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 <20220601100005.2989022-8-chenhuacai@loongson.cn>
Date:   Wed, 01 Jun 2022 13:23:13 +0100
From:   "Jiaxun Yang" <jiaxun.yang@flygoat.com>
To:     "Huacai Chen" <chenhuacai@loongson.cn>,
        "Arnd Bergmann" <arnd@arndb.de>,
        "Andy Lutomirski" <luto@kernel.org>,
        "Thomas Gleixner" <tglx@linutronix.de>,
        "Peter Zijlstra" <peterz@infradead.org>,
        "Andrew Morton" <akpm@linux-foundation.org>,
        "David Airlie" <airlied@linux.ie>,
        "Jonathan Corbet" <corbet@lwn.net>,
        "Linus Torvalds" <torvalds@linux-foundation.org>
Cc:     linux-arch@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, "Xuefeng Li" <lixuefeng@loongson.cn>,
        "Yanteng Si" <siyanteng@loongson.cn>,
        "Huacai Chen" <chenhuacai@gmail.com>,
        "Guo Ren" <guoren@kernel.org>, "Xuerui Wang" <kernel@xen0n.name>,
        "Stephen Rothwell" <sfr@canb.auug.org.au>,
        "WANG Xuerui" <git@xen0n.name>
Subject: Re: [PATCH V12 07/24] LoongArch: Add build infrastructure
Content-Type: text/plain;charset=utf-8
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Precedence: bulk


=E5=9C=A82022=E5=B9=B46=E6=9C=881=E6=97=A5=E5=85=AD=E6=9C=88 =E4=B8=8A=E5=
=8D=8810:59=EF=BC=8CHuacai Chen=E5=86=99=E9=81=93=EF=BC=9A
> Add Kbuild, Makefile, Kconfig and link script for LoongArch build
> infrastructure.
>
> Reviewed-by: Guo Ren <guoren@kernel.org>
> Reviewed-by: WANG Xuerui <git@xen0n.name>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

All good!

Just a note to myself: MIPS has -munaligned-access for strict align flag=
 and LA
has it=E2=80=99s own.

Thanks.

> ---
>  arch/loongarch/Kbuild                  |   6 +
>  arch/loongarch/Kconfig                 | 388 +++++++++++++++++++++++++
>  arch/loongarch/Kconfig.debug           |   0
>  arch/loongarch/Makefile                | 103 +++++++
>  arch/loongarch/boot/.gitignore         |   2 +
>  arch/loongarch/boot/Makefile           |  20 ++
>  arch/loongarch/boot/dts/Makefile       |   4 +
>  arch/loongarch/include/asm/Kbuild      |  30 ++
>  arch/loongarch/include/uapi/asm/Kbuild |   2 +
>  arch/loongarch/kernel/.gitignore       |   2 +
>  arch/loongarch/kernel/Makefile         |  21 ++
>  arch/loongarch/kernel/vmlinux.lds.S    | 117 ++++++++
>  arch/loongarch/lib/Makefile            |   6 +
>  arch/loongarch/mm/Makefile             |   9 +
>  arch/loongarch/pci/Makefile            |   7 +
>  arch/loongarch/vdso/.gitignore         |   2 +
>  scripts/subarch.include                |   2 +-
>  17 files changed, 720 insertions(+), 1 deletion(-)
>  create mode 100644 arch/loongarch/Kbuild
>  create mode 100644 arch/loongarch/Kconfig
>  create mode 100644 arch/loongarch/Kconfig.debug
>  create mode 100644 arch/loongarch/Makefile
>  create mode 100644 arch/loongarch/boot/.gitignore
>  create mode 100644 arch/loongarch/boot/Makefile
>  create mode 100644 arch/loongarch/boot/dts/Makefile
>  create mode 100644 arch/loongarch/include/asm/Kbuild
>  create mode 100644 arch/loongarch/include/uapi/asm/Kbuild
>  create mode 100644 arch/loongarch/kernel/.gitignore
>  create mode 100644 arch/loongarch/kernel/Makefile
>  create mode 100644 arch/loongarch/kernel/vmlinux.lds.S
>  create mode 100644 arch/loongarch/lib/Makefile
>  create mode 100644 arch/loongarch/mm/Makefile
>  create mode 100644 arch/loongarch/pci/Makefile
>  create mode 100644 arch/loongarch/vdso/.gitignore
>
> diff --git a/arch/loongarch/Kbuild b/arch/loongarch/Kbuild
> new file mode 100644
> index 000000000000..ab5373d0a24f
> --- /dev/null
> +++ b/arch/loongarch/Kbuild
> @@ -0,0 +1,6 @@
> +obj-y +=3D kernel/
> +obj-y +=3D mm/
> +obj-y +=3D vdso/
> +
> +# for cleaning
> +subdir- +=3D boot
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> new file mode 100644
> index 000000000000..d6ac80cf3922
> --- /dev/null
> +++ b/arch/loongarch/Kconfig
> @@ -0,0 +1,388 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config LOONGARCH
> +	bool
> +	default y
> +	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
> +	select ARCH_BINFMT_ELF_STATE
> +	select ARCH_ENABLE_MEMORY_HOTPLUG
> +	select ARCH_ENABLE_MEMORY_HOTREMOVE
