Reword the comment for `__cpu_has_fpu' to make it unambiguous this code
is for external floating-point units only, generally MIPS I processors
using the original CP1 hardware interface.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9673/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This allows the kernel to correctly detect an R16000 MIPS CPU on systems that
have those. Otherwise, such systems will detect the CPU as an R14000, due to
similarities in the CPU PRId value.
Signed-off-by: Joshua Kinard <kumba@gentoo.org>
Cc: Linux MIPS List <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/9092/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add architectural definitions and probing for the MIPS Common Device
Memory Map (CDMM) region. When supported and enabled at a particular
physical address, this region allows some number of per-CPU devices to
be discovered and controlled via MMIO.
A bit exists in Config3 to determine whether the feature is present, and
a CDMMBase CP0 register allows the region to be enabled at a particular
physical address.
[ralf@linux-mips.org: Sort conflict with other patches.]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9178/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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>
Add MIPS R6 support when decoding the config0 c0 register.
Also add MIPS R6 support when examining the ebase c0 register
to get the core number and when getting the shadow set number
from the srsctl c0 register.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Add a case in cpu_probe_mips for the MIPS generic QEMU processor ID.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
activate_mm() and switch_mm() call get_new_mmu_context() which in turn
can enable the HTW before the entryhi is changed with the new ASID.
Since the latter will enable the HTW in local_flush_tlb_all(),
then there is a small timing window where the HTW is running with the
new ASID but with an old pgd since the TLBMISS_HANDLER_SETUP_PGD
hasn't assigned a new one yet. In order to prevent that, we introduce a
simple htw counter to avoid starting HTW accidentally due to nested
htw_{start,stop}() sequences. Moreover, since various IPI calls can
enforce TLB flushing operations on a different core, such an operation
may interrupt another htw_{stop,start} in progress leading inconsistent
updates of the htw_seq variable. In order to avoid that, we disable the
interrupts whenever we update that variable.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 3.17+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9118/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull MIPS updates from Ralf Baechle:
"This is an unusually large pull request for MIPS - in parts because
lots of patches missed the 3.18 deadline but primarily because some
folks opened the flood gates.
- Retire the MIPS-specific phys_t with the generic phys_addr_t.
- Improvments for the backtrace code used by oprofile.
- Better backtraces on SMP systems.
- Cleanups for the Octeon platform code.
- Cleanups and fixes for the Loongson platform code.
- Cleanups and fixes to the firmware library.
- Switch ATH79 platform to use the firmware library.
- Grand overhault to the SEAD3 and Malta interrupt code.
- Move the GIC interrupt code to drivers/irqchip
- Lots of GIC cleanups and updates to the GIC code to use modern IRQ
infrastructures and features of the kernel.
- OF documentation updates for the GIC bindings
- Move GIC clocksource driver to drivers/clocksource
- Merge GIC clocksource driver with clockevent driver.
- Further updates to bring the GIC clocksource driver up to date.
- R3000 TLB code cleanups
- Improvments to the Loongson 3 platform code.
- Convert pr_warning to pr_warn.
- Merge a bunch of small lantiq and ralink fixes that have been
staged/lingering inside the openwrt tree for a while.
- Update archhelp for IP22/IP32
- Fix a number of issues for Loongson 1B.
- New clocksource and clockevent driver for Loongson 1B.
- Further work on clk handling for Loongson 1B.
- Platform work for Broadcom BMIPS.
- Error handling cleanups for TurboChannel.
- Fixes and optimization to the microMIPS support.
- Option to disable the FTLB.
- Dump more relevant information on machine check exception
- Change binfmt to allow arch to examine PT_*PROC headers
- Support for new style FPU register model in O32
- VDSO randomization.
- BCM47xx cleanups
- BCM47xx reimplement the way the kernel accesses NVRAM information.
- Random cleanups
- Add support for ATH25 platforms
- Remove pointless locking code in some PCI platforms.
- Some improvments to EVA support
- Minor Alchemy cleanup"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (185 commits)
MIPS: Add MFHC0 and MTHC0 instructions to uasm.
