Arnd Bergmann wrote: > On Wednesday 24 June 2009, Marco Stornelli wrote: >>> Actually, reading from /dev/mem is only valid on real RAM. If the nvram >>> is part of an IO memory mapping, you have to do mmap()+memcpy() rather >>> than read(). So dd won't do it, but it's still easy to read from user >>> space. >> For "security" reasons pram reserve the region of memory with >> reserve_mem_region_exclusive()..... > > That will only prevent other device drivers from stepping on it, > /dev/mem does not care about mem_region reservations. > > Arnd <>< >
Userland may not map this resource, so /dev/mem and the sysfs MMIO access will not be allowed. This restriction depends on STRICT_DEVMEM option. It's true that currently is only implemented in the x86 world. Marco -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
