Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 583 insertions, 0 deletions

diff --git a/arch/mips/Makefile b/arch/mips/Makefile
new file mode 100644
index 0000000000..f49807e1f1
--- /dev/null
+++ b/arch/mips/Makefile
@@ -0,0 +1,583 @@
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 1994, 95, 96, 2003 by Ralf Baechle
+# DECStation modifications by Paul M. Antoine, 1996
+# Copyright (C) 2002, 2003, 2004  Maciej W. Rozycki
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies.
+#
+
+archscripts: scripts_basic
+	$(Q)$(MAKE) $(build)=arch/mips/tools elf-entry
+ifeq ($(CONFIG_CPU_LOONGSON3_WORKAROUNDS),y)
+	$(Q)$(MAKE) $(build)=arch/mips/tools loongson3-llsc-check
+endif
+	$(Q)$(MAKE) $(build)=arch/mips/boot/tools relocs
+
+KBUILD_DEFCONFIG := 32r2el_defconfig
+KBUILD_DTBS      := dtbs
+
+#
+# Select the object file format to substitute into the linker script.
+#
+ifdef CONFIG_CPU_LITTLE_ENDIAN
+32bit-tool-archpref	= mipsel
+64bit-tool-archpref	= mips64el
+32bit-bfd		= elf32-tradlittlemips
+64bit-bfd		= elf64-tradlittlemips
+32bit-emul		= elf32ltsmip
+64bit-emul		= elf64ltsmip
+else
+32bit-tool-archpref	= mips
+64bit-tool-archpref	= mips64
+32bit-bfd		= elf32-tradbigmips
+64bit-bfd		= elf64-tradbigmips
+32bit-emul		= elf32btsmip
+64bit-emul		= elf64btsmip
+endif
+
+ifdef CONFIG_32BIT
+tool-archpref		= $(32bit-tool-archpref)
+UTS_MACHINE		:= mips
+endif
+ifdef CONFIG_64BIT
+tool-archpref		= $(64bit-tool-archpref)
+UTS_MACHINE		:= mips64
+endif
+
+ifdef cross_compiling
+  ifeq ($(CROSS_COMPILE),)
+    CROSS_COMPILE := $(call cc-cross-prefix, $(tool-archpref)-linux-  $(tool-archpref)-linux-gnu-  $(tool-archpref)-unknown-linux-gnu-)
+  endif
+endif
+
+ifdef CONFIG_FUNCTION_GRAPH_TRACER
+  ifndef KBUILD_MCOUNT_RA_ADDRESS
+    ifeq ($(call cc-option-yn,-mmcount-ra-address), y)
+      cflags-y += -mmcount-ra-address -DKBUILD_MCOUNT_RA_ADDRESS
+    endif
+  endif
+endif
+cflags-y += $(call cc-option, -mno-check-zero-division)
+
+ifdef CONFIG_32BIT
+ld-emul			= $(32bit-emul)
+vmlinux-32		= vmlinux
+vmlinux-64		= vmlinux.64
+
+cflags-y		+= -mabi=32
+endif
+
+ifdef CONFIG_64BIT
+ld-emul			= $(64bit-emul)
+vmlinux-32		= vmlinux.32
+vmlinux-64		= vmlinux
+
+cflags-y		+= -mabi=64
+endif
+
+all-$(CONFIG_BOOT_ELF32)	:= $(vmlinux-32)
+all-$(CONFIG_BOOT_ELF64)	:= $(vmlinux-64)
+all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlinuz
+
+#
+# GCC uses -G 0 -mabicalls -fpic as default.  We don't want PIC in the kernel
+# code since it only slows down the whole thing.  At some point we might make
+# use of global pointer optimizations but their use of $28 conflicts with
+# the current pointer optimization.
+#
+# The DECStation requires an ECOFF kernel for remote booting, other MIPS
+# machines may also.  Since BFD is incredibly buggy with respect to
+# crossformat linking we rely on the elf2ecoff tool for format conversion.