MIPS: Cosmetic cleanups of page table headers.
MIPS: Add CP0 macros for extended EntryLo registers
MIPS: Remove now unused definition of phys_t.
MIPS: Replace use of phys_t with phys_addr_t.
MIPS: Replace MIPS-specific 64BIT_PHYS_ADDR with generic PHYS_ADDR_T_64BIT
PCMCIA: Alchemy Don't select 64BIT_PHYS_ADDR in Kconfig.
MIPS: lib: memset: Clean up some MIPS{EL,EB} ifdefery
MIPS: iomap: Use __mem_{read,write}{b,w,l} for MMIO
MIPS: <asm/types.h> fix indentation.
MAINTAINERS: Add entry for BMIPS multiplatform kernel
MIPS: Enable VDSO randomization
MIPS: Remove a temporary hack for debugging cache flushes in SMTC configuration
MIPS: Remove declaration of obsolete arch_init_clk_ops()
MIPS: atomic.h: Reformat to fit in 79 columns
MIPS: Apply `.insn' to fixup labels throughout
MIPS: Fix microMIPS LL/SC immediate offsets
MIPS: Kconfig: Only allow 32-bit microMIPS builds
MIPS: signal.c: Fix an invalid cast in ISA mode bit handling
MIPS: mm: Only build one microassembler that is suitable
...
Add new 'noftlb' kernel command line option to disable the FTLB.
Since the kernel command line is not available when probing and
enabling the CPU features in cpu_probe(), we let the kernel configure
the FTLB during the config4 decode operation and we disable the FTLB later
on, once the command line has become available to us. This should have
no negative effects since FTLB isn't used so early in the boot process.
FTLB increases the effective TLB size leading to less TLB misses. However,
sometimes it's useful to be able to disable it when debugging memory related
core features or other hardware components.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/7586/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Based on the spatch
@@
expression e;
@@
- return (e);
+ return e;
with heavy hand editing because some of the changes are either whitespace
or identation only or result in excessivly long lines.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Make use of the Config6/FLTBP bit to set the probability of a TLBWR
instruction to hit the FTLB or the VTLB. A value of 0 (which may be
the default value on certain cores, such as proAptiv or P5600)
means that a TLBWR instruction will never hit the VTLB which
leads to performance limitations since it effectively decreases
the number of available TLB slots.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: <stable@vger.kernel.org> # v3.15+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8368/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
In CPU manual Loongson-3 is MIPS64R2 compatible, but during tests we
found that its EI/DI instructions have problems. So we just set the ISA
level to MIPS64R1.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/8320/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
All Loongson-2/3 processors support _CACHE_UNCACHED_ACCELERATED, not
only Loongson-3A.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/8319/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Different cores use different CCA values to achieve write-combine
memory writes. For cores that do not support write-combine we
set the default value to CCA:2 (uncached, non-coherent) which is the
default value as set by the kernel.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7402/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Detect the presence of MAAR using the MRP bit in Config5, and record
that presence using a CPU option bit. A cpu_has_maar macro will then
allow code to conditionalise upon the presence of MAARs.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7330/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The kernel relies upon MSA being disabled when a task begins running,
so that it can initialise or restore context in response to the
resulting MSA disabled exception. Previously the state of MSA following
boot was left as it was before the kernel ran, where MSA could
potentially have been enabled. Explicitly disable it during boot to
prevent any problems.
As a nice side effect the code reads a little better too.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7306/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Detect if the core supports unique exception codes for the
Read-Inhibit and Execute-Inhibit exceptions and set the
option accordingly. The RI/XI exception support is detected
by setting the 27th bit (IEC) of the PageGrain C0 register
and reading back the value of that register to verify the
bit is enabled.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7340/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Detect if the core implements the HTW and set the option accordingly.
