devmem: use mmap64 replace mmap

[Denys Vlasenko]

On Fri, Oct 8, 2021 at 10:16 AM xiechengliang <xiechengliang1 at huawei.com> wrote:
>
> I have built busybox with CONFIG_LFS=y, this problem still exists.
>
> mmap is defined in glibc as below:
> void *mmap(void *addr, size_t len, int prot , int flags , int fd, off_t offset);
> The type of last parameter offset is off_ t, so using mmap will still cause truncation problems.

????
With CONFIG_LFS=y, off_t should be (at least) 64-bit.

Tell me more about the architecture you are building for.
Is it bionic, maybe? They had some weird cases where off_t stays 32-bit.