PC needs to be saved if an exception can be generated by an helper.
This fixes a problem related to resuming the execution at unexpected address
after an exception (caused by MSA load/store instruction) has been serviced.
Backports commit 0af7a37054310384e00209e0a43efe95b7c19ef0 from qemu
All instructions which may change hflags terminate tb. However, this doesn't
work if such an instruction is placed in delay or forbidden slot.
gen_branch() clears MIPS_HFLAG_BMASK in ctx->hflags and then generates code
to overwrite hflags with ctx->hflags, consequently we loose any execution-time
hflags modifications. For example, in the following scenario hflag related to
Status.CU1 will not be updated:
/* Set Status.CU1 in delay slot */
mfc0 $24, $12, 0
lui $25, 0x2000
or $25, $25, $24
b check_Status_CU1
mtc0 $25, $12, 0
With this change we clear MIPS_HFLAG_BMASK in execution-time hflags if
instruction in delay or forbidden slot wants to terminate tb for some reason
(i.e. ctx->bstate != BS_NONE).
Also, die early and loudly if "unknown branch" is encountered as this should
never happen.
Backports commit a5f533909e746ca6e534b232fb42c9c6fd81b468 from qemu
CP0.BadVAddr is supposed to capture the most recent virtual address that caused
the exception. Currently this does not work correctly for unaligned instruction
fetch as translation is not stopped and CP0.BadVAddr is updated with subsequent
addresses.
Backports commit 62c688693bf2f0355fc5bad5dcc59c1cd2a51f1a from qemu
Save MSACSR state. Also remove fp_status, msa_fp_status, hflags and restore
them in post_load() from the architectural registers.
Float exception flags are not present in vmstate. Information they carry
is used only by softfloat caller who translates them into MIPS FCSR.Cause,
FCSR.Flags and then they are cleared. Therefore there is no need for saving
them in vmstate.
Backports commit 644511117e7ca9f26d633a59c202a297113a796c from qemu
Using rs = -1 in gen_logic_imm() for microMIPS LUI instruction is dangerous
and may bite us when implementing microMIPS R6 because in R6 AUI and LUI
are distinguished by rs value. Therefore use 0 for safety.
Backports commit 5e88759a52934a32502298f2c78c6dfaa144364b from qemu
The test is supposed to terminate TB if the end of the page is reached.
However, with current implementation it may never succeed for microMIPS or
mips16.
Backports commit fe2372910a09034591fd2cfc2d70cca43fccaa95 from qemu
Commit fecd264 added a number of fall-throughs, but neglected to
properly document them as intentional. Commit d922445 cleaned that up
for many, but not all cases. Take care of the remaining ones.
Backports commit b6f3b233eabb4df5d65ae9fbfb3d3c8befea0de7 from qemu
Reduce line wrapping throughout MSA helper macros by using a local float
status pointer rather than referring to the float status through the
environment each time. No functional change.
Backports commit 1a4d570017bf35d99340781ecb59dd3772464031 from qemu
Add missing calls to synchronise the SoftFloat status with the CP1.FSCR:
+ for the rounding and flush-to-zero modes upon processor reset,
+ for the flush-to-zero mode on FSCR updates through the GDB stub.
Refactor code accordingly and remove the redundant RESTORE_ROUNDING_MODE
macro.
Backports commit bb962386b82c1b0e9e12fdb6b9bb62106bf1f822 from qemu
Make CP0.Status writes made with the MTTC0 instruction respect this
register's mask just like all the other places. Also preserve the
current values of masked out bits.
Backports commit 1d725ae952a14b30c84b7bc81b218b8ba77dd311 from qemu
Make sure the address space is unconditionally wrapped on 32-bit
processors, that is ones that do not implement at least the MIPS III
ISA.
Also make MIPS16 SAVE and RESTORE instructions use address calculation
rather than plain arithmetic operations for stack pointer manipulation
so that their semantics for stack accesses follows the architecture
specification. That in particular applies to user software run on
64-bit processors with the CP0.Status.UX bit clear where the address
space is wrapped to 32 bits.
Backports commit c48245f0c62405f27266fcf08722d8c290520418 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
Fix CP0.Config3.ISAOnExc write accesses on microMIPS processors. This
bit is mandatory for any processor that implements the microMIPS
instruction set. This bit is r/w for processors that implement both the
standard MIPS and the microMIPS instruction set. This bit is r/o and
hardwired to 1 if only the microMIPS instruction set is implemented.
