
60 | break; |
61 | case AT_PAGESZ: | |
62 | page_size = auxv->a_un.a_val; | |
63 | break; | |
64 | } | |
65 | } | |
66 | if ( ! __kernel_vsyscall || ! vsyscall_ehdr || | |
67 | ! elf_aux_hwcap || ! elf_aux_platform || | |
68 | ! page_size || (vsyscall_ehdr % page_size) ) { | |
69 | __kernel_vsyscall = 0; | |
70 | vsyscall_ehdr = 0; | |
71 | elf_aux_hwcap = 0; | |
72 | elf_aux_platform = "i586"; | |
73 | } | |
74 | else { | |
75 | vsyscall_end = vsyscall_ehdr + page_size; | |
76 | } | |
77 | } |