Commit | Line | Data |
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b020632e MS |
1 | /* |
2 | * vdso setup for s390 | |
3 | * | |
4 | * Copyright IBM Corp. 2008 | |
5 | * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License (version 2 only) | |
9 | * as published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/mm.h> | |
17 | #include <linux/smp.h> | |
18 | #include <linux/stddef.h> | |
19 | #include <linux/unistd.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/user.h> | |
22 | #include <linux/elf.h> | |
23 | #include <linux/security.h> | |
24 | #include <linux/bootmem.h> | |
7757591a | 25 | #include <linux/compat.h> |
cbb870c8 | 26 | #include <asm/asm-offsets.h> |
b020632e MS |
27 | #include <asm/pgtable.h> |
28 | #include <asm/system.h> | |
29 | #include <asm/processor.h> | |
30 | #include <asm/mmu.h> | |
31 | #include <asm/mmu_context.h> | |
32 | #include <asm/sections.h> | |
33 | #include <asm/vdso.h> | |
34 | ||
b020632e MS |
35 | #if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT) |
36 | extern char vdso32_start, vdso32_end; | |
37 | static void *vdso32_kbase = &vdso32_start; | |
38 | static unsigned int vdso32_pages; | |
39 | static struct page **vdso32_pagelist; | |
40 | #endif | |
41 | ||
42 | #ifdef CONFIG_64BIT | |
43 | extern char vdso64_start, vdso64_end; | |
44 | static void *vdso64_kbase = &vdso64_start; | |
45 | static unsigned int vdso64_pages; | |
46 | static struct page **vdso64_pagelist; | |
47 | #endif /* CONFIG_64BIT */ | |
48 | ||
49 | /* | |
50 | * Should the kernel map a VDSO page into processes and pass its | |
51 | * address down to glibc upon exec()? | |
52 | */ | |
53 | unsigned int __read_mostly vdso_enabled = 1; | |
54 | ||
55 | static int __init vdso_setup(char *s) | |
56 | { | |
7aa79f94 MS |
57 | unsigned long val; |
58 | int rc; | |
59 | ||
60 | rc = 0; | |
61 | if (strncmp(s, "on", 3) == 0) | |
62 | vdso_enabled = 1; | |
63 | else if (strncmp(s, "off", 4) == 0) | |
64 | vdso_enabled = 0; | |
65 | else { | |
66 | rc = strict_strtoul(s, 0, &val); | |
67 | vdso_enabled = rc ? 0 : !!val; | |
68 | } | |
69 | return !rc; | |
b020632e MS |
70 | } |
71 | __setup("vdso=", vdso_setup); | |
72 | ||
73 | /* | |
74 | * The vdso data page | |
75 | */ | |
76 | static union { | |
77 | struct vdso_data data; | |
78 | u8 page[PAGE_SIZE]; | |
abe1ee3a | 79 | } vdso_data_store __page_aligned_data; |
b020632e MS |
80 | struct vdso_data *vdso_data = &vdso_data_store.data; |
81 | ||
c742b31c MS |
82 | /* |
83 | * Setup vdso data page. | |
84 | */ | |
85 | static void vdso_init_data(struct vdso_data *vd) | |
86 | { | |
14375bc4 | 87 | vd->ectg_available = user_mode != HOME_SPACE_MODE && test_facility(31); |
c742b31c MS |
88 | } |
89 | ||
90 | #ifdef CONFIG_64BIT | |
91 | /* | |
92 | * Setup per cpu vdso data page. | |
93 | */ | |
94 | static void vdso_init_per_cpu_data(int cpu, struct vdso_per_cpu_data *vpcd) | |
95 | { | |
96 | } | |
97 | ||
98 | /* | |
99 | * Allocate/free per cpu vdso data. | |
100 | */ | |
c742b31c | 101 | #define SEGMENT_ORDER 2 |
c742b31c MS |
102 | |
103 | int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore) | |
104 | { | |
105 | unsigned long segment_table, page_table, page_frame; | |
106 | u32 *psal, *aste; | |
107 | int i; | |
108 | ||
109 | lowcore->vdso_per_cpu_data = __LC_PASTE; | |
110 | ||
b11b5334 | 111 | if (user_mode == HOME_SPACE_MODE || !vdso_enabled) |
c742b31c MS |
112 | return 0; |
113 | ||
114 | segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER); | |
115 | page_table = get_zeroed_page(GFP_KERNEL | GFP_DMA); | |
116 | page_frame = get_zeroed_page(GFP_KERNEL); | |
117 | if (!segment_table || !page_table || !page_frame) | |
118 | goto out; | |
119 | ||
120 | clear_table((unsigned long *) segment_table, _SEGMENT_ENTRY_EMPTY, | |
121 | PAGE_SIZE << SEGMENT_ORDER); | |
122 | clear_table((unsigned long *) page_table, _PAGE_TYPE_EMPTY, | |
123 | 256*sizeof(unsigned long)); | |
124 | ||
125 | *(unsigned long *) segment_table = _SEGMENT_ENTRY + page_table; | |
126 | *(unsigned long *) page_table = _PAGE_RO + page_frame; | |
