* android12-5.10: (1647 commits)
FROMGIT: mm/page_owner: record the timestamp of all pages during free
UPSTREAM: mm/page_io: use pr_alert_ratelimited for swap read/write errors
ANDROID: roll back xt_IDLETIMER to 5.10.21 upstream/vanilla version
ANDROID: qcom: Add ip, rtnl and free related symbols
FROMGIT: power: supply: Fix build error when CONFIG_POWER_SUPPLY is not enabled.
FROMGIT: usb: dwc3: gadget: modify the scale in vbus_draw callback
BACKPORT: FROMLIST: usb: dwc3: gadget: Clear DEP flags after stop transfers in ep disable
FROMLIST: Makefile: fix GDB warning with CONFIG_RELR
ANDROID: refresh ABI XML before enabling KMI enforcement
Revert "Revert "ANDROID: GKI: Enable bounds sanitizer""
Revert "ANDROID: Revert "f2fs: fix to tag FIEMAP_EXTENT_MERGED in f2fs_fiemap()""
ANDROID: Enforce KMI stability
ANDROID: enable options prior to enforcing KMI
Revert "ANDROID: GKI: temporarily disable LTO/CFI"
ANDROID: gki_defconfig: Enable NET_CLS_{BASIC,TCINDEX,MATCHALL} & NET_ACT_{GACT,MIRRED}
FROMLIST: selftests: Add a MREMAP_DONTUNMAP selftest for shmem
FROMLIST: mm: Extend MREMAP_DONTUNMAP to non-anonymous mappings
ANDROID: GKI: enable CONFIG_CMA_SYSFS
ANDROID: make cma_sysfs experimental
FROMLIST: mm: cma: support sysfs
...
Change-Id: I6145eddeb253bea33164fc909e7790d30f17ef1f
Pull iommu updates from Joerg Roedel:
- Remove of the dev->archdata.iommu (or similar) pointers from most
architectures. Only Sparc is left, but this is private to Sparc as
their drivers don't use the IOMMU-API.
- ARM-SMMU updates from Will Deacon:
- Support for SMMU-500 implementation in Marvell Armada-AP806 SoC
- Support for SMMU-500 implementation in NVIDIA Tegra194 SoC
- DT compatible string updates
- Remove unused IOMMU_SYS_CACHE_ONLY flag
- Move ARM-SMMU drivers into their own subdirectory
- Intel VT-d updates from Lu Baolu:
- Misc tweaks and fixes for vSVA
- Report/response page request events
- Cleanups
- Move the Kconfig and Makefile bits for the AMD and Intel drivers into
their respective subdirectory.
- MT6779 IOMMU Support
- Support for new chipsets in the Renesas IOMMU driver
- Other misc cleanups and fixes (e.g. to improve compile test coverage)
* tag 'iommu-updates-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (77 commits)
iommu/amd: Move Kconfig and Makefile bits down into amd directory
iommu/vt-d: Move Kconfig and Makefile bits down into intel directory
iommu/arm-smmu: Move Arm SMMU drivers into their own subdirectory
iommu/vt-d: Skip TE disabling on quirky gfx dedicated iommu
iommu: Add gfp parameter to io_pgtable_ops->map()
iommu: Mark __iommu_map_sg() as static
iommu/vt-d: Rename intel-pasid.h to pasid.h
iommu/vt-d: Add page response ops support
iommu/vt-d: Report page request faults for guest SVA
iommu/vt-d: Add a helper to get svm and sdev for pasid
iommu/vt-d: Refactor device_to_iommu() helper
iommu/vt-d: Disable multiple GPASID-dev bind
iommu/vt-d: Warn on out-of-range invalidation address
iommu/vt-d: Fix devTLB flush for vSVA
iommu/vt-d: Handle non-page aligned address
iommu/vt-d: Fix PASID devTLB invalidation
iommu/vt-d: Remove global page support in devTLB flush
iommu/vt-d: Enforce PASID devTLB field mask
iommu: Make some functions static
iommu/amd: Remove double zero check
...
This patch adds description for MT6779 IOMMU.
MT6779 has two iommus, they are mm_iommu and apu_iommu which
both use ARM Short-Descriptor translation format.
In addition, mm_iommu and apu_iommu are two independent HW instance
, we need to set them separately.
The MT6779 IOMMU hardware diagram is as below, it is only a brief
diagram about iommu, it don't focus on the part of smi_larb, so
I don't describe the smi_larb detailedly.