+#
+cflags-y			+= -G 0 -mno-abicalls -fno-pic -pipe
+cflags-y			+= -msoft-float -Wa,-msoft-float
+LDFLAGS_vmlinux			+= -G 0 -static -n -nostdlib
+KBUILD_AFLAGS_MODULE		+= -mlong-calls
+KBUILD_CFLAGS_MODULE		+= -mlong-calls
+
+ifeq ($(CONFIG_RELOCATABLE),y)
+LDFLAGS_vmlinux			+= --emit-relocs
+endif
+
+cflags-y += -ffreestanding
+
+cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= -EB
+cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -EL
+
+cflags-$(CONFIG_SB1XXX_CORELIS)	+= $(call cc-option,-mno-sched-prolog) \
+				   -fno-omit-frame-pointer
+
+# Some distribution-specific toolchains might pass the -fstack-check
+# option during the build, which adds a simple stack-probe at the beginning
+# of every function.  This stack probe is to ensure that there is enough
+# stack space, else a SEGV is generated.  This is not desirable for MIPS
+# as kernel stacks are small, placed in unmapped virtual memory, and do not
+# grow when overflowed.  Especially on SGI IP27 platforms, this check will
+# lead to a NULL pointer dereference in _raw_spin_lock_irq.
+#
+# In disassembly, this stack probe appears at the top of a function as:
+#    sd		zero,<offset>(sp)
+# Where <offset> is a negative value.
+#
+cflags-y += -fno-stack-check
+
+# binutils from v2.35 when built with --enable-mips-fix-loongson3-llsc=yes,
+# supports an -mfix-loongson3-llsc flag which emits a sync prior to each ll
+# instruction to work around a CPU bug (see __SYNC_loongson3_war in asm/sync.h
+# for a description).
+#
+# We disable this in order to prevent the assembler meddling with the
+# instruction that labels refer to, ie. if we label an ll instruction:
+#
+# 1: ll v0, 0(a0)
+#
+# ...then with the assembler fix applied the label may actually point at a sync
+# instruction inserted by the assembler, and if we were using the label in an
+# exception table the table would no longer contain the address of the ll
+# instruction.
+#
+# Avoid this by explicitly disabling that assembler behaviour.
+#
+cflags-y += $(call cc-option,-Wa$(comma)-mno-fix-loongson3-llsc,)
+
+#
+# CPU-dependent compiler/assembler options for optimization.
+#
+cflags-$(CONFIG_CPU_R3000)	+= -march=r3000
+cflags-$(CONFIG_CPU_R4300)	+= -march=r4300 -Wa,--trap
+cflags-$(CONFIG_CPU_R4X00)	+= -march=r4600 -Wa,--trap
+cflags-$(CONFIG_CPU_TX49XX)	+= -march=r4600 -Wa,--trap
+cflags-$(CONFIG_CPU_MIPS32_R1)	+= -march=mips32 -Wa,--trap
+cflags-$(CONFIG_CPU_MIPS32_R2)	+= -march=mips32r2 -Wa,--trap
+cflags-$(CONFIG_CPU_MIPS32_R5)	+= -march=mips32r5 -Wa,--trap -modd-spreg
+cflags-$(CONFIG_CPU_MIPS32_R6)	+= -march=mips32r6 -Wa,--trap -modd-spreg
+cflags-$(CONFIG_CPU_MIPS64_R1)	+= -march=mips64 -Wa,--trap
+cflags-$(CONFIG_CPU_MIPS64_R2)	+= -march=mips64r2 -Wa,--trap
+cflags-$(CONFIG_CPU_MIPS64_R5)	+= -march=mips64r5 -Wa,--trap
+cflags-$(CONFIG_CPU_MIPS64_R6)	+= -march=mips64r6 -Wa,--trap
+cflags-$(CONFIG_CPU_P5600)	+= -march=p5600 -Wa,--trap -modd-spreg
+cflags-$(CONFIG_CPU_R5000)	+= -march=r5000 -Wa,--trap
+cflags-$(CONFIG_CPU_R5500)	+= $(call cc-option,-march=r5500,-march=r5000) \
+			-Wa,--trap
+cflags-$(CONFIG_CPU_NEVADA)	+= $(call cc-option,-march=rm5200,-march=r5000) \
+			-Wa,--trap
+cflags-$(CONFIG_CPU_RM7000)	+= $(call cc-option,-march=rm7000,-march=r5000) \
+			-Wa,--trap