Also, add a new kernel parameter called 'nohtw' allowing
the user to disable the htw support and fallback to the software
refill handler.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7335/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Loongson-3B is a 8-cores processor. In general it looks like there are
two Loongson-3A integrated in one chip: 8 cores are separated into two
groups (two NUMA node), each node has its own local memory.
Of course there are some differences between one Loongson-3B and two
Loongson-3A. E.g., the base addresses of IPI registers of each node are
not the same; Loongson-3A use ChipConfig register to enable/disable
clock, but Loongson-3B use FreqControl register instead.
There are two revision of Loongson-3B, the first revision is called as
Loongson-3B1000, whose frequency is 1GHz and has a PRid 0x6306, the
second revision is called as Loongson-3B1500, whose frequency is 1.5GHz
and has a PRid 0x6307. Both revisions has a bug that clock cannot be
disabled at runtime, but this will be fixed in future.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/7188/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This returns the CPUNum from the low order Ebase bits.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7012/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Update to commit 9c9b415c50 [MIPS:
Reimplement get_cycles().]
On systems were for whatever reasons we can't use the cycle counter, fall
back to the c0_random register as an entropy source. It has however a
very small range that makes it suitable for random_get_entropy only and
not get_cycles.
This optimised version compiles to 8 instructions in the fast path even in
the worst case of all the conditions to check being variable (including a
MFC0 move delay slot that is only required for very old processors):
828: 8cf90000 lw t9,0(a3)
828: R_MIPS_LO16 jiffies
82c: 40057800 mfc0 a1,c0_prid
830: 3c0200ff lui v0,0xff
834: 00a21024 and v0,a1,v0
838: 1040007d beqz v0,a30 <add_interrupt_randomness+0x22c>
83c: 3c030000 lui v1,0x0
83c: R_MIPS_HI16 cpu_data
840: 40024800 mfc0 v0,c0_count
844: 00000000 nop
848: 00409021 move s2,v0
84c: 8ce20000 lw v0,0(a3)
84c: R_MIPS_LO16 jiffies
On most targets the sequence will be shorter and on some it will reduce to
a single `MFC0 <reg>,c0_count', as all MIPS architecture (i.e. non-legacy
MIPS) processors require the CP0 Count register to be present.
The only known exception that reports MIPS architecture compliance, but
contrary to that lacks CP0 Count is the Ingenic JZ4740 thingy. For broken
platforms like that this code requires cpu_has_counter to be hardcoded to
0 (i.e. no variable setting is permitted) so as not to penalise all the
other good platforms out there.
The asm barrier is required so that the compiler does not pull any
potentially costly (cold cache!) `cpu_data' variable access into the fast
path.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: John Crispin <blogic@openwrt.org>
Cc: Andrew McGregor <andrewmcgr@gmail.com>
Cc: Dave Taht <dave.taht@bufferbloat.net>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Simon Kelley <simon@thekelleys.org.uk>
Cc: Jim Gettys <jg@freedesktop.org>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6702/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add support for the XLP5XX processor which is an 8 core variant of the
XLP9XX. Add XLP5XX cases to code which earlier handled XLP9XX.
Signed-off-by: Yonghong Song <ysong@broadcom.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6871/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.
Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
In cores which implement the MT ASE, the CPUNum in the EBase register is
a concatenation of the core number & the VPE ID within that core. In
order to retrieve the correct core number CPUNum must be shifted
appropriately to remove the VPE ID bits.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6666/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Basic Loongson-3 CPU support include CPU probing and TLB/cache
initializing.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Hongliang Tao <taohl@lemote.com>
Signed-off-by: Hua Yan <yanh@lemote.com>
Tested-by: Alex Smith <alex.smith@imgtec.com>
Reviewed-by: Alex Smith <alex.smith@imgtec.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6630
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Loongson-1 is a 32-bit MIPS CPU and Loongson-2/3 are 64-bit MIPS CPUs,
and both Loongson-2/3 has the same PRID IMP filed (0x6300). As a
result, renaming PRID_IMP_LOONGSON1 and PRID_IMP_LOONGSON2 to
PRID_IMP_LOONGSON_32 and PRID_IMP_LOONGSON_64 will make more sense.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Tested-by: Alex Smith <alex.smith@imgtec.com>
Reviewed-by: Alex Smith <alex.smith@imgtec.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6552/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Allow FTLB to be turned on or off for CPU_P5600 as well as CPU_PROAPTIV.
