toolchain: add llvm-bpf

include/bpf.mk

@@ -0,0 +1,83 @@
+BPF_DEPENDS := @HAS_BPF_TOOLCHAIN
+LLVM_VER:=
+
+CLANG_MIN_VER:=12
+
+ifneq ($(CONFIG_USE_LLVM_HOST),)
+  BPF_TOOLCHAIN_HOST_PATH:=$(call qstrip,$(CONFIG_BPF_TOOLCHAIN_HOST_PATH))
+  ifneq ($(BPF_TOOLCHAIN_HOST_PATH),)
+    BPF_PATH:=$(BPF_TOOLCHAIN_HOST_PATH)/bin:$(PATH)
+  else
+    BPF_PATH:=$(PATH)
+  endif
+  CLANG:=$(firstword $(shell PATH='$(BPF_PATH)' command -v clang clang-13 clang-12 clang-11))
+  LLVM_VER:=$(subst clang,,$(notdir $(CLANG)))
+endif
+ifneq ($(CONFIG_USE_LLVM_PREBUILT),)
+  CLANG:=$(TOPDIR)/llvm-bpf/bin/clang
+endif
+ifneq ($(CONFIG_USE_LLVM_BUILD),)
+  CLANG:=$(STAGING_DIR_HOST)/llvm-bpf/bin/clang
+endif
+
+LLVM_PATH:=$(dir $(CLANG))
+LLVM_LLC:=$(LLVM_PATH)/llc$(LLVM_VER)
+LLVM_DIS:=$(LLVM_PATH)/llvm-dis$(LLVM_VER)
+LLVM_OPT:=$(LLVM_PATH)/opt$(LLVM_VER)
+LLVM_STRIP:=$(LLVM_PATH)/llvm-strip$(LLVM_VER)
+
+BPF_KARCH:=mips
+BPF_ARCH:=mips$(if $(CONFIG_ARCH_64BIT),64)$(if $(CONFIG_BIG_ENDIAN),,el)
+BPF_TARGET:=bpf$(if $(CONFIG_BIG_ENDIAN),eb,el)
+
+BPF_HEADERS_DIR:=$(STAGING_DIR)/bpf-headers
+
+BPF_KERNEL_INCLUDE := \
+	-nostdinc -isystem $(TOOLCHAIN_DIR)/include \
+	-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include \
+	-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/asm/mach-generic \
+	-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/generated \
+	-I$(BPF_HEADERS_DIR)/include \
+	-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/uapi \
+	-I$(BPF_HEADERS_DIR)/arch/$(BPF_KARCH)/include/generated/uapi \
+	-I$(BPF_HEADERS_DIR)/include/uapi \
+	-I$(BPF_HEADERS_DIR)/include/generated/uapi \
+	-I$(BPF_HEADERS_DIR)/tools/lib \
+	-I$(BPF_HEADERS_DIR)/tools/testing/selftests \
+	-I$(BPF_HEADERS_DIR)/samples/bpf \
+	-include linux/kconfig.h -include asm_goto_workaround.h
+
+BPF_CFLAGS := \
+	$(BPF_KERNEL_INCLUDE) -I$(PKG_BUILD_DIR) \
+	-D__KERNEL__ -D__BPF_TRACING__ -DCONFIG_GENERIC_CSUM \
+	-D__TARGET_ARCH_${BPF_KARCH} \
+	-m$(if $(CONFIG_BIG_ENDIAN),big,little)-endian \
+	-fno-stack-protector -Wall \
+	-Wno-unused-value -Wno-pointer-sign \
+	-Wno-compare-distinct-pointer-types \
+	-Wno-gnu-variable-sized-type-not-at-end \
+	-Wno-address-of-packed-member -Wno-tautological-compare \
+	-Wno-unknown-warning-option \
+	-fno-asynchronous-unwind-tables \
+	-Wno-uninitialized -Wno-unused-variable \
+	-Wno-unused-label \
+	-O2 -emit-llvm -Xclang -disable-llvm-passes
+
+ifeq ($(DUMP),)
+  CLANG_VER:=$(shell $(CLANG) -dM -E - < /dev/null | grep __clang_major__ | cut -d' ' -f3)
+  CLANG_VER_VALID:=$(shell [ "$(CLANG_VER)" -ge "$(CLANG_MIN_VER)" ] && echo 1 )
+  ifeq ($(CLANG_VER_VALID),)
+    $(error ERROR: LLVM/clang version too old. Minimum required: $(CLANG_MIN_VER), found: $(CLANG_VER))
+  endif
+endif
+
+define CompileBPF
+	$(CLANG) -g -target $(BPF_ARCH)-linux-gnu $(BPF_CFLAGS) $(2) \
+		-c $(1) -o $(patsubst %.c,%.bc,$(1))
+	$(LLVM_OPT) -O2 -mtriple=$(BPF_TARGET) < $(patsubst %.c,%.bc,$(1)) > $(patsubst %.c,%.opt,$(1))
+	$(LLVM_DIS) < $(patsubst %.c,%.opt,$(1)) > $(patsubst %.c,%.S,$(1))
+	$(LLVM_LLC) -march=$(BPF_TARGET) -mcpu=v3 -filetype=obj -o $(patsubst %.c,%.o,$(1)) < $(patsubst %.c,%.S,$(1))
+	$(CP) $(patsubst %.c,%.o,$(1)) $(patsubst %.c,%.debug.o,$(1))
+	$(LLVM_STRIP) --strip-debug $(patsubst %.c,%.o,$(1))
+endef
+