+cflags-$(CONFIG_CPU_SB1)	+= $(call cc-option,-march=sb1,-march=r5000) \
+			-Wa,--trap
+cflags-$(CONFIG_CPU_SB1)	+= $(call cc-option,-mno-mdmx)
+cflags-$(CONFIG_CPU_SB1)	+= $(call cc-option,-mno-mips3d)
+cflags-$(CONFIG_CPU_R10000)	+= $(call cc-option,-march=r10000,-march=r8000) \
+			-Wa,--trap
+cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += $(call cc-option,-march=octeon) -Wa,--trap
+ifeq (,$(findstring march=octeon, $(cflags-$(CONFIG_CPU_CAVIUM_OCTEON))))
+cflags-$(CONFIG_CPU_CAVIUM_OCTEON) += -Wa,-march=octeon
+endif
+cflags-$(CONFIG_CAVIUM_CN63XXP1) += -Wa,-mfix-cn63xxp1
+cflags-$(CONFIG_CPU_BMIPS)	+= -march=mips32 -Wa,-mips32 -Wa,--trap
+
+cflags-$(CONFIG_CPU_LOONGSON2E) += -march=loongson2e -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap
+# Some -march= flags enable MMI instructions, and GCC complains about that
+# support being enabled alongside -msoft-float. Thus explicitly disable MMI.
+cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi)
+ifdef CONFIG_CPU_LOONGSON64
+cflags-$(CONFIG_CPU_LOONGSON64)	+= -Wa,--trap
+cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a
+cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2
+endif
+cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
+
+cflags-$(CONFIG_CPU_R4000_WORKAROUNDS)	+= $(call cc-option,-mfix-r4000,)
+cflags-$(CONFIG_CPU_R4400_WORKAROUNDS)	+= $(call cc-option,-mfix-r4400,)
+cflags-$(CONFIG_CPU_DADDI_WORKAROUNDS)	+= $(call cc-option,-mno-daddi,)
+ifdef CONFIG_CPU_LOONGSON2F_WORKAROUNDS
+cflags-$(CONFIG_CPU_NOP_WORKAROUNDS) += -Wa,-mfix-loongson2f-nop
+cflags-$(CONFIG_CPU_JUMP_WORKAROUNDS) += -Wa,-mfix-loongson2f-jump
+endif
+
+#
+# Some versions of binutils, not currently mainline as of 2019/02/04, support
+# an -mfix-loongson3-llsc flag which emits a sync prior to each ll instruction
+# to work around a CPU bug (see __SYNC_loongson3_war in asm/sync.h for a
+# description).
+#
+# We disable this in order to prevent the assembler meddling with the
+# instruction that labels refer to, ie. if we label an ll instruction:
+#
+# 1: ll v0, 0(a0)
+#
+# ...then with the assembler fix applied the label may actually point at a sync
+# instruction inserted by the assembler, and if we were using the label in an
+# exception table the table would no longer contain the address of the ll
+# instruction.
+#
+# Avoid this by explicitly disabling that assembler behaviour. If upstream
+# binutils does not merge support for the flag then we can revisit & remove
+# this later - for now it ensures vendor toolchains don't cause problems.
+#
+cflags-$(CONFIG_CPU_LOONGSON64)	+= $(call as-option,-Wa$(comma)-mno-fix-loongson3-llsc,)
+
+# For smartmips configurations, there are hundreds of warnings due to ISA overrides
+# in assembly and header files. smartmips is only supported for MIPS32r1 onwards
+# and there is no support for 64-bit. Various '.set mips2' or '.set mips3' or
+# similar directives in the kernel will spam the build logs with the following warnings:
+# Warning: the `smartmips' extension requires MIPS32 revision 1 or greater
+# or
+# Warning: the 64-bit MIPS architecture does not support the `smartmips' extension
+# Pass -Wa,--no-warn to disable all assembler warnings until the kernel code has
+# been fixed properly.
