xtensa: simplify addition of new core variants

Instead of adding new Kconfig options and Makefile rules for each new
core variant provide XTENSA_VARIANT_CUSTOM variant and record variant
name in the XTENSA_VARIANT_NAME variable. Adding new core variant now
means providing directory structure under arch/xtensa/variant and
specifying correct name in kernel configuration.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: make MMU-related configuration options depend on MMU

MMUv3 and HIGHMEM support are available only on configurations with MMU,
don't show them otherwise.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: sort 'select' statements in Kconfig

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: select HAVE_IDE only on platforms that may have it

HAVE_IDE is not a property of architecture but of a platform, and neither
ISS or XTFPGA support it.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: remove orphan MATH_EMULATION symbol

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: replace IOCTL code definitions with constants

This fixes userspace code that builds on other architectures but fails
on xtensa due to references to structures that other architectures don't
refer to. E.g. this fixes the following issue with python-2.7.8:

  python-2.7.8/Modules/termios.c:861:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERGETMULTI", TIOCSERGETMULTI},
  python-2.7.8/Modules/termios.c:870:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERSETMULTI", TIOCSERSETMULTI},
  python-2.7.8/Modules/termios.c:900:24: error: invalid application
     of 'sizeof' to incomplete type 'struct tty_struct'
     {"TIOCTTYGSTRUCT", TIOCTTYGSTRUCT},

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: fix address checks in dma_{alloc,free}_coherent

Virtual address is translated to the XCHAL_KSEG_CACHED region in the
dma_free_coherent, but is checked to be in the 0...XCHAL_KSEG_SIZE
range.

Change check for end of the range from 'addr >= X' to 'addr > X - 1' to
handle the case of X == 0.

Replace 'if (C) BUG();' construct with 'BUG_ON(C);'.

Cc: stable@vger.kernel.org
Signed-off-by: Alan Douglas <adouglas@cadence.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: add renameat2 syscall

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: fix access to THREAD_RA/THREAD_SP/THREAD_DS

With SMP and a lot of debug options enabled task_struct::thread gets out
of reach of s32i/l32i instructions with base pointing at task_struct,
breaking build with the following messages:

  arch/xtensa/kernel/entry.S: Assembler messages:
  arch/xtensa/kernel/entry.S:1002: Error: operand 3 of 'l32i.n' has invalid value '1048'
  arch/xtensa/kernel/entry.S:1831: Error: operand 3 of 's32i.n' has invalid value '1040'
  arch/xtensa/kernel/entry.S:1832: Error: operand 3 of 's32i.n' has invalid value '1044'

Change base to point to task_struct::thread in such cases.
Don't use a10 in _switch_to to save/restore prev pointer as a2 is not
clobbered.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: make fixmap region addressing grow with index

It's much easier to reason about alignment and coloring of regions
located in the fixmap when fixmap index is just a PFN within the fixmap
region. Change fixmap addressing so that index 0 corresponds to
FIXADDR_START instead of the FIXADDR_TOP.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: allow fixmap and kmap span more than one page table

To support aliasing cache both kmap region sizes are multiplied by the
number of data cache colors. After that expansion page tables that cover
kmap regions may become larger than one page. Correctly allocate and
initialize page tables in this case.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: fix TLBTEMP_BASE_2 region handling in fast_second_level_miss

Current definition of TLBTEMP_BASE_2 is always 32K above the
TLBTEMP_BASE_1, whereas fast_second_level_miss handler for the TLBTEMP
region analyzes virtual address bit (PAGE_SHIFT + DCACHE_ALIAS_ORDER)
to determine TLBTEMP region where the fault happened. The size of the
TLBTEMP region is also checked incorrectly: not 64K, but twice data
cache way size (whicht may as well be less than the instruction cache
way size).

Fix TLBTEMP_BASE_2 to be TLBTEMP_BASE_1 + data cache way size.
Provide TLBTEMP_SIZE that is a greater of doubled data cache way size or
the instruction cache way size, and use it to determine if the second
level TLB miss occured in the TLBTEMP region.

Practical occurence of page faults in the TLBTEMP area is extremely
rare, this code can be tested by deletion of all w[di]tlb instructions
in the tlbtemp_mapping region.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: implement clear_user_highpage and copy_user_highpage

Existing clear_user_page and copy_user_page cannot be used with highmem
because they calculate physical page address from its virtual address
and do it incorrectly in case of high memory page mapped with
kmap_atomic. Also kmap is not needed, as most likely userspace mapping
color would be different from the kmapped color.

Provide clear_user_highpage and copy_user_highpage functions that
determine if temporary mapping is needed for the pages. Move most of the
logic of the former clear_user_page and copy_user_page to
xtensa/mm/cache.c only leaving temporary mapping setup, invalidation and
clearing/copying in the xtensa/mm/misc.S. Rename these functions to
clear_page_alias and copy_page_alias.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: support aliasing cache in k[un]map_atomic

Map high memory pages at virtual addresses with color that match color
of their physical address. Existing cache alias management mechanisms
may be used with such pages.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: support aliasing cache in kmap

Define ARCH_PKMAP_COLORING and provide corresponding macro definitions
on cores with aliasing data cache.

Instead of single last_pkmap_nr maintain an array last_pkmap_nr_arr of
pkmap counters for each page color. Make sure that kmap maps physical
page at virtual address with color matching its physical address.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: support highmem in aliasing cache flushing code

Use __flush_invalidate_dcache_page_alias with alias set to color of the
page physical address instead of __flush_invalidate_dcache_page: this
works for high memory pages and mapping/unmapping to the TLBTEMP area is
virtually free.

Allow building configurations with aliasing cache and highmem enabled.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: configure kc705 for highmem

Enable all memory available on KC705 (1G - 128M) by default. Update memory
node in DTS and also limit usable memory in bootargs in case memmap is
passed from the bootloader.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: fix kernel/user jump out of fast_unaligned

Use correct register (a0, just read from the PS) to check user mode bit.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: add double exception fixup handler for fast_unaligned

fast_unaligned_fixup restores user registers and runs normal exception
handler in the current stack frame. Unaligned load/store is retried
after that.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
xtensa: make fast_unaligned store restartable

fast_unaligned may encounter DTLB miss or SEGFAULT during the store
emulation. Don't update epc1 and lcount until after the store emulation
is complete, so that the faulting store instruction could be replayed.
Remove duplicate code handling zero overhead loops and calculate new
epc1 and lcount in one place.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>