DMTC0 CP0_Cause does a redundant gen_io_start() and gen_io_end() pair,
even though this is done for all DMTC0 operations outside of the switch
statement. Remove these redundant calls.
Backports commit 51ca717b079dccae5b6cc9f45153f5044abd34f0 from qemu
Commit e350d8ca3ac7 ("target/mips: optimize indirect branches") made
indirect branches able to directly find the next TB and jump straight to
it without breaking out of translated code and going around the main
execution loop. This breaks the assumption in target/mips/translate.c
that BS_STOP is sufficient to cause pending interrupts to be handled,
since interrupts are only checked in the main loop.
Fix a few of these assumptions by using gen_save_pc to update the saved
PC and using BS_EXCP instead of BS_STOP:
- [D]MFC0 CP0_Count may trigger a timer interrupt which should be
immediately handled.
- [D]MTC0 CP0_Cause may trigger an interrupt (but in fact translation
was only even being stopped in the DMTC0 case).
- [D]MTC0 CP0_<any> when icount is used is assumed could potentially
cause interrupts.
- EI may trigger an interrupt which was pending. I specifically hit
this case when running KVM nested in mipsel-softmmu. A timer
interrupt while the 2nd guest was executing is caught by KVM which
switches back to the normal Linux exception base and re-enables
interrupts with EI. Since the above commit QEMU doesn't leave
translated code until the nested KVM has already restored the KVM
exception base and returned to the 2nd guest, at which point it is
too late to check for pending interrupts and it gets stuck in an
infinite loop of unhandled interrupts.
Something similar was needed for ARM in commit b29fd33db578
("target/arm: use DISAS_EXIT for eret handling").
Backports commit b74cddcbf6063f684725e3f8bca49a68e30cba71 from qemu
Improve the segment definitions used by get_physical_address() to yield
target_ulong types, e.g. 0xffffffff80000000 instead of 0x80000000. This
is in preparation for enabling emulation of MIPS KVM T&E segments in TCG
MIPS targets, which unlike KVM could potentially have 64-bit
target_ulong. In such a case the offset guest KSEG0 address ends up at
e.g. 0x000000008xxxxxxx instead of 0xffffffff8xxxxxxx.
This also allows the casts to int32_t that force sign extension to be
removed, which removes any confusion due to relational comparison of
unsigned (target_ulong) and signed (int32_t) types.
Backports commit 6743334568933199927af4992a04bfb3c30610f5 from qemu
Writing to the MIPS DESAVE register (and now the KScratch registers)
will stop translation, supposedly due to risk of execution mode
switches. However these registers are basically RW scratch registers
with no side effects so there is no risk of them triggering execution
mode changes.
Drop the bstate = BS_STOP for these registers for both mtc0 and dmtc0.
Backports commit cb539fd241900f51de7d21244f7a55422ad0d40a from qemu
Enable the CP0_EBase.WG (write gate) on the I6400 and MIPS64R2-generic
CPUs. This allows 64-bit guests to run KVM itself, which uses
CP0_EBase.WG to point CP0_EBase at XKPhys.
Backports commit bad63a8008a0aaefcd00542c89bee01623d7c9de from qemu
Add the Enhanced Virtual Addressing (EVA) feature to the P5600 core
configuration, along with the related Segmentation Control (SC) feature
and writable CP0_EBase.WG bit.
This allows it to run Malta EVA kernels.
Backports commit 574da58e4678b3c09048f268821295422d8cde6d from qemu
Implement the optional segmentation control feature in the virtual to
physical address translation code.
The fixed legacy segment and xkphys handling is replaced with a dynamic
layout based on the segmentation control registers (which should be set
up even when the feature is not exposed to the guest).
Backports commit 480e79aedd322fcfac17052caff21626ea7c78e2 from qemu
The optional segmentation control registers CP0_SegCtl0, CP0_SegCtl1 &
CP0_SegCtl2 control the behaviour and required privilege of the legacy
virtual memory segments.
Add them to the CP0 interface so they can be read and written when
CP0_Config3.SC=1, and initialise them to describe the standard legacy
layout so they can be used in future patches regardless of whether they
are exposed to the guest.
