Add Config4 and Config5 co-processor 0 registers, and add capability to
write the Config1, Config3, Config4, and Config5 registers using the KVM
API.
Only supported bits can be written, to minimise the chances of the guest
being given a configuration from e.g. QEMU that is inconsistent with
that being emulated, and as such the handling is in trap_emul.c as it
may need to be different for VZ. Currently the only modification
permitted is to make Config4 and Config5 exist via the M bits, but other
bits will be added for FPU and MSA support in future patches.
Care should be taken by userland not to change bits without fully
handling the possible extra state that may then exist and which the
guest may begin to use and depend on.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Various semi-used definitions exist in kvm_host.h for the default guest
config registers. Remove them and use the appropriate values directly
when initialising the Config registers.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Clean up KVM_GET_ONE_REG / KVM_SET_ONE_REG register definitions for
MIPS, to prepare for adding a new group for FPU & MSA vector registers.
Definitions are added for common bits in each group of registers, e.g.
KVM_REG_MIPS_CP0 = KVM_REG_MIPS | 0x10000, for the coprocessor 0
registers.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Implement access to the guest Processor Identification CP0 register
using the KVM_GET_ONE_REG and KVM_SET_ONE_REG ioctls. This allows the
owning process to modify and read back the value that is exposed to the
guest in this register.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Trap instructions are used by Linux to implement BUG_ON(), however KVM
doesn't pass trap exceptions on to the guest if they occur in guest
kernel mode, instead triggering an internal error "Exception Code: 13,
not yet handled". The guest kernel then doesn't get a chance to print
the usual BUG message and stack trace.
Implement handling of the trap exception so that it gets passed to the
guest and the user is left with a more useful log message.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
When handling floating point exceptions (FPEs) and MSA FPEs the Cause
bits of the appropriate control and status register (FCSR for FPEs and
MSACSR for MSA FPEs) are read and cleared before enabling interrupts,
presumably so that it doesn't have to go through the pain of restoring
those bits if the process is pre-empted, since writing those bits would
cause another immediate exception while still in the kernel.
The bits aren't normally ever restored again, since userland never
expects to see them set.
However for virtualisation it is necessary for the kernel to be able to
restore these Cause bits, as the guest may have been interrupted in an
FP exception handler but before it could read the Cause bits. This can
be done by registering a die notifier, to get notified of the exception
when such a value is restored, and if the PC was at the instruction
which is used to restore the guest state, the handler can step over it
and continue execution. The Cause bits can then remain set without
causing further exceptions.
For this to work safely a few changes are made:
- __build_clear_fpe and __build_clear_msa_fpe no longer clear the Cause
bits, and now return from exception level with interrupts disabled
instead of enabled.
- do_fpe() now clears the Cause bits and enables interrupts after
notify_die() is called, so that the notifier can chose to return from
exception without this happening.
- do_msa_fpe() acts similarly, but now actually makes use of the second
argument (msacsr) and calls notify_die() with the new DIE_MSAFP,
allowing die notifiers to be informed of MSA FPEs too.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Guest user mode can generate a guest MSA Disabled exception on an MSA
capable core by simply trying to execute an MSA instruction. Since this
exception is unknown to KVM it will be passed on to the guest kernel.
However guest Linux kernels prior to v3.15 do not set up an exception
handler for the MSA Disabled exception as they don't support any MSA
capable cores. This results in a guest OS panic.
Since an older processor ID may be being emulated, and MSA support is
not advertised to the guest, the correct behaviour is to generate a
Reserved Instruction exception in the guest kernel so it can send the
guest process an illegal instruction signal (SIGILL), as would happen
with a non-MSA-capable core.
Fix this as minimally as reasonably possible by preventing
kvm_mips_check_privilege() from relaying MSA Disabled exceptions from
guest user mode to the guest kernel, and handling the MSA Disabled
exception by emulating a Reserved Instruction exception in the guest,
via a new handle_msa_disabled() KVM callback.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.15+
The maximum word size is 64-bits since MSA state is saved using st.d
which stores two 64-bit words, therefore reimplement FPR_IDX using xor,
and only within each 64-bit word.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9169/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This reverts commit 02987633df.
The basic premise of the patch was incorrect since MSA context
(including FP state) is saved using st.d which stores two consecutive
64-bit words in memory rather than a single 128-bit word. This means
that even with big endian MSA, the FP state is still in the first 64-bit
word.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9168/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The expected semantics of __enable_fpu are for the FPU to be enabled
in the given mode if possible, otherwise for the FPU to be left
disabled and SIGFPE returned. The FPU was incorrectly being left
enabled in cases where the desired value for FR was unavailable.
