David Miller wrote: [Sat Sep 21 2013, 01:16:35AM EDT] > > Choose PAGE_OFFSET dynamically based upon cpu type. > > Original UltraSPARC-I (spitfire) chips only supported a 44-bit > virtual address space. > > Newer chips (T4 and later) support 52-bit virtual addresses > and up to 47-bits of physical memory space. > > Therefore we have to adjust PAGE_SIZE dynamically based upon > the capabilities of the chip. > > Note that this change alone does not allow us to support > 43-bit > physical memory, to do that we need to re-arrange our page table > support. The current encodings of the pmd_t and pgd_t pointers > restricts us to "32 + 11" == 43 bits. > > This change can waste quite a bit of memory for the various tables. > In particular, a future change should work to size and allocate > kern_linear_bitmap[] and sparc64_valid_addr_bitmap[] dynamically. > This isn't easy as we really cannot take a TLB miss when accessing > kern_linear_bitmap[]. We'd have to lock it into the TLB or similar. > > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Acked-by: Bob Picco <bob.picco@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
