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// 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;
}
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