From b2d438348024b75a1ee8b66b85d77f569a5dfed8 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Fri, 20 Sep 2013 21:50:41 -0700 Subject: sparc64: Make PAGE_OFFSET variable. 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 Acked-by: Bob Picco --- arch/sparc/lib/copy_page.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/sparc/lib/copy_page.S') diff --git a/arch/sparc/lib/copy_page.S b/arch/sparc/lib/copy_page.S index 4d2df328e514..dd16c61f3263 100644 --- a/arch/sparc/lib/copy_page.S +++ b/arch/sparc/lib/copy_page.S @@ -46,10 +46,10 @@ .type copy_user_page,#function copy_user_page: /* %o0=dest, %o1=src, %o2=vaddr */ lduw [%g6 + TI_PRE_COUNT], %o4 - sethi %uhi(PAGE_OFFSET), %g2 + sethi %hi(PAGE_OFFSET), %g2 sethi %hi(PAGE_SIZE), %o3 - sllx %g2, 32, %g2 + ldx [%g2 + %lo(PAGE_OFFSET)], %g2 sethi %hi(PAGE_KERNEL_LOCKED), %g3 ldx [%g3 + %lo(PAGE_KERNEL_LOCKED)], %g3 -- cgit v1.2.1