EMI
|
--------------------------------------
| |
MM_IOMMU APU_IOMMU
| |
SMI_COMMOM----------- APU_BUS
| | |
SMI_LARB(0~11) | |
| | |
| | --------------
| | | | |
Multimedia engine CCU VPU MDLA EMDA
All the connections are hardware fixed, software can not adjust it.
Signed-off-by: Chao Hao <chao.hao@mediatek.com>
Reviewed-by: Rob Herring <robh+dt@kernel.org>
Link: https://lore.kernel.org/r/20200703044127.27438-2-chao.hao@mediatek.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Pull iommu updates from Joerg Roedel:
"A big part of this is a change in how devices get connected to IOMMUs
in the core code. It contains the change from the old add_device() /
remove_device() to the new probe_device() / release_device()
call-backs.
As a result functionality that was previously in the IOMMU drivers has
been moved to the IOMMU core code, including IOMMU group allocation
for each device. The reason for this change was to get more robust
allocation of default domains for the iommu groups.
A couple of fixes were necessary after this was merged into the IOMMU
tree, but there are no known bugs left. The last fix is applied on-top
of the merge commit for the topic branches.
Other than that change, we have:
- Removal of the driver private domain handling in the Intel VT-d
driver. This was fragile code and I am glad it is gone now.
- More Intel VT-d updates from Lu Baolu:
- Nested Shared Virtual Addressing (SVA) support to the Intel VT-d
driver
- Replacement of the Intel SVM interfaces to the common IOMMU SVA
API
- SVA Page Request draining support
- ARM-SMMU Updates from Will:
- Avoid mapping reserved MMIO space on SMMUv3, so that it can be
claimed by the PMU driver
- Use xarray to manage ASIDs on SMMUv3
- Reword confusing shutdown message
- DT compatible string updates
- Allow implementations to override the default domain type
- A new IOMMU driver for the Allwinner Sun50i platform
- Support for ATS gets disabled for untrusted devices (like
Thunderbolt devices). This includes a PCI patch, acked by Bjorn.
- Some cleanups to the AMD IOMMU driver to make more use of IOMMU
core features.
- Unification of some printk formats in the Intel and AMD IOMMU
drivers and in the IOVA code.
- Updates for DT bindings
- A number of smaller fixes and cleanups.
* tag 'iommu-updates-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (109 commits)
iommu: Check for deferred attach in iommu_group_do_dma_attach()
iommu/amd: Remove redundant devid checks
iommu/amd: Store dev_data as device iommu private data
iommu/amd: Merge private header files
iommu/amd: Remove PD_DMA_OPS_MASK
iommu/amd: Consolidate domain allocation/freeing
iommu/amd: Free page-table in protection_domain_free()
iommu/amd: Allocate page-table in protection_domain_init()
iommu/amd: Let free_pagetable() not rely on domain->pt_root
iommu/amd: Unexport get_dev_data()
iommu/vt-d: Fix compile warning
iommu/vt-d: Remove real DMA lookup in find_domain
iommu/vt-d: Allocate domain info for real DMA sub-devices
iommu/vt-d: Only clear real DMA device's context entries
iommu: Remove iommu_sva_ops::mm_exit()
uacce: Remove mm_exit() op
iommu/sun50i: Constify sun50i_iommu_ops
iommu/hyper-v: Constify hyperv_ir_domain_ops
iommu/vt-d: Use pci_ats_supported()
iommu/arm-smmu-v3: Use pci_ats_supported()
...
Convert Renesas VMSA-Compatible IOMMU bindings documentation
to json-schema.
Note that original documentation doesn't mention renesas,ipmmu-vmsa
for R-Mobile APE6. But, R-Mobile APE6 is similar to the R-Car
Gen2. So, renesas,ipmmu-r8a73a4 belongs the renesas,ipmmu-vmsa
section.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>
json-schema versions draft7 and earlier have a weird behavior in that
any keywords combined with a '$ref' are ignored (silently). The correct
form was to put a '$ref' under an 'allOf'. This behavior is now changed
in the 2019-09 json-schema spec and '$ref' can be mixed with other
keywords. The json-schema library doesn't yet support this, but the
tooling now does a fixup for this and either way works.
This has been a constant source of review comments, so let's change this
treewide so everyone copies the simpler syntax.
