From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/loongarch/kernel/vdso.c | 209 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 209 insertions(+) create mode 100644 arch/loongarch/kernel/vdso.c (limited to 'arch/loongarch/kernel/vdso.c') diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c new file mode 100644 index 0000000000..14941e4be6 --- /dev/null +++ b/arch/loongarch/kernel/vdso.c @@ -0,0 +1,209 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Author: Huacai Chen + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +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; +} -- cgit v1.2.3