On MIPS64 we define the default CAC_BASE as one of the xkphys regions of
the virtual address space. Since the CCA is encoded in bits 61:59 of
xkphys addresses, fixing CAC_BASE to any particular one prevents us from
dynamically changing the CCA as we do for MIPS32 where CAC_BASE is
placed within kseg0. In order to make the kernel more generic, drop the
current kludge that gives CAC_BASE CCA=3 if CONFIG_DMA_NONCOHERENT is
selected (disregarding CONFIG_DMA_MAYBE_COHERENT) & CCA=5 (which is not
standardised by the architecture) otherwise. Instead read Config.K0 and
generate the appropriate offset into xkphys, presuming that either the
bootloader or early kernel code will have configured Config.K0
appropriately. This seems like the best option for a generic
implementation.
The ip27 spaces.h is adjusted to set its former value of CAC_BASE, since
it's the only user of CAC_BASE from assembly (in its smp_slave_setup
macro). This allows the generic case to focus solely on C code without
breaking ip27.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14351/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The KSEGX() macro is defined to 32-bit sign extend the address argument
and logically AND the result with 0xe0000000, with the final result
usually compared against one of the CKSEG macros. However the literal
0xe0000000 is unsigned as the high bit is set, and is therefore
zero-extended on 64-bit kernels, resulting in the sign extension bits of
the argument being masked to zero. This results in the odd situation
where:
KSEGX(CKSEG) != CKSEG
(0xffffffff80000000 & 0x00000000e0000000) != 0xffffffff80000000)
Fix this by 32-bit sign extending the 0xe0000000 literal using
_ACAST32_.
This will help some MIPS KVM code handling 32-bit guest addresses to
work on 64-bit host kernels, but will also affect KSEGX in
dec_kn01_be_backend() on a 64-bit DECstation kernel, and the SiByte DMA
page ops KSEGX check in clear_page() and copy_page() on 64-bit SB1
kernels, neither of which appear to be designed with 64-bit segments in
mind anyway.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Multiple Loongson-3A chips can be interconnected with HT0-bus. This is
a CC-NUMA system that every chip (node) has its own local memory and
cache coherency is maintained by hardware. The 64-bit physical memory
address format is as follows:
0x-0000-YZZZ-ZZZZ-ZZZZ
The high 16 bits should be 0, which means the real physical address
supported by Loongson-3 is 48-bit. The "Y" bits is the base address of
each node, which can be also considered as the node-id. The "Z" bits is
the address offset within a node, which means every node has a 44 bits
address space.
Macros XPHYSADDR and MAX_PHYSMEM_BITS are modified unconditionally,
because many other MIPS CPUs have also extended their address spaces.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7187/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Another whitespace clean-up, this removes tabs from between sentences in
some comments.
Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6103/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