The existing if statement is converted into a switch to allow for future
expansion.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6411/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add a case in cpu_probe_mips for the MIPS P5600 processor ID, which sets
the CPU type to the new CPU_P5600.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6409/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
No current systems implementing MSA include support for vector register
partitioning which makes it somewhat difficult to implement support for
it in the kernel. Thus for the moment the kernel includes no such
support. However if the kernel were to be run on a system which
implemented register partitioning then it would not function correctly,
mishandling MSA disabled exceptions. Print a warning if run on a system
with vector register partitioning implemented to indicate this problem
should it occur.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6494/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch adds support for probing the MSAP bit within the Config3
register in order to detect the presence of the MSA ASE. Presence of the
ASE will be indicated in /proc/cpuinfo. The value of the MSA
implementation register will be displayed at boot to aid debugging and
verification of a correct setup, as is done for the FPU.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6430/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The 1074K is a multiprocessing coherent processing system (CPS) based
on modified 74K cores. This patch makes the 1074K an actual unique
CPU type, instead of a 74K derivative, which it is not.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Reviewed-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6389/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Adds processor ID of XLP 9XX to asm/cpu.h. Update netlogic/xlp-hal/xlp.h
to add cpu_is_xlp9xx() and to update cpu_is_xlpii() to support XLP 9XX.
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6274/
The Fixed Page Size TLB (FTLB) is a set-associative dual entry TLB. Its
purpose is to reduce the number of TLB misses by increasing the effective
TLB size and keep the implementation complexity to minimum levels.
A supported core can have both VTLB and FTLB.
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6139/
MIPS32R3 introduced a new set of Segmentation Control registers which
increase the flexibility of the segmented-based memory scheme.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6131/
New Aptiv cores support the TLBINVF instruction for flushing
the VTLB.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6130/
CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs
do. In order to preserve backwards compatibility a 64-bit FPU will act
like a 32-bit FPU (by accessing doubles from the least significant 32
bits of an even-odd pair of FP registers) when the Status.FR bit is
zero, again just like a mips64 CPU. The standard O32 ABI is defined
expecting a 32-bit FPU, however recent toolchains support use of a
64-bit FPU from an O32 MIPS32 executable. When an ELF executable is
built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF
header.
With this patch the kernel will check the EF_MIPS_FP64 flag when
executing an O32 binary, and set Status.FR accordingly. The addition
of O32 64-bit FP support lessens the opportunity for optimisation in
the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is
introduced to allow this support to be disabled for those that don't
require it.
Inspired by an earlier patch by Leonid Yegoshin, but implemented more
cleanly & correctly.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/6154/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
There is no reliable way to tell R4000/R4400 SC and MC variations apart,
however simple heuristic should give good results. Only the MC version
supports coherent caching so we can rely on such a mode having been set
for KSEG0 by the power-on firmware to reliably indicate an MC processor.
SC processors reportedly hang on coherent cached memory accesses and Linux
is linked to a cached load address so the firmware has to use the correct
caching mode to download the kernel image in a cached mode successfully.
OTOH if the firmware chooses to use either the non-coherent cached or the
uncached mode for KSEG0 on an MC processor, then the SC variant will be
reported, just as we currently do, so no regression here.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: MIPS Mailing List <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/5882/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Currently the kernel will always use the FR=0 register model for O32. If
an O32 application did enable FR=1 mode, some data from another application
might be leaked in the extra registers becoming visible.
Iow, this patch is meant to make the kernel MIPS R5 tolerant but leaves
proper MIPS R5 support to a future patchset.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Replace hardcoded CP0 PRId and CP1 FPIR register access masks throughout.
The change does not touch places that use shifted or partial masks.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5838/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
