MIPS: spaces: Define a couple of handy macros

Define CKSEGX_SIZE to represent the size of each KSEG segment.

Introduce CKSEG0ADDR_OR_64BIT and CKSEG1ADDR_OR_64BIT to get an XPHYS
address in 64bits and CKSEG[01]ADDR() in 32 bits mode.

Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Remove KVM_GUEST support

KVM_GUEST is broken and unmaintained, so let's remove it.

Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Loongson64: Enlarge IO_SPACE_LIMIT

It can be very big on LS7A PCH systems.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MIPS: Allow auto-dection of ARCH_PFN_OFFSET & PHYS_OFFSET

On systems where physical memory begins at a non-zero address, defining
PHYS_OFFSET (which influences ARCH_PFN_OFFSET) can save us time & memory
by avoiding book-keeping for pages from address zero to the start of
memory.

Some MIPS platforms already make use of this, but with the definition of
PHYS_OFFSET being compile-time constant it hasn't been possible to
enable this optimization for a kernel which may run on systems with
varying physical memory base addresses.

Introduce a new Kconfig option CONFIG_MIPS_AUTO_PFN_OFFSET which, when
enabled, makes ARCH_PFN_OFFSET a variable & detects it from the boot
memory map (which for example may have been populated from DT). The
relationship with PHYS_OFFSET is reversed, with PHYS_OFFSET now being
based on ARCH_PFN_OFFSET. This is because ARCH_PFN_OFFSET is used far
more often, so avoiding the need for runtime calculation gives us a
smaller impact on kernel text size (0.1% rather than 0.15% for
64r6el_defconfig).

Signed-off-by: Paul Burton <paul.burton@mips.com>
Suggested-by: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
Patchwork: https://patchwork.linux-mips.org/patch/20048/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org

MIPS: Adjust MIPS64 CAC_BASE to reflect Config.K0

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>

MIPS: Fix KVM guest fixmap address

KVM guest kernels for trap & emulate run in user mode, with a modified
set of kernel memory segments. However the fixmap address is still in
the normal KSeg3 region at 0xfffe0000 regardless, causing problems when
cache alias handling makes use of them when handling copy on write.

Therefore define FIXADDR_TOP as 0x7ffe0000 in the guest kernel mapped
region when CONFIG_KVM_GUEST is defined.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # v3.10+
Patchwork: https://patchwork.linux-mips.org/patch/9887/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Fix multiple definitions of UNCAC_BASE.

Fix build error below:

arch/mips/include/asm/mach-generic/spaces.h:29:0: warning:
"UNCAC_BASE" redefined [enabled by default]
In file included from arch/mips/include/asm/addrspace.h:13:0,
from arch/mips/include/asm/barrier.h:11,
from arch/mips/include/asm/bitops.h:18,
from include/linux/bitops.h:22,
from include/linux/kernel.h:10,
from include/asm-generic/bug.h:13,
from arch/mips/include/asm/bug.h:41,
from include/linux/bug.h:4,
from include/linux/page-flags.h:9,
from kernel/bounds.c:9:
arch/mips/include/asm/mach-ar7/spaces.h:20:0: note: this is the
location of the previous definition

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5583/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

KVM/MIPS32: KVM Guest kernel support.

Both Guest kernel and Guest Userspace execute in UM. The memory map is as follows:
Guest User address space: 0x00000000 -> 0x40000000
Guest Kernel Unmapped: 0x40000000 -> 0x60000000
Guest Kernel Mapped: 0x60000000 -> 0x80000000
- Guest Usermode virtual memory is limited to 1GB.

Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Whitespace cleanup.

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>

MIPS: Move FIXADDR_TOP into spaces.h

Memory maps and addressing quirks are normally defined in <spaces.h>.
There are already three targets that need to override FIXADDR_TOP, and
others exist. This will be a cleaner approach than adding lots of
ifdefs in fixmap.h .

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1573/
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Move headfiles to new location below arch/mips/include

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>