package/kernel/bpf-headers/Makefile

@@ -0,0 +1,114 @@
+#
+# Copyright (C) 2006-2009 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+include $(TOPDIR)/rules.mk
+
+override QUILT:=
+override HOST_QUILT:=
+
+include $(INCLUDE_DIR)/kernel.mk
+
+
+PKG_NAME:=linux
+PKG_PATCHVER:=5.15
+# Manually include kernel version and hash from kernel details file
+include $(INCLUDE_DIR)/kernel-$(PKG_PATCHVER)
+
+PKG_VERSION:=$(PKG_PATCHVER)$(strip $(LINUX_VERSION-$(PKG_PATCHVER)))
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
+PKG_SOURCE_URL:=$(LINUX_SITE)
+PKG_HASH:=$(LINUX_KERNEL_HASH-$(strip $(PKG_VERSION)))
+PKG_BUILD_DIR:=$(KERNEL_BUILD_DIR)/bpf-headers/$(PKG_NAME)-$(PKG_VERSION)
+
+GENERIC_PLATFORM_DIR := $(CURDIR)/../../../target/linux/generic
+GENERIC_BACKPORT_DIR := $(GENERIC_PLATFORM_DIR)/backport$(if $(wildcard $(GENERIC_PLATFORM_DIR)/backport-$(PKG_PATCHVER)),-$(PKG_PATCHVER))
+GENERIC_PATCH_DIR := $(GENERIC_PLATFORM_DIR)/pending$(if $(wildcard $(GENERIC_PLATFORM_DIR)/pending-$(PKG_PATCHVER)),-$(PKG_PATCHVER))
+GENERIC_HACK_DIR := $(GENERIC_PLATFORM_DIR)/hack$(if $(wildcard $(GENERIC_PLATFORM_DIR)/hack-$(PKG_PATCHVER)),-$(PKG_PATCHVER))
+GENERIC_FILES_DIR := $(foreach dir,$(wildcard $(GENERIC_PLATFORM_DIR)/files $(GENERIC_PLATFORM_DIR)/files-$(PKG_PATCHVER)),"$(dir)")
+PATCH_DIR := $(CURDIR)/patches
+FILES_DIR :=
+
+REAL_LINUX_DIR := $(LINUX_DIR)
+LINUX_DIR := $(PKG_BUILD_DIR)
+
+include $(INCLUDE_DIR)/bpf.mk
+include $(INCLUDE_DIR)/package.mk
+
+define Package/bpf-headers
+  SECTION:=kernel
+  CATEGORY:=Kernel
+  TITLE:=eBPF kernel headers
+  BUILDONLY:=1
+  HIDDEN:=1
+endef
+
+PKG_CONFIG_PATH:=
+
+export HOST_EXTRACFLAGS=-I$(STAGING_DIR_HOST)/include
+
+KERNEL_MAKE := \
+	$(MAKE) -C $(PKG_BUILD_DIR) \
+		ARCH=$(BPF_KARCH) \
+		CROSS_COMPILE=$(BPF_ARCH)-linux- \
+		LLVM=1 CC="$(CLANG)" LD="$(TARGET_CROSS)ld" \
+		HOSTCC="$(HOSTCC)" \
+		HOSTCXX="$(HOSTCXX)" \
+		HOST_LOADLIBES="-L$(STAGING_DIR_HOST)/lib" \
+		KBUILD_HOSTLDLIBS="-L$(STAGING_DIR_HOST)/lib" \
+		CONFIG_SHELL="$(BASH)" \
+		INSTALL_HDR_PATH="$(PKG_BUILD_DIR)/user_headers"
+
+define Build/Patch
+	$(Kernel/Patch/Default)
+endef
+
+BPF_DOC = $(PKG_BUILD_DIR)/scripts/bpf_doc.py
+
+define Build/Configure/64
+	echo 'CONFIG_CPU_MIPS64_R2=y' >> $(PKG_BUILD_DIR)/.config
+	echo 'CONFIG_64BIT=y' >> $(PKG_BUILD_DIR)/.config
+endef
+
+define Build/Configure
+	grep -vE 'CONFIG_(CPU_.*ENDIAN|HZ)' $(PKG_BUILD_DIR)/arch/mips/configs/generic_defconfig > $(PKG_BUILD_DIR)/.config
+	echo 'CONFIG_CPU_$(if $(CONFIG_BIG_ENDIAN),BIG,LITTLE)_ENDIAN=y' >> $(PKG_BUILD_DIR)/.config
+	$(if $(CONFIG_ARCH_64BIT),$(Build/Configure/64))
+	grep CONFIG_HZ $(REAL_LINUX_DIR)/.config >> $(PKG_BUILD_DIR)/.config
+	yes '' | $(KERNEL_MAKE) oldconfig
+	grep 'CONFIG_HZ=' $(REAL_LINUX_DIR)/.config | \
+		cut -d= -f2 | \
+		bc -q $(LINUX_DIR)/kernel/time/timeconst.bc \
+		> $(LINUX_DIR)/include/generated/timeconst.h
+	$(BPF_DOC) --header \
+		--file $(LINUX_DIR)/tools/include/uapi/linux/bpf.h \
+		> $(PKG_BUILD_DIR)/tools/lib/bpf/bpf_helper_defs.h
+endef
+
+define Build/Compile
+	$(KERNEL_MAKE) archprepare headers_install
+endef
+
+define Build/InstallDev
+	mkdir -p $(1)/bpf-headers/arch $(1)/bpf-headers/tools
+	$(CP) \
+		$(PKG_BUILD_DIR)/arch/$(BPF_KARCH) \
+		$(1)/bpf-headers/arch/
+	$(CP) \
+		$(PKG_BUILD_DIR)/tools/lib \
+		$(PKG_BUILD_DIR)/tools/testing \
+		$(1)/bpf-headers/tools/
+	$(CP) \
+		$(PKG_BUILD_DIR)/include \
+		$(PKG_BUILD_DIR)/samples \
+		$(PKG_BUILD_DIR)/scripts \
+		$(PKG_BUILD_DIR)/user_headers \
+		$(1)/bpf-headers
+	$(CP) \
+		$(CURDIR)/files/stdarg.h \
+		$(1)/bpf-headers/include
+endef
+
+$(eval $(call BuildPackage,bpf-headers))

