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76 lines
2.0 KiB
76 lines
2.0 KiB
/*
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* arch/um/kernel/elf_aux.c
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*
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* Scan the Elf auxiliary vector provided by the host to extract
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* information about vsyscall-page, etc.
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*
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* Copyright (C) 2004 Fujitsu Siemens Computers GmbH
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* Author: Bodo Stroesser (bodo.stroesser@fujitsu-siemens.com)
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*/
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#include <elf.h>
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#include <stddef.h>
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#include "init.h"
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#include "elf_user.h"
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#include "mem_user.h"
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#include <kern_constants.h>
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/* Use the one from the kernel - the host may miss it, if having old headers. */
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#if UM_ELF_CLASS == UM_ELFCLASS32
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typedef Elf32_auxv_t elf_auxv_t;
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#else
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typedef Elf64_auxv_t elf_auxv_t;
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#endif
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/* These are initialized very early in boot and never changed */
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char * elf_aux_platform;
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long elf_aux_hwcap;
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unsigned long vsyscall_ehdr;
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unsigned long vsyscall_end;
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unsigned long __kernel_vsyscall;
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__init void scan_elf_aux( char **envp)
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{
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long page_size = 0;
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elf_auxv_t * auxv;
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while ( *envp++ != NULL) ;
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for ( auxv = (elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) {
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switch ( auxv->a_type ) {
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case AT_SYSINFO:
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__kernel_vsyscall = auxv->a_un.a_val;
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break;
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case AT_SYSINFO_EHDR:
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vsyscall_ehdr = auxv->a_un.a_val;
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/* See if the page is under TASK_SIZE */
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if (vsyscall_ehdr < (unsigned long) envp)
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vsyscall_ehdr = 0;
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break;
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case AT_HWCAP:
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elf_aux_hwcap = auxv->a_un.a_val;
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break;
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case AT_PLATFORM:
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/* elf.h removed the pointer elements from
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* a_un, so we have to use a_val, which is
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* all that's left.
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*/
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elf_aux_platform =
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(char *) (long) auxv->a_un.a_val;
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break;
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case AT_PAGESZ:
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page_size = auxv->a_un.a_val;
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break;
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}
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}
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if ( ! __kernel_vsyscall || ! vsyscall_ehdr ||
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! elf_aux_hwcap || ! elf_aux_platform ||
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! page_size || (vsyscall_ehdr % page_size) ) {
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__kernel_vsyscall = 0;
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vsyscall_ehdr = 0;
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elf_aux_hwcap = 0;
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elf_aux_platform = "i586";
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}
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else {
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vsyscall_end = vsyscall_ehdr + page_size;
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}
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}
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