linux/arch
Leonid Yegoshin e4aa1f153a MIPS: MSA unaligned memory access support
The MSA architecture specification allows for hardware to not implement
unaligned vector memory accesses in some or all cases. A typical example
of this is the I6400 core which does not implement unaligned vector
memory access when the memory crosses a page boundary. The architecture
also requires that such memory accesses complete successfully as far as
userland is concerned, so the kernel is required to emulate them.

This patch implements support for emulating unaligned MSA ld & st
instructions by copying between the user memory & the tasks FP context
in struct thread_struct, updating hardware registers from there as
appropriate in order to avoid saving & restoring the entire vector
context for each unaligned memory access.

Tested both using an I6400 CPU and with a QEMU build hacked to produce
AdEL exceptions for unaligned vector memory accesses.

[paul.burton@imgtec.com:
  - Remove #ifdef's
  - Move msa_op into enum major_op rather than #define
  - Replace msa_{to,from}_wd with {read,write}_msa_wr_{b,h,w,l} and the
    format-agnostic wrappers, removing the custom endian mangling for
    big endian systems.
  - Restructure the msa_op case in emulate_load_store_insn to share
    more code between the load & store cases.
  - Avoid the need for a temporary union fpureg on the stack by simply
    reusing the already suitably aligned context in struct
    thread_struct.
  - Use sizeof(*fpr) rather than hardcoding 16 as the size for user
    memory checks & copies.
  - Stop recalculating the address of the unaligned vector memory access
    and rely upon the value read from BadVAddr as we do for other
    unaligned memory access instructions.
  - Drop the now unused val8 & val16 fields in union fpureg.
  - Rewrite commit message.
  - General formatting cleanups.]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: Jie Chen <chenj@lemote.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/10573/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-09-03 12:07:40 +02:00
..
alpha mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
arc ARCv2: spinlock/rwlock/atomics: reduce 1 instruction in exponential backoff 2015-08-07 13:56:16 +05:30
arm Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-08-22 15:48:04 -07:00
arm64 arm64: VDSO: fix coarse clock monotonicity regression 2015-08-10 15:37:45 +01:00
avr32 avr32: handle NULL as a valid clock object 2015-07-27 09:14:07 +02:00
blackfin mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
c6x mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
cris mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
frv mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
h8300 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
hexagon mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
ia64 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
m32r m32r: Add ioreadXX/iowriteXX big-endian mmio accessors 2015-07-23 18:08:28 -07:00
m68k mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
metag mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
microblaze mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
mips MIPS: MSA unaligned memory access support 2015-09-03 12:07:40 +02:00
mn10300 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
nios2 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
openrisc mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
parisc parisc: mm: Fix a memory leak related to pmd not attached to the pgd 2015-07-19 08:56:14 +02:00
powerpc signal: fix information leak in copy_siginfo_from_user32 2015-08-07 04:39:40 +03:00
s390 Just two very small & simple patches. 2015-08-05 18:50:38 +03:00
score mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
sh mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
sparc sparc64: Fix userspace FPU register corruptions. 2015-08-06 19:13:25 -07:00
tile signal: fix information leak in copy_siginfo_from_user32 2015-08-07 04:39:40 +03:00
um mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
unicore32 mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
x86 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-08-22 08:15:36 -07:00
xtensa mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
.gitignore
Kconfig x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86 2015-07-18 03:42:51 +02:00