Without ensuring the FPU is disabled in this case, it would be
possible for userland to go on to execute further FP instructions
natively in the incorrect mode, rather than those instructions being
trapped & emulated as they need to be.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9167/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Uses of the cfcmsa & ctcmsa instructions were not being wrapped by a
macro in the case where the toolchain supports MSA, since the arguments
exactly match a typical use of the instructions. However using current
toolchains this leads to errors such as:
arch/mips/kernel/genex.S:437: Error: opcode not supported on this processor: mips32r2 (mips32r2) `cfcmsa $5,1'
Thus uses of the instructions must be in the context of a ".set msa"
directive, however doing that from the users of the instructions would
be messy due to the possibility that the toolchain does not support
MSA. Fix this by renaming the macros (prepending an underscore) in order
to avoid recursion when attempting to emit the instructions, and provide
implementations for the TOOLCHAIN_SUPPORTS_MSA case which ".set msa" as
appropriate.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9163/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Recursive macros made the code more concise & worked great for the
case where the toolchain doesn't support MSA. However, with toolchains
which do support MSA they lead to build failures such as:
arch/mips/kernel/r4k_switch.S: Assembler messages:
arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w(0+1)[2],$1'
arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w(0+1)[3],$1'
arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w((0+1)+1)[2],$1'
arch/mips/kernel/r4k_switch.S:148: Error: invalid operands `insert.w $w((0+1)+1)[3],$1'
...
Drop the recursion from msa_init_all_upper invoking the msa_init_upper
macro explicitly for each vector register.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9162/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Assuming at ($1) as the source or destination register of copy or
insert instructions:
- Simplifies the macros providing those instructions for toolchains
without MSA support.
- Avoids an unnecessary move instruction when at is used as the source
or destination register anyway.
- Is sufficient for the uses to be introduced in the kernel by a
subsequent patch.
Note that due to a patch ordering snafu on my part this also fixes the
currently broken build with MSA support enabled. The build has been
broken since commit c9017757c5 "MIPS: init upper 64b of vector
registers when MSA is first used", which this patch should have
preceeded.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9161/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The {save,restore}_fp_context{,32} functions require that the assembler
allows the use of sdc instructions on any FP register, and this is
acomplished by setting the arch to mips64r2 or mips64r6
(using MIPS_ISA_ARCH_LEVEL_RAW).
However this has the effect of enabling the assembler to use mips64
instructions in the expansion of pseudo-instructions. This was done in
the (now-reverted) commit eec43a224c "MIPS: Save/restore MSA context
around signals" which led to my mistakenly believing that there was an
assembler bug, when in reality the assembler was just emitting mips64
instructions. Avoid the issue for future commits which will add code to
r4k_fpu.S by pushing the .set MIPS_ISA_ARCH_LEVEL_RAW directives into
the functions that require it, and remove the spurious assertion
declaring the assembler bug.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
[james.hogan@imgtec.com: Rebase on v4.0-rc1 and reword commit message to
reflect use of MIPS_ISA_ARCH_LEVEL_RAW]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9612/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The lose_fpu() function only disables the FPU in CP0_Status.CU1 if the
FPU is in use and MSA isn't enabled.
This isn't necessarily a problem because KSTK_STATUS(current), the
version of CP0_Status stored on the kernel stack on entry from user
mode, does always get updated and gets restored when returning to user
mode, but I don't think it was intended, and it is inconsistent with the
case of only the FPU being in use. Sometimes leaving the FPU enabled may
also mask kernel bugs where FPU operations are executed when the FPU
might not be enabled.
So lets disable the FPU in the MSA case too.
Fixes: 33c771ba5c ("MIPS: save/disable MSA in lose_fpu")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9323/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull MIPS updates from Ralf Baechle:
"This is the main pull request for MIPS:
- a number of fixes that didn't make the 3.19 release.
- a number of cleanups.
- preliminary support for Cavium's Octeon 3 SOCs which feature up to
48 MIPS64 R3 cores with FPU and hardware virtualization.
- support for MIPS R6 processors.
Revision 6 of the MIPS architecture is a major revision of the MIPS
architecture which does away with many of original sins of the
architecture such as branch delay slots. This and other changes in
R6 require major changes throughout the entire MIPS core
architecture code and make up for the lion share of this pull
request.
- finally some preparatory work for eXtendend Physical Address
support, which allows support of up to 40 bit of physical address
space on 32 bit processors"
[ Ahh, MIPS can't leave the PAE brain damage alone. It's like
every CPU architect has to make that mistake, but pee in the snow
by changing the TLA. But whether it's called PAE, LPAE or XPA,
it's horrid crud - Linus ]
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (114 commits)
MIPS: sead3: Corrected get_c0_perfcount_int
MIPS: mm: Remove dead macro definitions
MIPS: OCTEON: irq: add CIB and other fixes
MIPS: OCTEON: Don't do acknowledge operations for level triggered irqs.