There is no other bit ever writable in CP0.Config3 so defining a
corresponding `CP0_Config3_rw_bitmask' member in `CPUMIPSState' is I
think an overkill. Therefore make the ability to write the bit rely on
the presence of ASE_MICROMIPS set in the instruction flags.
The read-only case of the microMIPS instruction set being implemented
only can be added when we add support for such a configuration. We do
not currently have such support, we have no instruction flag that would
control the presence of the standard MIPS instruction set nor any
associated code in instruction decoding.
This change is needed to boot a microMIPS Linux kernel successfully,
otherwise it hangs early on as interrupts are enabled and then the
exception handler invoked loops as its first instruction is interpreted
in the wrong execution mode and triggers another exception right away.
And then over and over again.
We already check the current setting of the CP0.Config3.ISAOnExc in
`set_hflags_for_handler' to set the ISA bit correctly on the exception
handler entry so it is the ability to set it that is missing only.
Backports commit 90f12d735d66ac1196d9a2bced039a432eefc03d from qemu
Fix microMIPS MOVE16 and MOVEP instructions on 64-bit processors by
using register addition operations.
This copies the approach taken with MIPS16 MOVE instructions (I8_MOV32R
and I8_MOVR32 opcodes) and follows the observation that OPC_ADDU expands
to tcg_gen_mov_tl whenever `rt' is 0 and `rs' is not, therefore copying
`rs' to `rd' verbatim. This is not the case with OPC_ADDIU where a
sign-extension from bit #31 is made, unless in the uninteresting case of
`rs' being 0, losing the upper 32 bits of the value copied for any
proper 64-bit values.
This also serves as an optimization as one op is produced in generated
code rather than two (again, unless `rs' is 0, where it doesn't change
anything).
Backports commit 7215d7e7aea85699bf516c3e8d84f6a22584da35 from qemu
Make writes to CP0.Status and CP0.Cause have the same effect as
executing corresponding MTC0 instructions would in Kernel Mode. Also
ignore writes in the user emulation mode.
Currently for requests from the GDB stub we write all the bits across
both registers, ignoring any read-only locations, and do not synchronise
the environment to evaluate side effects. We also write these registers
in the user emulation mode even though a real kernel presents them as
read only.
Backports commit 81a423e6c6d3ccaa79de4e58024369c660c1eeb4 from qemu
Correct these issues with the handling of CP0.Status for MIPSr6:
* only ignore the bit pattern of 0b11 on writes to CP0.Status.KSU, that
is for processors that do implement Supervisor Mode, let the bit
pattern be written to CP0.Status.UM:R0 freely (of course the value
written to read-only CP0.Status.R0 will be discarded anyway); this is
in accordance to the relevant architecture specification[1],
* check the newly written pattern rather than the current contents of
CP0.Status for the KSU bits being 0b11,
* use meaningful macro names to refer to CP0.Status bits rather than
magic numbers.
References:
[1] "MIPS Architecture For Programmers, Volume III: MIPS64 / microMIPS64
Privileged Resource Architecture", MIPS Technologies, Inc., Document
Number: MD00091, Revision 6.00, March 31, 2014, Table 9.45 "Status
Register Field Descriptions", pp. 210-211.
Backports commit f88f79ec9df06d26d84e1d2e0c02d2634b4d8583 from qemu
Correct MIPS16/microMIPS branch size calculation in PC adjustment
needed:
- to set the value of CP0.ErrorEPC at the entry to the reset exception,
- for the purpose of branch reexecution in the context of device I/O.
Follow the approach taken in `exception_resume_pc' for ordinary, Debug
and NMI exceptions.
MIPS16 and microMIPS branches can be 2 or 4 bytes in size and that has
to be reflected in calculation. Original MIPS ISA branches, which is
where this code originates from, are always 4 bytes long, just as all
original MIPS ISA instructions.
Backports commit c3577479815f5bcf9d38993967bca2115af245d8 from qemu
Restore the order of helpers that used to be: unary operations (generic,
then MIPS-specific), binary operations (generic, then MIPS-specific),
compare operations. At one point FMA operations were inserted at a
random place in the file, disregarding the preexisting order, and later
on even more operations sprinkled across the file. Revert the mess by
moving FMA operations to a new ternary class inserted after the binary
class and move the misplaced unary and binary operations to where they
belong.
