// 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/vdso_datastore.h>

#include <asm/page.h>
#include <asm/vdso.h>
#include <vdso/helpers.h>
#include <vdso/vsyscall.h>
#include <vdso/datapage.h>
#include <generated/vdso-offsets.h>

extern char vdso_start[], vdso_end[];

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;
}

struct loongarch_vdso_info vdso_info = {
        .vdso = vdso_start,
        .code_mapping = {
                .name = "[vdso]",
                .mremap = vdso_mremap,
        },
        .offset_sigreturn = vdso_offset_sigreturn,
};

static int __init init_vdso(void)
{
        unsigned long i, cpu, pfn;

        BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));

        for_each_possible_cpu(cpu)
                vdso_k_arch_data->pdata[cpu].node = cpu_to_node(cpu);

        vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start);
        vdso_info.code_mapping.pages =
                kzalloc_objs(struct page *, vdso_info.size / PAGE_SIZE);

        if (!vdso_info.code_mapping.pages)
                return -ENOMEM;

        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);

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 = vdso_install_vvar_mapping(mm, data_addr);
        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 |
                                       VM_SEALED_SYSMAP,
                                       &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;
}