How Linux Works I - How Linux Start Up

本文主要是介绍How Linux Works I - How Linux Start Up，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

Linux如何启动？

启动信息

内核启动初始化与启动选项

写在前面：上一个专栏中我写完了内核源码层面看Linux，我们把抽象层拉高一点，看看Linux是如何工作的！

Linux如何启动？

BIOS（Basic Input Output System）或者启动固件加载并运行引导装载程序（告知OS在哪里）

引导装载程序在磁盘上找到内核的位置，载入RAM中启动

初始化设备与驱动程序

挂载root文件系统

内核使用swapper进程（0号进程，PID = 1）来允许一个init进程，从这里开始，我们的程序将会被下放到用户态

init继续启动其他进程

最后的尾声就是启动一个登陆进程！是的，就是那个让你输入用户密码的那个界面就是登录进程完成的

启动信息

Linux内核启动信息去这里看：

sudo dmesg > demo.txt

这条指令可以将输出的信息发送到demo.txt文件当中，或者你想要在控制台上看

sudo dmesg | less

将会调度less程序使得日志分页。一些启动日志将会保存在/var/log/下面，不同的发行版会有不同的调整，比如说我这里就没有什么一下就可以找到的开机日志文件（Arch Linux）

[    0.000000] Linux version 6.8.8-arch1-1 (linux@archlinux) (gcc (GCC) 13.2.1 20240417, GNU ld (GNU Binutils) 2.42.0) #1 SMP PREEMPT_DYNAMIC Sun, 28 Apr 2024 15:59:47 +0000
[    0.000000] Command line: BOOT_IMAGE=/@/boot/vmlinuz-linux root=UUID=c6ae9e8b-6dd3-4a7b-99bf-fcedbd6ab74c rw rootflags=subvol=@ loglevel=3 quiet
[    0.000000] [Firmware Bug]: TSC doesn't count with P0 frequency!
[    0.000000] BIOS-provided physical RAM map:
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x0000000000000fff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x0000000000001000-0x000000000009ffff] usable
...
[   74.611975] systemd-journald[246]: /var/log/journal/deaaebab639c462183f85623319ae5fc/user-1000.journal: Journal file uses a different sequence number ID, rotating.
[  273.008400] systemd[1]: systemd 255.5-4-arch running in system mode (+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBFDISK +PCRE2 +PWQUALITY +P11KIT +QRENCODE +TPM2 +BZIP2 +LZ4 +XZ +ZLIB +ZSTD +BPF_FRAMEWORK +XKBCOMMON +UTMP -SYSVINIT default-hierarchy=unified)
[  273.008505] systemd[1]: Detected virtualization vmware.
[  273.008596] systemd[1]: Detected architecture x86-64.
[  273.424093] systemd[1]: bpf-lsm: LSM BPF program attached
[  352.419139] perf: interrupt took too long (2590 > 2500), lowering kernel.perf_event_max_sample_rate to 77100
[  390.817032] perf: interrupt took too long (3500 > 3237), lowering kernel.perf_event_max_sample_rate to 57000
[  527.871009] perf: interrupt took too long (4415 > 4375), lowering kernel.perf_event_max_sample_rate to 45300

内核启动初始化与启动选项

检查CPU
检查内存
检查设备总线
检测设备
设置附加内核子系统
挂载 root 目录
启动用户空间

这是我学习的这本书告知我的流程，我还是觉得没什么味道，这里写一个更加详细的，依照系统日志版本的

第一步，查看Linux内核版本，确定内核的一些设置参数（这里你可以看到我的系统是使用了支持SMP多核架构编译选项了的内核 + 支持动态抢占（这点是自从2.6开始就有了的CFS调度的特性）选项编译的内核）

[    0.000000] Linux version 6.8.8-arch1-1 (linux@archlinux) (gcc (GCC) 13.2.1 20240417, GNU ld (GNU Binutils) 2.42.0) #1 SMP PREEMPT_DYNAMIC Sun, 28 Apr 2024 15:59:47 +0000

