前言：

本人的作業系統作業，要求註釋最新版本的GNU Linux kernel 的Makefile檔案，我還沒用過Linux，一開啟這個Makefile真的是下了一跳……好多東西要註釋啊，忙活了一個下午，成果就寫個部落格吧。

參考：

Makefile：

# SPDX-License-Identifier: GPL-2.0
# SPDX-許可證-識別符：GPL-2.0
# 版本 = 4
# 修補版本號 = 18
# 次級版本號 = 15
# 附加資訊，一般預設為空，可以自行設定
# 此版本的名字
VERSION = 4
PATCHLEVEL = 18
SUBLEVEL = 15
EXTRAVERSION
 
 =
NAME = Merciless Moray

# *DOCUMENTATION*
# To see a list of typical targets execute "make help"
# More info can be located in ./README
# Comments in this file are targeted only to the developer, do not
# expect to learn how to build the kernel reading this file.

# That's our default target when none is given on the command line
 

PHONY := _all
_all:

# o Do not use make's built-in rules and variable
#   (this increases performance and avoids hard-to-debug behaviour);
# o Look for make include files relative to root of kernel src
# o 禁止使用內建的規則和變數
#	(這提高了效能並避免了難以除錯的行為);
# o 查詢與核心src有關的生成包含檔案

MAKEFLAGS += -rR --include-dir=$(
 
CURDIR)

# 非傳遞環境變數，不會傳遞到下一級Makefile
# Avoid funny character set dependencies
unexport LC_ALL
LC_COLLATE=C
LC_NUMERIC=C
export LC_COLLATE LC_NUMERIC

# 傳遞環境變數，環境變數會傳遞到下一級Makefile
# Avoid interference with shell env settings
unexport GREP_OPTIONS

# We are using a recursive build, so we need to do a little thinking
# to get the ordering right.
#
# Most importantly: sub-Makefiles should only ever modify files in
# their own directory. If in some directory we have a dependency on
# a file in another dir (which doesn't happen often, but it's often
# unavoidable when linking the built-in.a targets which finally
# turn into vmlinux), we will call a sub make in that other dir, and
# after that we are sure that everything which is in that other dir
# is now up to date.
#
# The only cases where we need to modify files which have global
# effects are thus separated out and done before the recursive
# descending is started. They are now explicitly listed as the
# prepare rule.

# Beautify output	//格式化的回顯控制
# ---------------------------------------------------------------------------
#
# Normally, we echo the whole command before executing it. By making
# that echo $($(quiet)$(cmd)), we now have the possibility to set
# $(quiet) to choose other forms of output instead, e.g.
#
#         quiet_cmd_cc_o_c = Compiling $(RELDIR)/[email protected]			//這個是簡化版的輸出
#         cmd_cc_o_c       = $(CC) $(c_flags) -c -o [email protected] $<	//這個是原版的輸出
#
# If $(quiet) is empty, the whole command will be printed.	//表示如果為空則完全回顯
# If it is set to "quiet_", only the short version will be printed.	//$(quiet)=quiet_表示只有版本顯示
# If it is set to "silent_", nothing will be printed at all, since	//表示完全不回顯
# the variable $(silent_cmd_cc_o_c) doesn't exist.
#
# 下面是$(Q)用作字首，如果$(Q)[email protected]表示不回顯，為空表示回顯
# A simple variant is to prefix commands with $(Q) - that's useful
# for commands that shall be hidden in non-verbose mode.
#
#	$(Q)ln [email protected] :<
#
# If KBUILD_VERBOSE equals 0 then the above command will be hidden.
# If KBUILD_VERBOSE equals 1 then the above command is displayed.
#
# 如果$(quiet)為空，則輸出原版編譯命令
# 如果$(quiet)為quiet_，則輸出簡化版本的
# 如果$(quiet)為silent_，則任何都不輸出，因為slient_cmd_cc_o_cc根本不存在
# 不過有個全域性的控制，如果KBUILD_VERBOSE為0，則輸出簡化版本，如果為1，則輸出簡化版本
#
# To put more focus on warnings, be less verbose as default
# Use 'make V=1' to see the full commands

