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410 lines
11 KiB
410 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp. |
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* <[email protected]> |
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*/ |
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#include <linux/errno.h> |
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#include <linux/sched.h> |
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#include <linux/kernel.h> |
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#include <linux/mm.h> |
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#include <linux/smp.h> |
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#include <linux/stddef.h> |
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#include <linux/unistd.h> |
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#include <linux/slab.h> |
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#include <linux/user.h> |
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#include <linux/elf.h> |
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#include <linux/security.h> |
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#include <linux/memblock.h> |
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#include <linux/syscalls.h> |
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#include <linux/time_namespace.h> |
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#include <vdso/datapage.h> |
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#include <asm/syscall.h> |
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#include <asm/processor.h> |
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#include <asm/mmu.h> |
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#include <asm/mmu_context.h> |
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#include <asm/prom.h> |
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#include <asm/machdep.h> |
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#include <asm/cputable.h> |
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#include <asm/sections.h> |
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#include <asm/firmware.h> |
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#include <asm/vdso.h> |
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#include <asm/vdso_datapage.h> |
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#include <asm/setup.h> |
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/* The alignment of the vDSO */ |
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#define VDSO_ALIGNMENT (1 << 16) |
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extern char vdso32_start, vdso32_end; |
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extern char vdso64_start, vdso64_end; |
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/* |
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* The vdso data page (aka. systemcfg for old ppc64 fans) is here. |
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* Once the early boot kernel code no longer needs to muck around |
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* with it, it will become dynamically allocated |
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*/ |
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static union { |
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struct vdso_arch_data data; |
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u8 page[PAGE_SIZE]; |
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} vdso_data_store __page_aligned_data; |
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struct vdso_arch_data *vdso_data = &vdso_data_store.data; |
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enum vvar_pages { |
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VVAR_DATA_PAGE_OFFSET, |
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VVAR_TIMENS_PAGE_OFFSET, |
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VVAR_NR_PAGES, |
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}; |
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static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma, |
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unsigned long text_size) |
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{ |
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unsigned long new_size = new_vma->vm_end - new_vma->vm_start; |
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if (new_size != text_size) |
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return -EINVAL; |
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current->mm->context.vdso = (void __user *)new_vma->vm_start; |
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return 0; |
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} |
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static int vdso32_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) |
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{ |
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return vdso_mremap(sm, new_vma, &vdso32_end - &vdso32_start); |
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} |
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static int vdso64_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) |
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{ |
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return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start); |
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} |
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static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, |
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struct vm_area_struct *vma, struct vm_fault *vmf); |
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static struct vm_special_mapping vvar_spec __ro_after_init = { |
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.name = "[vvar]", |
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.fault = vvar_fault, |
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}; |
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static struct vm_special_mapping vdso32_spec __ro_after_init = { |
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.name = "[vdso]", |
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.mremap = vdso32_mremap, |
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}; |
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static struct vm_special_mapping vdso64_spec __ro_after_init = { |
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.name = "[vdso]", |
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.mremap = vdso64_mremap, |
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}; |
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#ifdef CONFIG_TIME_NS |
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struct vdso_data *arch_get_vdso_data(void *vvar_page) |
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{ |
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return ((struct vdso_arch_data *)vvar_page)->data; |
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} |
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/* |
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* The vvar mapping contains data for a specific time namespace, so when a task |
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* changes namespace we must unmap its vvar data for the old namespace. |
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* Subsequent faults will map in data for the new namespace. |
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* |
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* For more details see timens_setup_vdso_data(). |
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*/ |
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int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) |
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{ |
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struct mm_struct *mm = task->mm; |
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struct vm_area_struct *vma; |
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mmap_read_lock(mm); |
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for (vma = mm->mmap; vma; vma = vma->vm_next) { |
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unsigned long size = vma->vm_end - vma->vm_start; |
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if (vma_is_special_mapping(vma, &vvar_spec)) |
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zap_page_range(vma, vma->vm_start, size); |
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} |
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mmap_read_unlock(mm); |
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return 0; |
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} |
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma) |
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{ |
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if (likely(vma->vm_mm == current->mm)) |
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return current->nsproxy->time_ns->vvar_page; |
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/* |
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* VM_PFNMAP | VM_IO protect .fault() handler from being called |
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* through interfaces like /proc/$pid/mem or |
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* process_vm_{readv,writev}() as long as there's no .access() |
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* in special_mapping_vmops. |
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* For more details check_vma_flags() and __access_remote_vm() |
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*/ |
