We currently have 2 commonly used methods for switching ISA within
assembly code, then restoring the original ISA.
1) Using a pair of .set push & .set pop directives. For example:
.set push
.set mips32r2
<some_insn>
.set pop
2) Using .set mips0 to restore the ISA originally specified on the
command line. For example:
.set mips32r2
<some_insn>
.set mips0
Unfortunately method 2 does not work with nanoMIPS toolchains, where the
assembler rejects the .set mips0 directive like so:
Error: cannot change ISA from nanoMIPS to mips0
In preparation for supporting nanoMIPS builds, switch all instances of
method 2 in generic non-platform-specific code to use push & pop as in
method 1 instead. The .set push & .set pop is arguably cleaner anyway,
and if nothing else it's good to consistently use one method.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21037/
Cc: linux-mips@linux-mips.org
New Loongson 3 CPU (since Loongson-3A R2, as opposed to Loongson-3A R1,
Loongson-3B R1 and Loongson-3B R2) has many enhancements, such as FTLB,
L1-VCache, EI/DI/Wait/Prefetch instruction, DSP/DSPv2 ASE, User Local
register, Read-Inhibit/Execute-Inhibit, SFB (Store Fill Buffer), Fast
TLB refill support, etc.
This patch introduce a config option, CONFIG_LOONGSON3_ENHANCEMENT, to
enable those enhancements which are not probed at run time. If you want
a generic kernel to run on all Loongson 3 machines, please say 'N'
here. If you want a high-performance kernel to run on new Loongson 3
machines only, please say 'Y' here.
Some additional explanations:
1) SFB locates between core and L1 cache, it causes memory access out
of order, so writel/outl (and other similar functions) need a I/O
reorder barrier.
2) Loongson 3 has a bug that di instruction can not save the irqflag,
so arch_local_irq_save() is modified. Since CPU_MIPSR2 is selected
by CONFIG_LOONGSON3_ENHANCEMENT, generic kernel doesn't use ei/di
at all.
3) CPU_HAS_PREFETCH is selected by CONFIG_LOONGSON3_ENHANCEMENT, so
MIPS_CPU_PREFETCH (used by uasm) probing is also put in this patch.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J . Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12755/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add hazard macros to <asm/hazards.h> for the following hazards around
tlbr (TLB read) instructions, which are used in TLB dumping code and
some KVM TLB management code:
- mtc0_tlbr_hazard
Between mtc0 (Index) and tlbr. This is copied from mtc0_tlbw_hazard in
all cases on the assumption that tlbr always has similar data user
timings to tlbw.
- tlb_read_hazard
Between tlbr and mfc0 (various TLB registers). This is copied from
tlbw_use_hazard in all cases on the assumption that tlbr has similar
data writer characteristics to tlbw, and mfc0 has similar data user
characteristics to loads and stores.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10078/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
TLB and COP0 hazards are handled in hardware for Netlogic XLR/XLS
SoCs. Update hazards.h to pick more optimal set of definitions when
compiling for XLR/XLS.
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: http://patchwork.linux-mips.org/patch/4788/
Signed-off-by: John Crispin <blogic@openwrt.org>
Having received another series of whitespace patches I decided to do this
once and for all rather than dealing with this kind of patches trickling
in forever.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add CONFIG_CPU_BMIPS* in all of the right places, so that BMIPS kernel
images will compile and run.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2955/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Use a tab on second and subsequent lines of multiline #if's, for
consistency with the next commit.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2954/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Remove the CONFIG_SOC_AU1X00 Kconfig symbol since its job can also be done
by MACH_ALCHEMY, now renamed to MIPS_ALCHEMY.
Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
To: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/1461/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Quoting from Loongson2FUserGuide.pdf:
5.22.1 Hazards
The processor detects most of the pipeline hazards in hardware, including
CP0 hazards and load hazards. No NOP instructions are required to correct
instruction sequences.
Signed-off-by: Zhang Le <r0bertz@gentoo.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The Alchemy manuals state:
"All pipeline hazards and dependencies are enforced by hardware interlocks
so that any sequence of instructions is guaranteed to execute correctly.
Therefore, it is not necessary to pad legacy MIPS hazards (such as
load delay slots and coprocessor accesses) with NOPs."
Run-tested on Au12x0, without any ill effects.
Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Current VR5500 processor support lacks of some functions which are
expected to be configured/synthesized on arch initialization.
Here're some VR5500A spec notes:
* All execution hazards are handled in hardware.
* Once VR5500A stops the operation of the pipeline by WAIT instruction,
it could return from the standby mode only when either a reset, NMI
request, or all enabled interrupts is/are detected. In other words,
if interrupts are disabled by Status.IE=0, it keeps in standby mode
even when interrupts are internally asserted.
Notes on WAIT: The operation of the processor is undefined if WAIT
insn is in the branch delay slot. The operation is also undefined
if WAIT insn is executed when Status.EXL and Status.ERL are set to 1.
* VR5500A core only implements the Load prefetch.
With these changes, it boots fine.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
For Cavium CPU, we treat the same as R10000, in that all hazards
are dealt with in hardware.
Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: Paul Gortmaker <Paul.Gortmaker@windriver.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Paul Burton