Commit 01f728857941 ("target-mips: Status.UX/SX/KX enable 32-bit address
wrapping") added a new hflag MIPS_HFLAG_AWRAP, which indicates that
64-bit addressing is disallowed in the current mode, so hflag users
don't need to worry about the complexities of working that out, for
example checking both MIPS_HFLAG_KSU and MIPS_HFLAG_UX.
However when exceptions are taken outside of exception level,
mips_cpu_do_interrupt() manipulates the env->hflags directly rather than
using compute_hflags() to update them, and this code wasn't updated
accordingly. As a result, when UX is cleared, MIPS_HFLAG_AWRAP is set,
but it doesn't get cleared on entry back into kernel mode due to an
exception. Kernel mode then cannot access the 64-bit segments resulting
in a nested exception loop. The same applies to errors and debug
exceptions.
Fix by updating mips_cpu_do_interrupt() to clear the MIPS_HFLAG_WRAP
flag when necessary, according to compute_hflags().
Backports commit 7871abb94c2f4adc39f2487f6edf5e69ba872a65 from qemu
Correct updating XContext.Region field on mmu exceptions.
If Config3.CTXTC = 0 then the R field of XContext has to be updated
with the value of bits 63..62 of the virtual address upon a TLB
exception.
Also fixed the below line which overs 80 characters.
Backports commit 60270f85cc93d2d34e45b7679c374b1d771f0eeb from qemu
Correct computation of vector offsets for EXCP_EXT_INTERRUPT.
For instance, if Cause.IV is 0 the vector offset should be 0x180.
Simplify the finding vector number logic for the Vectored Interrupts.
Backports commit da52a4dfcc4864fd2260ec4eab331f75b1f0240b from qemu
Tighten ISA level checks down to MIPS II that many of our instructions
are missing. Also make sure any 64-bit instruction enables are only
applied to 64-bit processors, that is ones that implement at least the
MIPS III ISA.
Backports commit d9224450208e0de62323b64ace91f98bc31d6e2c from qemu