第二步：找到内核位置

Command line: BOOT_IMAGE=/@/boot/vmlinuz-linux root=UUID=c6ae9e8b-6dd3-4a7b-99bf-fcedbd6ab74c rw rootflags=subvol=@ loglevel=3 quiet

vmlinuz是可引导的、压缩的内核。“vm”代表“Virtual Memory”。Linux 支持虚拟内存，不像老的操作系统比如DOS有640KB内存的限制。Linux能够使用硬盘空间作为虚拟内存，因此得名“vm”。vmlinuz是可执行的Linux内核，它位于/boot/vmlinuz，它一般是一个软链接。

第三步：开始使用BIOS自举检查的信息：比如说，我们上面提到的——检查内存：

[    0.000000] BIOS-provided physical RAM map:  # 是的，BIOS提供的物理RAM内存视图
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x0000000000000fff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x0000000000001000-0x000000000009ffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000000c0000-0x00000000000fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000000e655fff] usable
[    0.000000] BIOS-e820: [mem 0x000000000e656000-0x000000000e672fff] ACPI data
[    0.000000] BIOS-e820: [mem 0x000000000e673000-0x000000000efaafff] usable
[    0.000000] BIOS-e820: [mem 0x000000000efab000-0x000000000efaefff] reserved
[    0.000000] BIOS-e820: [mem 0x000000000efaf000-0x000000000efbcfff] usable
[    0.000000] BIOS-e820: [mem 0x000000000efbd000-0x000000000efc1fff] reserved
[    0.000000] BIOS-e820: [mem 0x000000000efc2000-0x000000000efc6fff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x000000000efc7000-0x000000000fee5fff] usable
[    0.000000] BIOS-e820: [mem 0x000000000fee6000-0x000000000ff55fff] reserved
[    0.000000] BIOS-e820: [mem 0x000000000ff56000-0x000000000ff71fff] ACPI data
[    0.000000] BIOS-e820: [mem 0x000000000ff72000-0x000000000ff75fff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x000000000ff76000-0x00000000bfffffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000ffc00000-0x00000000ffc29fff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000023fffffff] usable #  4G起始空间 - 8G

S在操作系统开始管理内存之前，首先要获取物理内存的信息，比如一共有多少物理地址是可用的，有哪些物理地址是被ACPI数据使用（关于PCI，ACPI我下面会简单的介绍，先不着急）

可以查询到的一些字段说明：

Usable：已经被映射到物理内存的物理地址。（也就是可用的）
Reserved：这些区间是没有被映射到任何地方，不能当作RAM来使用，但是kernel可以决定将这些区间映射到其他地方，比如PCI设备。通过检查/proc/iomem这个虚拟文件，就可以知道这些reserved的空间，是如何进一步分配给不同的设备来使用了。
ACPI data：映射到用来存放ACPI数据的RAM空间，操作系统应该将ACPI Table读入到这个区间内。
ACPI NVS：映射到用来存放ACPI数据的非易失性存储空间，操作系统不能使用。
Unusable：表示检测到发生错误的物理内存。这个在上面例子里没有，因为比较少见。

我们的物理地址检查到了8G的大小，符合我们的设置吗？符合！说明BIOS探测没有问题，且所有的物理内存都可用（至少没有Unusable）

确认开启NX保护机制，也就是说我们的内存页不可执行（CPU并不知道我们的来的流是数据是数据还是指令，把数据段当成指令段。。。嗯，你懂的）

NX即No-eXecute（不可执行）的意思，NX（DEP）的基本原理是将数据所在内存页标识为不可执行，当程序溢出成功转入shellcode时，程序会尝试在数据页面上执行指令，此时CPU就会抛出异常，而不是去执行恶意指令。

