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| author | David S. Miller <davem@davemloft.net> | 2013-09-21 08:50:41 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-11-13 03:22:34 +0400 |
| commit | b2d438348024b75a1ee8b66b85d77f569a5dfed8 (patch) | |
| tree | 057c725d9d058d326533d0947aedd226adb57540 /arch/sparc/kernel | |
| parent | f998c9c0d663b013e3aa3ba78908396c8c497218 (diff) | |
| download | linux-b2d438348024b75a1ee8b66b85d77f569a5dfed8.tar.xz | |
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 <davem@davemloft.net>
Acked-by: Bob Picco <bob.picco@oracle.com>
Diffstat (limited to 'arch/sparc/kernel')
| -rw-r--r-- | arch/sparc/kernel/ktlb.S | 30 | ||||
| -rw-r--r-- | arch/sparc/kernel/vmlinux.lds.S | 5 |
2 files changed, 30 insertions, 5 deletions
diff --git a/arch/sparc/kernel/ktlb.S b/arch/sparc/kernel/ktlb.S index 7ad46bc0c698..542e96ac4d39 100644 --- a/arch/sparc/kernel/ktlb.S +++ b/arch/sparc/kernel/ktlb.S @@ -153,12 +153,19 @@ kvmap_dtlb_tsb4m_miss: /* Clear the PAGE_OFFSET top virtual bits, shift * down to get PFN, and make sure PFN is in range. */ - sllx %g4, PAGE_OFFSET_VA_BITS, %g5 +661: sllx %g4, 0, %g5 + .section .page_offset_shift_patch, "ax" + .word 661b + .previous /* Check to see if we know about valid memory at the 4MB * chunk this physical address will reside within. */ - srlx %g5, PAGE_OFFSET_VA_BITS + MAX_PHYS_ADDRESS_BITS, %g2 +661: srlx %g5, MAX_PHYS_ADDRESS_BITS, %g2 + .section .page_offset_shift_patch, "ax" + .word 661b + .previous + brnz,pn %g2, kvmap_dtlb_longpath nop @@ -176,7 +183,11 @@ valid_addr_bitmap_patch: or %g7, %lo(sparc64_valid_addr_bitmap), %g7 .previous - srlx %g5, PAGE_OFFSET_VA_BITS + ILOG2_4MB, %g2 +661: srlx %g5, ILOG2_4MB, %g2 + .section .page_offset_shift_patch, "ax" + .word 661b + .previous + srlx %g2, 6, %g5 and %g2, 63, %g2 sllx %g5, 3, %g5 @@ -189,9 +200,18 @@ valid_addr_bitmap_patch: 2: sethi %hi(kpte_linear_bitmap), %g2 /* Get the 256MB physical address index. */ - sllx %g4, PAGE_OFFSET_VA_BITS, %g5 +661: sllx %g4, 0, %g5 + .section .page_offset_shift_patch, "ax" + .word 661b + .previous + or %g2, %lo(kpte_linear_bitmap), %g2 - srlx %g5, PAGE_OFFSET_VA_BITS + ILOG2_256MB, %g5 + +661: srlx %g5, ILOG2_256MB, %g5 + .section .page_offset_shift_patch, "ax" + .word 661b + .previous + and %g5, (32 - 1), %g7 /* Divide by 32 to get the offset into the bitmask. */ diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S index 0bacceb19150..932ff90fd760 100644 --- a/arch/sparc/kernel/vmlinux.lds.S +++ b/arch/sparc/kernel/vmlinux.lds.S @@ -122,6 +122,11 @@ SECTIONS *(.swapper_4m_tsb_phys_patch) __swapper_4m_tsb_phys_patch_end = .; } + .page_offset_shift_patch : { + __page_offset_shift_patch = .; + *(.page_offset_shift_patch) + __page_offset_shift_patch_end = .; + } .popc_3insn_patch : { __popc_3insn_patch = .; *(.popc_3insn_patch) |