On Wed, Sep 28, 2016 at 2:49 AM, Paddie O'Brien <paddieobrien@xxxxxxxxx> wrote:
Hi,
I have a system call that maps virtual to physical addresses. I have
disabled CONFIG_STRICT_DEVMEM and am reading from /dev/mem to verify
that the contents of the syscall-returned physical address match the
contents of the virtual address. It works fine up to a point. Reading
beyond byte 935321597 in /dev/mem throws a "bad address" error. Not
sure it's relevant but I'm running on virtual box and specifying 1GB
of RAM. Tried with 2GB of RAM and hit the same problem.
Any idea why I can't read beyond the above point?
Thanks.
Hi paddie
Is it 32 bit system?
If yes, it seems you are about to exceed boundary of kernel linear addres range, which is 0-896 MiB. The upper 896-1024 MiB (1 GiB) is reserved for dynamic mapping
CMIIW people.
--
regards,
Mulyadi Santosa
Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
Mulyadi Santosa
Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