+mips-cflags				:= $(cflags-y)
+ifeq ($(CONFIG_CPU_HAS_SMARTMIPS),y)
+smartmips-ase				:= $(call cc-option-yn,$(mips-cflags) -msmartmips)
+cflags-$(smartmips-ase)			+= -msmartmips -Wa,--no-warn
+endif
+ifeq ($(CONFIG_CPU_MICROMIPS),y)
+micromips-ase				:= $(call cc-option-yn,$(mips-cflags) -mmicromips)
+cflags-$(micromips-ase)			+= -mmicromips
+endif
+ifeq ($(CONFIG_CPU_HAS_MSA),y)
+toolchain-msa				:= $(call cc-option-yn,$(mips-cflags) -mhard-float -mfp64 -Wa$(comma)-mmsa)
+cflags-$(toolchain-msa)			+= -DTOOLCHAIN_SUPPORTS_MSA
+endif
+toolchain-virt				:= $(call cc-option-yn,$(mips-cflags) -mvirt)
+cflags-$(toolchain-virt)		+= -DTOOLCHAIN_SUPPORTS_VIRT
+# For -mmicromips, use -Wa,-fatal-warnings to catch unsupported -mxpa which
+# only warns
+xpa-cflags-y				:= $(mips-cflags)
+xpa-cflags-$(micromips-ase)		+= -mmicromips -Wa$(comma)-fatal-warnings
+toolchain-xpa				:= $(call cc-option-yn,$(xpa-cflags-y) -mxpa)
+cflags-$(toolchain-xpa)			+= -DTOOLCHAIN_SUPPORTS_XPA
+toolchain-crc				:= $(call cc-option-yn,$(mips-cflags) -Wa$(comma)-mcrc)
+cflags-$(toolchain-crc)			+= -DTOOLCHAIN_SUPPORTS_CRC
+toolchain-dsp				:= $(call cc-option-yn,$(mips-cflags) -Wa$(comma)-mdsp)
+cflags-$(toolchain-dsp)			+= -DTOOLCHAIN_SUPPORTS_DSP
+toolchain-ginv				:= $(call cc-option-yn,$(mips-cflags) -Wa$(comma)-mginv)
+cflags-$(toolchain-ginv)		+= -DTOOLCHAIN_SUPPORTS_GINV
+
+#
+# Firmware support
+#
+libs-$(CONFIG_FW_ARC)		+= arch/mips/fw/arc/
+libs-$(CONFIG_FW_CFE)		+= arch/mips/fw/cfe/
+libs-$(CONFIG_FW_SNIPROM)	+= arch/mips/fw/sni/
+libs-y				+= arch/mips/fw/lib/
+
+#
+# Kernel compression
+#
+ifdef CONFIG_SYS_SUPPORTS_ZBOOT
+COMPRESSION_FNAME		= vmlinuz
+else
+COMPRESSION_FNAME		= vmlinux
+endif
+
+#
+# Board-dependent options and extra files
+#
+include $(srctree)/arch/mips/Kbuild.platforms
+
+ifdef CONFIG_PHYSICAL_START
+load-y					= $(CONFIG_PHYSICAL_START)
+endif
+
+entry-y				= $(shell $(objtree)/arch/mips/tools/elf-entry vmlinux)
+cflags-y			+= -I$(srctree)/arch/mips/include/asm/mach-generic
+drivers-$(CONFIG_PCI)		+= arch/mips/pci/
+
+#
+# Automatically detect the build format. By default we choose
+# the elf format according to the load address.
+# We can always force a build with a 64-bits symbol format by
+# passing 'KBUILD_SYM32=no' option to the make's command line.
+#
+ifdef CONFIG_64BIT
+  ifndef KBUILD_SYM32
+    ifeq ($(shell expr $(load-y) \< 0xffffffff80000000), 0)
+      KBUILD_SYM32 = y
+    endif
+  endif
+
+  ifeq ($(KBUILD_SYM32), y)
+    cflags-$(KBUILD_SYM32) += -msym32 -DKBUILD_64BIT_SYM32
+  else
+    ifeq ($(CONFIG_CPU_DADDI_WORKAROUNDS), y)
+      $(error CONFIG_CPU_DADDI_WORKAROUNDS unsupported without -msym32)
+    endif
+  endif
+endif
+
+# When linking a 32-bit executable the LLVM linker cannot cope with a
+# 32-bit load address that has been sign-extended to 64 bits.  Simply
+# remove the upper 32 bits then, as it is safe to do so with other
+# linkers.