package/kernel/bpf-headers/files/stdarg.h

@@ -0,0 +1,19 @@
+#ifndef _STDARG_H
+#define _STDARG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef __builtin_va_list va_list;
+
+#define va_start(v,l)   __builtin_va_start(v,l)
+#define va_end(v)       __builtin_va_end(v)
+#define va_arg(v,l)     __builtin_va_arg(v,l)
+#define va_copy(d,s)    __builtin_va_copy(d,s)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

package/kernel/bpf-headers/patches/100-support_hz_300.patch

@@ -0,0 +1,20 @@
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -2988,6 +2988,9 @@ choice
+ 	config HZ_256
+ 		bool "256 HZ" if SYS_SUPPORTS_256HZ || SYS_SUPPORTS_ARBIT_HZ
+
++	config HZ_300
++		bool "300 HZ" if SYS_SUPPORTS_ARBIT_HZ
++
+ 	config HZ_1000
+ 		bool "1000 HZ" if SYS_SUPPORTS_1000HZ || SYS_SUPPORTS_ARBIT_HZ
+
+@@ -3039,6 +3042,7 @@ config HZ
+ 	default 128 if HZ_128
+ 	default 250 if HZ_250
+ 	default 256 if HZ_256
++	default 300 if HZ_300
+ 	default 1000 if HZ_1000
+ 	default 1024 if HZ_1024
+

package/kernel/bpf-headers/src/include/generated/bounds.h

@@ -0,0 +1,14 @@
+#ifndef __LINUX_BOUNDS_H__
+#define __LINUX_BOUNDS_H__
+/*
+ * DO NOT MODIFY.
+ *
+ * This file was generated by Kbuild
+ */
+
+#define NR_PAGEFLAGS 23 /* __NR_PAGEFLAGS */
+#define MAX_NR_ZONES 4 /* __MAX_NR_ZONES */
+#define NR_CPUS_BITS 1 /* ilog2(CONFIG_NR_CPUS) */
+#define SPINLOCK_SIZE 64 /* sizeof(spinlock_t) */
+
+#endif