Backports commit cec56a733dd2c3fa81dbedbecf03922258747f7d from qemu
The segmentation control feature allows a legacy memory segment to
become unmapped uncached at error level (according to CP0_Status.ERL),
and in fact the user segment is already treated in this way by QEMU.
Add a new MMU mode for this state so that QEMU's mappings don't persist
between ERL=0 and ERL=1.
Backports commit 42c86612d507c2a8789f2b8d920a244693c4ef7b from qemu
The MIPS mmu_idx is sometimes calculated from hflags without an env
pointer available as cpu_mmu_index() requires.
Create a common hflags_mmu_index() for the purpose of this calculation
which can operate on any hflags, not just with an env pointer, and
update cpu_mmu_index() itself and gen_intermediate_code() to use it.
Also update debug_post_eret() and helper_mtc0_status() to log the MMU
mode with the status change (SM, UM, or nothing for kernel mode) based
on cpu_mmu_index() rather than directly testing hflags.
This will also allow the logic to be more easily updated when a new MMU
mode is added.
Backports commit b0fc6003224543d2bdb172eca752656a6223e4a1 from qemu
When performing virtual to physical address translation, check the
required privilege level based on the mem_idx rather than the mode in
the hflags. This will allow EVA loads & stores to operate safely only on
user memory from kernel mode.
For the cases where the mmu_idx doesn't need to be overridden
(mips_cpu_get_phys_page_debug() and cpu_mips_translate_address()), we
calculate the required mmu_idx using cpu_mmu_index(). Note that this
only tests the MIPS_HFLAG_KSU bits rather than MIPS_HFLAG_MODE, so we
don't test the debug mode hflag MIPS_HFLAG_DM any longer. This should be
fine as get_physical_address() only compares against MIPS_HFLAG_UM and
MIPS_HFLAG_SM, neither of which should get set by compute_hflags() when
MIPS_HFLAG_DM is set.
Backports commit 9fbf4a58c90183b30bb2c8ad971ccce7e6716a16 from qemu
Implement decoding of microMIPS EVA load and store instruction groups in
the POOL31C pool. These use the same gen_ld(), gen_st(), gen_st_cond()
helpers as the MIPS32 decoding, passing the equivalent MIPS32 opcodes as
opc.
Backports commit 8fffc64696783b1ff1d17262d098976479895660 from qemu
Add CP0.ErrCtl register with WST, SPR and ITC bits. In 34K and interAptiv
processors these bits are used to enable CACHE instruction access to
different arrays. When WST=0, SPR=0 and ITC=1 the CACHE instruction will
access ITC tag values.
Generally we do not model caches and we have been treating the CACHE
instruction as NOP. But since CACHE can operate on ITC Tags new
MIPS_HFLAG_ITC_CACHE hflag is introduced to generate the helper only when
CACHE is in the ITC Access mode.
Backports commit 0d74a222c27e26fc40f4f6120c61c3f9ceaa3776 from qemu
Implement decoding of MIPS32 EVA loads and stores. These access the user
address space from kernel mode when implemented, so for each instruction
we need to check that EVA is available from Config5.EVA & check for
sufficient COP0 privilege (with the new check_eva()), and then override
the mem_idx used for the operation.
Unfortunately some Loongson 2E instructions use overlapping encodings,
so we must be careful not to prevent those from being decoded when EVA
is absent.
Backports commit 7696414729b2d0f870c80ad1dd637d854bc78847 from qemu
EVA load and store instructions access the user mode address map, so
they need to use mem_idx of MIPS_HFLAG_UM. Update the various utility
functions to allow mem_idx to be more easily overridden from the
decoding logic.
Specifically we add a mem_idx argument to the op_ld/st_* helpers used
for atomics, and a mem_idx local variable to gen_ld(), gen_st(), and
gen_st_cond().
Backports commit dd4096cd2ccc19384770f336c930259da7a54980 from qemu
Add support for the CP0_EBase.WG bit, which allows upper bits to be
written (bits 31:30 on MIPS32, or bits 63:30 on MIPS64), along with the
CP0_Config5.CV bit to control whether the exception vector for Cache
Error exceptions is forced into KSeg1.
This is necessary on MIPS32 to support Segmentation Control and Enhanced
Virtual Addressing (EVA) extensions (where KSeg1 addresses may not
represent an unmapped uncached segment).