127 | ||
128 | psal = (u32 *) (page_table + 256*sizeof(unsigned long)); | |
129 | aste = psal + 32; | |
130 | ||
131 | for (i = 4; i < 32; i += 4) | |
132 | psal[i] = 0x80000000; | |
133 | ||
134 | lowcore->paste[4] = (u32)(addr_t) psal; | |
135 | psal[0] = 0x20000000; | |
136 | psal[2] = (u32)(addr_t) aste; | |
137 | *(unsigned long *) (aste + 2) = segment_table + | |
138 | _ASCE_TABLE_LENGTH + _ASCE_USER_BITS + _ASCE_TYPE_SEGMENT; | |
139 | aste[4] = (u32)(addr_t) psal; | |
140 | lowcore->vdso_per_cpu_data = page_frame; | |
141 | ||
142 | vdso_init_per_cpu_data(cpu, (struct vdso_per_cpu_data *) page_frame); | |
143 | return 0; | |
144 | ||
145 | out: | |
146 | free_page(page_frame); | |
147 | free_page(page_table); | |
148 | free_pages(segment_table, SEGMENT_ORDER); | |
149 | return -ENOMEM; | |
150 | } | |
151 | ||
c742b31c MS |
152 | void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore) |
153 | { | |
154 | unsigned long segment_table, page_table, page_frame; | |
155 | u32 *psal, *aste; | |
156 | ||
b11b5334 | 157 | if (user_mode == HOME_SPACE_MODE || !vdso_enabled) |
c742b31c MS |
158 | return; |
159 | ||
160 | psal = (u32 *)(addr_t) lowcore->paste[4]; | |
161 | aste = (u32 *)(addr_t) psal[2]; | |
162 | segment_table = *(unsigned long *)(aste + 2) & PAGE_MASK; | |
163 | page_table = *(unsigned long *) segment_table; | |
164 | page_frame = *(unsigned long *) page_table; | |
165 | ||
166 | free_page(page_frame); | |
167 | free_page(page_table); | |
168 | free_pages(segment_table, SEGMENT_ORDER); | |
169 | } | |
c742b31c MS |
170 | |
171 | static void __vdso_init_cr5(void *dummy) | |
172 | { | |
173 | unsigned long cr5; | |
174 | ||
175 | cr5 = offsetof(struct _lowcore, paste); | |
176 | __ctl_load(cr5, 5, 5); | |
177 | } | |
178 | ||
179 | static void vdso_init_cr5(void) | |
180 | { | |
b11b5334 | 181 | if (user_mode != HOME_SPACE_MODE && vdso_enabled) |
c742b31c MS |
182 | on_each_cpu(__vdso_init_cr5, NULL, 1); |
183 | } | |
184 | #endif /* CONFIG_64BIT */ | |
185 | ||
b020632e MS |
186 | /* |
187 | * This is called from binfmt_elf, we create the special vma for the | |
188 | * vDSO and insert it into the mm struct tree | |
189 | */ | |
190 | int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) | |
191 | { | |
192 | struct mm_struct *mm = current->mm; | |
193 | struct page **vdso_pagelist; | |
194 | unsigned long vdso_pages; | |
195 | unsigned long vdso_base; | |
196 | int rc; | |
197 | ||
198 | if (!vdso_enabled) | |
199 | return 0; | |
200 | /* | |
201 | * Only map the vdso for dynamically linked elf binaries. | |
202 | */ | |
203 | if (!uses_interp) | |
204 | return 0; | |
205 | ||
b020632e MS |
206 | #ifdef CONFIG_64BIT |
207 | vdso_pagelist = vdso64_pagelist; | |
208 | vdso_pages = vdso64_pages; | |
209 | #ifdef CONFIG_COMPAT | |
7757591a | 210 | if (is_compat_task()) { |
b020632e MS |
211 | vdso_pagelist = vdso32_pagelist; |
212 | vdso_pages = vdso32_pages; | |
213 | } | |
214 | #endif | |
215 | #else | |
216 | vdso_pagelist = vdso32_pagelist; | |
217 | vdso_pages = vdso32_pages; | |
218 | #endif | |
219 | ||
220 | /* | |
221 | * vDSO has a problem and was disabled, just don't "enable" it for | |
222 | * the process | |
223 | */ | |
224 | if (vdso_pages == 0) | |
225 | return 0; | |
226 | ||
227 | current->mm->context.vdso_base = 0; | |
228 | ||
229 | /* | |
230 | * pick a base address for the vDSO in process space. We try to put | |
231 | * it at vdso_base which is the "natural" base for it, but we might | |
232 | * fail and end up putting it elsewhere. | |
233 | */ | |
234 | down_write(&mm->mmap_sem); | |
e7828bbd | 235 | vdso_base = get_unmapped_area(NULL, 0, vdso_pages << PAGE_SHIFT, 0, 0); |
b020632e MS |
236 | if (IS_ERR_VALUE(vdso_base)) { |
237 | rc = vdso_base; | |
238 | goto out_up; | |
239 | } | |
240 | ||
930e44fb HC |
241 | /* |
242 | * Put vDSO base into mm struct. We need to do this before calling | |
243 | * install_special_mapping or the perf counter mmap tracking code | |
244 | * will fail to recognise it as a vDSO (since arch_vma_name fails). | |