Scripted with ruamel.yaml with some manual fixups. Some minor whitespace
changes from the script.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # for I2C
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio
Reviewed-by: Stephen Boyd <sboyd@kernel.org> # clock
Signed-off-by: Rob Herring <robh@kernel.org>
Fix various inconsistencies in schema indentation. Most of these are
list indentation which should be 2 spaces more than the start of the
enclosing keyword. This doesn't matter functionally, but affects running
scripts which do transforms on the schema files.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-By: Vinod Koul <vkoul@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Setting 'additionalProperties: false' is frequently omitted, but is
important in order to check that there aren't extra undocumented
properties in a binding.
Ideally, we'd just add this automatically and make this the default, but
there's some cases where it doesn't work. For example, if a common
schema is referenced, then properties in the common schema aren't part
of what's considered for 'additionalProperties'. Also, sometimes there
are bus specific properties such as 'spi-max-frequency' that go into
bus child nodes, but aren't defined in the child node's schema.
So let's stick with the json-schema defined default and add
'additionalProperties: false' where needed. This will be a continual
review comment and game of wack-a-mole.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Stephen Boyd <sboyd@kernel.org> # clock
Acked-by: Lee Jones <lee.jones@linaro.org>
On Arm systems, some platform devices behind an SMMU may support the PASID
feature, which offers multiple address space. Let the firmware tell us
when a device supports PASID.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
Pull Devicetree updates from Rob Herring:
- DT schemas for PWM, syscon, power domains, SRAM, syscon-reboot,
syscon-poweroff, renesas-irqc, simple-pm-bus, renesas-bsc, pwm-rcar,
Renesas tpu, at24 eeprom, rtc-sh, Allwinner PS/2, sharp,ld-d5116z01b
panel, Arm SMMU, max77650, Meson CEC, Amlogic canvas and DWC3 glue,
Allwinner A10 mUSB and CAN, TI Davinci MDIO, QCom QCS404
interconnect, Unisoc/Spreadtrum SoCs and UART
- Convert a bunch of Samsung bindings to DT schema
- Convert a bunch of ST stm32 bindings to DT schema
- Realtek and Exynos additions to Arm Mali bindings
- Fix schema errors in RiscV CPU schema
- Various schema fixes from improved meta-schema checks
- Improve the handling of 'dma-ranges' and in particular fix DMA mask
setup on PCI bridges
- Fix a memory leak in add_changeset_property() and DT unit tests.
- Several documentation improvements for schema validation
- Rework build rules to improve schema validation errors
- Color output for dtx_diff
* tag 'devicetree-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (138 commits)
libfdt: define INT32_MAX and UINT32_MAX in libfdt_env.h
dt-bindings: arm: Remove leftover axentia.txt
of: unittest: fix memory leak in attach_node_and_children
of: overlay: add_changeset_property() memory leak
dt-bindings: interrupt-controller: arm,gic-v3: Add missing type to interrupt-partition-* nodes
dt-bindings: firmware: ixp4xx: Drop redundant minItems/maxItems
dt-bindings: power: Rename back power_domain.txt bindings to fix references
dt-bindings: i2c: stm32: Migrate i2c-stm32 documentation to yaml
dt-bindings: mtd: Convert stm32 fmc2-nand bindings to json-schema
dt-bindings: remoteproc: convert stm32-rproc to json-schema
dt-bindings: mailbox: convert stm32-ipcc to json-schema
dt-bindings: mfd: Convert stm32 low power timers bindings to json-schema
dt-bindings: interrupt-controller: Convert stm32-exti to json-schema
dt-bindings: crypto: Convert stm32 HASH bindings to json-schema
dt-bindings: rng: Convert stm32 RNG bindings to json-schema
dt-bindings: pwm: Convert Samsung PWM bindings to json-schema
dt-bindings: pwm: Convert PWM bindings to json-schema
dt-bindings: serial: Add a new compatible string for SC9863A
dt-bindings: serial: Convert sprd-uart to json-schema
dt-bindings: arm: Add bindings for Unisoc SC9863A
...
Convert Samsung Exynos Soc Power Domain bindings to DT schema format using
json-schema.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Convert the Arm SMMU binding to DT schema.
The existing binding doc doesn't cover the number of variations of
compatible properties found in .dts files. "qcom,msm8998-smmu-v2" was
also missing, so add it.
SoCFPGA Stratix10 has a single clock defined which doesn't match the
binding. This issue remains.