# 設定列印訊息級別，通過呼叫 make 時新增的引數 V 來修改
ifeq ("$(origin V)", "command line")
  KBUILD_VERBOSE = $(V)
endif
# 預設的KBUILD_VERBOSE的值被設定為0，也就意味著在編譯過程中，只輸出
# 預設我們是不回顯的，回顯即在命令執行前顯示要執行的命令
ifndef KBUILD_VERBOSE
  KBUILD_VERBOSE = 0
endif

ifeq ($(KBUILD_VERBOSE),1)	#這裡就是定義是否要回顯
  quiet =
  Q =						#不以@開頭表示回顯
else
  quiet=quiet_
  Q = @						#這裡以@開頭表示不回顯
endif

# If the user is running make -s (silent mode), suppress echoing of
# commands

ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
# 如果MAKEFLAGS中帶了-s表示完全不要回顯
  quiet=silent_
  tools_silent=s
endif

# 輸出quiet給子make
export quiet Q KBUILD_VERBOSE

# kbuild supports saving output files in a separate directory.
# To locate output files in a separate directory two syntaxes are supported.
# In both cases the working directory must be the root of the kernel src.
# 1) O=
# Use "make O=dir/to/store/output/files/"
#
# 2) Set KBUILD_OUTPUT
# Set the environment variable KBUILD_OUTPUT to point to the directory
# where the output files shall be placed.
# export KBUILD_OUTPUT=dir/to/store/output/files/
# make
#
# The O= assignment takes precedence over the KBUILD_OUTPUT environment
# variable.
# 上面這裡是介紹可以設定kbuild過程中的輸出檔案目的地址，有兩種方式：
# 第一種是在 make 引數中設定(make -O dir")
# 第二種方式是設定環境變數(export KBUILD_OUTPU=dir)

# KBUILD_SRC is not intended to be used by the regular user (for now),
# it is set on invocation of make with KBUILD_OUTPUT or O= specified.
ifeq ($(KBUILD_SRC),)
# 如果KBUILD_SRC值為空，就執行下面的操作
# 上面說的這個功能當前對一般使用者沒有用

# OK, Make called in directory where kernel src resides
# Do we want to locate output files in a separate directory?
# 如果命令列中定義了O變數來修改輸出目錄，就用使用者定義的這個目錄
ifeq ("$(origin O)", "command line")
  KBUILD_OUTPUT := $(O)
# 用於指定我們的輸出檔案的輸出目錄
endif

# Cancel implicit rules on top Makefile
# 取消隱式推導規則
$(CURDIR)/Makefile Makefile: ;
# CURDIR值為當前的核心原始碼目錄current.dir
# 上面操作是檢視當前目錄的Makefile是否為最新

ifneq ($(words $(subst :, ,$(CURDIR))), 1)
  $(error main directory cannot contain spaces nor colons)
endif

# 如果輸出目錄值不為空，正常情況下進入
ifneq ($(KBUILD_OUTPUT),)
# check that the output directory actually exists
# 上面說在輸出目錄中執行第二個make命令，傳入相關變數，並且檢查輸出目錄是否存在
saved-output := $(KBUILD_OUTPUT)
KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \
								&& pwd)
$(if $(KBUILD_OUTPUT),, \
     $(error failed to create output directory "$(saved-output)"))

# MAKECMDGOALS 是make的一個環境變數，儲存所有目標列表
# 下面這個命令將所有指明的目標列表和sub-make加入到PHONY中
PHONY += $(MAKECMDGOALS) sub-make

# 下面這個命令很是不明白，大概是用來過濾，太複雜了
# 簡單分析下，過濾掉MAKECMDGOALS中的_all sub-make和$(CURDIR)/Makefile，並將它們都賦值為sub-make
$(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
	@:

