19031fefdSWill Deacon /* 29031fefdSWill Deacon * VDSO implementation for AArch64 and vector page setup for AArch32. 39031fefdSWill Deacon * 49031fefdSWill Deacon * Copyright (C) 2012 ARM Limited 59031fefdSWill Deacon * 69031fefdSWill Deacon * This program is free software; you can redistribute it and/or modify 79031fefdSWill Deacon * it under the terms of the GNU General Public License version 2 as 89031fefdSWill Deacon * published by the Free Software Foundation. 99031fefdSWill Deacon * 109031fefdSWill Deacon * This program is distributed in the hope that it will be useful, 119031fefdSWill Deacon * but WITHOUT ANY WARRANTY; without even the implied warranty of 129031fefdSWill Deacon * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 139031fefdSWill Deacon * GNU General Public License for more details. 149031fefdSWill Deacon * 159031fefdSWill Deacon * You should have received a copy of the GNU General Public License 169031fefdSWill Deacon * along with this program. If not, see <http://www.gnu.org/licenses/>. 179031fefdSWill Deacon * 189031fefdSWill Deacon * Author: Will Deacon <will.deacon@arm.com> 199031fefdSWill Deacon */ 209031fefdSWill Deacon 219031fefdSWill Deacon #include <linux/kernel.h> 229031fefdSWill Deacon #include <linux/clocksource.h> 239031fefdSWill Deacon #include <linux/elf.h> 249031fefdSWill Deacon #include <linux/err.h> 259031fefdSWill Deacon #include <linux/errno.h> 269031fefdSWill Deacon #include <linux/gfp.h> 279031fefdSWill Deacon #include <linux/mm.h> 289031fefdSWill Deacon #include <linux/sched.h> 299031fefdSWill Deacon #include <linux/signal.h> 309031fefdSWill Deacon #include <linux/slab.h> 31c60b0c28SCatalin Marinas #include <linux/timekeeper_internal.h> 329031fefdSWill Deacon #include <linux/vmalloc.h> 339031fefdSWill Deacon 349031fefdSWill Deacon #include <asm/cacheflush.h> 359031fefdSWill Deacon #include <asm/signal32.h> 369031fefdSWill Deacon #include <asm/vdso.h> 379031fefdSWill Deacon #include <asm/vdso_datapage.h> 389031fefdSWill Deacon 399031fefdSWill Deacon extern char vdso_start, vdso_end; 409031fefdSWill Deacon static unsigned long vdso_pages; 419031fefdSWill Deacon static struct page **vdso_pagelist; 429031fefdSWill Deacon 439031fefdSWill Deacon /* 449031fefdSWill Deacon * The vDSO data page. 459031fefdSWill Deacon */ 469031fefdSWill Deacon static union { 479031fefdSWill Deacon struct vdso_data data; 489031fefdSWill Deacon u8 page[PAGE_SIZE]; 499031fefdSWill Deacon } vdso_data_store __page_aligned_data; 509031fefdSWill Deacon struct vdso_data *vdso_data = &vdso_data_store.data; 519031fefdSWill Deacon 529031fefdSWill Deacon #ifdef CONFIG_COMPAT 539031fefdSWill Deacon /* 549031fefdSWill Deacon * Create and map the vectors page for AArch32 tasks. 559031fefdSWill Deacon */ 569031fefdSWill Deacon static struct page *vectors_page[1]; 579031fefdSWill Deacon 589031fefdSWill Deacon static int alloc_vectors_page(void) 599031fefdSWill Deacon { 609031fefdSWill Deacon extern char __kuser_helper_start[], __kuser_helper_end[]; 619031fefdSWill Deacon int kuser_sz = __kuser_helper_end - __kuser_helper_start; 629031fefdSWill Deacon unsigned long vpage; 639031fefdSWill Deacon 649031fefdSWill Deacon vpage = get_zeroed_page(GFP_ATOMIC); 659031fefdSWill Deacon 669031fefdSWill Deacon if (!vpage) 679031fefdSWill Deacon return -ENOMEM; 689031fefdSWill Deacon 699031fefdSWill Deacon /* kuser helpers */ 709031fefdSWill Deacon memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, 719031fefdSWill Deacon kuser_sz); 729031fefdSWill Deacon 739031fefdSWill Deacon /* sigreturn code */ 749031fefdSWill Deacon memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, 759031fefdSWill Deacon aarch32_sigret_code, sizeof(aarch32_sigret_code)); 769031fefdSWill Deacon 779031fefdSWill Deacon flush_icache_range(vpage, vpage + PAGE_SIZE); 789031fefdSWill Deacon vectors_page[0] = virt_to_page(vpage); 799031fefdSWill Deacon 809031fefdSWill Deacon return 0; 819031fefdSWill Deacon } 829031fefdSWill Deacon arch_initcall(alloc_vectors_page); 839031fefdSWill Deacon 849031fefdSWill Deacon int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) 859031fefdSWill