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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; | |
2fea7f6c WD |
91 | static struct vm_special_mapping spec = { |
92 | .name = "[vectors]", | |
93 | .pages = vectors_page, | |
94 | ||
95 | }; | |
96 | void *ret; | |
9031fefd WD |
97 | |
98 | down_write(&mm->mmap_sem); | |
99 | current->mm->context.vdso = (void *)addr; | |
100 | ||
101 | /* Map vectors page at the high address. */ | |
2fea7f6c WD |
102 | ret = _install_special_mapping(mm, addr, PAGE_SIZE, |
103 | VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, | |
104 | &spec); | |
9031fefd WD |
105 | |
106 | up_write(&mm->mmap_sem); | |
107 | ||
2fea7f6c | 108 | return PTR_ERR_OR_ZERO(ret); |
9031fefd WD |
109 | } |
110 | #endif /* CONFIG_COMPAT */ | |
111 | ||
2fea7f6c WD |
112 | static struct vm_special_mapping vdso_spec[2]; |
113 | ||
9031fefd WD |
114 | static int __init vdso_init(void) |
115 | { | |
16fb1a9b NL |
116 | int i; |
117 | ||
118 | if (memcmp(&vdso_start, "\177ELF", 4)) { | |
119 | pr_err("vDSO is not a valid ELF object!\n"); | |
120 | return -EINVAL; | |
121 | } | |
9031fefd WD |
122 | |
123 | vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; | |
601255ae WD |
124 | pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n", |
125 | vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data); | |
9031fefd WD |
126 | |
127 | /* Allocate the vDSO pagelist, plus a page for the data. */ | |
16fb1a9b | 128 | vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *), |
9031fefd | 129 | GFP_KERNEL); |
16fb1a9b | 130 | if (vdso_pagelist == NULL) |
9031fefd | 131 | return -ENOMEM; |
9031fefd | 132 | |
601255ae | 133 | /* Grab the vDSO data page. */ |
97bbb54e | 134 | vdso_pagelist[0] = pfn_to_page(PHYS_PFN(__pa(vdso_data))); |
601255ae | 135 | |
9031fefd | 136 | /* Grab the vDSO code pages. */ |
16fb1a9b | 137 | for (i = 0; i < vdso_pages; i++) |
97bbb54e | 138 | vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa(&vdso_start)) + i); |
9031fefd | 139 | |
2fea7f6c WD |
140 | /* Populate the special mapping structures */ |
141 | vdso_spec[0] = (struct vm_special_mapping) { | |
601255ae | 142 | .name = "[vvar]", |
2fea7f6c WD |
143 | .pages = vdso_pagelist, |
144 | }; | |
145 | ||
146 | vdso_spec[1] = (struct vm_special_mapping) { | |
601255ae WD |
147 | .name = "[vdso]", |
148 | .pages = &vdso_pagelist[1], | |
2fea7f6c WD |
149 | }; |
150 | ||
16fb1a9b | 151 | return 0; |
9031fefd WD |
152 | } |
153 | arch_initcall(vdso_init); | |
154 | ||
155 | int arch_setup_additional_pages(struct linux_binprm *bprm, | |
156 | int uses_interp) | |
157 | { | |
158 | struct mm_struct *mm = current->mm; | |
87154938 | 159 | unsigned long vdso_base, vdso_text_len, vdso_mapping_len; |
2fea7f6c | 160 | void *ret; |
9031fefd | 161 | |
87154938 | 162 | vdso_text_len = vdso_pages << PAGE_SHIFT; |
9031fefd | 163 | /* Be sure to map the data page */ |
87154938 | 164 | vdso_mapping_len = vdso_text_len + PAGE_SIZE; |
9031fefd WD |
165 | |
166 | down_write(&mm->mmap_sem); | |
167 | vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); | |
168 | if (IS_ERR_VALUE(vdso_base)) { | |
2fea7f6c | 169 | ret = ERR_PTR(vdso_base); |
9031fefd WD |
170 | goto up_fail; |
171 | } | |
601255ae WD |
172 | ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, |
173 | VM_READ|VM_MAYREAD, | |
2fea7f6c WD |
174 | &vdso_spec[0]); |
175 | if (IS_ERR(ret)) | |
87154938 WD |
176 | goto up_fail; |
177 | ||
601255ae WD |
178 | vdso_base += PAGE_SIZE; |
179 | mm->context.vdso = (void *)vdso_base; | |
180 | ret = _install_special_mapping(mm, vdso_base, vdso_text_len, | |
181 | VM_READ|VM_EXEC| | |
182 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, | |
2fea7f6c WD |
183 | &vdso_spec[1]); |
184 | if (IS_ERR(ret)) | |
9031fefd | 185 | goto up_fail; |
9031fefd | 186 | |
601255ae | 187 | |
9031fefd | 188 | up_write(&mm->mmap_sem); |
87154938 | 189 | return 0; |
9031fefd | 190 | |
87154938 WD |
191 | up_fail: |
192 | mm->context.vdso = NULL; | |
193 | up_write(&mm->mmap_sem); | |
2fea7f6c | 194 | return PTR_ERR(ret); |
9031fefd WD |
195 | } |
196 | ||
9031fefd WD |
197 | /* |
198 | * Update the vDSO data page to keep in sync with kernel timekeeping. | |
199 | */ | |
c60b0c28 | 200 | void update_vsyscall(struct timekeeper *tk) |
9031fefd | 201 | { |
876e7881 | 202 | u32 use_syscall = strcmp(tk->tkr_mono.clock->name, "arch_sys_counter"); |
9031fefd WD |
203 | |
204 | ++vdso_data->tb_seq_count; | |
205 | smp_wmb(); | |
206 | ||
9031fefd | 207 | vdso_data->use_syscall = use_syscall; |
878854a3 NL |
208 | vdso_data->xtime_coarse_sec = tk->xtime_sec; |
209 | vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >> | |
210 | tk->tkr_mono.shift; | |
d4022a33 NL |
211 | vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; |
212 | vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; | |
9031fefd WD |
213 | |
214 | if (!use_syscall) { | |
876e7881 | 215 | vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; |
c60b0c28 | 216 | vdso_data->xtime_clock_sec = tk->xtime_sec; |
876e7881 PZ |
217 | vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec; |
218 | vdso_data->cs_mult = tk->tkr_mono.mult; | |
219 | vdso_data->cs_shift = tk->tkr_mono.shift; | |
9031fefd WD |
220 | } |
221 | ||
222 | smp_wmb(); | |
223 | ++vdso_data->tb_seq_count; | |
224 | } | |
225 | ||
226 | void update_vsyscall_tz(void) | |
227 | { | |
9031fefd WD |
228 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
229 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | |
9031fefd | 230 | } |