# Invoke a second make in the output directory, passing relevant variables
# 這個就是sub-make的值，大致就是將頂層Makefile定義的規則傳給下層資料夾中的Makefile中
sub-make:
	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))

# Leave processing to above invocation of make
# 表示執行完了子makefile,返回頂層make
skip-makefile := 1
endif # ifneq ($(KBUILD_OUTPUT),) #結束ifneq
endif # ifeq ($(KBUILD_SRC),) #結束ifeq

# We process the rest of the Makefile if this is the final invocation of make
# 表示如果skip-makefile為空，這按照分類執行，也就是不是整體進行make
ifeq ($(skip-makefile),)

# Do not print "Entering directory ...",
# but we want to display it when entering to the output directory
# so that IDEs/editors are able to understand relative filenames.
MAKEFLAGS += --no-print-directory

# Call a source code checker (by default, "sparse") as part of the
# C compilation.	//呼叫一個靜態分析工具作為c編譯器的部分
#
# Use 'make C=1' to enable checking of only re-compiled files.
# Use 'make C=2' to enable checking of *all* source files, regardless
# of whether they are re-compiled or not.
#
# See the file "Documentation/dev-tools/sparse.rst" for more details,
# including where to get the "sparse" utility.

# 設定語法檢查級別,預設級別為0
ifeq ("$(origin C)", "command line")
  KBUILD_CHECKSRC = $(C)
endif
ifndef KBUILD_CHECKSRC
  KBUILD_CHECKSRC = 0
endif

# 用M來指定外部模組的目錄
# Use make M=dir to specify directory of external module to build
# Old syntax make ... SUBDIRS=$PWD is still supported
# Setting the environment variable KBUILD_EXTMOD take precedence
# 下面是為了支援舊語法格式的Makefile的設定
ifdef SUBDIRS
  KBUILD_EXTMOD ?= $(SUBDIRS)
endif

ifeq ("$(origin M)", "command line")
  KBUILD_EXTMOD := $(M)
endif

ifeq ($(KBUILD_SRC),)
        # building in the source tree
        srctree := .
else
        ifeq ($(KBUILD_SRC)/,$(dir $(CURDIR)))
                # building in a subdirectory of the source tree
                srctree := ..
        else
                srctree := $(KBUILD_SRC)
        endif
endif

export KBUILD_CHECKSRC KBUILD_EXTMOD KBUILD_SRC

objtree		:= .
src		:= $(srctree)	# 將src設定為原始碼根目錄
obj		:= $(objtree)	#將obj設定位當前目錄

VPATH		:= $(srctree)$(if $(KBUILD_EXTMOD),:$(KBUILD_EXTMOD))

# 這裡是說當前目錄找不到原始檔時的搜尋目錄
export srctree objtree VPATH
# export用於要將指定變數輸出給子make

# To make sure we do not include .config for any of the *config targets
# catch them early, and hand them over to scripts/kconfig/Makefile
# It is allowed to specify more targets when calling make, including
# mixing *config targets and build targets.
# For example 'make oldconfig all'.
# Detect when mixed targets is specified, and make a second invocation
# of make so .config is not included in this case either (for *config).
# 下面這裡是保證呼叫make的時候輸入了*config目標，這是就不能包含.config檔案

version_h := include/generated/uapi/linux/version.h
old_version_h := include/linux/version.h

clean-targets := %clean mrproper cleandocs
no-dot-config-targets := $(clean-targets) \
			 cscope gtags TAGS tags help% %docs check% coccicheck \
			 $(version_h) headers_% archheaders archscripts \
			 kernelversion %src-pkg
no-sync-config-targets := $(no-dot-config-targets) install %install

config-targets  := 0
mixed-targets   := 0
dot-config      := 1
may-sync-config := 1

ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
	ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
		dot-config := 0
	endif
endif

ifneq ($(filter $(no-sync-config-targets), $(MAKECMDGOALS)),)
	ifeq ($(filter-out $(no-sync-config-targets), $(MAKECMDGOALS)),)
		may-sync-config := 0
	endif
endif

ifneq ($(KBUILD_EXTMOD),)
	may-sync-config := 0
endif

ifeq ($(KBUILD_EXTMOD),)
        ifneq ($(filter config %config,$(MAKECMDGOALS)),)
                config-targets := 1
                ifneq ($(words $(MAKECMDGOALS)),1)
                        mixed-targets := 1
                endif
        endif
endif

# For "make -j clean all", "make -j mrproper defconfig all", etc.
ifneq ($(filter $(clean-targets),$(MAKECMDGOALS)),)
        ifneq ($(filter-out $(clean-targets),$(MAKECMDGOALS)),)
                mixed-targets := 1
        endif
endif

# install and modules_install need also be processed one by one
ifneq ($(filter install,$(MAKECMDGOALS)),)
        ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
	        mixed-targets := 1
        endif
endif

ifeq ($(mixed-targets),1)
# ===========================================================================
# We're called with mixed targets (*config and build targets).
# Handle them one by one.

PHONY += $(MAKECMDGOALS) __build_one_by_one

$(filter-out __build_one_by_one, $(MAKECMDGOALS)): __build_one_by_one
	@:

__build_one_by_one:
	$(Q)set -e; \
	for i in $(MAKECMDGOALS); do \
		$(MAKE) -f $(srctree)/Makefile $$i; \
	done

else

# We need some generic definitions (do not try to remake the file).
# 這裡是定義了一些通用的srctree變數定義，這裡執行remake操作
scripts/Kbuild.include: ;
# 這裡的檔案包含了大量通用的函式和變數,已經為這個檔案建立了筆記，抽個時間進行分析，
# 還是先對那個進行分析吧，因為下面會用到它定義的很多變數
include scripts/Kbuild.include

# Read KERNELRELEASE from include/config/kernel.release (if it exists)
KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
# 設定版本號
KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION

include scripts/subarch.include

# Cross compiling and selecting different set of gcc/bin-utils
# ---------------------------------------------------------------------------
#
# When performing cross compilation for other architectures ARCH shall be set
# to the target architecture. (See arch/* for the possibilities).
# ARCH can be set during invocation of make:
# make ARCH=ia64
# Another way is to have ARCH set in the environment.
# The default ARCH is the host where make is executed.
# 當執行交叉編譯的時候，要將ARCH的值設定為目標的架構，支援的交媾可以在arch目錄下看到
# ARCH可以在執行make命令時設定，如make ARCH=arm
# 預設的ARCH是和Host相同

# CROSS_COMPILE specify the prefix used for all executables used
# during compilation. Only gcc and related bin-utils executables
# are prefixed with $(CROSS_COMPILE).
# CROSS_COMPILE can be set on the command line
# make CROSS_COMPILE=ia64-linux-
# Alternatively CROSS_COMPILE can be set in the environment.
# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
# 下面是處理交叉編譯這塊的，交叉編譯需要知道Host的架構和Target的架構吧
# CROSS_COMPILE是編譯時所有命令的字首，可以在執行make的時候指定如make CROSS_COMPILE=ia64-linux-
# CROSS_COMPILE也可以通過環境變數來設定
# 預設情況下是不需要CROSS_COMPILE來執行的，也就是不交叉編譯
ARCH		?= $(SUBARCH)	# 預設Host的架構與Target架構相同

# Architecture as present in compile.h
UTS_MACHINE 	:= $(ARCH)
SRCARCH 	:= $(ARCH)

# 下面是對x86結構的特殊照顧，不明白原因
# Additional ARCH settings for x86
ifeq ($(ARCH),i386)
        SRCARCH := x86
endif
ifeq ($(ARCH),x86_64)
        SRCARCH := x86
endif