第四步：静态初始化高级可编程中断控制器，也就是我们的APIC，管中断的！这里开始，定时器等跟中断相关的设备开始初始化

APIC: Static calls initialized

下面的e820是啥？嘿嘿，你知道的，任何一个手搓过Operating System的人都直到我们OS启动之后，还得进一步探测内存，方法？很简单，x86架构有一个简单的方式告知整个架构系统自己开始查RAM内存：也就是往RAX寄存器（如果是32位那就是往EAX，16位老古董？AX！）塞值：E820H，然后在我们向已经局部初始化的APIC发起一个中断：BIOS中断号15H

mov eax, $e820H
int 15h ; 15号中断

查得很快，我们的RAM局部图现在就会被排布成这样。

 0.000000] e820: update [mem 0x0c2c6018-0x0c2ce057] usable ==> usable
[    0.000000] e820: update [mem 0x0e60b018-0x0e60d057] usable ==> usable
[    0.000000] e820: update [mem 0x0e60b018-0x0e60d057] usable ==> usable
[    0.000000] e820: update [mem 0x0e609018-0x0e60a857] usable ==> usable
[    0.000000] e820: update [mem 0x0e609018-0x0e60a857] usable ==> usable
[    0.000000] extended physical RAM map:
[    0.000000] reserve setup_data: [mem 0x0000000000000000-0x0000000000000fff] ACPI NVS
[    0.000000] reserve setup_data: [mem 0x0000000000001000-0x000000000009ffff] usable
[    0.000000] reserve setup_data: [mem 0x00000000000c0000-0x00000000000fffff] reserved
[    0.000000] reserve setup_data: [mem 0x0000000000100000-0x000000000c2c6017] usable
[    0.000000] reserve setup_data: [mem 0x000000000c2c6018-0x000000000c2ce057] usable
[    0.000000] reserve setup_data: [mem 0x000000000c2ce058-0x000000000e609017] usable
[    0.000000] reserve setup_data: [mem 0x000000000e609018-0x000000000e60a857] usable
[    0.000000] reserve setup_data: [mem 0x000000000e60a858-0x000000000e60b017] usable
[    0.000000] reserve setup_data: [mem 0x000000000e60b018-0x000000000e60d057] usable
[    0.000000] reserve setup_data: [mem 0x000000000e60d058-0x000000000e655fff] usable
[    0.000000] reserve setup_data: [mem 0x000000000e656000-0x000000000e672fff] ACPI data
[    0.000000] reserve setup_data: [mem 0x000000000e673000-0x000000000efaafff] usable
[    0.000000] reserve setup_data: [mem 0x000000000efab000-0x000000000efaefff] reserved
[    0.000000] reserve setup_data: [mem 0x000000000efaf000-0x000000000efbcfff] usable
[    0.000000] reserve setup_data: [mem 0x000000000efbd000-0x000000000efc1fff] reserved
[    0.000000] reserve setup_data: [mem 0x000000000efc2000-0x000000000efc6fff] ACPI NVS
[    0.000000] reserve setup_data: [mem 0x000000000efc7000-0x000000000fee5fff] usable
[    0.000000] reserve setup_data: [mem 0x000000000fee6000-0x000000000ff55fff] reserved
[    0.000000] reserve setup_data: [mem 0x000000000ff56000-0x000000000ff71fff] ACPI data
[    0.000000] reserve setup_data: [mem 0x000000000ff72000-0x000000000ff75fff] ACPI NVS
[    0.000000] reserve setup_data: [mem 0x000000000ff76000-0x00000000bfffffff] usable
[    0.000000] reserve setup_data: [mem 0x00000000ffc00000-0x00000000ffc29fff] reserved
[    0.000000] reserve setup_data: [mem 0x0000000100000000-0x000000023fffffff] usable

下面就是EFI接手进一步启动工作EFI，是Extensible Firmware Interface的词头缩写，直译过来就是可扩展固件接口，它是用模块化、高级语言（主要是C语言）构建的一个小型化系统，它和BIOS一样，主要在启动过程中完成硬件初始化，但它是直接利用加载EFI驱动的方式，识别系统硬件并完成硬件初始化，彻底摒弃读各种中断执行。
不过这里，会确定下来我们的系统允许的平台和信息，使用的是SMBIOS（System Management BIOS），从而确认我们的主板信息等

efi: 
SMBIOS=0xefc2000 # ACPI数据的非易失性存储空间，操作系统不能使用，这里就是给SMBIOS用了
ACPI 2.0=0xe656000 # 看到上面的RAM配置图了吗，果然ACPI被安排到这里了
MEMATTR=0xfcc3798 # 这里存放着内存的属性表，是后续工作用来确定这块内存干啥的
# 对这部分源码有兴趣：/efi/memattr.c看看
INITRD=0xe608e98 # boot loader iniTIalized RAM disk，就是由 boot loader 初始化的内存盘,这是为了给初始化真正的文件系统之前，系统使用的文件系统，这里排布了他的位置！

