| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Author: Huacai Chen <chenhuacai@loongson.cn> |
| * Copyright (C) 2020-2022 Loongson Technology Corporation Limited |
| */ |
| |
| #include <linux/binfmts.h> |
| #include <linux/elf.h> |
| #include <linux/err.h> |
| #include <linux/init.h> |
| #include <linux/ioport.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/random.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/time_namespace.h> |
| #include <linux/timekeeper_internal.h> |
| |
| #include <asm/page.h> |
| #include <asm/vdso.h> |
| #include <vdso/helpers.h> |
| #include <vdso/vsyscall.h> |
| #include <generated/vdso-offsets.h> |
| |
| extern char vdso_start[], vdso_end[]; |
| |
| /* Kernel-provided data used by the VDSO. */ |
| static union { |
| u8 page[PAGE_SIZE]; |
| struct vdso_data data[CS_BASES]; |
| } generic_vdso_data __page_aligned_data; |
| |
| static union { |
| u8 page[LOONGARCH_VDSO_DATA_SIZE]; |
| struct loongarch_vdso_data vdata; |
| } loongarch_vdso_data __page_aligned_data; |
| |
| static struct page *vdso_pages[] = { NULL }; |
| struct vdso_data *vdso_data = generic_vdso_data.data; |
| struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata; |
| |
| static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) |
| { |
| current->mm->context.vdso = (void *)(new_vma->vm_start); |
| |
| return 0; |
| } |
| |
| static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, |
| struct vm_area_struct *vma, struct vm_fault *vmf) |
| { |
| unsigned long pfn; |
| struct page *timens_page = find_timens_vvar_page(vma); |
| |
| switch (vmf->pgoff) { |
| case VVAR_GENERIC_PAGE_OFFSET: |
| if (!timens_page) |
| pfn = sym_to_pfn(vdso_data); |
| else |
| pfn = page_to_pfn(timens_page); |
| break; |
| #ifdef CONFIG_TIME_NS |
| case VVAR_TIMENS_PAGE_OFFSET: |
| /* |
| * If a task belongs to a time namespace then a namespace specific |
| * VVAR is mapped with the VVAR_GENERIC_PAGE_OFFSET and the real |
| * VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET offset. |
| * See also the comment near timens_setup_vdso_data(). |
| */ |
| if (!timens_page) |
| return VM_FAULT_SIGBUS; |
| else |
| pfn = sym_to_pfn(vdso_data); |
| break; |
| #endif /* CONFIG_TIME_NS */ |
| case VVAR_LOONGARCH_PAGES_START ... VVAR_LOONGARCH_PAGES_END: |
| pfn = sym_to_pfn(&loongarch_vdso_data) + vmf->pgoff - VVAR_LOONGARCH_PAGES_START; |
| break; |
| default: |
| return VM_FAULT_SIGBUS; |
| } |
| |
| return vmf_insert_pfn(vma, vmf->address, pfn); |
| } |
| |
| struct loongarch_vdso_info vdso_info = { |
| .vdso = vdso_start, |
| .size = PAGE_SIZE, |
| .code_mapping = { |
| .name = "[vdso]", |
| .pages = vdso_pages, |
| .mremap = vdso_mremap, |
| }, |
| .data_mapping = { |
| .name = "[vvar]", |
| .fault = vvar_fault, |
| }, |
| .offset_sigreturn = vdso_offset_sigreturn, |
| }; |
| |
| static int __init init_vdso(void) |
| { |
| unsigned long i, cpu, pfn; |
| |
| BUG_ON(!PAGE_ALIGNED(vdso_info.vdso)); |
| BUG_ON(!PAGE_ALIGNED(vdso_info.size)); |
| |
| for_each_possible_cpu(cpu) |
| vdso_pdata[cpu].node = cpu_to_node(cpu); |
| |
| pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso)); |
| for (i = 0; i < vdso_info.size / PAGE_SIZE; i++) |
| vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i); |
| |
| return 0; |
| } |
| subsys_initcall(init_vdso); |
| |
| #ifdef CONFIG_TIME_NS |
| struct vdso_data *arch_get_vdso_data(void *vvar_page) |
| { |
| return (struct vdso_data *)(vvar_page); |
| } |
| |
| /* |
| * The vvar mapping contains data for a specific time namespace, so when a |
| * task changes namespace we must unmap its vvar data for the old namespace. |
| * Subsequent faults will map in data for the new namespace. |
| * |
| * For more details see timens_setup_vdso_data(). |
| */ |
| int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) |
| { |
| struct mm_struct *mm = task->mm; |
| struct vm_area_struct *vma; |
| |
| VMA_ITERATOR(vmi, mm, 0); |
| |
| mmap_read_lock(mm); |
| for_each_vma(vmi, vma) { |
| if (vma_is_special_mapping(vma, &vdso_info.data_mapping)) |
| zap_vma_pages(vma); |
| } |
| mmap_read_unlock(mm); |
| |
| return 0; |
| } |
| #endif |
| |
| static unsigned long vdso_base(void) |
| { |
| unsigned long base = STACK_TOP; |
| |
| if (current->flags & PF_RANDOMIZE) { |
| base += get_random_u32_below(VDSO_RANDOMIZE_SIZE); |
| base = PAGE_ALIGN(base); |
| } |
| |
| return base; |
| } |
| |
| int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |
| { |
| int ret; |
| unsigned long size, data_addr, vdso_addr; |
| struct mm_struct *mm = current->mm; |
| struct vm_area_struct *vma; |
| struct loongarch_vdso_info *info = current->thread.vdso; |
| |
| if (mmap_write_lock_killable(mm)) |
| return -EINTR; |
| |
| /* |
| * Determine total area size. This includes the VDSO data itself |
| * and the data pages. |
| */ |
| size = VVAR_SIZE + info->size; |
| |
| data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0); |
| if (IS_ERR_VALUE(data_addr)) { |
| ret = data_addr; |
| goto out; |
| } |
| |
| vma = _install_special_mapping(mm, data_addr, VVAR_SIZE, |
| VM_READ | VM_MAYREAD | VM_PFNMAP, |
| &info->data_mapping); |
| if (IS_ERR(vma)) { |
| ret = PTR_ERR(vma); |
| goto out; |
| } |
| |
| vdso_addr = data_addr + VVAR_SIZE; |
| vma = _install_special_mapping(mm, vdso_addr, info->size, |
| VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, |
| &info->code_mapping); |
| if (IS_ERR(vma)) { |
| ret = PTR_ERR(vma); |
| goto out; |
| } |
| |
| mm->context.vdso = (void *)vdso_addr; |
| ret = 0; |
| |
| out: |
| mmap_write_unlock(mm); |
| return ret; |
| } |