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c52d0d30 DD |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * Copyright (C) 2009, 2010 Cavium Networks, Inc. | |
7 | */ | |
8 | ||
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/err.h> | |
12 | #include <linux/sched.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/binfmts.h> | |
16 | #include <linux/elf.h> | |
17 | #include <linux/vmalloc.h> | |
18 | #include <linux/unistd.h> | |
ccd39880 | 19 | #include <linux/random.h> |
c52d0d30 DD |
20 | |
21 | #include <asm/vdso.h> | |
22 | #include <asm/uasm.h> | |
ccd39880 | 23 | #include <asm/processor.h> |
c52d0d30 DD |
24 | |
25 | /* | |
26 | * Including <asm/unistd.h> would give use the 64-bit syscall numbers ... | |
27 | */ | |
28 | #define __NR_O32_sigreturn 4119 | |
29 | #define __NR_O32_rt_sigreturn 4193 | |
30 | #define __NR_N32_rt_sigreturn 6211 | |
31 | ||
32 | static struct page *vdso_page; | |
33 | ||
34 | static void __init install_trampoline(u32 *tramp, unsigned int sigreturn) | |
35 | { | |
36 | uasm_i_addiu(&tramp, 2, 0, sigreturn); /* li v0, sigreturn */ | |
37 | uasm_i_syscall(&tramp, 0); | |
38 | } | |
39 | ||
40 | static int __init init_vdso(void) | |
41 | { | |
42 | struct mips_vdso *vdso; | |
43 | ||
44 | vdso_page = alloc_page(GFP_KERNEL); | |
45 | if (!vdso_page) | |
46 | panic("Cannot allocate vdso"); | |
47 | ||
48 | vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL); | |
49 | if (!vdso) | |
50 | panic("Cannot map vdso"); | |
51 | clear_page(vdso); | |
52 | ||
53 | install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn); | |
54 | #ifdef CONFIG_32BIT | |
55 | install_trampoline(vdso->signal_trampoline, __NR_sigreturn); | |
56 | #else | |
57 | install_trampoline(vdso->n32_rt_signal_trampoline, | |
58 | __NR_N32_rt_sigreturn); | |
59 | install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn); | |
60 | install_trampoline(vdso->o32_rt_signal_trampoline, | |
61 | __NR_O32_rt_sigreturn); | |
62 | #endif | |
63 | ||
64 | vunmap(vdso); | |
65 | ||
c52d0d30 DD |
66 | return 0; |
67 | } | |
1ed84537 | 68 | subsys_initcall(init_vdso); |
c52d0d30 DD |
69 | |
70 | static unsigned long vdso_addr(unsigned long start) | |
71 | { | |
ccd39880 PK |
72 | unsigned long offset = 0UL; |
73 | ||
74 | if (current->flags & PF_RANDOMIZE) { | |
75 | offset = get_random_int(); | |
76 | offset <<= PAGE_SHIFT; | |
77 | if (TASK_IS_32BIT_ADDR) | |
78 | offset &= 0xfffffful; | |
79 | else | |
80 | offset &= 0xffffffful; | |
81 | } | |
82 | ||
83 | return STACK_TOP + offset; | |
c52d0d30 DD |
84 | } |
85 | ||
86 | int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) | |
87 | { | |
88 | int ret; | |
89 | unsigned long addr; | |
90 | struct mm_struct *mm = current->mm; | |
91 | ||
92 | down_write(&mm->mmap_sem); | |
93 | ||
94 | addr = vdso_addr(mm->start_stack); | |
95 | ||
96 | addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0); | |
97 | if (IS_ERR_VALUE(addr)) { | |
98 | ret = addr; | |
99 | goto up_fail; | |
100 | } | |
101 | ||
102 | ret = install_special_mapping(mm, addr, PAGE_SIZE, | |
103 | VM_READ|VM_EXEC| | |
909af768 | 104 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, |
c52d0d30 DD |
105 | &vdso_page); |
106 | ||
107 | if (ret) | |
108 | goto up_fail; | |
109 | ||
110 | mm->context.vdso = (void *)addr; | |
111 | ||
112 | up_fail: | |
113 | up_write(&mm->mmap_sem); | |
114 | return ret; | |
115 | } | |
116 | ||
117 | const char *arch_vma_name(struct vm_area_struct *vma) | |
118 | { | |
119 | if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) | |
120 | return "[vdso]"; | |
121 | return NULL; | |
122 | } |