> +	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
> +	select ARCH_HAS_PTE_SPECIAL
> +	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
> +	select ARCH_INLINE_READ_LOCK if !PREEMPTION
> +	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
> +	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
> +	select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
> +	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
> +	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
> +	select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
> +	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
> +	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
> +	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
> +	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
> +	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
> +	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
> +	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
> +	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
> +	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
> +	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
> +	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
> +	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
> +	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
> +	select ARCH_MIGHT_HAVE_PC_PARPORT
> +	select ARCH_MIGHT_HAVE_PC_SERIO
> +	select ARCH_SPARSEMEM_ENABLE
> +	select ARCH_SUPPORTS_ACPI
> +	select ARCH_SUPPORTS_ATOMIC_RMW
> +	select ARCH_SUPPORTS_HUGETLBFS
> +	select ARCH_USE_BUILTIN_BSWAP
> +	select ARCH_USE_CMPXCHG_LOCKREF
> +	select ARCH_USE_QUEUED_RWLOCKS
> +	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
> +	select ARCH_WANTS_NO_INSTR
> +	select BUILDTIME_TABLE_SORT
> +	select COMMON_CLK
> +	select GENERIC_CLOCKEVENTS
> +	select GENERIC_CMOS_UPDATE
> +	select GENERIC_CPU_AUTOPROBE
> +	select GENERIC_ENTRY
> +	select GENERIC_FIND_FIRST_BIT
> +	select GENERIC_GETTIMEOFDAY
> +	select GENERIC_IRQ_MULTI_HANDLER
> +	select GENERIC_IRQ_PROBE
> +	select GENERIC_IRQ_SHOW
> +	select GENERIC_LIB_ASHLDI3
> +	select GENERIC_LIB_ASHRDI3
> +	select GENERIC_LIB_CMPDI2
> +	select GENERIC_LIB_LSHRDI3
> +	select GENERIC_LIB_UCMPDI2
> +	select GENERIC_PCI_IOMAP
> +	select GENERIC_SCHED_CLOCK
> +	select GENERIC_TIME_VSYSCALL
> +	select GPIOLIB
> +	select HAVE_ARCH_AUDITSYSCALL
> +	select HAVE_ARCH_COMPILER_H
> +	select HAVE_ARCH_MMAP_RND_BITS if MMU
> +	select HAVE_ARCH_SECCOMP_FILTER
> +	select HAVE_ARCH_TRACEHOOK
> +	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
> +	select HAVE_ASM_MODVERSIONS
> +	select HAVE_CONTEXT_TRACKING
> +	select HAVE_COPY_THREAD_TLS
> +	select HAVE_DEBUG_STACKOVERFLOW
> +	select HAVE_DMA_CONTIGUOUS
> +	select HAVE_EXIT_THREAD
> +	select HAVE_FAST_GUP
> +	select HAVE_GENERIC_VDSO
> +	select HAVE_IOREMAP_PROT
> +	select HAVE_IRQ_EXIT_ON_IRQ_STACK
> +	select HAVE_IRQ_TIME_ACCOUNTING
> +	select HAVE_MEMBLOCK
> +	select HAVE_MEMBLOCK_NODE_MAP
> +	select HAVE_MOD_ARCH_SPECIFIC
> +	select HAVE_NMI
> +	select HAVE_PERF_EVENTS
> +	select HAVE_REGS_AND_STACK_ACCESS_API
> +	select HAVE_RSEQ
> +	select HAVE_SYSCALL_TRACEPOINTS
> +	select HAVE_TIF_NOHZ
> +	select HAVE_VIRT_CPU_ACCOUNTING_GEN
> +	select IRQ_FORCED_THREADING
> +	select IRQ_LOONGARCH_CPU
> +	select MODULES_USE_ELF_RELA if MODULES
> +	select OF
> +	select OF_EARLY_FLATTREE
> +	select PERF_USE_VMALLOC
> +	select RTC_LIB
> +	select SPARSE_IRQ
> +	select SYSCTL_EXCEPTION_TRACE
> +	select SWIOTLB
> +	select TRACE_IRQFLAGS_SUPPORT
> +	select ZONE_DMA32
> +
> +config 32BIT
> +	bool
> +
> +config 64BIT
> +	def_bool y
> +
> +config CPU_HAS_FPU
> +	bool
> +	default y
> +
> +config CPU_HAS_PREFETCH
> +	bool
> +	default y
> +
> +config GENERIC_CALIBRATE_DELAY
> +	def_bool y
> +
> +config GENERIC_CSUM
> +	def_bool y
> +
> +config GENERIC_HWEIGHT
> +	def_bool y
> +
> +config L1_CACHE_SHIFT
> +	int
> +	default "6"
> +
> +config LOCKDEP_SUPPORT
> +	bool
> +	default y
> +
> +# MACH_LOONGSON32 and MACH_LOONGSON64 are delibrately carried over=20
> from the
> +# MIPS Loongson code, to preserve Loongson-specific code paths in=20
> drivers that
> +# are shared between architectures, and specifically expecting the=20
> symbols.
