diff options
Diffstat (limited to 'arch/arm64/kernel/vdso.c')
-rw-r--r-- | arch/arm64/kernel/vdso.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c new file mode 100644 index 00000000000..17948fc7d66 --- /dev/null +++ b/arch/arm64/kernel/vdso.c | |||
@@ -0,0 +1,261 @@ | |||
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> | ||
31 | #include <linux/vmalloc.h> | ||
32 | |||
33 | #include <asm/cacheflush.h> | ||
34 | #include <asm/signal32.h> | ||
35 | #include <asm/vdso.h> | ||
36 | #include <asm/vdso_datapage.h> | ||
37 | |||
38 | extern char vdso_start, vdso_end; | ||
39 | static unsigned long vdso_pages; | ||
40 | static struct page **vdso_pagelist; | ||
41 | |||
42 | /* | ||
43 | * The vDSO data page. | ||
44 | */ | ||
45 | static union { | ||
46 | struct vdso_data data; | ||
47 | u8 page[PAGE_SIZE]; | ||
48 | } vdso_data_store __page_aligned_data; | ||
49 | struct vdso_data *vdso_data = &vdso_data_store.data; | ||
50 | |||
51 | #ifdef CONFIG_COMPAT | ||
52 | /* | ||
53 | * Create and map the vectors page for AArch32 tasks. | ||
54 | */ | ||
55 | static struct page *vectors_page[1]; | ||
56 | |||
57 | static int alloc_vectors_page(void) | ||
58 | { | ||
59 | extern char __kuser_helper_start[], __kuser_helper_end[]; | ||
60 | int kuser_sz = __kuser_helper_end - __kuser_helper_start; | ||
61 | unsigned long vpage; | ||
62 | |||
63 | vpage = get_zeroed_page(GFP_ATOMIC); | ||
64 | |||
65 | if (!vpage) | ||
66 | return -ENOMEM; | ||
67 | |||
68 | /* kuser helpers */ | ||
69 | memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, | ||
70 | kuser_sz); | ||
71 | |||
72 | /* sigreturn code */ | ||
73 | memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, | ||
74 | aarch32_sigret_code, sizeof(aarch32_sigret_code)); | ||
75 | |||
76 | flush_icache_range(vpage, vpage + PAGE_SIZE); | ||
77 | vectors_page[0] = virt_to_page(vpage); | ||
78 | |||
79 | return 0; | ||
80 | } | ||
81 | arch_initcall(alloc_vectors_page); | ||
82 | |||
83 | int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) | ||
84 | { | ||
85 | struct mm_struct *mm = current->mm; | ||
86 | unsigned long addr = AARCH32_VECTORS_BASE; | ||
87 | int ret; | ||
88 | |||
89 | down_write(&mm->mmap_sem); | ||
90 | current->mm->context.vdso = (void *)addr; | ||
91 | |||
92 | /* Map vectors page at the high address. */ | ||
93 | ret = install_special_mapping(mm, addr, PAGE_SIZE, | ||
94 | VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, | ||
95 | vectors_page); | ||
96 | |||
97 | up_write(&mm->mmap_sem); | ||
98 | |||
99 | return ret; | ||
100 | } | ||
101 | #endif /* CONFIG_COMPAT */ | ||
102 | |||
103 | static int __init vdso_init(void) | ||
104 | { | ||
105 | struct page *pg; | ||
106 | char *vbase; | ||
107 | int i, ret = 0; | ||
108 | |||
109 | vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; | ||
110 | pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n", | ||
111 | vdso_pages + 1, vdso_pages, 1L, &vdso_start); | ||
112 | |||
113 | /* Allocate the vDSO pagelist, plus a page for the data. */ | ||
114 | vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1), | ||
115 | GFP_KERNEL); | ||
116 | if (vdso_pagelist == NULL) { | ||
117 | pr_err("Failed to allocate vDSO pagelist!\n"); | ||
118 | return -ENOMEM; | ||
119 | } | ||
120 | |||
121 | /* Grab the vDSO code pages. */ | ||
122 | for (i = 0; i < vdso_pages; i++) { | ||
123 | pg = virt_to_page(&vdso_start + i*PAGE_SIZE); | ||
124 | ClearPageReserved(pg); | ||
125 | get_page(pg); | ||
126 | vdso_pagelist[i] = pg; | ||
127 | } | ||
128 | |||
129 | /* Sanity check the shared object header. */ | ||
130 | vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL); | ||
131 | if (vbase == NULL) { | ||
132 | pr_err("Failed to map vDSO pagelist!\n"); | ||
133 | return -ENOMEM; | ||
134 | } else if (memcmp(vbase, "\177ELF", 4)) { | ||
