Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 */
 
#include <linux/err.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <asm/current.h>
#include <asm/page.h>
#include <kern_util.h>
#include <os.h>
 
pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
{
<------>pgd_t *pgd;
<------>p4d_t *p4d;
<------>pud_t *pud;
<------>pmd_t *pmd;
 
<------>if (mm == NULL)
<------><------>return NULL;
 
<------>pgd = pgd_offset(mm, addr);
<------>if (!pgd_present(*pgd))
<------><------>return NULL;
 
<------>p4d = p4d_offset(pgd, addr);
<------>if (!p4d_present(*p4d))
<------><------>return NULL;
 
<------>pud = pud_offset(p4d, addr);
<------>if (!pud_present(*pud))
<------><------>return NULL;
 
<------>pmd = pmd_offset(pud, addr);
<------>if (!pmd_present(*pmd))
<------><------>return NULL;
 
<------>return pte_offset_kernel(pmd, addr);
}
 
static pte_t *maybe_map(unsigned long virt, int is_write)
{
<------>pte_t *pte = virt_to_pte(current->mm, virt);
<------>int err, dummy_code;
 
<------>if ((pte == NULL) || !pte_present(*pte) ||
<------>    (is_write && !pte_write(*pte))) {
<------><------>err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
<------><------>if (err)
<------><------><------>return NULL;
<------><------>pte = virt_to_pte(current->mm, virt);
<------>}
<------>if (!pte_present(*pte))
<------><------>pte = NULL;
 
<------>return pte;
}
 
static int do_op_one_page(unsigned long addr, int len, int is_write,
<------><------> int (*op)(unsigned long addr, int len, void *arg), void *arg)
{
<------>struct page *page;
<------>pte_t *pte;
<------>int n;
 
<------>pte = maybe_map(addr, is_write);
<------>if (pte == NULL)
<------><------>return -1;
 
<------>page = pte_page(*pte);
#ifdef CONFIG_64BIT
<------>pagefault_disable();
<------>addr = (unsigned long) page_address(page) +
<------><------>(addr & ~PAGE_MASK);
#else
<------>addr = (unsigned long) kmap_atomic(page) +
<------><------>(addr & ~PAGE_MASK);
#endif
<------>n = (*op)(addr, len, arg);
 
#ifdef CONFIG_64BIT
<------>pagefault_enable();
#else
<------>kunmap_atomic((void *)addr);
#endif
 
<------>return n;
}
 
static long buffer_op(unsigned long addr, int len, int is_write,
<------><------>      int (*op)(unsigned long, int, void *), void *arg)
{
<------>long size, remain, n;
 
<------>size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
<------>remain = len;
 
<------>n = do_op_one_page(addr, size, is_write, op, arg);
<------>if (n != 0) {
<------><------>remain = (n < 0 ? remain : 0);
<------><------>goto out;
<------>}
 
<------>addr += size;
<------>remain -= size;
<------>if (remain == 0)
<------><------>goto out;
 
<------>while (addr < ((addr + remain) & PAGE_MASK)) {
<------><------>n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
<------><------>if (n != 0) {
<------><------><------>remain = (n < 0 ? remain : 0);
<------><------><------>goto out;
<------><------>}
 
<------><------>addr += PAGE_SIZE;
<------><------>remain -= PAGE_SIZE;
<------>}
<------>if (remain == 0)
<------><------>goto out;
 
<------>n = do_op_one_page(addr, remain, is_write, op, arg);
<------>if (n != 0) {
<------><------>remain = (n < 0 ? remain : 0);
<------><------>goto out;
<------>}
 
<------>return 0;
 out:
<------>return remain;
}
 
static int copy_chunk_from_user(unsigned long from, int len, void *arg)
{
<------>unsigned long *to_ptr = arg, to = *to_ptr;
 
<------>memcpy((void *) to, (void *) from, len);
<------>*to_ptr += len;
<------>return 0;
}
 
unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
<------>if (uaccess_kernel()) {
<------><------>memcpy(to, (__force void*)from, n);
<------><------>return 0;
<------>}
 
<------>return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
}
EXPORT_SYMBOL(raw_copy_from_user);
 
static int copy_chunk_to_user(unsigned long to, int len, void *arg)
{
<------>unsigned long *from_ptr = arg, from = *from_ptr;
 
<------>memcpy((void *) to, (void *) from, len);
<------>*from_ptr += len;
<------>return 0;
}
 
unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
<------>if (uaccess_kernel()) {
<------><------>memcpy((__force void *) to, from, n);
<------><------>return 0;
<------>}
 
<------>return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
}
EXPORT_SYMBOL(raw_copy_to_user);
 
static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
{
<------>char **to_ptr = arg, *to = *to_ptr;
<------>int n;
 
<------>strncpy(to, (void *) from, len);
<------>n = strnlen(to, len);
<------>*to_ptr += n;
 
<------>if (n < len)
<------>        return 1;
<------>return 0;
}
 
long __strncpy_from_user(char *dst, const char __user *src, long count)
{
<------>long n;
<------>char *ptr = dst;
 
<------>if (uaccess_kernel()) {
<------><------>strncpy(dst, (__force void *) src, count);
<------><------>return strnlen(dst, count);
<------>}
 
<------>n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
<------><------>      &ptr);
<------>if (n != 0)
<------><------>return -EFAULT;
<------>return strnlen(dst, count);
}
EXPORT_SYMBOL(__strncpy_from_user);
 
static int clear_chunk(unsigned long addr, int len, void *unused)
{
<------>memset((void *) addr, 0, len);
<------>return 0;
}
 
unsigned long __clear_user(void __user *mem, unsigned long len)
{
<------>if (uaccess_kernel()) {
<------><------>memset((__force void*)mem, 0, len);
<------><------>return 0;
<------>}
 
<------>return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
}
EXPORT_SYMBOL(__clear_user);
 
static int strnlen_chunk(unsigned long str, int len, void *arg)
{
<------>int *len_ptr = arg, n;
 
<------>n = strnlen((void *) str, len);
<------>*len_ptr += n;
 
<------>if (n < len)
<------><------>return 1;
<------>return 0;
}
 
long __strnlen_user(const void __user *str, long len)
{
<------>int count = 0, n;
 
<------>if (uaccess_kernel())
<------><------>return strnlen((__force char*)str, len) + 1;
 
<------>n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
<------>if (n == 0)
<------><------>return count + 1;
<------>return 0;
}
EXPORT_SYMBOL(__strnlen_user);