The return address argument to the softmmu template helpers was
confused. In the legacy case, we wanted to indicate that there
is no return address, and so passed in NULL. However, we then
immediately subtracted GETPC_ADJ from NULL, resulting in a non-zero
value, indicating the presence of an (invalid) return address.
Push the GETPC_ADJ subtraction down to the only point it's required:
immediately before use within cpu_restore_state_from_tb, after all
NULL pointer checks have been completed.
This makes GETPC and GETRA identical. Remove GETRA as the lesser
used macro, replacing all uses with GETPC.
Backports commit 01ecaf438b1eb46abe23392c8ce5b7628b0c8cf5 from qemu
There are functions tlb_fill(), cpu_unaligned_access() and
do_unaligned_access() that are called with access type and mmu index
arguments. But these arguments are named 'is_write' and 'is_user' in their
declarations. The patches fix the arguments to avoid a confusion.
Backports commit b35399bb4e9968296a12303b00f9f2066470e987 from qemu
ASID currently has uint8_t type which is too small since some processors
support more than 8 bits ASID. Therefore change its type to uint16_t.
Backports commit 2d72e7b047d800c9f99262466f65a98684ecca14 from qemu
This patch implements read and write access rules for Mips floating
point control and status register (FCR31). The change can be divided
into following parts:
- Add fields that will keep FCR31's R/W bitmask in procesor
definitions and processor float_status structure.
- Add appropriate value for FCR31's R/W bitmask for each supported
processor.
- Add function for setting snan_bit_is_one, and integrate it in
appropriate places.
- Modify handling of CTC1 (case 31) instruction to use FCR31's R/W
bitmask.
- Modify handling user mode executables for Mips, in relation to the
bit EF_MIPS_NAN2008 from ELF header, that is in turn related to
reading and writing to FCR31.
- Modify gdb behavior in relation to FCR31.
Backports commit 599bc5e89c46f95f86ccad0d747d041c89a28806 from qemu
New set of helpers for handling nan2008-syle versions of instructions
<CEIL|CVT|FLOOR|ROUND|TRUNC>.<L|W>.<S|D>, for Mips R6.
All involved instructions have float operand and integer result. Their
core functionality is implemented via invocations of appropriate SoftFloat
functions. The problematic cases are when the operand is a NaN, and also
when the operand (float) is out of the range of the result.
Here one can distinguish three cases:
CASE MIPS-A: (FCR31.NAN2008 == 1)
1. Operand is a NaN, result should be 0;
2. Operand is larger than INT_MAX, result should be INT_MAX;
3. Operand is smaller than INT_MIN, result should be INT_MIN.
CASE MIPS-B: (FCR31.NAN2008 == 0)
1. Operand is a NaN, result should be INT_MAX;
2. Operand is larger than INT_MAX, result should be INT_MAX;
3. Operand is smaller than INT_MIN, result should be INT_MAX.
CASE SoftFloat:
1. Operand is a NaN, result is INT_MAX;
2. Operand is larger than INT_MAX, result is INT_MAX;
3. Operand is smaller than INT_MIN, result is INT_MIN.
Current implementation of <CEIL|CVT|FLOOR|ROUND|TRUNC>.<L|W>.<S|D>
implements case MIPS-B. This patch relates to case MIPS-A. For case
MIPS-A, only return value for NaN-operands should be corrected after
appropriate SoftFloat library function is called.
Related MSA instructions FTRUNC_S and FTINT_S already handle well
all cases, in the fashion similar to the code from this patch.
Backports commit 87552089b62fa229d2ff86906e4e779177fb5835 from qemu
This patch modifies SoftFloat library so that it can be configured in
run-time in relation to the meaning of signaling NaN bit, while, at the
same time, strictly preserving its behavior on all existing platforms.
Background:
In floating-point calculations, there is a need for denoting undefined or
unrepresentable values. This is achieved by defining certain floating-point
numerical values to be NaNs (which stands for "not a number"). For additional
reasons, virtually all modern floating-point unit implementations use two
kinds of NaNs: quiet and signaling. The binary representations of these two
kinds of NaNs, as a rule, differ only in one bit (that bit is, traditionally,
the first bit of mantissa).
