The GW54xx can provide PWM4 out either the off-board backlight connector
or the off-board digital I/O connector. By default the pinmux routes it
to the backlight connector but this pinctl alternate provides documentation
for those who may want to change it.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Since uboot v2016.01-rc2, which supported basic psci for i.mx7d.
So imx7d's second core can be enabled by psci.
Without arch timer, every timer event will be boardcasted to each core.
arch timer has local timer irq for each core.
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Though the keyboard and other driver will continue to support the legacy
"gpio-key,wakeup", "linux,wakeup" and "enable-sdio-wakeup" boolean
property to enable the wakeup source, "wakeup-source" is the new
standard binding.
This patch replaces all the legacy wakeup properties with the unified
"wakeup-source" property in order to avoid any futher copy-paste
duplication.
Cc: Sascha Hauer <kernel@pengutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This adds the remaining SAI instances SAI0, SAI1 and SAI3. All
instances are very similar, except that the DMA channel of SAI3
is available on MUX1 (compared to MUX0 for SAI0-SAI2). Also,
SAI3 has a slightly different memory map due to a deeper FIFO,
however in practice the current driver works for SAI3 fine.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Pull MIPS updates from Ralf Baechle:
"This is the main pull request for MIPS for 4.5 plus some 4.4 fixes.
The executive summary:
- ATH79 platform improvments, use DT bindings for the ATH79 USB PHY.
- Avoid useless rebuilds for zboot.
- jz4780: Add NEMC, BCH and NAND device tree nodes
- Initial support for the MicroChip's DT platform. As all the device
drivers are missing this is still of limited use.
- Some Loongson3 cleanups.
- The unavoidable whitespace polishing.
- Reduce clock skew when synchronizing the CPU cycle counters on CPU
startup.
- Add MIPS R6 fixes.
- Lots of cleanups across arch/mips as fallout from KVM.
- Lots of minor fixes and changes for IEEE 754-2008 support to the
FPU emulator / fp-assist software.
- Minor Ralink, BCM47xx and bcm963xx platform support improvments.
- Support SMP on BCM63168"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (84 commits)
MIPS: zboot: Add support for serial debug using the PROM
MIPS: zboot: Avoid useless rebuilds
MIPS: BMIPS: Enable ARCH_WANT_OPTIONAL_GPIOLIB
MIPS: bcm63xx: nvram: Remove unused bcm63xx_nvram_get_psi_size() function
MIPS: bcm963xx: Update bcm_tag field image_sequence
MIPS: bcm963xx: Move extended flash address to bcm_tag header file
MIPS: bcm963xx: Move Broadcom BCM963xx image tag data structure
MIPS: bcm63xx: nvram: Use nvram structure definition from header file
MIPS: bcm963xx: Add Broadcom BCM963xx board nvram data structure
MAINTAINERS: Add KVM for MIPS entry
MIPS: KVM: Add missing newline to kvm_err()
MIPS: Move KVM specific opcodes into asm/inst.h
MIPS: KVM: Use cacheops.h definitions
MIPS: Break down cacheops.h definitions
MIPS: Use EXCCODE_ constants with set_except_vector()
MIPS: Update trap codes
MIPS: Move Cause.ExcCode trap codes to mipsregs.h
MIPS: KVM: Make kvm_mips_{init,exit}() static
MIPS: KVM: Refactor added offsetof()s
MIPS: KVM: Convert EXPORT_SYMBOL to _GPL
...
As most platforms implement the PROM serial interface prom_putchar()
add a simple bridge to allow re-using this code for zboot.
Signed-off-by: Alban Bedel <albeu@free.fr>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11811/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add dummy.o to the targets list, and fill targets automatically from
$(vmlinuzobjs) to avoid having to maintain two lists.
When building with XZ compression copy ashldi3.c to the build
directory to use a different object file for the kernel and zboot.
Without this the same object file need to be build with different
flags which cause a rebuild at every run.
Signed-off-by: Alban Bedel <albeu@free.fr>
Cc: linux-mips@linux-mips.org
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11810/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Remove bcm63xx_nvram_get_psi_size() as it now has no users.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: MIPS Mailing List <linux-mips@linux-mips.org>
Cc: MTD Maling List <linux-mtd@lists.infradead.org>
Patchwork: https://patchwork.linux-mips.org/patch/11836/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Move Broadcom BCM963xx image tag data structure to include/linux/
so that drivers outside of mach-bcm63xx can use it.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: MIPS Mailing List <linux-mips@linux-mips.org>
Cc: MTD Maling List <linux-mtd@lists.infradead.org>
Patchwork: https://patchwork.linux-mips.org/patch/11832/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Use the common definition of the nvram structure from the header file
include/linux/bcm963xx_nvram.h instead of maintaining a separate copy.