> +config MACH_LOONGSON32
> +	def_bool 32BIT
> +
> +config MACH_LOONGSON64
> +	def_bool 64BIT
> +
> +config PAGE_SIZE_4KB
> +	bool
> +
> +config PAGE_SIZE_16KB
> +	bool
> +
> +config PAGE_SIZE_64KB
> +	bool
> +
> +config PGTABLE_2LEVEL
> +	bool
> +
> +config PGTABLE_3LEVEL
> +	bool
> +
> +config PGTABLE_4LEVEL
> +	bool
> +
> +config PGTABLE_LEVELS
> +	int
> +	default 2 if PGTABLE_2LEVEL
> +	default 3 if PGTABLE_3LEVEL
> +	default 4 if PGTABLE_4LEVEL
> +
> +config SCHED_OMIT_FRAME_POINTER
> +	bool
> +	default y
> +
> +menu "Kernel type and options"
> +
> +source "kernel/Kconfig.hz"
> +
> +choice
> +	prompt "Page Table Layout"
> +	default 16KB_2LEVEL if 32BIT
> +	default 16KB_3LEVEL if 64BIT
> +	help
> +	  Allows choosing the page table layout, which is a combination
> +	  of page size and page table levels. The size of virtual memory
> +	  address space are determined by the page table layout.
> +
> +config 4KB_3LEVEL
> +	bool "4KB with 3 levels"
> +	select PAGE_SIZE_4KB
> +	select PGTABLE_3LEVEL
> +	help
> +	  This option selects 4KB page size with 3 level page tables, which
> +	  support a maximum of 39 bits of application virtual memory.
> +
> +config 4KB_4LEVEL
> +	bool "4KB with 4 levels"
> +	select PAGE_SIZE_4KB
> +	select PGTABLE_4LEVEL
> +	help
> +	  This option selects 4KB page size with 4 level page tables, which
> +	  support a maximum of 48 bits of application virtual memory.
> +
> +config 16KB_2LEVEL
> +	bool "16KB with 2 levels"
> +	select PAGE_SIZE_16KB
> +	select PGTABLE_2LEVEL
> +	help
> +	  This option selects 16KB page size with 2 level page tables, which
> +	  support a maximum of 36 bits of application virtual memory.
> +
> +config 16KB_3LEVEL
> +	bool "16KB with 3 levels"
> +	select PAGE_SIZE_16KB
> +	select PGTABLE_3LEVEL
> +	help
> +	  This option selects 16KB page size with 3 level page tables, which
> +	  support a maximum of 47 bits of application virtual memory.
> +
> +config 64KB_2LEVEL
> +	bool "64KB with 2 levels"
> +	select PAGE_SIZE_64KB
> +	select PGTABLE_2LEVEL
> +	help
> +	  This option selects 64KB page size with 2 level page tables, which
> +	  support a maximum of 42 bits of application virtual memory.
> +
> +config 64KB_3LEVEL
> +	bool "64KB with 3 levels"
> +	select PAGE_SIZE_64KB
> +	select PGTABLE_3LEVEL
> +	help
> +	  This option selects 64KB page size with 3 level page tables, which
> +	  support a maximum of 55 bits of application virtual memory.
