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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 | ||
5a9e3e15 | 21 | #include <linux/cache.h> |
9031fefd WD |
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> | |
5a9e3e15 | 27 | #include <linux/kernel.h> |
9031fefd WD |
28 | #include <linux/mm.h> |
29 | #include <linux/sched.h> | |
30 | #include <linux/signal.h> | |
31 | #include <linux/slab.h> | |
c60b0c28 | 32 | #include <linux/timekeeper_internal.h> |
9031fefd WD |
33 | #include <linux/vmalloc.h> |
34 | ||
35 | #include <asm/cacheflush.h> | |
36 | #include <asm/signal32.h> | |
37 | #include <asm/vdso.h> | |
38 | #include <asm/vdso_datapage.h> | |
39 | ||
dbbb08f5 | 40 | extern char vdso_start[], vdso_end[]; |
5a9e3e15 | 41 | static unsigned long vdso_pages __ro_after_init; |
9031fefd WD |
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 | */ | |
5a9e3e15 | 56 | static struct page *vectors_page[1] __ro_after_init; |
9031fefd | 57 | |
1aed28f9 | 58 | static int __init alloc_vectors_page(void) |
9031fefd WD |
59 | { |
60 | extern char __kuser_helper_start[], __kuser_helper_end[]; | |
a1d5ebaf ML |
61 | extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; |
62 | ||
9031fefd | 63 | int kuser_sz = __kuser_helper_end - __kuser_helper_start; |
a1d5ebaf | 64 | int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; |
9031fefd WD |
65 | unsigned long vpage; |
66 | ||
67 | vpage = get_zeroed_page(GFP_ATOMIC); | |
68 | ||
69 | if (!vpage) | |
70 | return -ENOMEM; | |
71 | ||
72 | /* kuser helpers */ | |
73 | memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, | |
74 | kuser_sz); | |
75 | ||
76 | /* sigreturn code */ | |
77 | memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, | |
a1d5ebaf | 78 | __aarch32_sigret_code_start, sigret_sz); |
9031fefd WD |
79 | |
80 | flush_icache_range(vpage, vpage + PAGE_SIZE); | |
81 | vectors_page[0] = virt_to_page(vpage); | |
82 | ||
83 | return 0; | |
84 | } | |
85 | arch_initcall(alloc_vectors_page); | |
86 | ||
87 | int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) | |
88 | { | |
89 | struct mm_struct *mm = current->mm; | |
90 | unsigned long addr = AARCH32_VECTORS_BASE; | |
b6d081bd | 91 | static const struct vm_special_mapping spec = { |
2fea7f6c WD |
92 | .name = "[vectors]", |
93 | .pages = vectors_page, | |
94 | ||
95 | }; | |
96 | void *ret; | |
9031fefd | 97 | |
69048176 MH |
98 | if (down_write_killable(&mm->mmap_sem)) |
99 | return -EINTR; | |
9031fefd WD |
100 | current->mm->context.vdso = (void *)addr; |
101 | ||
102 | /* Map vectors page at the high address. */ | |
2fea7f6c WD |
103 | ret = _install_special_mapping(mm, addr, PAGE_SIZE, |
104 | VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, | |
105 | &spec); | |
9031fefd WD |
106 | |
107 | up_write(&mm->mmap_sem); | |
108 | ||
2fea7f6c | 109 | return PTR_ERR_OR_ZERO(ret); |
9031fefd WD |
110 | } |
111 | #endif /* CONFIG_COMPAT */ | |
112 | ||
73958695 DS |
113 | static int vdso_mremap(const struct vm_special_mapping *sm, |
114 | struct vm_area_struct *new_vma) | |
115 | { | |
116 | unsigned long new_size = new_vma->vm_end - new_vma->vm_start; | |
117 | unsigned long vdso_size = vdso_end - vdso_start; | |
118 | ||
119 | if (vdso_size != new_size) | |
120 | return -EINVAL; | |
121 | ||
122 | current->mm->context.vdso = (void *)new_vma->vm_start; | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
5a9e3e15 JZ |
127 | static struct vm_special_mapping vdso_spec[2] __ro_after_init = { |
128 | { | |
129 | .name = "[vvar]", | |
130 | }, | |
131 | { | |
132 | .name = "[vdso]", | |
73958695 | 133 | .mremap = vdso_mremap, |
5a9e3e15 JZ |
134 | }, |
135 | }; | |
2fea7f6c | 136 | |
9031fefd WD |
137 | static int __init vdso_init(void) |
138 | { | |
16fb1a9b | 139 | int i; |
5a9e3e15 | 140 | struct page **vdso_pagelist; |
2077be67 | 141 | unsigned long pfn; |
16fb1a9b | 142 | |
dbbb08f5 | 143 | if (memcmp(vdso_start, "\177ELF", 4)) { |
16fb1a9b NL |
144 | pr_err("vDSO is not a valid ELF object!\n"); |
145 | return -EINVAL; | |
146 | } | |
9031fefd | 147 | |
dbbb08f5 | 148 | vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; |
9031fefd WD |
149 | |