Read the version 5 size of nvram data from memory and then call the
new checksum verification function from the header file.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: MIPS Mailing List <linux-mips@linux-mips.org>
Cc: MTD Maling List <linux-mtd@lists.infradead.org>
Patchwork: https://patchwork.linux-mips.org/patch/11831/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The header arch/mips/kvm/opcode.h defines a few extra opcodes which
aren't in arch/mips/include/uapi/asm/inst.h. There's nothing KVM
specific about them, so lets move them into inst.h where they belong and
delete the header.
Note that mfmcz_op is renamed to mfmc0_op to match the instruction set
manual, and wait_op was already added to inst.h in commit b0a3eae2b9
("MIPS: inst.h: define COP0 wait op"), merged in v3.16-rc1.
Signed-off-by: James Hogan <james.hogan@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
Patchwork: https://patchwork.linux-mips.org/patch/11895/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Drop the custom cache operation code definitions used by KVM for
emulating guest CACHE instructions, and switch to use the existing
definitions in <asm/cacheops.h>.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11893/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Most of the cache op codes defined in cacheops.h are split into a 2-bit
cache identifier, and a 3-bit cache op code which does largely the same
thing semantically regardless of the cache identifier.
To allow the use of these definitions by KVM for decoding cache ops,
break the definitions down into parts where it makes sense to do so, and
add masks for the Cache and Op field within the cache op.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11892/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The first argument to set_except_vector is the ExcCode, which we now
have definitions for. Lets make use of them.
Signed-off-by: James Hogan <james.hogan@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
Patchwork: https://patchwork.linux-mips.org/patch/11894/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add a few missing trap codes.
[ralf@linux-mips.org: Drop removal of exception codes. I don't care what
the incomplete architecture spec says; it can't change existing hardware
and VCEI is supported indeed.]
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11890/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Move the Cause.ExcCode trap code definitions from kvm_host.h to
mipsregs.h, since they describe architectural bits rather than KVM
specific constants, and change the prefix from T_ to EXCCODE_.
Signed-off-by: James Hogan <james.hogan@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
Patchwork: https://patchwork.linux-mips.org/patch/11891/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The module init and exit functions have no need to be global, so make
them static.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11889/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
When calculating the offsets into the commpage for dynamically
translated mtc0/mfc0 guest instructions, multiple offsetof()s are added
together to find the offset of the specific register in the mips_coproc,
within the commpage.
Simplify each of these cases to a single offsetof() to find the offset
of the specific register within the commpage.
Signed-off-by: James Hogan <james.hogan@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
Patchwork: https://patchwork.linux-mips.org/patch/11888/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Export symbols only to GPL modules to match other KVM symbols in
virt/kvm/ and arch/*/kvm/.
Signed-off-by: James Hogan <james.hogan@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
Patchwork: https://patchwork.linux-mips.org/patch/11887/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The function kvm_mips_host_tlb_inv_index() is unused, so drop it
completely.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11886/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The CAUSEB_DC and CAUSEF_DC definitions used by KVM are defined in
asm/kvm_host.h, but all the other Cause register field definitions are
found in asm/mipsregs.h.
Lets reunite the DC bit definitions with its friends in mipsregs.h.
Signed-off-by: James Hogan <james.hogan@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
Patchwork: https://patchwork.linux-mips.org/patch/11885/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Some definitions in the MIPS asm/kvm_host.h are completely unused, so
lets drop them.
MS_TO_NS is no longer used since commit e30492bbe9 ("MIPS: KVM:
Rewrite count/compare timer emulation"). The others don't appear ever to
have been used.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11884/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This adds basic DTS configuration for the PIC32MZDA chip and in turn the
PIC32MZDA Starter Kit.
Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12104/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This adds support for the Microchip PIC32 MIPS microcontroller with the
specific variant PIC32MZDA. PIC32MZDA is based on the MIPS m14KEc core
and boots using device tree.
This includes an early pin setup and early clock setup needed prior to
device tree being initialized. In additon, an interface is provided to
synchronize access to registers shared across several peripherals.
Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12097/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The cp0_tcstatus member of struct pt_regs was removed along with the
rest of SMTC in v3.16, commit b633648c5a ("MIPS: MT: Remove SMTC
support"), however recent uprobes support in v4.3 added back a reference
to it in the regoffset_table[] in ptrace.c. Remove it.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Fixes: 40e084a506 ("MIPS: Add uprobes support.")
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11920/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linux-gpio@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11925/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linux-gpio@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11924/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linux-gpio@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11923/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: Alban Bedel <albeu@free.fr>
Cc: linux-mips@linux-mips.org
Cc: linux-gpio@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11922/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-mips@linux-mips.org
Cc: linux-gpio@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11921/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Change the CONFIG_MIPS_CMDLINE_EXTEND to CONFIG_MIPS_CMDLINE_DTB_EXTEND
to resolve the EXTEND_WITH_PROM macro.
Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Fixes: 2024972ef5 ("MIPS: Make the kernel arguments from dtb available")
Reviewed-by: Alexander Sverdlin <alexander.svedlin@gmail.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11909/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The kernel currently assumes that a core will start up in legacy mode
using the exception base provided through the CM GCR registers. If a
core has been configured in hardware to start in EVA mode, these
assumptions will fail.
This patch ensures that secondary cores are initialized to meet these
assumptions.
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11907/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix the description of the microMIPS NOP16 encoding or MM_NOP16, which
is not equivalent to the MIPS16 NOP instruction. This is 0x0c00 and
represents the microMIPS `MOVE16 $0, $0' operation, whereas MIPS16 NOP
is encoded as 0x6500, representing `MOVE $0, $16'.
Also fix a typo in `mm_fp0_format' description.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12177/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Remove irrelevant content from the description of the emulation frame in
`mips_dsemul', referring to bare-metal configurations. Update the text,
reflecting the change made with commit ba3049ed40 ("MIPS: Switch FPU
emulator trap to BREAK instruction."), where we switched from using an
address error exception on an unaligned access to the use of a BREAK 514
instruction causing a breakpoint exception instead.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12176/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Emulate the microMIPS ADDIUPC instruction directly in `mips_dsemul'. If
executed in the emulation frame, this instruction produces an incorrect
result, because the value of the PC there is not the same as where the
instruction originated.
Reshape code so as to handle all microMIPS cases together.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12175/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Complement commit 102cedc32a ("MIPS: microMIPS: Floating point
support.") which introduced microMIPS FPU emulation, but did not adjust
the encoding of the BREAK instruction used to terminate the branch delay
slot emulation frame. Consequently the execution of any such frame is
indeterminate and, depending on CPU configuration, will result in random
code execution or an offending program being terminated with SIGILL.
This is because the regular MIPS BREAK instruction is encoded with the 0
major and the 0xd minor opcode, however in the microMIPS instruction set
this major/minor opcode pair denotes an encoding reserved for the DSP
ASE. Instead the microMIPS BREAK instruction is encoded with the 0
major and the 0x7 minor opcode.
Use the correct BREAK encoding for microMIPS FPU emulation then.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12174/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Correct formatting breakage introduced with commit 102cedc32a ("MIPS:
microMIPS: Floating point support."), so that further changes to this
code can be consistent.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12173/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix an issue introduced with commit 9ab4471c9f ("MIPS: math-emu:
Correct delay-slot exception propagation") where the emulation of a NOP
instruction signals the need to terminate the emulation loop. This in
turn, if the PC has not changed from the entry to the loop, will cause
the kernel to terminate the program with SIGILL.
Consider this program:
static double div(double d)
{
do
d /= 2.0;
while (d > .5);
return d;
}
int main(int argc, char **argv)
{
return div(argc);
}
which gets compiled to the following binary code:
00400490 <main>:
400490: 44840000 mtc1 a0,$f0
400494: 3c020040 lui v0,0x40
400498: d44207f8 ldc1 $f2,2040(v0)
40049c: 46800021 cvt.d.w $f0,$f0
4004a0: 46220002 mul.d $f0,$f0,$f2
4004a4: 4620103c c.lt.d $f2,$f0
4004a8: 4501fffd bc1t 4004a0 <main+0x10>
4004ac: 00000000 nop
4004b0: 4620000d trunc.w.d $f0,$f0
4004b4: 03e00008 jr ra
4004b8: 44020000 mfc1 v0,$f0
4004bc: 00000000 nop
Where the FPU emulator is used, depending on the number of command-line
arguments this code will either run to completion or terminate with
SIGILL.
If no arguments are specified, then BC1T will not be taken, NOP will not
be emulated and code will complete successfully.
If one argument is specified, then BC1T will be taken once and NOP will
be emulated. At this point the entry PC value will be 0x400498 and the
new PC value, set by `mips_dsemul' will be 0x4004a0, the target of BC1T.
The emulation loop will terminate, but SIGILL will not be issued,
because the PC has changed. The FPU emulator will be entered again and
on the second execution BC1T will not be taken, NOP will not be emulated
and code will complete successfully.
If two or more arguments are specified, then the first execution of BC1T
will proceed as above. Upon reentering the FPU emulator the emulation
loop will continue to BC1T, at which point the branch will be taken and
NOP emulated again. At this point however the entry PC value will be
0x4004a0, the same as the target of BC1T. This will make the emulator
conclude that execution has not advanced and therefore an unsupported
FPU instruction has been encountered, and SIGILL will be sent to the
process.
Fix the problem by extending the internal API of `mips_dsemul', making
it return -1 if no delay slot emulation frame has been made, the
instruction has been handled and execution of the emulation loop needs
to continue as if nothing happened. Remove code from `mips_dsemul' to
reproduce steps made by the emulation loop at the conclusion of each
iteration, as those will be reached normally now. Adjust call sites
accordingly. Document the API.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12172/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Bhuvanchandra DV