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WARN(1, "vvar_page accessed remotely"); |
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return NULL; |
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} |
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#else |
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma) |
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{ |
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return NULL; |
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} |
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#endif |
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static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, |
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struct vm_area_struct *vma, struct vm_fault *vmf) |
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{ |
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struct page *timens_page = find_timens_vvar_page(vma); |
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unsigned long pfn; |
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switch (vmf->pgoff) { |
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case VVAR_DATA_PAGE_OFFSET: |
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if (timens_page) |
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pfn = page_to_pfn(timens_page); |
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else |
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pfn = virt_to_pfn(vdso_data); |
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break; |
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#ifdef CONFIG_TIME_NS |
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case VVAR_TIMENS_PAGE_OFFSET: |
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/* |
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* If a task belongs to a time namespace then a namespace |
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* specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and |
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* the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET |
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* offset. |
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* See also the comment near timens_setup_vdso_data(). |
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*/ |
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if (!timens_page) |
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return VM_FAULT_SIGBUS; |
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pfn = virt_to_pfn(vdso_data); |
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break; |
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#endif /* CONFIG_TIME_NS */ |
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default: |
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return VM_FAULT_SIGBUS; |
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} |
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return vmf_insert_pfn(vma, vmf->address, pfn); |
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} |
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/* |
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* This is called from binfmt_elf, we create the special vma for the |
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* vDSO and insert it into the mm struct tree |
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*/ |
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static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |
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{ |
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unsigned long vdso_size, vdso_base, mappings_size; |
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struct vm_special_mapping *vdso_spec; |
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unsigned long vvar_size = VVAR_NR_PAGES * PAGE_SIZE; |
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struct mm_struct *mm = current->mm; |
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struct vm_area_struct *vma; |
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if (is_32bit_task()) { |
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vdso_spec = &vdso32_spec; |
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vdso_size = &vdso32_end - &vdso32_start; |
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vdso_base = VDSO32_MBASE; |
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} else { |
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vdso_spec = &vdso64_spec; |
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vdso_size = &vdso64_end - &vdso64_start; |
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/* |
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* On 64bit we don't have a preferred map address. This |
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* allows get_unmapped_area to find an area near other mmaps |
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* and most likely share a SLB entry. |
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*/ |
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vdso_base = 0; |
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} |
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mappings_size = vdso_size + vvar_size; |
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mappings_size += (VDSO_ALIGNMENT - 1) & PAGE_MASK; |
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/* |
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* pick a base address for the vDSO in process space. We try to put it |
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* at vdso_base which is the "natural" base for it, but we might fail |
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* and end up putting it elsewhere. |
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* Add enough to the size so that the result can be aligned. |
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*/ |
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vdso_base = get_unmapped_area(NULL, vdso_base, mappings_size, 0, 0); |
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if (IS_ERR_VALUE(vdso_base)) |
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return vdso_base; |
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/* Add required alignment. */ |
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vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT); |
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/* |
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* Put vDSO base into mm struct. We need to do this before calling |
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* install_special_mapping or the perf counter mmap tracking code |
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* will fail to recognise it as a vDSO. |
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*/ |
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mm->context.vdso = (void __user *)vdso_base + vvar_size; |
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vma = _install_special_mapping(mm, vdso_base, vvar_size, |
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VM_READ | VM_MAYREAD | VM_IO | |
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VM_DONTDUMP | VM_PFNMAP, &vvar_spec); |
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if (IS_ERR(vma)) |
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return PTR_ERR(vma); |
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/* |
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* our vma flags don't have VM_WRITE so by default, the process isn't |
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* allowed to write those pages. |
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* gdb can break that with ptrace interface, and thus trigger COW on |
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* those pages but it's then your responsibility to never do that on |
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* the "data" page of the vDSO or you'll stop getting kernel updates |
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* and your nice userland gettimeofday will be totally dead. |
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* It's fine to use that for setting breakpoints in the vDSO code |
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* pages though. |
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*/ |
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vma = _install_special_mapping(mm, vdso_base + vvar_size, vdso_size, |
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VM_READ | VM_EXEC | VM_MAYREAD | |
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VM_MAYWRITE | VM_MAYEXEC, vdso_spec); |
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if (IS_ERR(vma)) |
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do_munmap(mm, vdso_base, vvar_size, NULL); |
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return PTR_ERR_OR_ZERO(vma); |
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} |
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |
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{ |
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struct mm_struct *mm = current->mm; |
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int rc; |
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mm->context.vdso = NULL; |
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if (mmap_write_lock_killable(mm)) |
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return -EINTR; |
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rc = __arch_setup_additional_pages(bprm, uses_interp); |
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if (rc) |
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mm->context.vdso = NULL; |
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mmap_write_unlock(mm); |