# Additional ARCH settings for sparc
ifeq ($(ARCH),sparc32)
       SRCARCH := sparc
endif
ifeq ($(ARCH),sparc64)
       SRCARCH := sparc
endif

# Additional ARCH settings for sh
ifeq ($(ARCH),sh64)
       SRCARCH := sh
endif

# 聲稱的配置檔名
KCONFIG_CONFIG	?= .config
export KCONFIG_CONFIG

# 設定kbuild使用的Shell
# SHELL used by kbuild
CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
	  else if [ -x /bin/bash ]; then echo /bin/bash; \
	  else echo sh; fi ; fi)

HOST_LFS_CFLAGS := $(shell getconf LFS_CFLAGS 2>/dev/null)
HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)

# 設定編譯器，和全域性編譯FLAGS
HOSTCC       = gcc
HOSTCXX      = g++
HOSTCFLAGS   := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 \
		-fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS)
HOSTCXXFLAGS := -O2 $(HOST_LFS_CFLAGS)
HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS)
HOST_LOADLIBES := $(HOST_LFS_LIBS)

# Make variables (CC, etc...)
# 定義一系列Make變數，大部分都是編譯階段使用的一些工具，如as,cc,ar,nm,objcopy等
AS		= $(CROSS_COMPILE)as
LD		= $(CROSS_COMPILE)ld
CC		= $(CROSS_COMPILE)gcc
CPP		= $(CC) -E
AR		= $(CROSS_COMPILE)ar
NM		= $(CROSS_COMPILE)nm
STRIP		= $(CROSS_COMPILE)strip
OBJCOPY		= $(CROSS_COMPILE)objcopy
OBJDUMP		= $(CROSS_COMPILE)objdump
LEX		= flex
YACC		= bison
AWK		= awk
GENKSYMS	= scripts/genksyms/genksyms
INSTALLKERNEL  := installkernel
DEPMOD		= /sbin/depmod
PERL		= perl
PYTHON		= python
PYTHON2		= python2
PYTHON3		= python3
CHECK		= sparse	# 預設的字串檢查

CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
		  -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
NOSTDINC_FLAGS  =
CFLAGS_MODULE   =
AFLAGS_MODULE   =
LDFLAGS_MODULE  =
CFLAGS_KERNEL	=
AFLAGS_KERNEL	=
LDFLAGS_vmlinux =

# Use USERINCLUDE when you must reference the UAPI directories only.
USERINCLUDE    := \
		-I$(srctree)/arch/$(SRCARCH)/include/uapi \
		-I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
		-I$(srctree)/include/uapi \
		-I$(objtree)/include/generated/uapi \
                -include $(srctree)/include/linux/kconfig.h

# Use LINUXINCLUDE when you must reference the include/ directory.
# Needed to be compatible with the O= option
LINUXINCLUDE    := \
		-I$(srctree 
 

            
  
           

              
              
            
            
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巨集定義中要將整體和變數都 

  
 

    

    
    
Linux Kernel 4.21已更新：優化AMD 7nm Zen2架構
     
 lock   size   dpi   分享圖片   wid   rdp   qos   創建   idc   


導讀
AMD 7nm Zen2處理器預計將於明年第一季推出，采用下一代7nm EPYC。 Linux Kernel 4.21已經更新，以優化AMD 7nm EPYC Rome（羅馬）處理器。
 

  
 

    

    
    
linux kernel 4.6 移植到imx280手札
     
 
                
資源簡介
周立功過節發招，49元買了imx280核心板：
ARM926EJ-S 架構 arm v5TE 指令集，cpu最高能跑450M
預設光碟資料是 比較老的uboot-2009加linux-2.6核心。
因為本人電腦是ubuntu環境，周立功提供的燒寫環境都不適用與我的 

  
 

    