+ifdef CONFIG_64BIT
+	load-ld			= $(load-y)
+else
+	load-ld			= $(subst 0xffffffff,0x,$(load-y))
+endif
+
+KBUILD_AFLAGS	+= $(cflags-y)
+KBUILD_CFLAGS	+= $(cflags-y)
+KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y) -DLINKER_LOAD_ADDRESS=$(load-ld)
+KBUILD_CPPFLAGS += -DDATAOFFSET=$(if $(dataoffset-y),$(dataoffset-y),0)
+
+bootvars-y	= VMLINUX_LOAD_ADDRESS=$(load-y) \
+		  LINKER_LOAD_ADDRESS=$(load-ld) \
+		  VMLINUX_ENTRY_ADDRESS=$(entry-y) \
+		  PLATFORM="$(platform-y)" \
+		  ITS_INPUTS="$(its-y)"
+ifdef CONFIG_32BIT
+bootvars-y	+= ADDR_BITS=32
+endif
+ifdef CONFIG_64BIT
+bootvars-y	+= ADDR_BITS=64
+endif
+
+# 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
+
+KBUILD_LDFLAGS		+= -m $(ld-emul)
+
+ifdef need-compiler
+CHECKFLAGS += $(shell $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
+	grep -E -vw '__GNUC_(MINOR_|PATCHLEVEL_)?_' | \
+	sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/" -e 's/\$$/&&/g')
+endif
+
+OBJCOPYFLAGS		+= --remove-section=.reginfo
+
+libs-y			+= arch/mips/lib/
+libs-$(CONFIG_MIPS_FP_SUPPORT) += arch/mips/math-emu/
+
+drivers-y			+= arch/mips/crypto/
+
+# suspend and hibernation support
+drivers-$(CONFIG_PM)	+= arch/mips/power/
+
+# boot image targets (arch/mips/boot/)
+boot-y			:= vmlinux.bin
+boot-y			+= vmlinux.ecoff
+boot-y			+= vmlinux.srec
+boot-y			+= uImage
+boot-y			+= uImage.bin
+boot-y			+= uImage.bz2
+boot-y			+= uImage.gz
+boot-y			+= uImage.lzma
+boot-y			+= uImage.lzo
+boot-y			+= vmlinux.itb
+boot-y			+= vmlinux.gz.itb
+boot-y			+= vmlinux.bz2.itb
+boot-y			+= vmlinux.lzma.itb
+boot-y			+= vmlinux.lzo.itb
+
+# compressed boot image targets (arch/mips/boot/compressed/)
+bootz-y			:= vmlinuz
+bootz-y			+= vmlinuz.bin
+bootz-y			+= vmlinuz.ecoff
+bootz-y			+= vmlinuz.srec
+bootz-y			+= uzImage.bin
+bootz-y			+= vmlinuz.itb
+
+#
+# Some machines like the Indy need 32-bit ELF binaries for booting purposes.
+# Other need ECOFF, so we build a 32-bit ELF binary for them which we then
+# convert to ECOFF using elf2ecoff.
+#
+quiet_cmd_32 = OBJCOPY $@
+	cmd_32 = $(OBJCOPY) -O $(32bit-bfd) $(OBJCOPYFLAGS) $< $@
+vmlinux.32: vmlinux
+	$(call cmd,32)
+
+#
+# The 64-bit ELF tools are pretty broken so at this time we generate 64-bit
+# ELF files from 32-bit files by conversion.
