Re: [PATCH V11 05/22] LoongArch: Add build infrastructure

[Guo Ren <guoren@kernel.org>]

Reviewed-by: Guo Ren <guoren@kernel.org>

On Wed, May 18, 2022 at 5:32 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
>
> Add Kbuild, Makefile, Kconfig and link script for LoongArch build
> infrastructure.
>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  arch/loongarch/Kbuild                  |   6 +
>  arch/loongarch/Kconfig                 | 395 +++++++++++++++++++++++++
>  arch/loongarch/Kconfig.debug           |   0
>  arch/loongarch/Makefile                | 105 +++++++
>  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, 729 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 += kernel/
> +obj-y += mm/
> +obj-y += vdso/
> +
> +# for cleaning
> +subdir- += boot
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> new file mode 100644
> index 000000000000..09902903bba8
> --- /dev/null
> +++ b/arch/loongarch/Kconfig
> @@ -0,0 +1,395 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config LOONGARCH
> +       bool
> +       default y
> +       select ACPI_MCFG if ACPI
> +       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_KMEMLEAK
> +       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_PCI
> +       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 PCI
> +       select PCI_DOMAINS_GENERIC
> +       select PCI_ECAM if ACPI
> +       select PCI_MSI_ARCH_FALLBACKS
> +       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 from the
> +# MIPS Loongson code, to preserve Loongson-specific code paths in drivers that
> +# are shared between architectures, and specifically expecting the 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 kernel
> +         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 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.debug
> new file mode 100644
> index 000000000000..e69de29bb2d1
> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
> new file mode 100644
> index 000000000000..6dcc0495bec9
> --- /dev/null
> +++ b/arch/loongarch/Makefile
> @@ -0,0 +1,105 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Author: Huacai Chen <chenhuacai@loongson.cn>
> +# Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> +
> +boot   := arch/loongarch/boot
> +
> +ifndef CONFIG_EFI_STUB
> +KBUILD_IMAGE   = $(boot)/vmlinux
> +else
> +KBUILD_IMAGE   = $(boot)/vmlinux.efi
> +endif
> +
> +#
> +# Select the object file format to substitute into the linker script.
> +#
> +64bit-tool-archpref    = loongarch64
> +32bit-bfd              = elf32-loongarch
> +64bit-bfd              = elf64-loongarch
> +32bit-emul             = elf32loongarch
> +64bit-emul             = elf64loongarch
> +
> +ifdef CONFIG_64BIT
> +tool-archpref          = $(64bit-tool-archpref)
> +UTS_MACHINE            := loongarch64
> +endif
> +
> +ifneq ($(SUBARCH),$(ARCH))
> +  ifeq ($(CROSS_COMPILE),)
> +    CROSS_COMPILE := $(call cc-cross-prefix, $(tool-archpref)-linux-  $(tool-archpref)-linux-gnu-  $(tool-archpref)-unknown-linux-gnu-)
> +  endif
> +endif
> +
> +ifdef CONFIG_64BIT
> +ld-emul                        = $(64bit-emul)
> +cflags-y               += -mabi=lp64s
> +endif
> +
> +cflags-y                       += -G0 -pipe -msoft-float
> +LDFLAGS_vmlinux                        += -G0 -static -n -nostdlib
> +KBUILD_AFLAGS_KERNEL           += -Wa,-mla-global-with-pcrel
> +KBUILD_CFLAGS_KERNEL           += -Wa,-mla-global-with-pcrel
> +KBUILD_AFLAGS_MODULE           += -Wa,-mla-global-with-abs
> +KBUILD_CFLAGS_MODULE           += -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs
> +
> +cflags-y += -ffreestanding
> +cflags-y += $(call cc-option, -mno-check-zero-division)
> +
> +load-y         = 0x9000000000200000
> +bootvars-y     = VMLINUX_LOAD_ADDRESS=$(load-y)
> +
> +drivers-$(CONFIG_PCI)          += arch/loongarch/pci/
> +
> +KBUILD_AFLAGS  += $(cflags-y)
> +KBUILD_CFLAGS  += $(cflags-y)
> +KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(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 += -fno-asynchronous-unwind-tables
> +
> +# Don't emit unaligned accesses.