Up to 2008, standards for floating-point did not specify all details about
binary representation of NaNs. More specifically, the meaning of the bit
that is used for distinguishing between signaling and quiet NaNs was not
strictly prescribed. (IEEE 754-2008 was the first floating-point standard
that defined that meaning clearly, see [1], p. 35) As a result, different
platforms took different approaches, and that presented considerable
challenge for multi-platform emulators like QEMU.
Mips platform represents the most complex case among QEMU-supported
platforms regarding signaling NaN bit. Up to the Release 6 of Mips
architecture, "1" in signaling NaN bit denoted signaling NaN, which is
opposite to IEEE 754-2008 standard. From Release 6 on, Mips architecture
adopted IEEE standard prescription, and "0" denotes signaling NaN. On top of
that, Mips architecture for SIMD (also known as MSA, or vector instructions)
also specifies signaling bit in accordance to IEEE standard. MSA unit can be
implemented with both pre-Release 6 and Release 6 main processor units.
QEMU uses SoftFloat library to implement various floating-point-related
instructions on all platforms. The current QEMU implementation allows for
defining meaning of signaling NaN bit during build time, and is implemented
via preprocessor macro called SNAN_BIT_IS_ONE.
On the other hand, the change in this patch enables SoftFloat library to be
configured in run-time. This configuration is meant to occur during CPU
initialization, at the moment when it is definitely known what desired
behavior for particular CPU (or any additional FPUs) is.
The change is implemented so that it is consistent with existing
implementation of similar cases. This means that structure float_status is
used for passing the information about desired signaling NaN bit on each
invocation of SoftFloat functions. The additional field in float_status is
called snan_bit_is_one, which supersedes macro SNAN_BIT_IS_ONE.
IMPORTANT:
This change is not meant to create any change in emulator behavior or
functionality on any platform. It just provides the means for SoftFloat
library to be used in a more flexible way - in other words, it will just
prepare SoftFloat library for usage related to Mips platform and its
specifics regarding signaling bit meaning, which is done in some of
subsequent patches from this series.
Further break down of changes:
1) Added field snan_bit_is_one to the structure float_status, and
correspondent setter function set_snan_bit_is_one().
2) Constants <float16|float32|float64|floatx80|float128>_default_nan
(used both internally and externally) converted to functions
<float16|float32|float64|floatx80|float128>_default_nan(float_status*).
This is necessary since they are dependent on signaling bit meaning.
At the same time, for the sake of code cleanup and simplicity, constants
<floatx80|float128>_default_nan_<low|high> (used only internally within
SoftFloat library) are removed, as not needed.
3) Added a float_status* argument to SoftFloat library functions
XXX_is_quiet_nan(XXX a_), XXX_is_signaling_nan(XXX a_),
XXX_maybe_silence_nan(XXX a_). This argument must be present in
order to enable correct invocation of new version of functions
XXX_default_nan(). (XXX is <float16|float32|float64|floatx80|float128>
here)
4) Updated code for all platforms to reflect changes in SoftFloat library.
This change is twofolds: it includes modifications of SoftFloat library
functions invocations, and an addition of invocation of function
set_snan_bit_is_one() during CPU initialization, with arguments that
are appropriate for each particular platform. It was established that
all platforms zero their main CPU data structures, so snan_bit_is_one(0)
in appropriate places is not added, as it is not needed.
[1] "IEEE Standard for Floating-Point Arithmetic",
IEEE Computer Society, August 29, 2008.
Backports commit af39bc8c49224771ec0d38f1b693ea78e221d7bc from qemu
exec-all.h contains TCG-specific definitions. It is not needed outside
TCG-specific files such as translate.c, exec.c or *helper.c.
One generic function had snuck into include/exec/exec-all.h; move it to
include/qom/cpu.h.