MIPS: OCTEON: More OCTEONIII support
MIPS: OCTEON: Remove setting of processor specific CVMCTL icache bits.
MIPS: OCTEON: Core-15169 Workaround and general CVMSEG cleanup.
MIPS: OCTEON: Update octeon-model.h code for new SoCs.
MIPS: OCTEON: Implement DCache errata workaround for all CN6XXX
MIPS: OCTEON: Add little-endian support to asm/octeon/octeon.h
MIPS: OCTEON: Implement the core-16057 workaround
MIPS: OCTEON: Delete unused COP2 saving code
MIPS: OCTEON: Use correct instruction to read 64-bit COP0 register
MIPS: OCTEON: Save and restore CP2 SHA3 state
MIPS: OCTEON: Fix FP context save.
MIPS: OCTEON: Save/Restore wider multiply registers in OCTEON III CPUs
MIPS: boot: Provide more uImage options
MIPS: Remove unneeded #ifdef __KERNEL__ from asm/processor.h
MIPS: ip22-gio: Remove legacy suspend/resume support
mips: pci: Add ifdef around pci_proc_domain
...
CN38XX pass 1 required icache prefetching to be turned off. This chip never
reached production and is long dead. Other processor specific icache settings
are done by the bootloader. Remove these bits from the kernel.
Signed-off-by: Chad Reese <kreese@caviumnetworks.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/8944/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Also update union octeon_cvmemctl with new OCTEON II fields.
[aleksey.makarov@auriga.com: use __BITFIELD_FIELD]
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8940/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The wide multiplier is twice as wide, so we need to save twice as much
state. Detect the multiplier type (CPU type) at start up and install
model specific handlers.
[aleksey.makarov@auriga.com:
conflict resolution,
support for old compilers]
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Leonid Rosenboim <lrosenboim@caviumnetworks.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8933/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
There are currently no gio device drivers that implement suspend/resume
and this patch removes the bus specific legacy suspend and resume callbacks.
This will allow us to eventually remove struct bus_type legacy suspend and
resume support altogether.
gio device drivers wanting to implement suspend and resume can use dev PM
ops which will work out of the box without further modifications necessary.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8920/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* Clean up white spaces and tabs.
* Get rid of remaining hardcoded values for calculating
shifts and masks.
* Get rid of redundant macro values.
* Do not use page table bits directly in #ifdef's.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9287/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Provide correct siginfo_t.si_stime on MIPS64
Bug description:
MIPS version of copy_siginfo() is not aware of alignment on platforms with
64-bit long integers, which leads to an incorrect si_stime passed to signal
handlers, because the last element (si_stime) of _sifields._sigchld is not
copied. If _MIPS_SZLONG is 64, then the _sifields starts at the offset of
4 * sizeof(int).
Patch description:
Use the generic copy_siginfo, which doesn't have this problem.
Signed-off-by: Petr Malat <oss@malat.biz>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8671/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
NAND:
* Add new Hisilicon NAND driver for Hip04
* Add default reboot handler, to ensure all outstanding erase transactions
complete in time
* jz4740: convert to use GPIO descriptor API
* Atmel: add support for sama5d4
* Change default bitflip threshold to 75% of correction strength
* Miscellaneous cleanups and bugfixes
SPI NOR:
* Freescale QuadSPI:
- Fix a few probe() and remove() issues
- Add a MAINTAINERS entry for this driver
- Tweak transfer size to increase read performance
- Add suspend/resume support
* Add Micron quad I/O support
* ST FSM SPI: miscellaneous fixes
JFFS2:
* gracefully handle corrupted 'offset' field found on flash
Other:
* bcm47xxpart: add tweaks for a few new devices
* mtdconcat: set return lengths properly for mtd_write_oob()
* map_ram: enable use with mtdoops
* maps: support fallback to ROM/UBI for write-protected NOR flash
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Merge tag 'for-linus-20150216' of git://git.infradead.org/linux-mtd
Pull MTD updates from Brian Norris:
"NAND:
- Add new Hisilicon NAND driver for Hip04
- Add default reboot handler, to ensure all outstanding erase
transactions complete in time
- jz4740: convert to use GPIO descriptor API
- Atmel: add support for sama5d4
- Change default bitflip threshold to 75% of correction strength
- Miscellaneous cleanups and bugfixes
SPI NOR:
- Freescale QuadSPI:
- Fix a few probe() and remove() issues
- Add a MAINTAINERS entry for this driver
- Tweak transfer size to increase read performance
- Add suspend/resume support
- Add Micron quad I/O support
- ST FSM SPI: miscellaneous fixes
JFFS2:
- gracefully handle corrupted 'offset' field found on flash
