tcg/arm: fix TLB access in qemu-ld/st ops

The TCG arm backend considers likely that the offset to the TLB
entries does not exceed 12 bits for mem_index = 0. In practice this is
not true for at least the MIPS target.

The current patch fixes that by loading the bits 23-12 with a separate
instruction, and using loads with address writeback, independently of
the value of mem_idx. In total this allow a 24-bit offset, which is a
lot more than needed.

Cc: Andrzej Zaborowski <balrogg@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-stable@nongnu.org
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
tcg/arm: fix cross-endian qemu_st16

The bswap16 TCG opcode assumes that the high bytes of the temp equal
to 0 before calling it. The ARM backend implementation takes this
assumption to slightly optimize the generated code.

The same implementation is called for implementing the cross-endian
qemu_st16 opcode, where this assumption is not true anymore. One way to
fix that would be to zero the high bytes before calling it. Given the
store instruction just ignore them, it is possible to provide a slightly
more optimized version. With ARMv6+ the rev16 instruction does the work
correctly. For lower ARM versions the patch provides a version which
behaves correctly with non-zero high bytes, but fill them with junk.

Cc: Andrzej Zaborowski <balrogg@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-stable@nongnu.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
target-openrisc: remove conflicting definitions from cpu.h

On an ARM host, the registers definitions from cpu.h clash
with /usr/include/sys/ucontext.h. As there are unused, just remove
them.

Cc: Jia Liu <proljc@gmail.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
target-mips: Add comments on POOL32Axf encoding

  Current QEMU MIPS POOL32AXF encoding comes from microMIPS32
and microMIPS32 DSP. Add comment here to help reading.

Signed-off-by: Chen Wei-Ren <chenwj@iis.sinica.edu.tw>
Reviewed-by: Eric Johnson <ericj@mips.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
target-mips: Clean up microMIPS32 major opcode

  I check MIPS microMIPS manual [1], and found the major opcode might
be wrong. I add a comment to explicitly indicate what manual I am refering
to, and according that manual I remove microMIPS32 major opcodes 0x1f.
As for others, like 0x16, 0x17, 0x36 and 0x37, they are for higher-order
MIPS ISA level or new revision of this microMIPS architecture. Quote
from Johnson, they are belong MIPS64 [2].

[1] http://www.mips.com/products/architectures/micromips/#specifications

    MIPS Architecture for Programmers Volume II-B:
      The microMIPS32 Instruction Set (Revision 3.05)

    MD00582-2B-microMIPS-AFP-03.05.pdf

[2] http://www.mips.com/products/architectures/mips64/

    MIPS Architecture For Programmers
      Volume II-A: The MIPS64 Instruction Set

    MD00087-2B-MIPS64BIS-AFP-03.51.pdf

Signed-off-by: Chen Wei-Ren <chenwj@iis.sinica.edu.tw>
Reviewed-by: Eric Johnson <ericj@mips.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
tcg: mark local temps as MEM in dead_temp()

In dead_temp, local temps should always be marked as back to memory,
even if they have not been allocated (i.e. they are discared before
cross a basic block).

It fixes the following assertion in target-xtensa:

    qemu-system-xtensa: tcg/tcg.c:1665: temp_save: Assertion `s->temps[temp].val_type == 2 || s->temps[temp].fixed_reg' failed.
    Aborted

Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
target-mips: remove POOL48A from the microMIPS decoding

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>