It is also useful on MIPS64 to allow the exception base to reside in
XKPhys, and possibly out of range of KSEG0 and KSEG1.
Backports commit 74dbf824a1313b6064bbebb981a7440951d70896 from qemu
There is no need to invalidate any shadow TLB entries when the ASID
changes or when access to one of the 64-bit segments has been disabled,
since doing so doesn't reveal to software whether any TLB entries have
been evicted into the shadow half of the TLB.
Therefore weaken the tlb flushes in these cases to only flush the QEMU
TLB.
Backports commit 9658e4c342e6ae0d775101f8f6bb6efb16789af1 from qemu
Writing specific TLB entries with TLBWI flushes shadow TLB entries
unless an existing entry is having its access permissions upgraded. This
is necessary as software would from then on expect the previous mapping
in that entry to no longer be in effect (even if QEMU has quietly
evicted it to the shadow TLB on a TLBWR).
However it won't do this if only EHINV, XI, or RI bits have been set,
even if that results in a reduction of permissions, so add the necessary
checks to invoke the flush when these bits are set.
Backports commit eff6ff9431aa9776062a5f4a08d1f6503ca9995a from qemu
Using MFC0 to read CP0_UserLocal uses tcg_gen_ld32s_tl, however
CP0_UserLocal is a target_ulong. On a big endian host with a MIPS64
target this reads and sign extends the more significant half of the
64-bit register.
Fix this by using ld_tl to load the whole target_ulong and ext32s_tl to
sign extend it, as done for various other target_ulong COP0 registers.
Backports commit e40df9a80bb7cdb0a4ca650985fa9fe572097fa7 from qemu
This patch fixes setting DExcCode field of CP0 Debug register
when SDBBP instruction is executed. According to EJTAG specification,
this field must be set to the value 9 (Bp).
Backports commit c6c2c0fc32362ba234ae3bdad1a55c2d6aefaa12 from qemu
This patch fixes the msa copy_[s|u]_df instruction emulation when
the destination register rd is zero. Without this patch the zero
register would get clobbered, which should never happen because it
is supposed to be hardwired to 0.
Fix this corner case by explicitly checking rd = 0 and effectively
making these instructions emulation no-op in that case.
Backports commit cab4888136a92250fdd401402622824994f7ce0b from qemu
It is unnecessary to test R6 from delay/forbidden slot check
in gen_msa_branch().
https://bugs.launchpad.net/qemu/+bug/1663287
Backports commit 075a1fe788d36b271ec25507466c30b9a90b5d54 from qemu
this fixes many warnings like:
target/mips/translate.c:6253:13: warning: Value stored to 'rn' is never read
rn = "invalid sel";
^ ~~~~~~~~~~~~~
Backports commit 3570d7f6672836140f0a1ec9bf95dd5ea50a2aaa from qemu
static code analyzer complain:
target/mips/helper.c:453:5: warning: Function call argument is an uninitialized value
qemu_log_mask(CPU_LOG_MMU,
^~~~~~~~~~~~~~~~~~~~~~~~~~
'physical' and 'prot' are uninitialized if 'ret' is not TLBRET_MATCH.
Backports commit def74c0cf05722b2e502d4b4f1219966c5b0cbd3 from qemu
Provide a new cpu_supports_isa function which allows callers to
determine whether a CPU supports one of the ISA_ flags, by testing
whether the associated struct mips_def_t sets the ISA flags in its
insn_flags field.
An example use of this is to allow boards which generate bootloader code
to determine the properties of the CPU that will be used, for example
whether the CPU is 64 bit or which architecture revision it implements.
Backports commit bed9e5ceb158c886d548fe59675a6eba18baeaeb from qemu
We've currently got 18 architectures in QEMU, and thus 18 target-xxx
folders in the root folder of the QEMU source tree. More architectures
(e.g. RISC-V, AVR) are likely to be included soon, too, so the main
folder of the QEMU sources slowly gets quite overcrowded with the
target-xxx folders.
To disburden the main folder a little bit, let's move the target-xxx
folders into a dedicated target/ folder, so that target-xxx/ simply
becomes target/xxx/ instead.
Backports commit fcf5ef2ab52c621a4617ebbef36bf43b4003f4c0 from qemu