Backports commit 63c915526d6a54a95919ebece83fa9ca631b2508 from qemu
Commit b00c72180c36 ("target-mips: add PC, XNP reg numbers to RDHWR")
changed the rdhwr helpers to use check_hwrena() to check the register
being accessed is enabled in CP0_HWREna when used from user mode. If
that check fails an EXCP_RI exception is raised at the host PC
calculated with GETPC().
However check_hwrena() may not be fully inlined as the
do_raise_exception() part of it is common regardless of the arguments.
This causes GETPC() to calculate the address in the call in the helper
instead of the generated code calling the helper. No TB will be found
and the EPC reported with the resulting guest RI exception points to the
beginning of the TB instead of the RDHWR instruction.
We can't reliably force check_hwrena() to be inlined, and converting it
to a macro would be ugly, so instead pass the host PC in as an argument,
with each rdhwr helper passing GETPC(). This should avoid any dependence
on compiler behaviour, and in practice seems to ensure the full inlining
of check_hwrena() on x86_64.
This issue causes failures when running a MIPS KVM (trap & emulate)
guest in a MIPS QEMU TCG guest, as the inner guest kernel will do a
RDHWR of counter, which is disabled in the outer guest's CP0_HWREna by
KVM so it can emulate the inner guest's counter. The emulation fails and
the RI exception is passed to the inner guest.
Backports commit d96391c1ffeb30a0afa695c86579517c69d9a889 from qemu
The MAAR register is a read/write register included in Release 5
of the architecture that defines the accessibility attributes of
physical address regions. In particular, MAAR defines whether an
instruction fetch or data load can speculatively access a memory
region within the physical address bounds specified by MAAR.
As QEMU doesn't do speculative access, hence this patch only
provides ability to access the registers.
Backports commit f6d4dd810983fdf3d1c9fb81838167efef63d1c8 from qemu
MIPS Release 6 provides multi-threading features which replace
pre-R6 MT Module. CP0.Config3.MT is always 0 in R6, instead there is new
CP0.Config5.VP (Virtual Processor) bit which indicates presence of
multi-threading support which includes CP0.GlobalNumber register and
DVP/EVP instructions.
Backports commit 01bc435b44b8802cc4697faa07d908684afbce4e from qemu
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes.
Backports commit c684822ad29968af09735148f03a511bc514589d from qemu
cvt.s.d and cvt.d.s are FP operations and thus need to convert input
sNaN into corresponding qNaN. Explicitely use the floatXX_maybe_silence_nan
functions for that as the floatXX_to_floatXX functions do not do that.
Backports commit 1aa56f6ee7d2375b0734e98ba69cc41416894bbc from qemu
CP0.Status.KX/SX/UX bits are responsible for enabling access to 64-bit
Kernel/Supervisor/User Segments. If bit is cleared an access to
corresponding segment should generate Address Error Exception.
However, the guest may still be able to access some pages belonging to
the disabled 64-bit segment because we forget to flush QEMU TLB.
This patch fixes it.
Backports commit f93c3a8d0c0c1038dbe1e957eb8ab92671137975 from qemu
Add Performance Counter (4) and XNP (5) register numbers to RDHWR.
Add check_hwrena() to simplify access control checkings.
Add RDHWR support to microMIPS R6.
Backports commit b00c72180c36510bf9b124e190bd520e3b7e1358 from qemu
This patch improves exception handling in MIPS.
Instructions generate several types of exceptions.
When exception is generated, it breaks the execution of the current
translation block. Implementation of the exceptions handling does not
correctly restore icount for the instruction which caused the exception.
In most cases icount will be decreased by the value equal to the size of
TB. This patch passes pointer to the translation block internals to the
exception handler. It allows correct restoring of the icount value.
Backports commit 9c708c7f9fbb813a3fac02f2728e51e62f2f5ffc from qemu
For RDHWR on the CP0.Count register, env->CP0_Count was being returned.
This value is a delta against the QEMU_CLOCK_VIRTUAL clock, not the
correct current value of CP0.Count. Use cpu_mips_get_count() instead.