Other:
- bcm47xxpart: add tweaks for a few new devices
- mtdconcat: set return lengths properly for mtd_write_oob()
- map_ram: enable use with mtdoops
- maps: support fallback to ROM/UBI for write-protected NOR flash"
* tag 'for-linus-20150216' of git://git.infradead.org/linux-mtd: (46 commits)
mtd: hisilicon: && vs & typo
jffs2: fix handling of corrupted summary length
mtd: hisilicon: add device tree binding documentation
mtd: hisilicon: add a new NAND controller driver for hisilicon hip04 Soc
mtd: avoid registering reboot notifier twice
mtd: concat: set the return lengths properly
mtd: kconfig: replace PPC_OF with PPC
mtd: denali: remove unnecessary stubs
mtd: nand: remove redundant local variable
MAINTAINERS: add maintainer entry for FREESCALE QUAD SPI driver
mtd: fsl-quadspi: improve read performance by increase AHB transfer size
mtd: fsl-quadspi: Remove unnecessary 'map_failed' label
mtd: fsl-quadspi: Remove unneeded success/error messages
mtd: fsl-quadspi: Fix the error paths
mtd: nand: omap: drop condition with no effect
mtd: nand: jz4740: Convert to GPIO descriptor API
mtd: nand: Request strength instead of bytes for soft BCH
mtd: nand: default bitflip-reporting threshold to 75% of correction strength
mtd: atmel_nand: introduce a new compatible string for sama5d4 chip
mtd: atmel_nand: return max bitflips in all sectors in pmecc_correction()
...
The previous implementation did not cover all possible FPU combinations
and it silently allowed ABI incompatible objects to be loaded with the
wrong ABI. For example, the previous logic would set the FP_64 ABI as
the matching ABI for an FP_XX object combined with an FP_64A object.
This was wrong, and the matching ABI should have been FP_64A.
The previous logic is now replaced with a new one which determines
the appropriate FPU mode to be used rather than the FP ABI. This has
the advantage that the entire logic is much simpler since it is the FPU
mode we are interested in rather than the FP ABI resulting to code
simplifications. This also removes the now obsolete FP32XX_HYBRID_FPRS
option.
Cc: Matthew Fortune <Matthew.Fortune@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
MIPS R2 FPU instructions are also present in MIPS R6 so amend the
preprocessor definitions to take MIPS R6 into consideration.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
The ERETNC instruction, introduced in MIPS R5, is similar to the ERET
one, except it does not clear the LLB bit in the LLADDR register.
This feature is necessary to safely emulate R2 LL/SC instructions.
However, on context switches, we need to clear the LLAddr/LLB bit
in order to make sure that an SC instruction from the new thread
will never succeed if it happens to interrupt an LL operation on the
same address from the previous thread.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
MIPS R6 removed quite a few R2 instructions. However, there
is plenty of <R6 userland code so we add an in-kernel emulator
so we can still be able to execute all R2 userland out there.
The emulator comes with a handy debugfs under /mips/ directory
(r2-emul-stats) to provide some basic statistics of the
instructions that are being emulated.
Below are some statistics from booting a minimal buildroot image:
Instruction Total BDslot
------------------------------
movs 236969 0
hilo 56686 0
muls 55279 0
divs 10941 0
dsps 0 0
bops 1 0
traps 0 0
fpus 0 0
loads 214981 17
stores 103364 0
llsc 56898 0
dsemul 150418 0
jr 370158
bltzl 43
bgezl 1594
bltzll 0
bgezll 0
bltzal 39
bgezal 39
beql 14503
bnel 138741
blezl 0
bgtzl 3988
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
If Config5/LLB is set in the core, then software can write the LLB
bit in the LLADDR register.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
The LLBIT (bit 4) in the Config5 CP0 register indicates the software
availability of the Load-Linked bit. This bit is only set by hardware
and it has the following meaning:
0: LLB functionality is not supported
1: LLB functionality is supported. The following feature are also
supported:
- ERETNC instruction. Similar to ERET but it does not clear the LLB
bit in the LLAddr register.
- CP0 LLAddr/LLB bit must be set
- LLbit is software accessible through the LLAddr[0]
This will be used later on to emulate R2 LL/SC instructions.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
MIPS R6 introduced the following two branch instructions for COP1:
BC1EQZ: Branch if Cop1 (FPR) Register Bit 0 is Equal to Zero
BC1NEZ: Branch if Cop1 (FPR) Register Bit 0 is Not Equal to Zero
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
The MIPS R6 JR instruction is an alias to the JALR one, so it may
need emulation for non-R6 userlands.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Add the MIPS R6 related preprocessor definitions for save/restore
FPU related functions. We also set the appropriate ISA level
so the final return instruction "jr ra" will produce the correct
opcode on R6.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
James Hogan