+#
+quiet_cmd_64 = OBJCOPY $@
+	cmd_64 = $(OBJCOPY) -O $(64bit-bfd) $(OBJCOPYFLAGS) $< $@
+vmlinux.64: vmlinux
+	$(call cmd,64)
+
+all:	$(all-y) $(KBUILD_DTBS)
+
+# boot
+$(boot-y): $(vmlinux-32) FORCE
+	$(Q)$(MAKE) $(build)=arch/mips/boot VMLINUX=$(vmlinux-32) \
+		$(bootvars-y) arch/mips/boot/$@
+
+ifdef CONFIG_SYS_SUPPORTS_ZBOOT
+# boot/compressed
+$(bootz-y): $(vmlinux-32) FORCE
+	$(Q)$(MAKE) $(build)=arch/mips/boot/compressed \
+		$(bootvars-y) 32bit-bfd=$(32bit-bfd) arch/mips/boot/$@
+else
+vmlinuz: FORCE
+	@echo '   CONFIG_SYS_SUPPORTS_ZBOOT is not enabled'
+	/bin/false
+endif
+
+
+CLEAN_FILES += vmlinux.32 vmlinux.64
+
+# device-trees
+core-y += arch/mips/boot/dts/
+
+archprepare:
+ifdef CONFIG_MIPS32_N32
+	@$(kecho) '  Checking missing-syscalls for N32'
+	$(Q)$(MAKE) $(build)=. missing-syscalls missing_syscalls_flags="-mabi=n32"
+endif
+ifdef CONFIG_MIPS32_O32
+	@$(kecho) '  Checking missing-syscalls for O32'
+	$(Q)$(MAKE) $(build)=. missing-syscalls missing_syscalls_flags="-mabi=32"
+endif
+
+install:
+	$(Q)install -D -m 755 vmlinux $(INSTALL_PATH)/vmlinux-$(KERNELRELEASE)
+ifdef CONFIG_SYS_SUPPORTS_ZBOOT
+	$(Q)install -D -m 755 vmlinuz $(INSTALL_PATH)/vmlinuz-$(KERNELRELEASE)
+endif
+	$(Q)install -D -m 644 .config $(INSTALL_PATH)/config-$(KERNELRELEASE)
+	$(Q)install -D -m 644 System.map $(INSTALL_PATH)/System.map-$(KERNELRELEASE)
+
+archheaders:
+	$(Q)$(MAKE) $(build)=arch/mips/kernel/syscalls all
+
+define archhelp
+	echo '  install              - install kernel into $(INSTALL_PATH)'
+	echo '  vmlinux.ecoff        - ECOFF boot image'
+	echo '  vmlinux.bin          - Raw binary boot image'
+	echo '  vmlinux.srec         - SREC boot image'
+	echo '  vmlinux.32           - 64-bit boot image wrapped in 32bits (IP22/IP32)'
+	echo '  vmlinuz              - Compressed boot(zboot) image'
+	echo '  vmlinuz.ecoff        - ECOFF zboot image'
+	echo '  vmlinuz.bin          - Raw binary zboot image'
+	echo '  vmlinuz.srec         - SREC zboot image'
+	echo '  uImage               - U-Boot image'
+	echo '  uImage.bin           - U-Boot image (uncompressed)'
+	echo '  uImage.bz2           - U-Boot image (bz2)'
+	echo '  uImage.gz            - U-Boot image (gzip)'
+	echo '  uImage.lzma          - U-Boot image (lzma)'
+	echo '  uImage.lzo           - U-Boot image (lzo)'
+	echo '  uzImage.bin          - U-Boot image (self-extracting)'
+	echo
+	echo '  These will be default as appropriate for a configured platform.'
+	echo
+	echo '  If you are targeting a system supported by generic kernels you may'
+	echo '  configure the kernel for a given architecture target like so:'
+	echo
+	echo '  {micro32,32,64}{r1,r2,r6}{el,}_defconfig <BOARDS="list of boards">'
+	echo
+	echo '  Where BOARDS is some subset of the following:'
+	for board in $(sort $(BOARDS)); do echo "    $${board}"; done
+	echo
+	echo '  Specifically the following generic default configurations are'
+	echo '  supported:'
+	echo
+	$(foreach cfg,$(generic_defconfigs),
+	  printf "  %-24s - Build generic kernel for $(call describe_generic_defconfig,$(cfg))\n" $(cfg);)
+	echo
+	echo '  The following legacy default configurations have been converted to'
+	echo '  generic and can still be used:'
+	echo
+	$(foreach cfg,$(sort $(legacy_defconfigs)),
+	  printf "  %-24s - Build $($(cfg)-y)\n" $(cfg);)
+	echo
+	echo '  Otherwise, the following default configurations are available:'
+endef
+
+generic_config_dir = $(srctree)/arch/$(ARCH)/configs/generic
+generic_defconfigs :=
+
+#
+# If the user generates a generic kernel configuration without specifying a
+# list of boards to include the config fragments for, default to including all
+# available board config fragments.
