diff options
Diffstat (limited to 'arch/arm64/kernel/vdso.c')
| -rw-r--r-- | arch/arm64/kernel/vdso.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c new file mode 100644 index 000000000..ec37ab3f5 --- /dev/null +++ b/arch/arm64/kernel/vdso.c @@ -0,0 +1,231 @@ +/* + * VDSO implementation for AArch64 and vector page setup for AArch32. + * + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.deacon@arm.com> + */ + +#include <linux/kernel.h> +#include <linux/clocksource.h> +#include <linux/elf.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/gfp.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/signal.h> +#include <linux/slab.h> +#include <linux/timekeeper_internal.h> +#include <linux/vmalloc.h> + +#include <asm/cacheflush.h> +#include <asm/signal32.h> +#include <asm/vdso.h> +#include <asm/vdso_datapage.h> + +extern char vdso_start, vdso_end; +static unsigned long vdso_pages; +static struct page **vdso_pagelist; + +/* + * The vDSO data page. + */ +static union { + struct vdso_data data; + u8 page[PAGE_SIZE]; +} vdso_data_store __page_aligned_data; +struct vdso_data *vdso_data = &vdso_data_store.data; + +#ifdef CONFIG_COMPAT +/* + * Create and map the vectors page for AArch32 tasks. + */ +static struct page *vectors_page[1]; + +static int alloc_vectors_page(void) +{ + extern char __kuser_helper_start[], __kuser_helper_end[]; + extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; + + int kuser_sz = __kuser_helper_end - __kuser_helper_start; + int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; + unsigned long vpage; + + vpage = get_zeroed_page(GFP_ATOMIC); + + if (!vpage) + return -ENOMEM; + + /* kuser helpers */ + memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, + kuser_sz); + + /* sigreturn code */ + memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, + __aarch32_sigret_code_start, sigret_sz); + + flush_icache_range(vpage, vpage + PAGE_SIZE); + vectors_page[0] = virt_to_page(vpage); + + return 0; +} +arch_initcall(alloc_vectors_page); + +int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + unsigned long addr = AARCH32_VECTORS_BASE; + static struct vm_special_mapping spec = { + .name = "[vectors]", + .pages = vectors_page, + + }; + void *ret; + + down_write(&mm->mmap_sem); + current->mm->context.vdso = (void *)addr; + + /* Map vectors page at the high address. */ + ret = _install_special_mapping(mm, addr, PAGE_SIZE, + VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, + &spec); + + up_write(&mm->mmap_sem); + + return PTR_ERR_OR_ZERO(ret); +} +#endif /* CONFIG_COMPAT */ + +static struct vm_special_mapping vdso_spec[2]; + +static int __init vdso_init(void) +{ + int i; + + if (memcmp(&vdso_start, "\177ELF", 4)) { + pr_err("vDSO is not a valid ELF object!\n"); + return -EINVAL; + } + + vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; + pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n", + vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data); + + /* Allocate the vDSO pagelist, plus a page for the data. */ + vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *), + GFP_KERNEL); + if (vdso_pagelist == NULL) + return -ENOMEM; + + /* Grab the vDSO data page. */ + vdso_pagelist[0] = virt_to_page(vdso_data); + + /* Grab the vDSO code pages. */ + for (i = 0; i < vdso_pages; i++) + vdso_pagelist[i + 1] = virt_to_page(&vdso_start + i * PAGE_SIZE); + + /* Populate the special mapping structures */ + vdso_spec[0] = (struct vm_special_mapping) { + .name = "[vvar]", + .pages = vdso_pagelist, + }; + + vdso_spec[1] = (struct vm_special_mapping) { + .name = "[vdso]", + .pages = &vdso_pagelist[1], + }; + + return 0; +} +arch_initcall(vdso_init); + +int arch_setup_additional_pages(struct linux_binprm *bprm, + int uses_interp) +{ + struct mm_struct *mm = current->mm; + unsigned long vdso_base, vdso_text_len, vdso_mapping_len; + void *ret; + + vdso_text_len = vdso_pages << PAGE_SHIFT; + /* Be sure to map the data page */ + vdso_mapping_len = vdso_text_len + PAGE_SIZE; + + down_write(&mm->mmap_sem); + vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); + if (IS_ERR_VALUE(vdso_base)) { + ret = ERR_PTR(vdso_base); + goto up_fail; + } + ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, + VM_READ|VM_MAYREAD, + &vdso_spec[0]); + if (IS_ERR(ret)) + goto up_fail; + + vdso_base += PAGE_SIZE; + mm->context.vdso = (void *)vdso_base; + ret = _install_special_mapping(mm, vdso_base, vdso_text_len, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, + &vdso_spec[1]); + if (IS_ERR(ret)) + goto up_fail; + + + up_write(&mm->mmap_sem); + return 0; + +up_fail: + mm->context.vdso = NULL; + up_write(&mm->mmap_sem); + return PTR_ERR(ret); +} + +/* + * Update the vDSO data page to keep in sync with kernel timekeeping. + */ +void update_vsyscall(struct timekeeper *tk) +{ + struct timespec xtime_coarse; + u32 use_syscall = strcmp(tk->tkr_mono.clock->name, "arch_sys_counter"); + + ++vdso_data->tb_seq_count; + smp_wmb(); + + xtime_coarse = __current_kernel_time(); + vdso_data->use_syscall = use_syscall; + vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec; + vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec; + vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; + vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; + + if (!use_syscall) { + vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; + vdso_data->xtime_clock_sec = tk->xtime_sec; + vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec; + vdso_data->cs_mult = tk->tkr_mono.mult; + vdso_data->cs_shift = tk->tkr_mono.shift; + } + + smp_wmb(); + ++vdso_data->tb_seq_count; +} + +void update_vsyscall_tz(void) +{ + vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; + vdso_data->tz_dsttime = sys_tz.tz_dsttime; +} |