> +
> +endchoice
> +
> +config CMDLINE
> +	string "Built-in kernel command line"
> +	help
> +	  For most platforms, the arguments for the kernel's command line
> +	  are provided at run-time, during boot. However, there are cases
> +	  where either no arguments are being provided or the provided
> +	  arguments are insufficient or even invalid.
> +
> +	  When that occurs, it is possible to define a built-in command
> +	  line here and choose how the kernel should use it later on.
> +
> +choice
> +	prompt "Kernel command line type"
> +	default CMDLINE_BOOTLOADER
> +	help
> +	  Choose how the kernel will handle the provided built-in command
> +	  line.
> +
> +config CMDLINE_BOOTLOADER
> +	bool "Use bootloader kernel arguments if available"
> +	help
> +	  Prefer the command-line passed by the boot loader if available.
> +	  Use the built-in command line as fallback in case we get nothing
> +	  during boot. This is the default behaviour.
> +
> +config CMDLINE_EXTEND
> +	bool "Use built-in to extend bootloader kernel arguments"
> +	help
> +	  The command-line arguments provided during boot will be
> +	  appended to the built-in command line. This is useful in
> +	  cases where the provided arguments are insufficient and
> +	  you don't want to or cannot modify them.
> +
> +config CMDLINE_FORCE
> +	bool "Always use the built-in kernel command string"
> +	help
> +	  Always use the built-in command line, even if we get one during
> +	  boot. This is useful in case you need to override the provided
> +	  command line on systems where you don't have or want control
> +	  over it.
> +
> +endchoice
> +
> +config DMI
> +	bool "Enable DMI scanning"
> +	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
> +	default y
> +	help
> +	  This enables SMBIOS/DMI feature for systems, and scanning of
> +	  DMI to identify machine quirks.
> +
> +config EFI
> +	bool "EFI runtime service support"
> +	select UCS2_STRING
> +	select EFI_PARAMS_FROM_FDT
> +	select EFI_RUNTIME_WRAPPERS
> +	help
> +	  This enables the kernel to use EFI runtime services that are
> +	  available (such as the EFI variable services).
> +
> +config EFI_STUB
> +	bool "EFI boot stub support"
> +	default y
> +	depends on EFI
> +	select EFI_GENERIC_STUB
> +	help
> +	  This kernel feature allows the kernel to be loaded directly by
> +	  EFI firmware without the use of a bootloader.
> +
> +config FORCE_MAX_ZONEORDER
> +	int "Maximum zone order"
> +	range 14 64 if PAGE_SIZE_64KB
> +	default "14" if PAGE_SIZE_64KB
> +	range 12 64 if PAGE_SIZE_16KB
> +	default "12" if PAGE_SIZE_16KB
> +	range 11 64
> +	default "11"
> +	help
> +	  The kernel memory allocator divides physically contiguous memory
> +	  blocks into "zones", where each zone is a power of two number of
> +	  pages.  This option selects the largest power of two that the kern=
el
> +	  keeps in the memory allocator.  If you need to allocate very large
> +	  blocks of physically contiguous memory, then you may need to
> +	  increase this value.
> +
> +	  This config option is actually maximum order plus one. For example,
> +	  a value of 11 means that the largest free memory block is 2^10=20
> pages.
> +
> +	  The page size is not necessarily 4KB.  Keep this in mind
> +	  when choosing a value for this option.
> +
> +config SECCOMP
> +	bool "Enable seccomp to safely compute untrusted bytecode"
> +	depends on PROC_FS
> +	default y
> +	help
> +	  This kernel feature is useful for number crunching applications
> +	  that may need to compute untrusted bytecode during their
> +	  execution. By using pipes or other transports made available to
> +	  the process as file descriptors supporting the read/write
> +	  syscalls, it's possible to isolate those applications in
> +	  their own address space using seccomp. Once seccomp is
> +	  enabled via /proc/<pid>/seccomp, it cannot be disabled
> +	  and the task is only allowed to execute a few safe syscalls
> +	  defined by each seccomp mode.
> +
> +	  If unsure, say Y. Only embedded should say N here.
> +
> +endmenu
> +
> +config ARCH_SELECT_MEMORY_MODEL
> +	def_bool y
> +
> +config ARCH_FLATMEM_ENABLE
> +	def_bool y
> +
> +config ARCH_SPARSEMEM_ENABLE
> +	def_bool y
> +	help
> +	  Say Y to support efficient handling of sparse physical memory,
> +	  for architectures which are either NUMA (Non-Uniform Memory Access)
> +	  or have huge holes in the physical address space for other reasons.
> +	  See <file:Documentation/vm/numa.rst> for more.
