1,025
社区成员
发帖
与我相关
我的任务
分享
static ssize_t read_mem(struct file * file, char __user * buf,
size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
ssize_t read, sz;
char *ptr;
if (!valid_phys_addr_range(p, count))
return -EFAULT;
static inline int valid_phys_addr_range(unsigned long addr, size_t count)
{
if (addr + count > __pa(high_memory))
return 0;
return 1;
}
#ifdef CONFIG_HIGHMEM
high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
#else
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
#endif