diff options
Diffstat (limited to 'arch/loongarch/kernel/vdso.c')
| -rw-r--r-- | arch/loongarch/kernel/vdso.c | 98 |
1 files changed, 82 insertions, 16 deletions
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c index eaebd2e0f725..14941e4be66d 100644 --- a/arch/loongarch/kernel/vdso.c +++ b/arch/loongarch/kernel/vdso.c @@ -14,6 +14,7 @@ #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> @@ -26,12 +27,17 @@ extern char vdso_start[], vdso_end[]; /* Kernel-provided data used by the VDSO. */ static union { - u8 page[VDSO_DATA_SIZE]; + 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 = loongarch_vdso_data.vdata.data; +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) @@ -41,6 +47,43 @@ static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struc 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, @@ -51,6 +94,7 @@ struct loongarch_vdso_info vdso_info = { }, .data_mapping = { .name = "[vvar]", + .fault = vvar_fault, }, .offset_sigreturn = vdso_offset_sigreturn, }; @@ -73,6 +117,37 @@ static int __init init_vdso(void) } 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; @@ -88,7 +163,7 @@ static unsigned long vdso_base(void) int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { int ret; - unsigned long vvar_size, size, data_addr, vdso_addr; + 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; @@ -100,32 +175,23 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) * Determine total area size. This includes the VDSO data itself * and the data pages. */ - vvar_size = VDSO_DATA_SIZE; - size = vvar_size + info->size; + 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; } - vdso_addr = data_addr + VDSO_DATA_SIZE; - vma = _install_special_mapping(mm, data_addr, vvar_size, - VM_READ | VM_MAYREAD, + 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; } - /* Map VDSO data page. */ - ret = remap_pfn_range(vma, data_addr, - virt_to_phys(&loongarch_vdso_data) >> PAGE_SHIFT, - vvar_size, PAGE_READONLY); - if (ret) - goto out; - - /* Map VDSO code page. */ + 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); |