150 | /* Allocate the vDSO pagelist, plus a page for the data. */ | |
16fb1a9b | 151 | vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *), |
9031fefd | 152 | GFP_KERNEL); |
16fb1a9b | 153 | if (vdso_pagelist == NULL) |
9031fefd | 154 | return -ENOMEM; |
9031fefd | 155 | |
601255ae | 156 | /* Grab the vDSO data page. */ |
2077be67 LA |
157 | vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data)); |
158 | ||
601255ae | 159 | |
9031fefd | 160 | /* Grab the vDSO code pages. */ |
dbbb08f5 | 161 | pfn = sym_to_pfn(vdso_start); |
2077be67 | 162 | |
16fb1a9b | 163 | for (i = 0; i < vdso_pages; i++) |
2077be67 | 164 | vdso_pagelist[i + 1] = pfn_to_page(pfn + i); |
9031fefd | 165 | |
5a9e3e15 JZ |
166 | vdso_spec[0].pages = &vdso_pagelist[0]; |
167 | vdso_spec[1].pages = &vdso_pagelist[1]; | |
2fea7f6c | 168 | |
16fb1a9b | 169 | return 0; |
9031fefd WD |
170 | } |
171 | arch_initcall(vdso_init); | |
172 | ||
173 | int arch_setup_additional_pages(struct linux_binprm *bprm, | |
174 | int uses_interp) | |
175 | { | |
176 | struct mm_struct *mm = current->mm; | |
87154938 | 177 | unsigned long vdso_base, vdso_text_len, vdso_mapping_len; |
2fea7f6c | 178 | void *ret; |
9031fefd | 179 | |
87154938 | 180 | vdso_text_len = vdso_pages << PAGE_SHIFT; |
9031fefd | 181 | /* Be sure to map the data page */ |
87154938 | 182 | vdso_mapping_len = vdso_text_len + PAGE_SIZE; |
9031fefd | 183 | |
69048176 MH |
184 | if (down_write_killable(&mm->mmap_sem)) |
185 | return -EINTR; | |
9031fefd WD |
186 | vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); |
187 | if (IS_ERR_VALUE(vdso_base)) { | |
2fea7f6c | 188 | ret = ERR_PTR(vdso_base); |
9031fefd WD |
189 | goto up_fail; |
190 | } | |
601255ae WD |
191 | ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, |
192 | VM_READ|VM_MAYREAD, | |
2fea7f6c WD |
193 | &vdso_spec[0]); |
194 | if (IS_ERR(ret)) | |
87154938 WD |
195 | goto up_fail; |
196 | ||
601255ae WD |
197 | vdso_base += PAGE_SIZE; |
198 | mm->context.vdso = (void *)vdso_base; | |
199 | ret = _install_special_mapping(mm, vdso_base, vdso_text_len, | |
200 | VM_READ|VM_EXEC| | |
201 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, | |
2fea7f6c WD |
202 | &vdso_spec[1]); |
203 | if (IS_ERR(ret)) | |
9031fefd | 204 | goto up_fail; |
9031fefd | 205 | |
601255ae | 206 | |
9031fefd | 207 | up_write(&mm->mmap_sem); |
87154938 | 208 | return 0; |
9031fefd | 209 | |
87154938 WD |
210 | up_fail: |
211 | mm->context.vdso = NULL; | |
212 | up_write(&mm->mmap_sem); | |
2fea7f6c | 213 | return PTR_ERR(ret); |
9031fefd WD |
214 | } |
215 | ||
9031fefd WD |
216 | /* |
217 | * Update the vDSO data page to keep in sync with kernel timekeeping. | |
218 | */ | |
c60b0c28 | 219 | void update_vsyscall(struct timekeeper *tk) |
9031fefd | 220 | { |
1d8f51d4 | 221 | u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct; |
9031fefd WD |
222 | |
223 | ++vdso_data->tb_seq_count; | |
224 | smp_wmb(); | |
225 | ||
9031fefd | 226 | vdso_data->use_syscall = use_syscall; |
878854a3 NL |
227 | vdso_data->xtime_coarse_sec = tk->xtime_sec; |
228 | vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >> | |
229 | tk->tkr_mono.shift; | |
d4022a33 NL |
230 | vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; |
231 | vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; | |
9031fefd | 232 | |
b2aed72f VF |
233 | /* Read without the seqlock held by clock_getres() */ |
234 | WRITE_ONCE(vdso_data->hrtimer_res, hrtimer_resolution); | |
235 | ||
9031fefd | 236 | if (!use_syscall) { |
49eea433 | 237 | /* tkr_mono.cycle_last == tkr_raw.cycle_last */ |
876e7881 | 238 | vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; |
fc6eead7 JS |
239 | vdso_data->raw_time_sec = tk->raw_sec; |
240 | vdso_data->raw_time_nsec = tk->tkr_raw.xtime_nsec; | |
c60b0c28 | 241 | vdso_data->xtime_clock_sec = tk->xtime_sec; |
876e7881 | 242 | vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec; |
49eea433 KB |
243 | vdso_data->cs_mono_mult = tk->tkr_mono.mult; |
244 | vdso_data->cs_raw_mult = tk->tkr_raw.mult; | |
245 | /* tkr_mono.shift == tkr_raw.shift */ | |
876e7881 | 246 | vdso_data->cs_shift = tk->tkr_mono.shift; |
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 | } |