查出来我的主板信息了：哈哈，是虚拟机！

DMI: VMware, Inc. VMware7,1/440BX Desktop Reference Platform, BIOS VMW71.00V.18452719.B64.2108091906 08/09/2021

所以，他会初始化虚拟机作用下的系统调用转发等工作（你知道的，虚拟机本身就是寄宿在客机上的，中间的一些步骤没啥好看的）

[    0.000000] vmware: hypercall mode: 0x01
[    0.000000] Hypervisor detected: VMware
[    0.000000] vmware: TSC freq read from hypervisor : 3193.892 MHz
[    0.000000] vmware: Host bus clock speed read from hypervisor : 66000000 Hz
[    0.000000] vmware: using clock offset of 4464998876 ns # 没啥好看的，查出来是vmware，，做一些工作

下一步，确定主板架构之后，读取CPU相关的信息，更新我们的RAM mapping：

[    0.000013] tsc: Detected 3193.892 MHz processor # 时间戳计数器（TSC，Time Stamp Counter）
[    0.320730] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[    0.320737] e820: remove [mem 0x000a0000-0x000fffff] usable

TSC可以到我讲定时测量的部分看看，与之相关的还有HPET！

准备为查好的内存建立页表，划分空间的3GB-4GB部分为内核使用！

[    0.320879] x86/PAT: Configuration [0-7]: WB  WC  UC- UC  WB  WP  UC- WT  
# 令人激动的一步！再这里开始，我们的后3GB - 4GB内存划分给了内核
[    0.320935] e820: update [mem 0xc0000000-0xffffffff] usable ==> reserved
[    0.320938] last_pfn = 0xc0000 max_arch_pfn = 0x400000000
[    0.323887] Using GB pages for direct mapping
[    0.324326] Secure boot disabled

说一下：

Strong Uncacheable （UC）:这种cache类型的memory，任何读写操作都不经过cache。一般是memory-map的IO地址可以使用这种类型。一般的ram强烈推荐不使用这种cache，否则效率会非常低。
Write Back！（WB）最常见的 cacheable write
Uncacheable （UC-）:特性与UC(Strong uncacheable)相同，唯一不同的是，这种类型的memory，可以通过修改MTRR来把它改变成WC
Write Combining （WC）:这种类型的cache，特性与UC相似，不同的地方是它可以被speculative read（预先随机读取，这个小机制我们在看文件系统的时候还会看到！）每次write都可能被delay，write的内容会buffer到一个叫“write combining buffer”的地方。可以通过对MTRR编程来设置WC，也可以通过设置PAT来设置WC(pat是什么？)
Write – through （WT）:这个很好理解，每次write，都要write到memory，同时write到对应的cache（if write hits）。WT方式保证了cache与memory是一致的。这种类型的memory，read和write，都跟一般的cache一样。只是write的时候，当写到了cache中，不会立即write到memory里（这个就跟WT不一样了）。CPU会等到适当的时候再write到memory里—比如当cache满了。这种类型是效率最高的类型，
Write-protected （WP）:Read跟wb一样，但每次write，都会引起cache invalidate

同时，针对AMD（这里透过虚拟机查到了我的电脑是AMD64，可以支持AMD的大TLB缓存）（Using GB pages for direct mapping）

下面初始化就是存放APIC中的一些数据结构的一些结构说明

FADT (Fixed ACPI Description Table) ，主要放了一些硬件信息和DSDT的地址。
MADT(Multiple APIC Description Table )，描述了中断硬件相关的信息。
PPTT(Processor Properties Topology Table), 描述了CPU相关的信息。
MCFG(PCI Express memory mapped configuration space base address Description Table) PCIE内存空间先关的地址。
GTDT(Generic Timer Description Table), 描述了timer相关的信息。
SPCR(Serial Port Console Redirection Table), 描述了串口相关的信息。
DBG2(Debug Port Table)，描述了Debug口相关信息。
IORT(I/O Remapping Table), 描述了IO Remap相关信息。