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Robin Murphy <Robin.Murphy@arm.com>
Cc: iommu@lists.linux-foundation.org
Signed-off-by: Rob Herring <robh@kernel.org>
This patch adds decriptions for mt8183 IOMMU and SMI.
mt8183 has only one M4U like mt8173 and is also MTK IOMMU gen2 which
uses ARM Short-Descriptor translation table format.
The mt8183 M4U-SMI HW diagram is as below:
EMI
|
M4U
|
----------
| |
gals0-rx gals1-rx
| |
| |
gals0-tx gals1-tx
| |
------------
SMI Common
------------
|
+-----+-----+--------+-----+-----+-------+-------+
| | | | | | | |
| | gals-rx gals-rx | gals-rx gals-rx gals-rx
| | | | | | | |
| | | | | | | |
| | gals-tx gals-tx | gals-tx gals-tx gals-tx
| | | | | | | |
larb0 larb1 IPU0 IPU1 larb4 larb5 larb6 CCU
disp vdec img cam venc img cam
All the connections are HW fixed, SW can NOT adjust it.
Compared with mt8173, we add a GALS(Global Async Local Sync) module
between SMI-common and M4U, and additional GALS between larb2/3/5/6
and SMI-common. GALS can help synchronize for the modules in different
clock frequency, it can be seen as a "asynchronous fifo".
GALS can only help transfer the command/data while it doesn't have
the configuring register, thus it has the special "smi" clock and it
doesn't have the "apb" clock. From the diagram above, we add "gals0"
and "gals1" clocks for smi-common and add a "gals" clock for smi-larb.
>From the diagram above, IPU0/IPU1(Image Processor Unit) and CCU(Camera
Control Unit) is connected with smi-common directly, we can take them
as "larb2", "larb3" and "larb7", and their register spaces are
different with the normal larb.
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Splitting GART and Memory Controller wasn't a good decision that was made
back in the day. Given that the GART driver wasn't ever been used by
anything in the kernel, we decided that it will be better to correct the
mistakes of the past and merge two bindings into a single one. As a result
there is a DT ABI change for the Memory Controller that allows not to
break newer kernels using older DT and not to break older kernels using
newer DT, that is done by changing the 'compatible' of the node to
'tegra20-mc-gart' and adding a new-required clock property. The new clock
property also puts the tegra20-mc binding in line with the bindings of the
later Tegra generations.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Qcom's implementation of arm,mmu-500 works well with current
arm-smmu driver implementation. Adding a soc specific compatible
along with arm,mmu-500 makes the bindings future safe.
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Pull ARM SoC device tree updates from Arnd Bergmann:
"There are close to 800 indivudal changesets in this branch again,
which feels like a lot. There are particularly many changes for the
NVIDIA Tegra platform this time, in fact more than it has seen in the
two years since the v4.9 merge window. Aside from this, it's been
fairly normal, with lots of changes going into Renesas R-CAR, NXP
i.MX, Allwinner Sunxi, Samsung Exynos, and TI OMAP.
Most of the changes are for adding new features into existing boards,
for brevity I'm only mentioning completely new machines and SoCs here.
For the first time I think we have (slightly) more new 64-bit hardware
than 32-bit:
Two boards get added for TI OMAP: Moxa UC-2101 is an industrial
computer, see https://www.moxa.com/product/UC-2100.htm; GTA04A5 is a
minor variation of the motherboards of the GTA04 phone, see
https://shop.goldelico.com/wiki.php?page=GTA04A5
Clearfog is a nice little board for quad-core Marvell Armada 8040
network processor, see
https://www.solid-run.com/marvell-armada-family/clearfog-gt-8k/
Two additional server boards come with the Aspeed baseboard management
controllers: Stardragon4800 is an arm64 reference platform made by HXT
(based on Qualcomm's server chips), and TiogaPass is an Open Compute
mainboard with x86 CPUs. Both use the ARM11 based AST2500 chips in the
BMC.
NXP i.MX usually sees a lot of new boards each release. This time
there we only add one minor variant: ConnectCore 6UL SBC Pro uses the
same SoM design as the ConnectCore 6UL SBC Express added later.
However, there is a new chip, the i.MX6ULZ, which is an even smaller
variant of the i.MX6ULL, with features removed. There is also support
for the reference board design, the i.MX6ULZ 14x14 EVK.
