Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / arch / sh / kernel / vsyscall / vsyscall.c
blob1d6d51a1ce7955bb055cc2169b3e22d7c997d3b2
1 /*
2 * arch/sh/kernel/vsyscall/vsyscall.c
4 * Copyright (C) 2006 Paul Mundt
6 * vDSO randomization
7 * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License. See the file "COPYING" in the main directory of this archive
11 * for more details.
13 #include <linux/mm.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/gfp.h>
17 #include <linux/module.h>
18 #include <linux/elf.h>
19 #include <linux/sched.h>
20 #include <linux/err.h>
23 * Should the kernel map a VDSO page into processes and pass its
24 * address down to glibc upon exec()?
26 unsigned int __read_mostly vdso_enabled = 1;
27 EXPORT_SYMBOL_GPL(vdso_enabled);
29 static int __init vdso_setup(char *s)
31 vdso_enabled = simple_strtoul(s, NULL, 0);
32 return 1;
34 __setup("vdso=", vdso_setup);
37 * These symbols are defined by vsyscall.o to mark the bounds
38 * of the ELF DSO images included therein.
40 extern const char vsyscall_trapa_start, vsyscall_trapa_end;
41 static struct page *syscall_pages[1];
43 int __init vsyscall_init(void)
45 void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
46 syscall_pages[0] = virt_to_page(syscall_page);
49 * XXX: Map this page to a fixmap entry if we get around
50 * to adding the page to ELF core dumps
53 memcpy(syscall_page,
54 &vsyscall_trapa_start,
55 &vsyscall_trapa_end - &vsyscall_trapa_start);
57 return 0;
60 /* Setup a VMA at program startup for the vsyscall page */
61 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
63 struct mm_struct *mm = current->mm;
64 unsigned long addr;
65 int ret;
67 down_write(&mm->mmap_sem);
68 addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
69 if (IS_ERR_VALUE(addr)) {
70 ret = addr;
71 goto up_fail;
74 ret = install_special_mapping(mm, addr, PAGE_SIZE,
75 VM_READ | VM_EXEC |
76 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC |
77 VM_ALWAYSDUMP,
78 syscall_pages);
79 if (unlikely(ret))
80 goto up_fail;
82 current->mm->context.vdso = (void *)addr;
84 up_fail:
85 up_write(&mm->mmap_sem);
86 return ret;
89 const char *arch_vma_name(struct vm_area_struct *vma)
91 if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
92 return "[vdso]";
94 return NULL;
97 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
99 return NULL;
102 int in_gate_area(struct mm_struct *mm, unsigned long address)
104 return 0;
107 int in_gate_area_no_mm(unsigned long address)
109 return 0;