> +
> +config ARCH_ENABLE_THP_MIGRATION
> +	def_bool y
> +	depends on TRANSPARENT_HUGEPAGE
> +
> +config ARCH_MEMORY_PROBE
> +	def_bool y
> +	depends on MEMORY_HOTPLUG
> +
> +config MMU
> +	bool
> +	default y
> +
> +config ARCH_MMAP_RND_BITS_MIN
> +	default 12
> +
> +config ARCH_MMAP_RND_BITS_MAX
> +	default 18
> +
> +menu "Power management options"
> +
> +source "drivers/acpi/Kconfig"
> +
> +endmenu
> +
> +source "drivers/firmware/Kconfig"
> diff --git a/arch/loongarch/Kconfig.debug b/arch/loongarch/Kconfig.deb=
ug
> new file mode 100644
> index 000000000000..e69de29bb2d1
> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
> new file mode 100644
> index 000000000000..07a70ef73bdc
> --- /dev/null
> +++ b/arch/loongarch/Makefile
> @@ -0,0 +1,103 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Author: Huacai Chen <chenhuacai@loongson.cn>
> +# Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> +
> +boot	:=3D arch/loongarch/boot
> +
> +ifndef CONFIG_EFI_STUB
> +KBUILD_IMAGE	=3D $(boot)/vmlinux
> +else
> +KBUILD_IMAGE	=3D $(boot)/vmlinux.efi
> +endif
> +
> +#
> +# Select the object file format to substitute into the linker script.
> +#
> +64bit-tool-archpref	=3D loongarch64
> +32bit-bfd		=3D elf32-loongarch
> +64bit-bfd		=3D elf64-loongarch
> +32bit-emul		=3D elf32loongarch
> +64bit-emul		=3D elf64loongarch
> +
> +ifdef CONFIG_64BIT
> +tool-archpref		=3D $(64bit-tool-archpref)
> +UTS_MACHINE		:=3D loongarch64
> +endif
> +
> +ifneq ($(SUBARCH),$(ARCH))
> +  ifeq ($(CROSS_COMPILE),)
> +    CROSS_COMPILE :=3D $(call cc-cross-prefix, $(tool-archpref)-linux=
- =20
> $(tool-archpref)-linux-gnu-  $(tool-archpref)-unknown-linux-gnu-)
> +  endif
> +endif
> +
> +ifdef CONFIG_64BIT
> +ld-emul			=3D $(64bit-emul)
> +cflags-y		+=3D -mabi=3Dlp64s
> +endif
> +
> +cflags-y			+=3D -G0 -pipe -msoft-float
> +LDFLAGS_vmlinux			+=3D -G0 -static -n -nostdlib
> +KBUILD_AFLAGS_KERNEL		+=3D -Wa,-mla-global-with-pcrel
> +KBUILD_CFLAGS_KERNEL		+=3D -Wa,-mla-global-with-pcrel
> +KBUILD_AFLAGS_MODULE		+=3D -Wa,-mla-global-with-abs
> +KBUILD_CFLAGS_MODULE		+=3D -fplt=20
> -Wa,-mla-global-with-abs,-mla-local-with-abs
> +
> +cflags-y +=3D -ffreestanding
> +cflags-y +=3D $(call cc-option, -mno-check-zero-division)
> +
> +load-y		=3D 0x9000000000200000
> +bootvars-y	=3D VMLINUX_LOAD_ADDRESS=3D$(load-y)
> +
> +KBUILD_AFLAGS	+=3D $(cflags-y)
> +KBUILD_CFLAGS	+=3D $(cflags-y)
> +KBUILD_CPPFLAGS +=3D -DVMLINUX_LOAD_ADDRESS=3D$(load-y)
> +
> +# This is required to get dwarf unwinding tables into .debug_frame
> +# instead of .eh_frame so we don't discard them.
> +KBUILD_CFLAGS +=3D -fno-asynchronous-unwind-tables
> +
> +# Don't emit unaligned accesses.
> +# Not all LoongArch cores support unaligned access, and as kernel we=20
> can't
> +# rely on others to provide emulation for these accesses.
