LoongArch: Add build infrastructure

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>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Kbuild

+obj-y += kernel/
+obj-y += mm/
+obj-y += vdso/
+
+# for cleaning
+subdir- += boot

arch/loongarch/Makefile

+# SPDX-License-Identifier: GPL-2.0
+#
+# Author: Huacai Chen <chenhuacai@loongson.cn>
+# Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+
+boot	:= arch/loongarch/boot
+
+KBUILD_IMAGE	= $(boot)/vmlinux
+
+#
+# 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)
+
+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/
+
+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

arch/loongarch/boot/.gitignore

+# SPDX-License-Identifier: GPL-2.0-only
+vmlinux*

arch/loongarch/boot/Makefile

+#
+# 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)

arch/loongarch/boot/dts/Makefile

+# SPDX-License-Identifier: GPL-2.0-only
+dtstree	:= $(srctree)/$(src)
+
+dtb-y := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts))

arch/loongarch/include/asm/Kbuild

+# 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

arch/loongarch/include/uapi/asm/Kbuild

+# SPDX-License-Identifier: GPL-2.0
+generic-y += kvm_para.h

arch/loongarch/kernel/.gitignore

+# SPDX-License-Identifier: GPL-2.0-only
+vmlinux.lds

arch/loongarch/kernel/Makefile

+# 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)

arch/loongarch/kernel/vmlinux.lds.S

+/* 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>
+
+/*
+ * 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)
+	}
+}

arch/loongarch/lib/Makefile

+# 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

arch/loongarch/mm/Makefile

+# 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

arch/loongarch/pci/Makefile

+# 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

arch/loongarch/vdso/.gitignore

+# SPDX-License-Identifier: GPL-2.0-only
+vdso.lds

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/)