Allow page table bit to swap endianness.
Reorganize watchpoints out of i/o path.
Return host address from probe_write / probe_access.

# gpg: Signature made Tue 03 Sep 2019 16:47:50 BST
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth/tags/pull-tcg-20190903: (36 commits)
  tcg: Factor out probe_write() logic into probe_access()
  tcg: Make probe_write() return a pointer to the host page
  s390x/tcg: Pass a size to probe_write() in do_csst()
  hppa/tcg: Call probe_write() also for CONFIG_USER_ONLY
  mips/tcg: Call probe_write() for CONFIG_USER_ONLY as well
  tcg: Enforce single page access in probe_write()
  tcg: Factor out CONFIG_USER_ONLY probe_write() from s390x code
  s390x/tcg: Fix length calculation in probe_write_access()
  s390x/tcg: Use guest_addr_valid() instead of h2g_valid() in probe_write_access()
  tcg: Check for watchpoints in probe_write()
  cputlb: Handle watchpoints via TLB_WATCHPOINT
  cputlb: Remove double-alignment in store_helper
  cputlb: Fix size operand for tlb_fill on unaligned store
  exec: Factor out cpu_watchpoint_address_matches
  cputlb: Fold TLB_RECHECK into TLB_INVALID_MASK
  exec: Factor out core logic of check_watchpoint()
  exec: Move user-only watchpoint stubs inline
  target/sparc: sun4u Invert Endian TTE bit
  target/sparc: Add TLB entry with attributes
  cputlb: Byte swap memory transaction attribute
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>