Hello, On Wed, Sep 12, 2012 at 08:08:30PM -0400, Cyril Chemparathy wrote: > >So, a function which takes phys_addr_t for goal and limit but returns > >void * doesn't make much sense unless the function creates directly > >addressable mapping somewhere. > > On the 32-bit PAE platform in question, physical memory is located > outside the 4GB range. Therefore phys_to_virt takes a 64-bit > physical address and returns a 32-bit kernel mapped lowmem pointer.
Yes but phys_to_virt() can return the vaddr only if the physical address is already mapped in the kernel address space; otherwise, you need one of the kmap*() calls which may not be online early in the boot and consumes either the vmalloc area or fixmaps. bootmem interface can't handle unmapped memory. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