> +# Not all LoongArch cores support unaligned access, and as kernel we can't
> +# rely on others to provide emulation for these accesses.
> +KBUILD_CFLAGS += $(call cc-option,-mstrict-align)
> +
> +KBUILD_CFLAGS += -isystem $(shell $(CC) -print-file-name=include)
> +
> +KBUILD_LDFLAGS += -m $(ld-emul)
> +
> +ifdef CONFIG_LOONGARCH
> +CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
> +       egrep -vw '__GNUC_(MINOR_|PATCHLEVEL_)?_' | \
> +       sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/" -e 's/\$$/&&/g')
> +endif
> +
> +head-y := arch/loongarch/kernel/head.o
> +
> +libs-y += arch/loongarch/lib/
> +libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
> +
> +ifeq ($(KBUILD_EXTMOD),)
> +prepare: vdso_prepare
> +vdso_prepare: prepare0
> +       $(Q)$(MAKE) $(build)=arch/loongarch/vdso include/generated/vdso-offsets.h
> +endif
> +
> +PHONY += vdso_install
> +vdso_install:
> +       $(Q)$(MAKE) $(build)=arch/loongarch/vdso $@
> +
> +all:   $(KBUILD_IMAGE)
> +
> +$(KBUILD_IMAGE): vmlinux
> +       $(Q)$(MAKE) $(build)=$(boot) $(bootvars-y) $@
> +
> +install:
> +       $(Q)install -D -m 755 $(KBUILD_IMAGE) $(INSTALL_PATH)/vmlinux-$(KERNELRELEASE)
> +       $(Q)install -D -m 644 .config $(INSTALL_PATH)/config-$(KERNELRELEASE)
> +       $(Q)install -D -m 644 System.map $(INSTALL_PATH)/System.map-$(KERNELRELEASE)
> +
> +define archhelp
> +       echo '  install              - install kernel into $(INSTALL_PATH)'
> +       echo
> +endef
> diff --git a/arch/loongarch/boot/.gitignore 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/Makefile
> 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 := .comment .note .options .note.gnu.build-id
> +strip-flags   := $(addprefix --remove-section=,$(drop-sections)) -S
> +OBJCOPYFLAGS_vmlinux.efi := -O binary $(strip-flags)
> +
> +targets := vmlinux
> +quiet_cmd_strip = STRIP          $@
> +      cmd_strip = $(STRIP) -s -o $@ $<
> +
> +$(obj)/vmlinux: vmlinux FORCE
> +       $(call if_changed,strip)
> +
> +targets += vmlinux.efi
> +$(obj)/vmlinux.efi: $(obj)/vmlinux FORCE
> +       $(call if_changed,objcopy)
> diff --git a/arch/loongarch/boot/dts/Makefile 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        := $(srctree)/$(src)
> +
> +dtb-y := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts))
> diff --git a/arch/loongarch/include/asm/Kbuild 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 += dma-contiguous.h
> +generic-y += export.h
> +generic-y += parport.h
> +generic-y += early_ioremap.h
> +generic-y += qrwlock.h
> +generic-y += qrwlock_types.h
> +generic-y += spinlock.h
> +generic-y += spinlock_types.h
> +generic-y += rwsem.h
> +generic-y += segment.h
> +generic-y += user.h
> +generic-y += stat.h
> +generic-y += fcntl.h
> +generic-y += ioctl.h
> +generic-y += ioctls.h
> +generic-y += mman.h
> +generic-y += msgbuf.h
> +generic-y += sembuf.h
> +generic-y += shmbuf.h
> +generic-y += statfs.h
> +generic-y += socket.h
> +generic-y += sockios.h
> +generic-y += termios.h
> +generic-y += termbits.h
> +generic-y += poll.h
> +generic-y += param.h
> +generic-y += posix_types.h
> +generic-y += resource.h
> +generic-y += kvm_para.h
