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