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9031fefd WD |
1 | /* |
2 | * VDSO implementation for AArch64 and vector page setup for AArch32. | |
3 | * | |
4 | * Copyright (C) 2012 ARM Limited | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
17 | * | |
18 | * Author: Will Deacon <will.deacon@arm.com> | |
19 | */ | |
20 | ||
21 | #include <linux/kernel.h> | |
22 | #include <linux/clocksource.h> | |
23 | #include <linux/elf.h> | |
24 | #include <linux/err.h> | |
25 | #include <linux/errno.h> | |
26 | #include <linux/gfp.h> | |
27 | #include <linux/mm.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/signal.h> | |
30 | #include <linux/slab.h> | |
c60b0c28 | 31 | #include <linux/timekeeper_internal.h> |
9031fefd WD |
32 | #include <linux/vmalloc.h> |
33 | ||
34 | #include <asm/cacheflush.h> | |
35 | #include <asm/signal32.h> | |
36 | #include <asm/vdso.h> | |
37 | #include <asm/vdso_datapage.h> | |
38 | ||
39 | extern char vdso_start, vdso_end; | |
40 | static unsigned long vdso_pages; | |
41 | static struct page **vdso_pagelist; | |
42 | ||
43 | /* | |
44 | * The vDSO data page. | |
45 | */ | |
46 | static union { | |
47 | struct vdso_data data; | |
48 | u8 page[PAGE_SIZE]; | |
49 | } vdso_data_store __page_aligned_data; | |
50 | struct vdso_data *vdso_data = &vdso_data_store.data; | |
51 | ||
52 | #ifdef CONFIG_COMPAT | |
53 | /* | |
54 | * Create and map the vectors page for AArch32 tasks. | |
55 | */ | |
56 | static struct page *vectors_page[1]; | |
57 | ||
58 | static int alloc_vectors_page(void) | |
59 | { | |
60 | extern char __kuser_helper_start[], __kuser_helper_end[]; | |
61 | int kuser_sz = __kuser_helper_end - __kuser_helper_start; | |
62 | unsigned long vpage; | |
63 | ||
64 | vpage = get_zeroed_page(GFP_ATOMIC); | |
65 | ||
66 | if (!vpage) | |
67 | return -ENOMEM; | |
68 | ||
69 | /* kuser helpers */ | |
70 | memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, | |
71 | kuser_sz); | |
72 | ||
73 | /* sigreturn code */ | |
74 | memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, | |
75 | aarch32_sigret_code, sizeof(aarch32_sigret_code)); | |
76 | ||
77 | flush_icache_range(vpage, vpage + PAGE_SIZE); | |
78 | vectors_page[0] = virt_to_page(vpage); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | arch_initcall(alloc_vectors_page); | |
83 | ||
84 | int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) | |
85 | { | |
86 | struct mm_struct *mm = current->mm; | |
87 | unsigned long addr = AARCH32_VECTORS_BASE; | |
88 | int ret; | |
89 | ||
90 | down_write(&mm->mmap_sem); | |
91 | current->mm->context.vdso = (void *)addr; | |
92 | ||
93 | /* Map vectors page at the high address. */ | |
94 | ret = install_special_mapping(mm, addr, PAGE_SIZE, | |
95 | VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, | |
96 | vectors_page); | |
97 | ||
98 | up_write(&mm->mmap_sem); | |
99 | ||
100 | return ret; | |
101 | } | |
102 | #endif /* CONFIG_COMPAT */ | |
103 | ||
104 | static int __init vdso_init(void) | |
105 | { | |
106 | struct page *pg; | |
107 | char *vbase; | |
108 | int i, ret = 0; | |
109 | ||
110 | vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; | |
111 | pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n", | |
112 | vdso_pages + 1, vdso_pages, 1L, &vdso_start); | |
113 | ||
114 | /* Allocate the vDSO pagelist, plus a page for the data. */ | |
115 | vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1), | |
116 | GFP_KERNEL); | |
117 | if (vdso_pagelist == NULL) { | |
118 | pr_err("Failed to allocate vDSO pagelist!\n"); | |
119 | return -ENOMEM; | |
120 | } | |
121 | ||
122 | /* Grab the vDSO code pages. */ | |
123 | for (i = 0; i < vdso_pages; i++) { | |
124 | pg = virt_to_page(&vdso_start + i*PAGE_SIZE); | |
125 | ClearPageReserved(pg); | |
126 | get_page(pg); | |
127 | vdso_pagelist[i] = pg; | |
128 | } | |
129 | ||
130 | /* Sanity check the shared object header. */ | |
131 | vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL); | |
132 | if (vbase == NULL) { | |
133 | pr_err("Failed to map vDSO pagelist!\n"); | |