A new Raspberry Pi variant gets added, this one is the CM3 compute
module based on bcm2837, it was launched in early 2017 but only now
added to the kernel, both as 32-bit and as 64-bit files, as we tend to
do for Raspberry Pi.
On the Allwinner side, everything is again about cheap development
boards, usually of the "Fruit Pi" variety. The new ones this time are:
- Orange Pi Zero Plus2: http://www.orangepi.org/OrangePiZeroPlus2/
- Orange Pi One Plus: http://www.orangepi.org/OrangePiOneplus/
- Pine64 LTS: https://www.pine64.org/?product=pine-a64-lts
- Banana Pi M2+ H5: http://www.banana-pi.org/m2plus.html
The last one of these is now a 64-bit version of the earlier Banana Pi
M2+ H3, with the same board layout.
Similarly, for Rockchips, get get another variant of the 32-bit Asus
Tinker board, the model 'S' based on rk3288, and three now boards
based on the popular RK3399 chip:
- ROC-RK3399-PC: https://libre.computer/products/boards/roc-rk3399-pc/
- Rock960: https://www.96boards.org/product/rock960/
- RockPro64: https://www.pine64.org/?page_id=61454
These are all quite powerful boards with lots of RAM and I/O, and the
RK3399 is the same chip used in several Chromebooks. Finally, we get
support for the PX30 (aka rk3326) chip, which is based on the low-end
64-bit Cortex-A35 CPU core. So far, only the evaluation board is
supported.
One more Banana Pi is added with a Mediatek chip: Banana Pi R64 is
based on the MT7622 WiFi router platform, and the first product I've
seen with a 64-bit Mediatek chip in that market:
http://www.banana-pi.org/r64.html
For HiSilicon, we gain support for the Hi3670 SoC and HiKey 370
development board, which are similar to the Hi3660 and Hikey 360
respectively, but add support for an NPU.
Amlogic gets initial support for the Meson-G12A chip (S905D2), another
quad-core Cortex-A53 SoC, and its evaluation platform. On the 32-bit
side, we gain support for an actual end-user product, the Endless
Computers Endless Mini based on Meson8b (S805), see
https://endlessos.com/computers/
Qualcomm adds support for their MSM8998 SoC and evaluation platform.
This chip is commonly known as the Snapdragon 835, and is used in
high-end phones as well as low-end laptops.
For Renesas, a very bare support for the r8a774a1 (RZ/G2M) is added,
but no boards for this one. However, we do add boards for the
previously added r8a77965 (R-Car M3-N): the M3NULCB Kingfisher and the
M3NULCB Starter Kit Pro.
While we have lots of DT changes for NVIDIA to update the existing
files, the only board that gets added is the Toradex Colibri T20 on
Colibri Evaluation Board for the old Tegra2.
Synaptics add support for their AS370 SoC, which is part of the
(formerly Marvell) Berlin line of set-top-box chips used e.g. in the
various Google Chromecast. Only the .dtsi gets added at this point, no
actual machines"
* tag 'armsoc-dt' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (721 commits)
ARM: dts: socfgpa: remove ethernet aliases from dtsi
arm64: dts: stratix10: add ethernet aliases
dt-bindings: mediatek: Add bindig for MT7623 IOMMU and SMI
dt-bindings: mediatek: Add JPEG Decoder binding for MT7623
dt-bindings: iommu: mediatek: Add binding for MT7623
dt-bindings: clock: mediatek: add support for MT7623
ARM: dts: mvebu: armada-385-db-88f6820-amc: auto-detect nand ECC properites
ARM: dts: da850-lego-ev3: slow down A/DC as much as possible
ARM: dts: da850-evm: Enable tca6416 on baseboard
arm64: dts: uniphier: Add USB2 PHY nodes
arm64: dts: uniphier: Add USB3 controller nodes
ARM: dts: uniphier: Add USB2 PHY nodes
ARM: dts: uniphier: Add USB3 controller nodes
arm64: dts: meson-axg: s400: disable emmc
arm64: dts: meson-axg: s400: add missing emmc pwrseq
arm64: dts: clearfog-gt-8k: add PCIe slot description
ARM: dts: at91: sama5d4_xplained: even nand memory partitions
ARM: dts: at91: sama5d3_xplained: even nand memory partitions
ARM: dts: at91: at91sam9x5cm: even nand memory partitions
ARM: dts: at91: sama5d2_ptc_ek: fix bootloader env offsets
...
Simon Xue