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return rc; |
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} |
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#define VDSO_DO_FIXUPS(type, value, bits, sec) do { \ |
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void *__start = (void *)VDSO##bits##_SYMBOL(&vdso##bits##_start, sec##_start); \ |
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void *__end = (void *)VDSO##bits##_SYMBOL(&vdso##bits##_start, sec##_end); \ |
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\ |
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do_##type##_fixups((value), __start, __end); \ |
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} while (0) |
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static void __init vdso_fixup_features(void) |
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{ |
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#ifdef CONFIG_PPC64 |
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VDSO_DO_FIXUPS(feature, cur_cpu_spec->cpu_features, 64, ftr_fixup); |
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VDSO_DO_FIXUPS(feature, cur_cpu_spec->mmu_features, 64, mmu_ftr_fixup); |
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VDSO_DO_FIXUPS(feature, powerpc_firmware_features, 64, fw_ftr_fixup); |
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VDSO_DO_FIXUPS(lwsync, cur_cpu_spec->cpu_features, 64, lwsync_fixup); |
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#endif /* CONFIG_PPC64 */ |
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#ifdef CONFIG_VDSO32 |
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VDSO_DO_FIXUPS(feature, cur_cpu_spec->cpu_features, 32, ftr_fixup); |
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VDSO_DO_FIXUPS(feature, cur_cpu_spec->mmu_features, 32, mmu_ftr_fixup); |
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#ifdef CONFIG_PPC64 |
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VDSO_DO_FIXUPS(feature, powerpc_firmware_features, 32, fw_ftr_fixup); |
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#endif /* CONFIG_PPC64 */ |
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VDSO_DO_FIXUPS(lwsync, cur_cpu_spec->cpu_features, 32, lwsync_fixup); |
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#endif |
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} |
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/* |
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* Called from setup_arch to initialize the bitmap of available |
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* syscalls in the systemcfg page |
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*/ |
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static void __init vdso_setup_syscall_map(void) |
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{ |
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unsigned int i; |
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for (i = 0; i < NR_syscalls; i++) { |
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if (sys_call_table[i] != (unsigned long)&sys_ni_syscall) |
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vdso_data->syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f); |
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if (IS_ENABLED(CONFIG_COMPAT) && |
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compat_sys_call_table[i] != (unsigned long)&sys_ni_syscall) |
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vdso_data->compat_syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f); |
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} |
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} |
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#ifdef CONFIG_PPC64 |
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int vdso_getcpu_init(void) |
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{ |
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unsigned long cpu, node, val; |
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/* |
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* SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node |
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* in the next 16 bits. The VDSO uses this to implement getcpu(). |
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*/ |
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cpu = get_cpu(); |
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WARN_ON_ONCE(cpu > 0xffff); |
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node = cpu_to_node(cpu); |
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WARN_ON_ONCE(node > 0xffff); |
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val = (cpu & 0xffff) | ((node & 0xffff) << 16); |
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mtspr(SPRN_SPRG_VDSO_WRITE, val); |
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get_paca()->sprg_vdso = val; |
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put_cpu(); |
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return 0; |
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} |
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/* We need to call this before SMP init */ |
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early_initcall(vdso_getcpu_init); |
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#endif |
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static struct page ** __init vdso_setup_pages(void *start, void *end) |
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{ |
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int i; |
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struct page **pagelist; |
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int pages = (end - start) >> PAGE_SHIFT; |
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pagelist = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL); |
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if (!pagelist) |
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panic("%s: Cannot allocate page list for VDSO", __func__); |
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for (i = 0; i < pages; i++) |
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pagelist[i] = virt_to_page(start + i * PAGE_SIZE); |
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return pagelist; |
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} |
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static int __init vdso_init(void) |
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{ |
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#ifdef CONFIG_PPC64 |
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/* |
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* Fill up the "systemcfg" stuff for backward compatibility |
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*/ |
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strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64"); |
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vdso_data->version.major = SYSTEMCFG_MAJOR; |
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vdso_data->version.minor = SYSTEMCFG_MINOR; |
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vdso_data->processor = mfspr(SPRN_PVR); |
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/* |
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* Fake the old platform number for pSeries and add |
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* in LPAR bit if necessary |
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*/ |
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vdso_data->platform = 0x100; |
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if (firmware_has_feature(FW_FEATURE_LPAR)) |
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vdso_data->platform |= 1; |
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vdso_data->physicalMemorySize = memblock_phys_mem_size(); |
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vdso_data->dcache_size = ppc64_caches.l1d.size; |
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vdso_data->dcache_line_size = ppc64_caches.l1d.line_size; |
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vdso_data->icache_size = ppc64_caches.l1i.size; |
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vdso_data->icache_line_size = ppc64_caches.l1i.line_size; |
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vdso_data->dcache_block_size = ppc64_caches.l1d.block_size; |
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vdso_data->icache_block_size = ppc64_caches.l1i.block_size; |
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vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size; |
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vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size; |
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#endif /* CONFIG_PPC64 */ |
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vdso_setup_syscall_map(); |
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vdso_fixup_features(); |
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if (IS_ENABLED(CONFIG_VDSO32)) |
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vdso32_spec.pages = vdso_setup_pages(&vdso32_start, &vdso32_end); |
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if (IS_ENABLED(CONFIG_PPC64)) |
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vdso64_spec.pages = vdso_setup_pages(&vdso64_start, &vdso64_end); |
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smp_wmb(); |
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return 0; |
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} |
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arch_initcall(vdso_init);
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