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"
14#include "mem_user.h"
 
15
16typedef Elf32_auxv_t elf_auxv_t;
17
18/* These are initialized very early in boot and never changed */
19char * elf_aux_platform;
20extern long elf_aux_hwcap;
21unsigned long vsyscall_ehdr;
22unsigned long vsyscall_end;
23unsigned long __kernel_vsyscall;
24
25__init void scan_elf_aux( char **envp)
26{
27	long page_size = 0;
28	elf_auxv_t * auxv;
29
30	while ( *envp++ != NULL) ;
31
32	for ( auxv = (elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) {
33		switch ( auxv->a_type ) {
34			case AT_SYSINFO:
35				__kernel_vsyscall = auxv->a_un.a_val;
36				/* See if the page is under TASK_SIZE */
37				if (__kernel_vsyscall < (unsigned long) envp)
38					__kernel_vsyscall = 0;
39				break;
40			case AT_SYSINFO_EHDR:
41				vsyscall_ehdr = auxv->a_un.a_val;
42				/* See if the page is under TASK_SIZE */
43				if (vsyscall_ehdr < (unsigned long) envp)
44					vsyscall_ehdr = 0;
45				break;
46			case AT_HWCAP:
47				elf_aux_hwcap = auxv->a_un.a_val;
48				break;
49			case AT_PLATFORM:
50                                /* elf.h removed the pointer elements from
51                                 * a_un, so we have to use a_val, which is
52                                 * all that's left.
53                                 */
54				elf_aux_platform =
55					(char *) (long) auxv->a_un.a_val;
56				break;
57			case AT_PAGESZ:
58				page_size = auxv->a_un.a_val;
59				break;
60		}
61	}
62	if ( ! __kernel_vsyscall || ! vsyscall_ehdr ||
63	     ! elf_aux_hwcap || ! elf_aux_platform ||
64	     ! page_size || (vsyscall_ehdr % page_size) ) {
65		__kernel_vsyscall = 0;
66		vsyscall_ehdr = 0;
67		elf_aux_hwcap = 0;
68		elf_aux_platform = "i586";
69	}
70	else {
71		vsyscall_end = vsyscall_ehdr + page_size;
72	}
73}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 *  arch/um/kernel/elf_aux.c
 4 *
 5 *  Scan the ELF auxiliary vector provided by the host to extract
 6 *  information about vsyscall-page, etc.
 7 *
 8 *  Copyright (C) 2004 Fujitsu Siemens Computers GmbH
 9 *  Author: Bodo Stroesser (bodo.stroesser@fujitsu-siemens.com)
10 */
11#include <elf.h>
12#include <stddef.h>
13#include <init.h>
14#include <elf_user.h>
15#include <mem_user.h>
16#include "internal.h"
17
18typedef Elf32_auxv_t elf_auxv_t;
19
20/* These are initialized very early in boot and never changed */
21char * elf_aux_platform;
22extern long elf_aux_hwcap;
23unsigned long vsyscall_ehdr;
24unsigned long vsyscall_end;
25unsigned long __kernel_vsyscall;
26
27__init void scan_elf_aux( char **envp)
28{
29	long page_size = 0;
30	elf_auxv_t * auxv;
31
32	while ( *envp++ != NULL) ;
33
34	for ( auxv = (elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) {
35		switch ( auxv->a_type ) {
36			case AT_SYSINFO:
37				__kernel_vsyscall = auxv->a_un.a_val;
38				/* See if the page is under TASK_SIZE */
39				if (__kernel_vsyscall < (unsigned long) envp)
40					__kernel_vsyscall = 0;
41				break;
42			case AT_SYSINFO_EHDR:
43				vsyscall_ehdr = auxv->a_un.a_val;
44				/* See if the page is under TASK_SIZE */
45				if (vsyscall_ehdr < (unsigned long) envp)
46					vsyscall_ehdr = 0;
47				break;
48			case AT_HWCAP:
49				elf_aux_hwcap = auxv->a_un.a_val;
50				break;
51			case AT_PLATFORM:
52                                /* elf.h removed the pointer elements from
53                                 * a_un, so we have to use a_val, which is
54                                 * all that's left.
55                                 */
56				elf_aux_platform =
57					(char *) (long) auxv->a_un.a_val;
58				break;
59			case AT_PAGESZ:
60				page_size = auxv->a_un.a_val;
61				break;
62		}
63	}
64	if ( ! __kernel_vsyscall || ! vsyscall_ehdr ||
65	     ! elf_aux_hwcap || ! elf_aux_platform ||
66	     ! page_size || (vsyscall_ehdr % page_size) ) {
67		__kernel_vsyscall = 0;
68		vsyscall_ehdr = 0;
69		elf_aux_hwcap = 0;
70		elf_aux_platform = "i586";
71	}
72	else {
73		vsyscall_end = vsyscall_ehdr + page_size;
74	}
75}