135 | pr_err("vDSO is not a valid ELF object!\n"); | ||
136 | ret = -EINVAL; | ||
137 | goto unmap; | ||
138 | } | ||
139 | |||
140 | /* Grab the vDSO data page. */ | ||
141 | pg = virt_to_page(vdso_data); | ||
142 | get_page(pg); | ||
143 | vdso_pagelist[i] = pg; | ||
144 | |||
145 | unmap: | ||
146 | vunmap(vbase); | ||
147 | return ret; | ||
148 | } | ||
149 | arch_initcall(vdso_init); | ||
150 | |||
151 | int arch_setup_additional_pages(struct linux_binprm *bprm, | ||
152 | int uses_interp) | ||
153 | { | ||
154 | struct mm_struct *mm = current->mm; | ||
155 | unsigned long vdso_base, vdso_mapping_len; | ||
156 | int ret; | ||
157 | |||
158 | /* Be sure to map the data page */ | ||
159 | vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT; | ||
160 | |||
161 | down_write(&mm->mmap_sem); | ||
162 | vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); | ||
163 | if (IS_ERR_VALUE(vdso_base)) { | ||
164 | ret = vdso_base; | ||
165 | goto up_fail; | ||
166 | } | ||
167 | mm->context.vdso = (void *)vdso_base; | ||
168 | |||
169 | ret = install_special_mapping(mm, vdso_base, vdso_mapping_len, | ||
170 | VM_READ|VM_EXEC| | ||
171 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, | ||
172 | vdso_pagelist); | ||
173 | if (ret) { | ||
174 | mm->context.vdso = NULL; | ||
175 | goto up_fail; | ||
176 | } | ||
177 | |||
178 | up_fail: | ||
179 | up_write(&mm->mmap_sem); | ||
180 | |||
181 | return ret; | ||
182 | } | ||
183 | |||
184 | const char *arch_vma_name(struct vm_area_struct *vma) | ||
185 | { | ||
186 | /* | ||
187 | * We can re-use the vdso pointer in mm_context_t for identifying | ||
188 | * the vectors page for compat applications. The vDSO will always | ||
189 | * sit above TASK_UNMAPPED_BASE and so we don't need to worry about | ||
190 | * it conflicting with the vectors base. | ||
191 | */ | ||
192 | if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) { | ||
193 | #ifdef CONFIG_COMPAT | ||
194 | if (vma->vm_start == AARCH32_VECTORS_BASE) | ||
195 | return "[vectors]"; | ||
196 | #endif | ||
197 | return "[vdso]"; | ||
198 | } | ||
199 | |||
200 | return NULL; | ||
201 | } | ||
202 | |||
203 | /* | ||
204 | * We define AT_SYSINFO_EHDR, so we need these function stubs to keep | ||
205 | * Linux happy. | ||
206 | */ | ||
207 | int in_gate_area_no_mm(unsigned long addr) | ||
208 | { | ||
209 | return 0; | ||
210 | } | ||
211 | |||
212 | int in_gate_area(struct mm_struct *mm, unsigned long addr) | ||
213 | { | ||
214 | return 0; | ||
215 | } | ||
216 | |||
217 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) | ||
218 | { | ||
219 | return NULL; | ||
220 | } | ||
221 | |||
222 | /* | ||
223 | * Update the vDSO data page to keep in sync with kernel timekeeping. | ||
224 | */ | ||
225 | void update_vsyscall(struct timespec *ts, struct timespec *wtm, | ||
226 | struct clocksource *clock, u32 mult) | ||
227 | { | ||
228 | struct timespec xtime_coarse; | ||
229 | u32 use_syscall = strcmp(clock->name, "arch_sys_counter"); | ||
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) { | ||
240 | vdso_data->cs_cycle_last = clock->cycle_last; | ||
241 | vdso_data->xtime_clock_sec = ts->tv_sec; | ||
242 | vdso_data->xtime_clock_nsec = ts->tv_nsec; | ||
243 | vdso_data->cs_mult = mult; | ||
244 | vdso_data->cs_shift = clock->shift; | ||
245 | vdso_data->wtm_clock_sec = wtm->tv_sec; | ||
246 | vdso_data->wtm_clock_nsec = wtm->tv_nsec; | ||
247 | } | ||
248 | |||
249 | smp_wmb(); | ||
250 | ++vdso_data->tb_seq_count; | ||
251 | } | ||
252 | |||
253 | void update_vsyscall_tz(void) | ||
254 | { | ||
255 | ++vdso_data->tb_seq_count; | ||
256 | smp_wmb(); | ||
257 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; | ||
258 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; | ||
259 | smp_wmb(); | ||
260 | ++vdso_data->tb_seq_count; | ||
261 | } | ||