看完了：

[    0.324369] ACPI: Reserving SRAT table memory at [mem 0xe6560c0-0xe65698f]
[    0.324370] ACPI: Reserving FACP table memory at [mem 0xe671bf8-0xe671ceb]
[    0.324370] ACPI: Reserving DSDT table memory at [mem 0xe656990-0xe671bf7]
[    0.324371] ACPI: Reserving FACS table memory at [mem 0xff75000-0xff7503f]
[    0.324371] ACPI: Reserving FACS table memory at [mem 0xff75000-0xff7503f]
[    0.324372] ACPI: Reserving APIC table memory at [mem 0xe672000-0xe672741]
[    0.324372] ACPI: Reserving MCFG table memory at [mem 0xe672742-0xe67277d]
[    0.324373] ACPI: Reserving HPET table memory at [mem 0xe67277e-0xe6727b5]
[    0.324373] ACPI: Reserving WAET table memory at [mem 0xe6727b6-0xe6727dd]
[    0.324374] ACPI: Reserving WSMT table memory at [mem 0xe6727de-0xe672805]
[    0.324410] system APIC only can use physical flat
[    0.324415] APIC: Switched APIC routing to: physical flat # 物理平坦模型！

在下面就是初始化各个表，这里不再枚举！

[    0.324445] SRAT: PXM 0 -> APIC 0x00 -> Node 0
[    0.324447] SRAT: PXM 0 -> APIC 0x01 -> Node 0
[    0.324447] SRAT: PXM 0 -> APIC 0x02 -> Node 0
[    0.324447] SRAT: PXM 0 -> APIC 0x03 -> Node 0
...

开始初始化一些子系统：比如说

PM: hibernation: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.543907] PM: hibernation: Registered nosave memory: [mem 0x000a0000-0x000bffff]
[    0.543907] PM: hibernation: Registered nosave memory: [mem 0x000c0000-0x000fffff]
[    0.543908] PM: hibernation: Registered nosave memory: [mem 0x0c2c6000-0x0c2c6fff]
[    0.543909] PM: hibernation: Registered nosave memory: [mem 0x0c2ce000-0x0c2cefff]
[    0.543910] PM: hibernation: Registered nosave memory: [mem 0x0e609000-0x0e609fff]
[    0.543910] PM: hibernation: Registered nosave memory: [mem 0x0e60a000-0x0e60afff]
[    0.543910] PM: hibernation: Registered nosave memory: [mem 0x0e60b000-0x0e60bfff]
[    0.543911] PM: hibernation: Registered nosave memory: [mem 0x0e60d000-0x0e60dfff]
[    0.543912] PM: hibernation: Registered nosave memory: [mem 0x0e656000-0x0e672fff]
[    0.543912] PM: hibernation: Registered nosave memory: [mem 0x0efab000-0x0efaefff]
[    0.543913] PM: hibernation: Registered nosave memory: [mem 0x0efbd000-0x0efc1fff]
[    0.543914] PM: hibernation: Registered nosave memory: [mem 0x0efc2000-0x0efc6fff]
[    0.543914] PM: hibernation: Registered nosave memory: [mem 0x0fee6000-0x0ff55fff]
[    0.543915] PM: hibernation: Registered nosave memory: [mem 0x0ff56000-0x0ff71fff]
[    0.543915] PM: hibernation: Registered nosave memory: [mem 0x0ff72000-0x0ff75fff]
[    0.543916] PM: hibernation: Registered nosave memory: [mem 0xc0000000-0xffbfffff]
[    0.543916] PM: hibernation: Registered nosave memory: [mem 0xffc00000-0xffc29fff]
[    0.543917] PM: hibernation: Registered nosave memory: [mem 0xffc2a000-0xffffffff]
# 这里就是电源管理系统，他开始注册监察内存，信息是从先前的排查中获取的