> +KBUILD_CFLAGS +=3D $(call cc-option,-mstrict-align)
> +
> +KBUILD_CFLAGS +=3D -isystem $(shell $(CC) -print-file-name=3Dinclude)
> +
> +KBUILD_LDFLAGS	+=3D -m $(ld-emul)
> +
> +ifdef CONFIG_LOONGARCH
> +CHECKFLAGS +=3D $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null =
| \
> +	egrep -vw '__GNUC_(MINOR_|PATCHLEVEL_)?_' | \
> +	sed -e "s/^\#define /-D'/" -e "s/ /'=3D'/" -e "s/$$/'/" -e 's/\$$/&&=
/g')
> +endif
> +
> +head-y :=3D arch/loongarch/kernel/head.o
> +
> +libs-y +=3D arch/loongarch/lib/
> +libs-$(CONFIG_EFI_STUB) +=3D=20
> $(objtree)/drivers/firmware/efi/libstub/lib.a
> +
> +ifeq ($(KBUILD_EXTMOD),)
> +prepare: vdso_prepare
> +vdso_prepare: prepare0
> +	$(Q)$(MAKE) $(build)=3Darch/loongarch/vdso=20
> include/generated/vdso-offsets.h
> +endif
> +
> +PHONY +=3D vdso_install
> +vdso_install:
> +	$(Q)$(MAKE) $(build)=3Darch/loongarch/vdso $@
> +
> +all:	$(KBUILD_IMAGE)
> +
> +$(KBUILD_IMAGE): vmlinux
> +	$(Q)$(MAKE) $(build)=3D$(boot) $(bootvars-y) $@
> +
> +install:
> +	$(Q)install -D -m 755 $(KBUILD_IMAGE)=20
> $(INSTALL_PATH)/vmlinux-$(KERNELRELEASE)
> +	$(Q)install -D -m 644 .config $(INSTALL_PATH)/config-$(KERNELRELEASE)
> +	$(Q)install -D -m 644 System.map=20
> $(INSTALL_PATH)/System.map-$(KERNELRELEASE)
> +
> +define archhelp
> +	echo '  install              - install kernel into $(INSTALL_PATH)'
> +	echo
> +endef
> diff --git a/arch/loongarch/boot/.gitignore=20
> b/arch/loongarch/boot/.gitignore
> new file mode 100644
> index 000000000000..49423ee96ef3
> --- /dev/null
> +++ b/arch/loongarch/boot/.gitignore
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +vmlinux*
> diff --git a/arch/loongarch/boot/Makefile b/arch/loongarch/boot/Makefi=
le
> new file mode 100644
> index 000000000000..b39d50a7a3df
> --- /dev/null
> +++ b/arch/loongarch/boot/Makefile
> @@ -0,0 +1,20 @@
> +#
> +# arch/loongarch/boot/Makefile
> +#
> +# Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> +#
> +
> +drop-sections :=3D .comment .note .options .note.gnu.build-id
> +strip-flags   :=3D $(addprefix --remove-section=3D,$(drop-sections)) =
-S
> +OBJCOPYFLAGS_vmlinux.efi :=3D -O binary $(strip-flags)
> +
> +targets :=3D vmlinux
> +quiet_cmd_strip =3D STRIP	  $@
> +      cmd_strip =3D $(STRIP) -s -o $@ $<
> +
> +$(obj)/vmlinux: vmlinux FORCE
> +	$(call if_changed,strip)
> +
> +targets +=3D vmlinux.efi
> +$(obj)/vmlinux.efi: $(obj)/vmlinux FORCE
> +	$(call if_changed,objcopy)
> diff --git a/arch/loongarch/boot/dts/Makefile=20
> b/arch/loongarch/boot/dts/Makefile
> new file mode 100644
> index 000000000000..5f1f55e911ad
> --- /dev/null
> +++ b/arch/loongarch/boot/dts/Makefile
> @@ -0,0 +1,4 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +dtstree	:=3D $(srctree)/$(src)
> +
> +dtb-y :=3D $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard=20
> $(dtstree)/*.dts))
> diff --git a/arch/loongarch/include/asm/Kbuild=20
> b/arch/loongarch/include/asm/Kbuild
> new file mode 100644
> index 000000000000..83bc0681e72b
> --- /dev/null
> +++ b/arch/loongarch/include/asm/Kbuild
> @@ -0,0 +1,30 @@