Backports commit cdfcad788394ff53e317043e07b8e34f4987c659 from qemu
This is set to true when the index is for an instruction fetch
translation.
The core get_page_addr_code() sets it, as do the SOFTMMU_CODE_ACCESS
acessors.
All targets ignore it for now, and all other callers pass "false".
This will allow targets who wish to split the mmu index between
instruction and data accesses to do so. A subsequent patch will
do just that for PowerPC.
Backports commit 97ed5ccdee95f0b98bedc601ff979e368583472c 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
Fix Debug Mode flag clearing, and when DERET is placed between LL and SC
do not make SC fail.
Backports commit fe87c2b36ae9c1c9a5279f3891f3bce1b573baa0 from qemu
When syncing the task ASID with EntryHi, correctly or the value instead
of assigning it.
Backports commit 6a973e6b6584221bed89a01e755b88e58b496652 from qemu
CP0.PageGrain.ELPA enables support for large physical addresses. This field
is encoded as follows:
0: Large physical address support is disabled.
1: Large physical address support is enabled.
If this bit is a 1, the following changes occur to coprocessor 0 registers:
- The PFNX field of the EntryLo0 and EntryLo1 registers is writable and
concatenated with the PFN field to form the full page frame number.
- Access to optional COP0 registers with PA extension, LLAddr, TagLo is
defined.
P5600 can operate in 32-bit or 40-bit Physical Address Mode. Therefore if
XPA is disabled (CP0.PageGrain.ELPA = 0) then assume 32-bit Address Mode.
In MIPS64 assume 36 as default PABITS (when CP0.PageGrain.ELPA = 0).
env->PABITS value is constant and indicates maximum PABITS available on
a core, whereas env->PAMask is calculated from env->PABITS and is also
affected by CP0.PageGrain.ELPA.
Backports commit e117f52636d04502fab28bd3abe93347c29f39a5 from qemu
Update tlb->PFN to contain PFN concatenated with PFNX. PFNX is 0 if large
physical address is not supported.
Backports commit cd0d45c40133ef8b409aede5ad8a99aeaf6a70fe from qemu
Extend EntryLo0, EntryLo1, LLAddr and TagLo from 32 to 64 bits in MIPS32.
Introduce gen_move_low32() function which moves low 32 bits from 64-bit
temp to GPR; it sign extends 32-bit value on MIPS64 and truncates on
MIPS32.
Backports commit 284b731a6ae47b9ebabb9613e753c4d83cf75dd3 from qemu
ERETNC is identical to ERET except that an ERETNC will not clear the LLbit
that is set by execution of an LL instruction, and thus when placed between
an LL and SC sequence, will never cause the SC to fail.
Presence of ERETNC is denoted by the Config5.LLB.
Backports commit ce9782f40ac16660ea9437bfaa2c9c34d5ed8110 from qemu
MIPS SIMD Architecture vector loads and stores require misalignment support.
MSA Memory access should work as an atomic operation. Therefore, it has to
check validity of all addresses for a vector store access if it is spanning
into two pages.
Separating helper functions for each data format as format is known in
translation.
To use mmu_idx from cpu_mmu_index() instead of calculating it from hflag.
Removing save_cpu_state() call in translation because it is able to use
cpu_restore_state() on fault as GETRA() is passed.
Backports commit adc370a48fd26b92188fa4848dfb088578b1936c from qemu
This relatively small architectural feature adds the following:
FIR.FREP: Read-only. If FREP=1, then Config5.FRE and Config5.UFE are
available.
Config5.FRE: When enabled all single-precision FP arithmetic instructions,
LWC1/LWXC1/MTC1, SWC1/SWXC1/MFC1 cause a Reserved Instructions
exception.
Config5.UFE: Allows user to write/read Config5.FRE using CTC1/CFC1
instructions.
Enable the feature in MIPS64R6-generic CPU.
Backports commit 7c979afd11b09a16634699dd6344e3ba10c9677e 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
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
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
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
