2 * VDSO implementation for AArch64 and vector page setup for AArch32.
4 * Copyright (C) 2012 ARM Limited
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.
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.
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/>.
18 * Author: Will Deacon <will.deacon@arm.com>
21 #include <linux/cache.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/kernel.h>
29 #include <linux/sched.h>
30 #include <linux/signal.h>
31 #include <linux/slab.h>
32 #include <linux/timekeeper_internal.h>
33 #include <linux/vmalloc.h>
35 #include <asm/cacheflush.h>
36 #include <asm/signal32.h>
38 #include <asm/vdso_datapage.h>
40 extern char vdso_start, vdso_end;
41 static unsigned long vdso_pages __ro_after_init;
47 struct vdso_data data;
49 } vdso_data_store __page_aligned_data;
50 struct vdso_data *vdso_data = &vdso_data_store.data;
54 * Create and map the vectors page for AArch32 tasks.
56 static struct page *vectors_page[1] __ro_after_init;
58 static int __init alloc_vectors_page(void)
60 extern char __kuser_helper_start[], __kuser_helper_end[];
61 extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
63 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
64 int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
67 vpage = get_zeroed_page(GFP_ATOMIC);
73 memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
77 memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
78 __aarch32_sigret_code_start, sigret_sz);
80 flush_icache_range(vpage, vpage + PAGE_SIZE);
81 vectors_page[0] = virt_to_page(vpage);
85 arch_initcall(alloc_vectors_page);
87 int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
89 struct mm_struct *mm = current->mm;
90 unsigned long addr = AARCH32_VECTORS_BASE;
91 static const struct vm_special_mapping spec = {
93 .pages = vectors_page,
98 if (down_write_killable(&mm->mmap_sem))
100 current->mm->context.vdso = (void *)addr;
102 /* Map vectors page at the high address. */
103 ret = _install_special_mapping(mm, addr, PAGE_SIZE,
104 VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
107 up_write(&mm->mmap_sem);
109 return PTR_ERR_OR_ZERO(ret);
111 #endif /* CONFIG_COMPAT */
113 static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
122 static int __init vdso_init(void)
125 struct page **vdso_pagelist;
128 if (memcmp(&vdso_start, "\177ELF", 4)) {
129 pr_err("vDSO is not a valid ELF object!\n");
133 vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
134 pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
135 vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data);
137 /* Allocate the vDSO pagelist, plus a page for the data. */
138 vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
140 if (vdso_pagelist == NULL)
143 /* Grab the vDSO data page. */
144 vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data));
147 /* Grab the vDSO code pages. */
148 pfn = sym_to_pfn(&vdso_start);
150 for (i = 0; i < vdso_pages; i++)
151 vdso_pagelist[i + 1] = pfn_to_page(pfn + i);
153 vdso_spec[0].pages = &vdso_pagelist[0];
154 vdso_spec[1].pages = &vdso_pagelist[1];
158 arch_initcall(vdso_init);
160 int arch_setup_additional_pages(struct linux_binprm *bprm,
163 struct mm_struct *mm = current->mm;
164 unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
167 vdso_text_len = vdso_pages << PAGE_SHIFT;
168 /* Be sure to map the data page */
169 vdso_mapping_len = vdso_text_len + PAGE_SIZE;
171 if (down_write_killable(&mm->mmap_sem))
173 vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
174 if (IS_ERR_VALUE(vdso_base)) {
175 ret = ERR_PTR(vdso_base);
178 ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
184 vdso_base += PAGE_SIZE;
185 mm->context.vdso = (void *)vdso_base;
186 ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
188 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
194 up_write(&mm->mmap_sem);
198 mm->context.vdso = NULL;
199 up_write(&mm->mmap_sem);
204 * Update the vDSO data page to keep in sync with kernel timekeeping.
206 void update_vsyscall(struct timekeeper *tk)
208 u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
210 ++vdso_data->tb_seq_count;
213 vdso_data->use_syscall = use_syscall;
214 vdso_data->xtime_coarse_sec = tk->xtime_sec;
215 vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>
217 vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
218 vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
221 /* tkr_mono.cycle_last == tkr_raw.cycle_last */
222 vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
223 vdso_data->raw_time_sec = tk->raw_sec;
224 vdso_data->raw_time_nsec = tk->tkr_raw.xtime_nsec;
225 vdso_data->xtime_clock_sec = tk->xtime_sec;
226 vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
227 vdso_data->cs_mono_mult = tk->tkr_mono.mult;
228 vdso_data->cs_raw_mult = tk->tkr_raw.mult;
229 /* tkr_mono.shift == tkr_raw.shift */
230 vdso_data->cs_shift = tk->tkr_mono.shift;
234 ++vdso_data->tb_seq_count;
237 void update_vsyscall_tz(void)
239 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
240 vdso_data->tz_dsttime = sys_tz.tz_dsttime;