> +# SPDX-License-Identifier: GPL-2.0
> +generic-y +=3D dma-contiguous.h
> +generic-y +=3D export.h
> +generic-y +=3D parport.h
> +generic-y +=3D early_ioremap.h
> +generic-y +=3D qrwlock.h
> +generic-y +=3D qrwlock_types.h
> +generic-y +=3D spinlock.h
> +generic-y +=3D spinlock_types.h
> +generic-y +=3D rwsem.h
> +generic-y +=3D segment.h
> +generic-y +=3D user.h
> +generic-y +=3D stat.h
> +generic-y +=3D fcntl.h
> +generic-y +=3D ioctl.h
> +generic-y +=3D ioctls.h
> +generic-y +=3D mman.h
> +generic-y +=3D msgbuf.h
> +generic-y +=3D sembuf.h
> +generic-y +=3D shmbuf.h
> +generic-y +=3D statfs.h
> +generic-y +=3D socket.h
> +generic-y +=3D sockios.h
> +generic-y +=3D termios.h
> +generic-y +=3D termbits.h
> +generic-y +=3D poll.h
> +generic-y +=3D param.h
> +generic-y +=3D posix_types.h
> +generic-y +=3D resource.h
> +generic-y +=3D kvm_para.h
> diff --git a/arch/loongarch/include/uapi/asm/Kbuild=20
> b/arch/loongarch/include/uapi/asm/Kbuild
> new file mode 100644
> index 000000000000..4aa680ca2e5f
> --- /dev/null
> +++ b/arch/loongarch/include/uapi/asm/Kbuild
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +generic-y +=3D kvm_para.h
> diff --git a/arch/loongarch/kernel/.gitignore=20
> b/arch/loongarch/kernel/.gitignore
> new file mode 100644
> index 000000000000..bbb90f92d051
> --- /dev/null
> +++ b/arch/loongarch/kernel/.gitignore
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +vmlinux.lds
> diff --git a/arch/loongarch/kernel/Makefile=20
> b/arch/loongarch/kernel/Makefile
> new file mode 100644
> index 000000000000..e5a3b2fb9961
> --- /dev/null
> +++ b/arch/loongarch/kernel/Makefile
> @@ -0,0 +1,21 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Makefile for the Linux/LoongArch kernel.
> +#
> +
> +extra-y		:=3D head.o vmlinux.lds
> +
> +obj-y		+=3D cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
> +		   traps.o irq.o idle.o process.o dma.o mem.o io.o reset.o switch.o=
 \
> +		   elf.o syscall.o signal.o time.o topology.o inst.o ptrace.o vdso.o
> +
> +obj-$(CONFIG_ACPI)		+=3D acpi.o
> +obj-$(CONFIG_EFI) 		+=3D efi.o
> +
> +obj-$(CONFIG_CPU_HAS_FPU)	+=3D fpu.o
> +
> +obj-$(CONFIG_MODULES)		+=3D module.o module-sections.o
> +
> +obj-$(CONFIG_PROC_FS)		+=3D proc.o
> +
> +CPPFLAGS_vmlinux.lds		:=3D $(KBUILD_CFLAGS)
> diff --git a/arch/loongarch/kernel/vmlinux.lds.S=20
> b/arch/loongarch/kernel/vmlinux.lds.S
> new file mode 100644
> index 000000000000..7da4c4d7c50d
> --- /dev/null
> +++ b/arch/loongarch/kernel/vmlinux.lds.S
> @@ -0,0 +1,117 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#include <linux/sizes.h>
> +#include <asm/asm-offsets.h>
> +#include <asm/thread_info.h>
> +
> +#define PAGE_SIZE _PAGE_SIZE
> +
> +/*
> + * Put .bss..swapper_pg_dir as the first thing in .bss. This will
> + * ensure that it has .bss alignment (64K).
> + */
> +#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir)
> +
> +#include <asm-generic/vmlinux.lds.h>
> +#include "image-vars.h"
> +
> +/*
> + * Max avaliable Page Size is 64K, so we set SectionAlignment
> + * field of EFI application to 64K.
