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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[]; | |
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; | |
91 | int ret; | |
92 | ||
93 | down_write(&mm->mmap_sem); | |
94 | current->mm->context.vdso = (void *)addr; | |
95 | ||
96 | /* Map vectors page at the high address. */ | |
97 | ret = install_special_mapping(mm, addr, PAGE_SIZE, | |
98 | VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, | |
99 | vectors_page); | |
100 | ||
101 | up_write(&mm->mmap_sem); | |
102 | ||
103 | return ret; | |
104 | } | |
105 | #endif /* CONFIG_COMPAT */ | |
106 | ||
107 | static int __init vdso_init(void) | |
108 | { | |
16fb1a9b NL |
109 | int i; |
110 | ||
111 | if (memcmp(&vdso_start, "\177ELF", 4)) { | |
112 | pr_err("vDSO is not a valid ELF object!\n"); | |
113 | return -EINVAL; | |
114 | } | |
9031fefd WD |
115 | |
116 | vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; | |
117 | pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n", | |
118 | vdso_pages + 1, vdso_pages, 1L, &vdso_start); | |
119 | ||
120 | /* Allocate the vDSO pagelist, plus a page for the data. */ | |
16fb1a9b | 121 | vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *), |
9031fefd | 122 | GFP_KERNEL); |
16fb1a9b | 123 | if (vdso_pagelist == NULL) |
9031fefd | 124 | return -ENOMEM; |
9031fefd WD |
125 | |
126 | /* Grab the vDSO code pages. */ | |
16fb1a9b NL |
127 | for (i = 0; i < vdso_pages; i++) |
128 | vdso_pagelist[i] = virt_to_page(&vdso_start + i * PAGE_SIZE); | |
9031fefd WD |
129 | |
130 | /* Grab the vDSO data page. */ | |
16fb1a9b | 131 | vdso_pagelist[i] = virt_to_page(vdso_data); |
9031fefd | 132 | |
16fb1a9b | 133 | return 0; |
9031fefd WD |
134 | } |
135 | arch_initcall(vdso_init); | |
136 | ||
137 | int arch_setup_additional_pages(struct linux_binprm *bprm, | |
138 | int uses_interp) | |
139 | { | |
140 | struct mm_struct *mm = current->mm; | |
141 | unsigned long vdso_base, vdso_mapping_len; | |
142 | int ret; | |
143 | ||
144 | /* Be sure to map the data page */ | |
145 | vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT; | |
146 | ||
147 | down_write(&mm->mmap_sem); | |
148 | vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); | |
149 | if (IS_ERR_VALUE(vdso_base)) { | |
150 | ret = vdso_base; | |
151 | goto up_fail; | |
152 | } | |
153 | mm->context.vdso = (void *)vdso_base; | |
154 | ||
155 | ret = install_special_mapping(mm, vdso_base, vdso_mapping_len, | |
156 | VM_READ|VM_EXEC| | |
157 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, | |
158 | vdso_pagelist); | |
159 | if (ret) { | |
160 | mm->context.vdso = NULL; | |
161 | goto up_fail; | |
162 | } | |
163 | ||
164 | up_fail: | |
165 | up_write(&mm->mmap_sem); | |
166 | ||
167 | return ret; | |
168 | } | |
169 | ||
170 | const char *arch_vma_name(struct vm_area_struct *vma) | |
171 | { | |
172 | /* | |
173 | * We can re-use the vdso pointer in mm_context_t for identifying | |
174 | * the vectors page for compat applications. The vDSO will always | |
175 | * sit above TASK_UNMAPPED_BASE and so we don't need to worry about | |
176 | * it conflicting with the vectors base. | |
177 | */ | |
178 | if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) { | |
179 | #ifdef CONFIG_COMPAT | |
180 | if (vma->vm_start == AARCH32_VECTORS_BASE) | |
181 | return "[vectors]"; | |
182 | #endif | |
183 | return "[vdso]"; | |
184 | } | |
185 | ||
186 | return NULL; | |
187 | } | |
188 | ||
189 | /* | |
190 | * We define AT_SYSINFO_EHDR, so we need these function stubs to keep | |
191 | * Linux happy. | |
192 | */ | |
193 | int in_gate_area_no_mm(unsigned long addr) | |
194 | { | |
195 | return 0; | |
196 | } | |
197 | ||
198 | int in_gate_area(struct mm_struct *mm, unsigned long addr) | |
199 | { | |
200 | return 0; | |
201 | } | |
202 | ||
203 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) | |
204 | { | |
205 | return NULL; | |
206 | } | |
207 | ||
208 | /* | |
209 | * Update the vDSO data page to keep in sync with kernel timekeeping. | |
210 | */ | |
c60b0c28 | 211 | void update_vsyscall(struct timekeeper *tk) |
9031fefd WD |
212 | { |
213 | struct timespec xtime_coarse; | |
c60b0c28 | 214 | u32 use_syscall = strcmp(tk->clock->name, "arch_sys_counter"); |
9031fefd WD |
215 | |
216 | ++vdso_data->tb_seq_count; | |
217 | smp_wmb(); | |
218 | ||
219 | xtime_coarse = __current_kernel_time(); | |
220 | vdso_data->use_syscall = use_syscall; | |
221 | vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec; | |
222 | vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec; | |
d4022a33 NL |
223 | vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; |
224 | vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; | |
9031fefd WD |
225 | |
226 | if (!use_syscall) { | |
c60b0c28 CM |
227 | vdso_data->cs_cycle_last = tk->clock->cycle_last; |
228 | vdso_data->xtime_clock_sec = tk->xtime_sec; | |
45a7905f | 229 | vdso_data->xtime_clock_nsec = tk->xtime_nsec; |
c60b0c28 CM |
230 | vdso_data->cs_mult = tk->mult; |
231 | vdso_data->cs_shift = tk->shift; | |
9031fefd WD |
232 | } |
233 | ||
234 | smp_wmb(); | |
235 | ++vdso_data->tb_seq_count; | |
236 | } | |
237 | ||
238 | void update_vsyscall_tz(void) | |
239 | { | |
9031fefd WD |
240 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
241 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
9031fefd | 242 | } |