134 | return -ENOMEM; | |
135 | } else if (memcmp(vbase, "\177ELF", 4)) { | |
136 | pr_err("vDSO is not a valid ELF object!\n"); | |
137 | ret = -EINVAL; | |
138 | goto unmap; | |
139 | } | |
140 | ||
141 | /* Grab the vDSO data page. */ | |
142 | pg = virt_to_page(vdso_data); | |
143 | get_page(pg); | |
144 | vdso_pagelist[i] = pg; | |
145 | ||
146 | unmap: | |
147 | vunmap(vbase); | |
148 | return ret; | |
149 | } | |
150 | arch_initcall(vdso_init); | |
151 | ||
152 | int arch_setup_additional_pages(struct linux_binprm *bprm, | |
153 | int uses_interp) | |
154 | { | |
155 | struct mm_struct *mm = current->mm; | |
156 | unsigned long vdso_base, vdso_mapping_len; | |
157 | int ret; | |
158 | ||
159 | /* Be sure to map the data page */ | |
160 | vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT; | |
161 | ||
162 | down_write(&mm->mmap_sem); | |
163 | vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); | |
164 | if (IS_ERR_VALUE(vdso_base)) { | |
165 | ret = vdso_base; | |
166 | goto up_fail; | |
167 | } | |
168 | mm->context.vdso = (void *)vdso_base; | |
169 | ||
170 | ret = install_special_mapping(mm, vdso_base, vdso_mapping_len, | |
171 | VM_READ|VM_EXEC| | |
172 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, | |
173 | vdso_pagelist); | |
174 | if (ret) { | |
175 | mm->context.vdso = NULL; | |
176 | goto up_fail; | |
177 | } | |
178 | ||
179 | up_fail: | |
180 | up_write(&mm->mmap_sem); | |
181 | ||
182 | return ret; | |
183 | } | |
184 | ||
185 | const char *arch_vma_name(struct vm_area_struct *vma) | |
186 | { | |
187 | /* | |
188 | * We can re-use the vdso pointer in mm_context_t for identifying | |
189 | * the vectors page for compat applications. The vDSO will always | |
190 | * sit above TASK_UNMAPPED_BASE and so we don't need to worry about | |
191 | * it conflicting with the vectors base. | |
192 | */ | |
193 | if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) { | |
194 | #ifdef CONFIG_COMPAT | |
195 | if (vma->vm_start == AARCH32_VECTORS_BASE) | |
196 | return "[vectors]"; | |
197 | #endif | |
198 | return "[vdso]"; | |
199 | } | |
200 | ||
201 | return NULL; | |
202 | } | |
203 | ||
204 | /* | |
205 | * We define AT_SYSINFO_EHDR, so we need these function stubs to keep | |
206 | * Linux happy. | |
207 | */ | |
208 | int in_gate_area_no_mm(unsigned long addr) | |
209 | { | |
210 | return 0; | |
211 | } | |
212 | ||
213 | int in_gate_area(struct mm_struct *mm, unsigned long addr) | |
214 | { | |
215 | return 0; | |
216 | } | |
217 | ||
218 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) | |
219 | { | |
220 | return NULL; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Update the vDSO data page to keep in sync with kernel timekeeping. | |
225 | */ | |
c60b0c28 | 226 | void update_vsyscall(struct timekeeper *tk) |
9031fefd WD |
227 | { |
228 | struct timespec xtime_coarse; | |
c60b0c28 | 229 | u32 use_syscall = strcmp(tk->clock->name, "arch_sys_counter"); |
9031fefd WD |
230 | |
231 | ++vdso_data->tb_seq_count; | |
232 | smp_wmb(); | |
233 | ||
234 | xtime_coarse = __current_kernel_time(); | |
235 | vdso_data->use_syscall = use_syscall; | |
236 | vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec; | |
237 | vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec; | |
238 | ||
239 | if (!use_syscall) { | |
c60b0c28 CM |
240 | vdso_data->cs_cycle_last = tk->clock->cycle_last; |
241 | vdso_data->xtime_clock_sec = tk->xtime_sec; | |
45a7905f | 242 | vdso_data->xtime_clock_nsec = tk->xtime_nsec; |
c60b0c28 CM |
243 | vdso_data->cs_mult = tk->mult; |
244 | vdso_data->cs_shift = tk->shift; | |
245 | vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; | |
246 | vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; | |
9031fefd WD |
247 | } |
248 | ||
249 | smp_wmb(); | |
250 | ++vdso_data->tb_seq_count; | |
251 | } | |
252 | ||
253 | void update_vsyscall_tz(void) | |
254 | { | |
9031fefd WD |
255 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
256 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
9031fefd | 257 | } |