Deacon { 869031fefdSWill Deacon struct mm_struct *mm = current->mm; 879031fefdSWill Deacon unsigned long addr = AARCH32_VECTORS_BASE; 889031fefdSWill Deacon int ret; 899031fefdSWill Deacon 909031fefdSWill Deacon down_write(&mm->mmap_sem); 919031fefdSWill Deacon current->mm->context.vdso = (void *)addr; 929031fefdSWill Deacon 939031fefdSWill Deacon /* Map vectors page at the high address. */ 949031fefdSWill Deacon ret = install_special_mapping(mm, addr, PAGE_SIZE, 959031fefdSWill Deacon VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, 969031fefdSWill Deacon vectors_page); 979031fefdSWill Deacon 989031fefdSWill Deacon up_write(&mm->mmap_sem); 999031fefdSWill Deacon 1009031fefdSWill Deacon return ret; 1019031fefdSWill Deacon } 1029031fefdSWill Deacon #endif /* CONFIG_COMPAT */ 1039031fefdSWill Deacon 1049031fefdSWill Deacon static int __init vdso_init(void) 1059031fefdSWill Deacon { 1069031fefdSWill Deacon struct page *pg; 1079031fefdSWill Deacon char *vbase; 1089031fefdSWill Deacon int i, ret = 0; 1099031fefdSWill Deacon 1109031fefdSWill Deacon vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; 1119031fefdSWill Deacon pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n", 1129031fefdSWill Deacon vdso_pages + 1, vdso_pages, 1L, &vdso_start); 1139031fefdSWill Deacon 1149031fefdSWill Deacon /* Allocate the vDSO pagelist, plus a page for the data. */ 1159031fefdSWill Deacon vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1), 1169031fefdSWill Deacon GFP_KERNEL); 1179031fefdSWill Deacon if (vdso_pagelist == NULL) { 1189031fefdSWill Deacon pr_err("Failed to allocate vDSO pagelist!\n"); 1199031fefdSWill Deacon return -ENOMEM; 1209031fefdSWill Deacon } 1219031fefdSWill Deacon 1229031fefdSWill Deacon /* Grab the vDSO code pages. */ 1239031fefdSWill Deacon for (i = 0; i < vdso_pages; i++) { 1249031fefdSWill Deacon pg = virt_to_page(&vdso_start + i*PAGE_SIZE); 1259031fefdSWill Deacon ClearPageReserved(pg); 1269031fefdSWill Deacon get_page(pg); 1279031fefdSWill Deacon vdso_pagelist[i] = pg; 1289031fefdSWill Deacon } 1299031fefdSWill Deacon 1309031fefdSWill Deacon /* Sanity check the shared object header. */ 1319031fefdSWill Deacon vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL); 1329031fefdSWill Deacon if (vbase == NULL) { 1339031fefdSWill Deacon pr_err("Failed to map vDSO pagelist!\n"); 1349031fefdSWill Deacon return -ENOMEM; 1359031fefdSWill Deacon } else if (memcmp(vbase, "\177ELF", 4)) { 1369031fefdSWill Deacon pr_err("vDSO is not a valid ELF object!\n"); 1379031fefdSWill Deacon ret = -EINVAL; 1389031fefdSWill Deacon goto unmap; 1399031fefdSWill Deacon } 1409031fefdSWill Deacon 1419031fefdSWill Deacon /* Grab the vDSO data page. */ 1429031fefdSWill Deacon pg = virt_to_page(vdso_data); 1439031fefdSWill Deacon get_page(pg); 1449031fefdSWill Deacon vdso_pagelist[i] = pg; 1459031fefdSWill Deacon 1469031fefdSWill Deacon unmap: 1479031fefdSWill Deacon vunmap(vbase); 1489031fefdSWill Deacon return ret; 1499031fefdSWill Deacon } 1509031fefdSWill Deacon arch_initcall(vdso_init); 1519031fefdSWill Deacon 1529031fefdSWill Deacon int arch_setup_additional_pages(struct linux_binprm *bprm, 1539031fefdSWill Deacon int uses_interp) 1549031fefdSWill Deacon { 1559031fefdSWill Deacon struct mm_struct *mm = current->mm; 1569031fefdSWill Deacon unsigned long vdso_base, vdso_mapping_len; 1579031fefdSWill Deacon int ret; 1589031fefdSWill Deacon 1599031fefdSWill Deacon /* Be sure to map the data page */ 1609031fefdSWill Deacon vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT; 1619031fefdSWill Deacon 1629031fefdSWill Deacon down_write(&mm->mmap_sem); 1639031fefdSWill Deacon vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); 1649031fefdSWill Deacon if (IS_ERR_VALUE(vdso_base)) { 1659031fefdSWill Deacon ret = vdso_base; 1669031fefdSWill Deacon goto up_fail; 1679031fefdSWill Deacon } 1689031fefdSWill Deacon mm->context.vdso = (void *)vdso_base; 1699031fefdSWill Deacon 1709031fefdSWill Deacon ret = install_special_mapping(mm, vdso_base, vdso_mapping_len, 1719031fefdSWill Deacon VM_READ|VM_EXEC| 1729031fefdSWill Deacon VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 