245 | */ | |
246 | current->mm->context.vdso_base = vdso_base; | |
247 | ||
b020632e MS |
248 | /* |
249 | * our vma flags don't have VM_WRITE so by default, the process | |
250 | * isn't allowed to write those pages. | |
251 | * gdb can break that with ptrace interface, and thus trigger COW | |
252 | * on those pages but it's then your responsibility to never do that | |
253 | * on the "data" page of the vDSO or you'll stop getting kernel | |
254 | * updates and your nice userland gettimeofday will be totally dead. | |
255 | * It's fine to use that for setting breakpoints in the vDSO code | |
256 | * pages though | |
257 | * | |
258 | * Make sure the vDSO gets into every core dump. | |
259 | * Dumping its contents makes post-mortem fully interpretable later | |
260 | * without matching up the same kernel and hardware config to see | |
261 | * what PC values meant. | |
262 | */ | |
263 | rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, | |
264 | VM_READ|VM_EXEC| | |
265 | VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| | |
266 | VM_ALWAYSDUMP, | |
267 | vdso_pagelist); | |
268 | if (rc) | |
930e44fb | 269 | current->mm->context.vdso_base = 0; |
b020632e MS |
270 | out_up: |
271 | up_write(&mm->mmap_sem); | |
272 | return rc; | |
273 | } | |
274 | ||
275 | const char *arch_vma_name(struct vm_area_struct *vma) | |
276 | { | |
277 | if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base) | |
278 | return "[vdso]"; | |
279 | return NULL; | |
280 | } | |
281 | ||
282 | static int __init vdso_init(void) | |
283 | { | |
284 | int i; | |
285 | ||
c742b31c MS |
286 | if (!vdso_enabled) |
287 | return 0; | |
288 | vdso_init_data(vdso_data); | |
b020632e MS |
289 | #if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT) |
290 | /* Calculate the size of the 32 bit vDSO */ | |
291 | vdso32_pages = ((&vdso32_end - &vdso32_start | |
292 | + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1; | |
293 | ||
294 | /* Make sure pages are in the correct state */ | |
295 | vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 1), | |
296 | GFP_KERNEL); | |
297 | BUG_ON(vdso32_pagelist == NULL); | |
298 | for (i = 0; i < vdso32_pages - 1; i++) { | |
299 | struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); | |
300 | ClearPageReserved(pg); | |
301 | get_page(pg); | |
302 | vdso32_pagelist[i] = pg; | |
303 | } | |
304 | vdso32_pagelist[vdso32_pages - 1] = virt_to_page(vdso_data); | |
305 | vdso32_pagelist[vdso32_pages] = NULL; | |
306 | #endif | |
307 | ||
308 | #ifdef CONFIG_64BIT | |
309 | /* Calculate the size of the 64 bit vDSO */ | |
310 | vdso64_pages = ((&vdso64_end - &vdso64_start | |
311 | + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1; | |
312 | ||
313 | /* Make sure pages are in the correct state */ | |
314 | vdso64_pagelist = kzalloc(sizeof(struct page *) * (vdso64_pages + 1), | |
315 | GFP_KERNEL); | |
316 | BUG_ON(vdso64_pagelist == NULL); | |
317 | for (i = 0; i < vdso64_pages - 1; i++) { | |
318 | struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); | |
319 | ClearPageReserved(pg); | |
320 | get_page(pg); | |
321 | vdso64_pagelist[i] = pg; | |
322 | } | |
323 | vdso64_pagelist[vdso64_pages - 1] = virt_to_page(vdso_data); | |
324 | vdso64_pagelist[vdso64_pages] = NULL; | |
c742b31c | 325 | #ifndef CONFIG_SMP |
81ffa041 HC |
326 | if (vdso_alloc_per_cpu(0, &S390_lowcore)) |
327 | BUG(); | |
c742b31c MS |
328 | #endif |
329 | vdso_init_cr5(); | |
b020632e MS |
330 | #endif /* CONFIG_64BIT */ |
331 | ||
332 | get_page(virt_to_page(vdso_data)); | |
333 | ||
334 | smp_wmb(); | |
335 | ||
336 | return 0; | |
337 | } | |
338 | arch_initcall(vdso_init); | |
339 | ||
cae5d390 | 340 | int in_gate_area_no_mm(unsigned long addr) |
b020632e MS |
341 | { |
342 | return 0; | |
343 | } | |
344 | ||
83b964bb | 345 | int in_gate_area(struct mm_struct *mm, unsigned long addr) |
b020632e MS |
346 | { |
347 | return 0; | |
348 | } | |
349 | ||
31db58b3 | 350 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) |
b020632e MS |
351 | { |
352 | return NULL; | |
353 | } |