2 * arch/um/kernel/elf_aux.c
4 * Scan the Elf auxiliary vector provided by the host to extract
5 * information about vsyscall-page, etc.
7 * Copyright (C) 2004 Fujitsu Siemens Computers GmbH
8 * Author: Bodo Stroesser (bodo.stroesser@fujitsu-siemens.com)
15 #include <kern_constants.h>
17 /* Use the one from the kernel - the host may miss it, if having old headers. */
18 #if UM_ELF_CLASS == UM_ELFCLASS32
19 typedef Elf32_auxv_t elf_auxv_t;
21 typedef Elf64_auxv_t elf_auxv_t;
24 char * elf_aux_platform;
27 unsigned long vsyscall_ehdr;
28 unsigned long vsyscall_end;
30 unsigned long __kernel_vsyscall;
32 __init void scan_elf_aux( char **envp)
37 while ( *envp++ != NULL) ;
39 for ( auxv = (elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) {
40 switch ( auxv->a_type ) {
42 __kernel_vsyscall = auxv->a_un.a_val;
43 /* See if the page is under TASK_SIZE */
44 if (__kernel_vsyscall < (unsigned long) envp)
45 __kernel_vsyscall = 0;
48 vsyscall_ehdr = auxv->a_un.a_val;
49 /* See if the page is under TASK_SIZE */
50 if (vsyscall_ehdr < (unsigned long) envp)
54 elf_aux_hwcap = auxv->a_un.a_val;
57 /* elf.h removed the pointer elements from
58 * a_un, so we have to use a_val, which is
62 (char *) (long) auxv->a_un.a_val;
65 page_size = auxv->a_un.a_val;
69 if ( ! __kernel_vsyscall || ! vsyscall_ehdr ||
70 ! elf_aux_hwcap || ! elf_aux_platform ||
71 ! page_size || (vsyscall_ehdr % page_size) ) {
72 __kernel_vsyscall = 0;
75 elf_aux_platform = "i586";
78 vsyscall_end = vsyscall_ehdr + page_size;