target/llvm-bpf/Makefile

@@ -0,0 +1,30 @@
+#
+# Copyright (C) 2021 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+override MAKEFLAGS=
+
+LLVM_VERSION := $(shell cat $(STAGING_DIR_HOST)/llvm-bpf/.llvm-version)
+
+LLVM_BPF_PREFIX := llvm-bpf-$(LLVM_VERSION).$(HOST_OS)-$(HOST_ARCH)
+LLVM_TAR := $(BIN_DIR)/$(LLVM_BPF_PREFIX).tar.xz
+
+$(LLVM_TAR): $(STAGING_DIR_HOST)/llvm-bpf/.llvm-version
+	tar -C $(STAGING_DIR_HOST) \
+		-I '$(STAGING_DIR_HOST)/bin/xz -7e -T$(if $(filter 1,$(NPROC)),2,0)' \
+		$(if $(SOURCE_DATE_EPOCH),--mtime="@$(SOURCE_DATE_EPOCH)") \
+		-cf $@.tmp llvm-bpf $(LLVM_BPF_PREFIX)
+	mv $@.tmp $@
+
+download:
+prepare:
+compile: $(LLVM_TAR)
+install: compile
+
+clean:
+	rm -f $(LLVM_TAR)

toolchain/Config.in

@@ -37,6 +37,39 @@ menuconfig TARGET_OPTIONS
 
 		  Most people will answer N.
 
+	choice BPF_TOOLCHAIN
+		prompt "BPF toolchain" if DEVEL
+		default BPF_TOOLCHAIN_BUILD_LLVM if BUILDBOT
+		default BPF_TOOLCHAIN_PREBUILT if HAS_PREBUILT_LLVM_TOOLCHAIN
+		default BPF_TOOLCHAIN_NONE
+
+		config BPF_TOOLCHAIN_NONE
+			bool "None"
+
+		config BPF_TOOLCHAIN_PREBUILT
+			bool "Use prebuilt LLVM toolchain"
+			depends on HAS_PREBUILT_LLVM_TOOLCHAIN
+			select USE_LLVM_PREBUILT
+
+		config BPF_TOOLCHAIN_HOST
+			select USE_LLVM_HOST
+			bool "Use host LLVM toolchain"
+
+		config BPF_TOOLCHAIN_BUILD_LLVM
+			select USE_LLVM_BUILD
+			bool "Build LLVM toolchain for eBPF"
+			help
+			  If enabled, a LLVM toolchain for building eBPF binaries will be built.
+			  If this is not enabled, eBPF packages can only be built if the host
+			  has a suitable toolchain
+	endchoice
+
+	config BPF_TOOLCHAIN_HOST_PATH
+		string
+		depends on BPF_TOOLCHAIN_HOST
+		prompt "Host LLVM toolchain path (prefix)" if DEVEL
+		default "/usr/local/opt/llvm" if HOST_OS_MACOS
+		default ""
 
 menuconfig EXTERNAL_TOOLCHAIN
 	bool
@@ -266,6 +299,26 @@ config GDB_PYTHON
 
 	help
 	  Enable the python bindings for GDB to allow using python in the gdb shell.
+
+config HAS_BPF_TOOLCHAIN
+	bool
+
+config HAS_PREBUILT_LLVM_TOOLCHAIN
+	def_bool $(shell, [ -f llvm-bpf/.llvm-version ] && echo y || echo n)
+
+config USE_LLVM_HOST
+	select HAS_BPF_TOOLCHAIN
+	bool
+
+config USE_LLVM_PREBUILT
+	select HAS_BPF_TOOLCHAIN
+	default y if !DEVEL && !BUILDBOT && HAS_PREBUILT_LLVM_TOOLCHAIN
+	bool
+
+config USE_LLVM_BUILD
+	default y if !DEVEL && BUILDBOT
+	select HAS_BPF_TOOLCHAIN
+	bool	  
 
 config USE_GLIBC
 	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN && (arc)

tools/Makefile

@@ -35,6 +35,7 @@ tools-$(CONFIG_TARGET_mxs) += elftosb sdimage
 tools-$(CONFIG_TARGET_tegra) += cbootimage cbootimage-configs
 tools-$(CONFIG_USES_MINOR) += kernel2minor
 tools-$(CONFIG_USE_SPARSE) += sparse
+tools-$(CONFIG_USE_LLVM_BUILD) += llvm-bpf
 
 # builddir dependencies
 $(curdir)/autoconf/compile := $(curdir)/m4/compile
@@ -57,6 +58,7 @@ $(curdir)/isl/compile := $(curdir)/gmp/compile
 $(curdir)/libressl/compile := $(curdir)/pkgconf/compile
 $(curdir)/libtool/compile := $(curdir)/m4/compile $(curdir)/autoconf/compile $(curdir)/automake/compile $(curdir)/missing-macros/compile
 $(curdir)/lzma-old/compile := $(curdir)/zlib/compile
+$(curdir)/llvm-bpf/compile := $(curdir)/cmake/compile
 $(curdir)/meson/compile := $(curdir)/ninja/compile
 $(curdir)/make-ext4fs/compile := $(curdir)/zlib/compile
 $(curdir)/missing-macros/compile := $(curdir)/autoconf/compile