Backports commit 8fc605b8aa257feb3e69d44794a765bd492b573b from qemu
Remove the `FLOAT_OP' macro, unused since commit
b6d96beda3a6cbf20a2d04a609eff78adebd8859 [Use temporary registers for
the MIPS FPU emulation.].
Backports commit 51fdea945ae7adae8d7e4a1624e35bb7f714b58f from qemu
Move the call to `update_fcr31' in `helper_float_cvtw_s' after the
exception flag check, for consistency with the remaining helpers that do
it last too.
Backports commit 2b09f94cdbf5c54e2278d7f3aed2eceff3494790 from qemu
Backports commits d75de74967f631a7d0b538d4b88f96f9c426bfe2, 6225a4a0e39cb24e7b9e1d4d2c1a3e6eaee18e85, and d2bfa6e6222baa0218bd0658499d38bac56ac34c from qemu
Add the M14K and M14Kc processors from MIPS Technologies that are the
original implementation of the microMIPS ISA. They are dual instruction
set processors, implementing both the microMIPS and the standard MIPSr32
ISA.
These processors correspond to the M4K and 4KEc CPUs respectively,
except with support for the microMIPS instruction set added, support for
the MCU ASE added and two extra interrupt lines, making a total of 8
hardware interrupts plus 2 software interrupts. The remaining parts of
the microarchitecture, in particular the pipeline, stayed unchanged.
The presence of the microMIPS ASE is is reflected in the configuration
added. We currently have no support for the MCU ASE, including in
particular the ACLR, ASET and IRET instructions in either encoding, and
we have no support for the extra interrupt lines, including bits in
CP0.Status and CP0.Cause registers, so these features are not marked,
making our support diverge from real hardware.
Backports commit 11f5ea105c06bec72e9bc9a700fa65d60afb5ec3 from qemu
Make the data type used for the CP0.Config4 and CP0.Config5 registers
and their mask signed, for consistency with the remaining 32-bit CP0
registers, like CP0.Config0, etc.
Backports commit 8280b12c0e4b515d707509dde4ddde05d9bda4ef from qemu
Add the 5KEc and 5KEf processors from MIPS Technologies that are the
original implementation of the MIPS64r2 ISA.
Silicon for these processors has never been taped out and no soft cores
were released even. They do exist though, a CP0.PRId value has been
assigned and experimental RTLs produced at the time the MIPS64r2 ISA has
been finalized. The settings introduced here faithfully reproduce that
hardware.
As far the implementation goes these processors are the same as the 5Kc
and the 5Kf CPUs respectively, except implementing the MIPS64r2 rather
than the original MIPS64 instruction set. There must have been some
updates to the CP0 architecture as mandated by the ISA, such as the
addition of the EBase register, although I am not sure about the exact
details, no documentation has ever been produced for these processors.
The remaining parts of the microarchitecture, in particular the
pipeline, stayed unchanged. Or to put it another way, the difference
between a 5K and a 5KE CPU corresponds to one between a 4K and a 4KE
CPU, except for the 64-bit rather than 32-bit ISA.
Backports commit 36b86e0dc2be93fc538fe7e11e0fda1a198f0135 from qemu
While we're at it, emit the opcode adjacent to where we currently
record data for search_pc. This puts gen_io_start et al on the
"correct" side of the marker.
Backports commit 667b8e29c5b1d8c5b4e6ad5f780ca60914eb6e96 from qemu
The checks in dins is required to avoid triggering an assertion
in tcg_gen_deposit_tl. The check in dext is just for completeness.
Fold the other D cases in via fallthru.
Backports commit b7f26e523914b982a1c1bfa8295f77ff9787c33c from qemu
This is improved type checking for the translators -- it's no longer
possible to accidentally swap arguments to the branch functions.
Note that the code generating backends still manipulate labels as int.
With notable exceptions, the scope of the change is just a few lines
for each target, so it's not worth building extra machinery to do this
change in per-target increments.
Backports commit 42a268c241183877192c376d03bd9b6d527407c7 from qemu
The method by which we count the number of ops emitted
is going to change. Abstract that away into some inlines.
Backports commit fe700adb3db5b028b504423b946d4ee5200a8f2f from qemu.
Thus, use cpu_env as the parameter, not TCG_AREG0 directly.
Update all uses in the translators.
Backports commit e1ccc05444676b92c63708096e36582be27fbee1 from qemu