+#
+ifeq ($(BOARDS),)
+BOARDS = $(patsubst board-%.config,%,$(notdir $(wildcard $(generic_config_dir)/board-*.config)))
+endif
+
+#
+# Generic kernel configurations which merge generic_defconfig with the
+# appropriate config fragments from arch/mips/configs/generic/, resulting in
+# the ability to easily configure the kernel for a given architecture,
+# endianness & set of boards without duplicating the needed configuration in
+# hundreds of defconfig files.
+#
+define gen_generic_defconfigs
+$(foreach bits,$(1),$(foreach rev,$(2),$(foreach endian,$(3),
+target := $(bits)$(rev)$(filter el,$(endian))_defconfig
+generic_defconfigs += $$(target)
+$$(target): $(generic_config_dir)/$(bits)$(rev).config
+$$(target): $(generic_config_dir)/$(endian).config
+)))
+endef
+
+$(eval $(call gen_generic_defconfigs,32 64,r1 r2 r6,eb el))
+$(eval $(call gen_generic_defconfigs,micro32,r2,eb el))
+
+define describe_generic_defconfig
+$(subst 32r,MIPS32 r,$(subst 64r,MIPS64 r,$(subst el, little endian,$(patsubst %_defconfig,%,$(1)))))
+endef
+
+.PHONY: $(generic_defconfigs)
+$(generic_defconfigs):
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh \
+		-m -O $(objtree) $(srctree)/arch/$(ARCH)/configs/generic_defconfig $^ | \
+		grep -Ev '^#'
+	$(Q)cp $(KCONFIG_CONFIG) $(objtree)/.config.$@
+	$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig \
+		KCONFIG_CONFIG=$(objtree)/.config.$@ >/dev/null
+	$(Q)$(CONFIG_SHELL) $(srctree)/arch/$(ARCH)/tools/generic-board-config.sh \
+		$(srctree) $(objtree) $(objtree)/.config.$@ $(KCONFIG_CONFIG) \
+		"$(origin BOARDS)" $(BOARDS)
+	$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
+
+#
+# Prevent generic merge_config rules attempting to merge single fragments
+#
+$(generic_config_dir)/%.config: ;
+
+#
+# Prevent direct use of generic_defconfig, which is intended to be used as the
+# basis of the various ISA-specific targets generated above.
+#
+.PHONY: generic_defconfig
+generic_defconfig:
+	$(Q)echo "generic_defconfig is not intended for direct use, but should instead be"
+	$(Q)echo "used via an ISA-specific target from the following list:"
+	$(Q)echo
+	$(Q)for cfg in $(generic_defconfigs); do echo "  $${cfg}"; done
+	$(Q)echo
+	$(Q)false
+
+#
+# Legacy defconfig compatibility - these targets used to be real defconfigs but
+# now that the boards have been converted to use the generic kernel they are
+# wrappers around the generic rules above.
+#
+legacy_defconfigs		+= ocelot_defconfig
+ocelot_defconfig-y		:= 32r2el_defconfig BOARDS=ocelot
+
+legacy_defconfigs		+= sead3_defconfig
+sead3_defconfig-y		:= 32r2el_defconfig BOARDS=sead-3
+
+legacy_defconfigs		+= sead3micro_defconfig
+sead3micro_defconfig-y		:= micro32r2el_defconfig BOARDS=sead-3
+
+legacy_defconfigs		+= xilfpga_defconfig
+xilfpga_defconfig-y		:= 32r2el_defconfig BOARDS=xilfpga
+
+legacy_defconfigs		+= pistachio_defconfig
+pistachio_defconfig-y		:= 32r2el_defconfig BOARDS=marduk
+
+.PHONY: $(legacy_defconfigs)
+$(legacy_defconfigs):
+	$(Q)$(MAKE) -f $(srctree)/Makefile $($@-y)