1739031fefdSWill Deacon vdso_pagelist); 1749031fefdSWill Deacon if (ret) { 1759031fefdSWill Deacon mm->context.vdso = NULL; 1769031fefdSWill Deacon goto up_fail; 1779031fefdSWill Deacon } 1789031fefdSWill Deacon 1799031fefdSWill Deacon up_fail: 1809031fefdSWill Deacon up_write(&mm->mmap_sem); 1819031fefdSWill Deacon 1829031fefdSWill Deacon return ret; 1839031fefdSWill Deacon } 1849031fefdSWill Deacon 1859031fefdSWill Deacon const char *arch_vma_name(struct vm_area_struct *vma) 1869031fefdSWill Deacon { 1879031fefdSWill Deacon /* 1889031fefdSWill Deacon * We can re-use the vdso pointer in mm_context_t for identifying 1899031fefdSWill Deacon * the vectors page for compat applications. The vDSO will always 1909031fefdSWill Deacon * sit above TASK_UNMAPPED_BASE and so we don't need to worry about 1919031fefdSWill Deacon * it conflicting with the vectors base. 1929031fefdSWill Deacon */ 1939031fefdSWill Deacon if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) { 1949031fefdSWill Deacon #ifdef CONFIG_COMPAT 1959031fefdSWill Deacon if (vma->vm_start == AARCH32_VECTORS_BASE) 1969031fefdSWill Deacon return "[vectors]"; 1979031fefdSWill Deacon #endif 1989031fefdSWill Deacon return "[vdso]"; 1999031fefdSWill Deacon } 2009031fefdSWill Deacon 2019031fefdSWill Deacon return NULL; 2029031fefdSWill Deacon } 2039031fefdSWill Deacon 2049031fefdSWill Deacon /* 2059031fefdSWill Deacon * We define AT_SYSINFO_EHDR, so we need these function stubs to keep 2069031fefdSWill Deacon * Linux happy. 2079031fefdSWill Deacon */ 2089031fefdSWill Deacon int in_gate_area_no_mm(unsigned long addr) 2099031fefdSWill Deacon { 2109031fefdSWill Deacon return 0; 2119031fefdSWill Deacon } 2129031fefdSWill Deacon 2139031fefdSWill Deacon int in_gate_area(struct mm_struct *mm, unsigned long addr) 2149031fefdSWill Deacon { 2159031fefdSWill Deacon return 0; 2169031fefdSWill Deacon } 2179031fefdSWill Deacon 2189031fefdSWill Deacon struct vm_area_struct *get_gate_vma(struct mm_struct *mm) 2199031fefdSWill Deacon { 2209031fefdSWill Deacon return NULL; 2219031fefdSWill Deacon } 2229031fefdSWill Deacon 2239031fefdSWill Deacon /* 2249031fefdSWill Deacon * Update the vDSO data page to keep in sync with kernel timekeeping. 2259031fefdSWill Deacon */ 226c60b0c28SCatalin Marinas void update_vsyscall(struct timekeeper *tk) 2279031fefdSWill Deacon { 2289031fefdSWill Deacon struct timespec xtime_coarse; 229c60b0c28SCatalin Marinas u32 use_syscall = strcmp(tk->clock->name, "arch_sys_counter"); 2309031fefdSWill Deacon 2319031fefdSWill Deacon ++vdso_data->tb_seq_count; 2329031fefdSWill Deacon smp_wmb(); 2339031fefdSWill Deacon 2349031fefdSWill Deacon xtime_coarse = __current_kernel_time(); 2359031fefdSWill Deacon vdso_data->use_syscall = use_syscall; 2369031fefdSWill Deacon vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec; 2379031fefdSWill Deacon vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec; 2389031fefdSWill Deacon 2399031fefdSWill Deacon if (!use_syscall) { 240c60b0c28SCatalin Marinas vdso_data->cs_cycle_last = tk->clock->cycle_last; 241c60b0c28SCatalin Marinas vdso_data->xtime_clock_sec = tk->xtime_sec; 242c60b0c28SCatalin Marinas vdso_data->xtime_clock_nsec = tk->xtime_nsec >> tk->shift; 243c60b0c28SCatalin Marinas vdso_data->cs_mult = tk->mult; 244c60b0c28SCatalin Marinas vdso_data->cs_shift = tk->shift; 245c60b0c28SCatalin Marinas vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; 246c60b0c28SCatalin Marinas vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; 2479031fefdSWill Deacon } 2489031fefdSWill Deacon 2499031fefdSWill Deacon smp_wmb(); 2509031fefdSWill Deacon ++vdso_data->tb_seq_count; 2519031fefdSWill Deacon } 2529031fefdSWill Deacon 2539031fefdSWill Deacon void update_vsyscall_tz(void) 2549031fefdSWill Deacon { 2559031fefdSWill Deacon ++vdso_data->tb_seq_count; 2569031fefdSWill Deacon smp_wmb(); 2579031fefdSWill Deacon vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 2589031fefdSWill Deacon vdso_data->tz_dsttime = sys_tz.tz_dsttime; 2599031fefdSWill Deacon smp_wmb(); 2609031fefdSWill Deacon ++vdso_data->tb_seq_count; 2619031fefdSWill Deacon } 262