    
    
使用qemu虛擬機器執行樹莓派(linux kernel 4.9)
     
 
							
							
							
    2018年5月8日更新，https://github.com/dhruvvyas90/qemu-rpi-kernel的專案已經更新，現已支援4.9核心的編譯，大家可以參考編譯。 
    同時按照本文操作也可以將樹莓派虛擬起來，不過會遇到模組載入錯誤， 

  
 

    

    
    
linux-kernel-4.4 移植 （1）啟動
     
 開發   app   dts   linaro   present   設備   fst   cmd   6.0   開發環境：win10 64位 + VMware12 + Ubuntu14.04 32位

工具鏈：linaro提供的gcc-linaro-6.1.1-2016.08-x86_64_arm- 

  
 

    

    
    
MS17-010 EternalBlue SMB Remote Windows Kernel Pool Corruption 2017-05-18 16:45
     
 oca   spool   hub   per   bash   .exe   xpl   del   all   
wget "https://raw.githubusercontent.com/rapid7/metasploit-framework/6d81ca42087efd6548bfcf924172 

  
 

    

    
    
Linux四周第四次課（4月16日）
     
 解壓縮工具四周第四次課（4月16日）6.1 壓縮打包介紹6.2 gzip壓縮工具6.3 bzip2壓縮工具	6.4 xz壓縮工具壓縮打包介紹在windows下，是按照後綴名來決定用什麽軟件打開相應的文件在linux下，後綴名並非是打開某種內容的關鍵，但是要尊重和按照約定俗稱的來進行使用壓縮類型：windows 

  
 

    

    
    
2018-4-18 Linux學習筆記
     
 20.5 shell腳本中的邏輯判斷   20.6 文件目錄屬性判斷   20.7 if特殊用法   20.8/20.9 case判斷   20.5 shell腳本中的邏輯判斷
格式1：if 條件 ; then 語句; fi
格式2：if 條件; then 語句; else 語句; fi
格式3：if …;  

  
 

    

    
    
基於Linux Kernel Version 4.13.0-36-generic的源碼分析進程模型
     
 快速   交換   .com   linux操作系統   parent   div   n)   算法   計數   一、簡介
本文主要基於Linux Kernel Version 4.13.0-36-generic的源代碼，來進行深入分析其進程模型，具體包含的內容如下：
1.    操作系統是怎麽組織進程的 

  
 

    

    
    
Linux核心追蹤[4.13] Linux Kernel TLS
     
  
 
 
 
         核心的4.13版本實現了一個TLS功能(根據 RFC 5288)，google員工Dave Watson受到FreeBSD的Netflix的專案啟發(FreeBSD網路很強大啊)，實現這個功能的初衷是為了優化tls應用協議的效能(略微有 

  
 

    

    
    
Linux idle程序建立過程（kernel 4.14）
     
  
 
  
  
 idle程序是核心建立的第一個程序，也常常被叫做swapper 程序: 
 
asmlinkage __visible void __init start_kernel(void)
{
    char *command_line;
    char *after_dashes;

   

  
 

    

    
    
Ubuntu 16.04 上安裝 arm-linux-gcc-4.4.3
     
 參考連結：https://blog.csdn.net/zz56z56/article/details/83021583 
注：正常安裝後，不同使用者切換，需重新重新整理環境變數：source /etc/profile 
一、下載arm-linux-gcc-4.4.3.tar交叉編譯包 
　　1.ARM官網下載 

  
 

    

    
    
android4.1 平板隱藏System Bar 發表於1年前(2012-11-05 18:24)   閱讀（1985） | 評論（4） 16人收藏此文章, 我要收藏 贊0 android4.1 平
     
 
/**
* @author wilber
* @target 4.1
* @requirements:4.1平板隱藏系統欄
* @theme android4.1 平板隱藏System Bar
* @remark 轉載請註明出處http://my.oschina.net/wilber
*/


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