> + */
> +PECOFF_FILE_ALIGN =3D 0x200;
> +PECOFF_SEGMENT_ALIGN =3D 0x10000;
> +
> +OUTPUT_ARCH(loongarch)
> +ENTRY(kernel_entry)
> +PHDRS {
> +	text PT_LOAD FLAGS(7);	/* RWX */
> +	note PT_NOTE FLAGS(4);	/* R__ */
> +}
> +
> +jiffies	 =3D jiffies_64;
> +
> +SECTIONS
> +{
> +	. =3D VMLINUX_LOAD_ADDRESS;
> +
> +	_text =3D .;
> +	HEAD_TEXT_SECTION
> +
> +	. =3D ALIGN(PECOFF_SEGMENT_ALIGN);
> +	.text : {
> +		TEXT_TEXT
> +		SCHED_TEXT
> +		CPUIDLE_TEXT
> +		LOCK_TEXT
> +		KPROBES_TEXT
> +		IRQENTRY_TEXT
> +		SOFTIRQENTRY_TEXT
> +		*(.fixup)
> +		*(.gnu.warning)
> +	} :text =3D 0
> +	. =3D ALIGN(PECOFF_SEGMENT_ALIGN);
> +	_etext =3D .;
> +
> +	EXCEPTION_TABLE(16)
> +
> +	. =3D ALIGN(PECOFF_SEGMENT_ALIGN);
> +	__init_begin =3D .;
> +	__inittext_begin =3D .;
> +
> +	INIT_TEXT_SECTION(PAGE_SIZE)
> +	.exit.text : {
> +		EXIT_TEXT
> +	}
> +
> +	. =3D ALIGN(PECOFF_SEGMENT_ALIGN);
> +	__inittext_end =3D .;
> +
> +	__initdata_begin =3D .;
> +
> +	INIT_DATA_SECTION(16)
> +	.exit.data : {
> +		EXIT_DATA
> +	}
> +
> +	.init.bss : {
> +		*(.init.bss)
> +	}
> +	. =3D ALIGN(PECOFF_SEGMENT_ALIGN);
> +	__initdata_end =3D .;
> +
> +	__init_end =3D .;
> +
> +	_sdata =3D .;
> +	RO_DATA(4096)
> +	RW_DATA(1 << CONFIG_L1_CACHE_SHIFT, PAGE_SIZE, THREAD_SIZE)
> +
> +	.sdata : {
> +		*(.sdata)
> +	}
> +	.edata_padding : { BYTE(0); . =3D ALIGN(PECOFF_FILE_ALIGN); }
> +	_edata =3D  .;
> +
> +	BSS_SECTION(0, SZ_64K, 8)
> +	. =3D ALIGN(PECOFF_SEGMENT_ALIGN);
> +
> +	_end =3D .;
> +
> +	STABS_DEBUG
> +	DWARF_DEBUG
> +
> +	.gptab.sdata : {
> +		*(.gptab.data)
> +		*(.gptab.sdata)
> +	}
> +	.gptab.sbss : {
> +		*(.gptab.bss)
> +		*(.gptab.sbss)
> +	}
> +
> +	DISCARDS
> +	/DISCARD/ : {
> +		*(.gnu.attributes)
> +		*(.options)
> +		*(.eh_frame)
> +	}
> +}
> diff --git a/arch/loongarch/lib/Makefile b/arch/loongarch/lib/Makefile
> new file mode 100644
> index 000000000000..e36635fccb69
> --- /dev/null
> +++ b/arch/loongarch/lib/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Makefile for LoongArch-specific library files.
> +#
> +
> +lib-y	+=3D delay.o clear_user.o copy_user.o dump_tlb.o
> diff --git a/arch/loongarch/mm/Makefile b/arch/loongarch/mm/Makefile
> new file mode 100644
> index 000000000000..8ffc6383f836
> --- /dev/null
> +++ b/arch/loongarch/mm/Makefile
> @@ -0,0 +1,9 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Makefile for the Linux/LoongArch-specific parts of the memory=20
> manager.
> +#
> +
> +obj-y				+=3D init.o cache.o tlb.o tlbex.o extable.o \
> +				   fault.o ioremap.o maccess.o mmap.o pgtable.o page.o
> +
> +obj-$(CONFIG_HUGETLB_PAGE)	+=3D hugetlbpage.o
> diff --git a/arch/loongarch/pci/Makefile b/arch/loongarch/pci/Makefile
> new file mode 100644
> index 000000000000..8101ef3df71c
> --- /dev/null
> +++ b/arch/loongarch/pci/Makefile
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Makefile for the PCI specific kernel interface routines under Linux.
> +#
> +
> +obj-y				+=3D pci.o
> +obj-$(CONFIG_ACPI)		+=3D acpi.o
> diff --git a/arch/loongarch/vdso/.gitignore=20
> b/arch/loongarch/vdso/.gitignore
> new file mode 100644
> index 000000000000..652e31d82582
> --- /dev/null
> +++ b/arch/loongarch/vdso/.gitignore
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +vdso.lds
> diff --git a/scripts/subarch.include b/scripts/subarch.include
> index 776849a3c500..4bd327d0ae42 100644
> --- a/scripts/subarch.include
> +++ b/scripts/subarch.include
> @@ -10,4 +10,4 @@ SUBARCH :=3D $(shell uname -m | sed -e s/i.86/x86/ -=
e=20
> s/x86_64/x86/ \
>  				  -e s/s390x/s390/ \
>  				  -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
>  				  -e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ \
> -				  -e s/riscv.*/riscv/)
> +				  -e s/riscv.*/riscv/ -e s/loongarch.*/loongarch/)
> --=20
> 2.27.0

--=20
- Jiaxun