> diff --git a/arch/loongarch/include/uapi/asm/Kbuild 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 += kvm_para.h
> diff --git a/arch/loongarch/kernel/.gitignore 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 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                := head.o vmlinux.lds
> +
> +obj-y          += 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)             += acpi.o
> +obj-$(CONFIG_EFI)              += efi.o
> +
> +obj-$(CONFIG_CPU_HAS_FPU)      += fpu.o
> +
> +obj-$(CONFIG_MODULES)          += module.o module-sections.o
> +
> +obj-$(CONFIG_PROC_FS)          += proc.o
> +
> +CPPFLAGS_vmlinux.lds           := $(KBUILD_CFLAGS)
> diff --git a/arch/loongarch/kernel/vmlinux.lds.S 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 = 0x200;
> +PECOFF_SEGMENT_ALIGN = 0x10000;
> +
> +OUTPUT_ARCH(loongarch)
> +ENTRY(kernel_entry)
> +PHDRS {
> +       text PT_LOAD FLAGS(7);  /* RWX */
> +       note PT_NOTE FLAGS(4);  /* R__ */
> +}
> +
> +jiffies         = jiffies_64;
> +
> +SECTIONS
> +{
> +       . = VMLINUX_LOAD_ADDRESS;
> +
> +       _text = .;
> +       HEAD_TEXT_SECTION
> +
> +       . = ALIGN(PECOFF_SEGMENT_ALIGN);
> +       .text : {
> +               TEXT_TEXT
> +               SCHED_TEXT
> +               CPUIDLE_TEXT
> +               LOCK_TEXT
> +               KPROBES_TEXT
> +               IRQENTRY_TEXT
> +               SOFTIRQENTRY_TEXT
> +               *(.fixup)
> +               *(.gnu.warning)
> +       } :text = 0
> +       . = ALIGN(PECOFF_SEGMENT_ALIGN);
> +       _etext = .;
> +
> +       EXCEPTION_TABLE(16)
> +
> +       . = ALIGN(PECOFF_SEGMENT_ALIGN);
> +       __init_begin = .;
> +       __inittext_begin = .;
> +
> +       INIT_TEXT_SECTION(PAGE_SIZE)
> +       .exit.text : {
> +               EXIT_TEXT
> +       }
> +
> +       . = ALIGN(PECOFF_SEGMENT_ALIGN);
> +       __inittext_end = .;
> +
> +       __initdata_begin = .;
> +
> +       INIT_DATA_SECTION(16)
> +       .exit.data : {
> +               EXIT_DATA
> +       }
> +
> +       .init.bss : {
> +               *(.init.bss)
> +       }
> +       . = ALIGN(PECOFF_SEGMENT_ALIGN);
> +       __initdata_end = .;
> +
> +       __init_end = .;
> +
> +       _sdata = .;
> +       RO_DATA(4096)
> +       RW_DATA(1 << CONFIG_L1_CACHE_SHIFT, PAGE_SIZE, THREAD_SIZE)
> +
> +       .sdata : {
> +               *(.sdata)
> +       }
> +       .edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGN); }
> +       _edata =  .;
> +
> +       BSS_SECTION(0, SZ_64K, 8)
> +       . = ALIGN(PECOFF_SEGMENT_ALIGN);
> +
> +       _end = .;
> +
> +       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  += 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 manager.
> +#
> +
> +obj-y                          += 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)     += 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                          += pci.o
> +obj-$(CONFIG_ACPI)             += acpi.o
> diff --git a/arch/loongarch/vdso/.gitignore 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 := $(shell uname -m | sed -e s/i.86/x86/ -e 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/)
> --
> 2.27.0
>


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/