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/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>
28 #include <linux/sched.h>
29 #include <linux/signal.h>
30 #include <linux/slab.h>
31 #include <linux/timekeeper_internal.h>
32 #include <linux/vmalloc.h>
34 #include <asm/cacheflush.h>
35 #include <asm/signal32.h>
37 #include <asm/vdso_datapage.h>
39 extern char vdso_start, vdso_end;
40 static unsigned long vdso_pages;
41 static struct page **vdso_pagelist;
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];
58 static int 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;
93 down_write(&mm->mmap_sem);
94 current->mm->context.vdso = (void *)addr;
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,
101 up_write(&mm->mmap_sem);
105 #endif /* CONFIG_COMPAT */
107 static int __init vdso_init(void)
111 if (memcmp(&vdso_start, "\177ELF", 4)) {
112 pr_err("vDSO is not a valid ELF object!\n");
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);
120 /* Allocate the vDSO pagelist, plus a page for the data. */
121 vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
123 if (vdso_pagelist == NULL)
126 /* Grab the vDSO code pages. */
127 for (i = 0; i < vdso_pages; i++)
128 vdso_pagelist[i] = virt_to_page(&vdso_start + i * PAGE_SIZE);
130 /* Grab the vDSO data page. */
131 vdso_pagelist[i] = virt_to_page(vdso_data);
135 arch_initcall(vdso_init);
137 int arch_setup_additional_pages(struct linux_binprm *bprm,
140 struct mm_struct *mm = current->mm;
141 unsigned long vdso_base, vdso_mapping_len;
144 /* Be sure to map the data page */
145 vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT;
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)) {
153 mm->context.vdso = (void *)vdso_base;
155 ret = install_special_mapping(mm, vdso_base, vdso_mapping_len,
157 VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
160 mm->context.vdso = NULL;
165 up_write(&mm->mmap_sem);
170 const char *arch_vma_name(struct vm_area_struct *vma)
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.
178 if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) {
180 if (vma->vm_start == AARCH32_VECTORS_BASE)
190 * We define AT_SYSINFO_EHDR, so we need these function stubs to keep
193 int in_gate_area_no_mm(unsigned long addr)
198 int in_gate_area(struct mm_struct *mm, unsigned long addr)
203 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
209 * Update the vDSO data page to keep in sync with kernel timekeeping.
211 void update_vsyscall(struct timekeeper *tk)
213 struct timespec xtime_coarse;
214 u32 use_syscall = strcmp(tk->clock->name, "arch_sys_counter");
216 ++vdso_data->tb_seq_count;
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;
223 vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
224 vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
227 vdso_data->cs_cycle_last = tk->clock->cycle_last;
228 vdso_data->xtime_clock_sec = tk->xtime_sec;
229 vdso_data->xtime_clock_nsec = tk->xtime_nsec;
230 vdso_data->cs_mult = tk->mult;
231 vdso_data->cs_shift = tk->shift;
235 ++vdso_data->tb_seq_count;
238 void update_vsyscall_tz(void)
240 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
241 vdso_data->tz_dsttime = sys_tz.tz_dsttime;