这里开始初始化我们内核要使用的per-cpu变量了，从这里开始我们慢慢熟悉起来了：

[    0.602809] pcpu-alloc: s225280 r8192 d28672 u262144 alloc=1*2097152
[    0.602812] pcpu-alloc: [0] 000 001 002 003 004 005 006 007 
[    0.602815] pcpu-alloc: [0] 008 009 010 011 012 013 014 015 
[    0.602818] pcpu-alloc: [0] 016 017 018 019 020 021 022 023 
[    0.602820] pcpu-alloc: [0] 024 025 026 027 028 029 030 031 
[    0.602823] pcpu-alloc: [0] 032 033 034 035 036 037 038 039 
[    0.602825] pcpu-alloc: [0] 040 041 042 043 044 045 046 047 
[    0.602828] pcpu-alloc: [0] 048 049 050 051 052 053 054 055 
[    0.602830] pcpu-alloc: [0] 056 057 058 059 060 061 062 063 
[    0.602833] pcpu-alloc: [0] 064 065 066 067 068 069 070 071 
[    0.602835] pcpu-alloc: [0] 072 073 074 075 076 077 078 079 
[    0.602838] pcpu-alloc: [0] 080 081 082 083 084 085 086 087 
[    0.602840] pcpu-alloc: [0] 088 089 090 091 092 093 094 095 
[    0.602843] pcpu-alloc: [0] 096 097 098 099 100 101 102 103 
[    0.602845] pcpu-alloc: [0] 104 105 106 107 108 109 110 111 
[    0.602848] pcpu-alloc: [0] 112 113 114 115 116 117 118 119 
[    0.602850] pcpu-alloc: [0] 120 121 122 123 124 125 126 127

基础的中断硬件支持激活，内存排查，页表等建立已经结束，我们开始真正的引导内核进入，下面是它打印先前设备接管的信息：

# 内核
[    0.602882] Kernel command line: BOOT_IMAGE=/@/boot/vmlinuz-linux root=UUID=c6ae9e8b-6dd3-4a7b-99bf-fcedbd6ab74c rw rootflags=subvol=@ loglevel=3 quiet
[    0.602926] Unknown kernel command line parameters "BOOT_IMAGE=/@/boot/vmlinuz-linux", will be passed to user space.
[    0.602947] random: crng init done
[    0.602948] printk: log_buf_len individual max cpu contribution: 4096 bytes
[    0.602948] printk: log_buf_len total cpu_extra contributions: 520192 bytes
[    0.602949] printk: log_buf_len min size: 131072 bytes
[    0.610763] printk: log_buf_len: 1048576 bytes
[    0.610765] printk: early log buf free: 103752(79%)
[    0.624062] Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes, linear)
[    0.630705] Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes, linear)
[    0.633598] Fallback order for Node 0: 0 
[    0.633618] Built 1 zonelists, mobility grouping on.  Total pages: 2063943
[    0.633620] Policy zone: Normal
[    0.638437] mem auto-init: stack:all(zero), heap alloc:on, heap free:off
[    0.638444] software IO TLB: area num 128.
[    0.736554] Memory: 8058148K/8387472K available (16384K kernel code, 2121K rwdata, 12976K rodata, 3448K init, 3776K bss, 329064K reserved, 0K cma-reserved)
[    0.737128] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=128, Nodes=1 # 啊哈！slub缓存器
[    0.737308] ftrace: allocating 49155 entries in 193 pages
[    0.748068] ftrace: allocated 193 pages with 3 groups

初始化为了高性能运转的RCU机制：

RCU全称Read-Copy-Update，是linux内核中实现的一种可扩展的高性能同步机制，其功能是希望读线程没有同步开销，或者让同步开销变得很小，不需要使用原子操作指令和内存屏障，即可访问；而把需要同步的任务交给写线程，写线程等待所有读线程完成后才会把旧数据销毁。RCU原理可概括为：RCU记录了所有指向共享数据的指针的使用者，当要修改共享数据时，首先会创建一个副本，在副本中修改，当所有读访问线程都离开读临界区之后，指针将指向新修改后副本的指针，并且删除旧的数据。

[    0.750281] rcu: Preemptible hierarchical RCU implementation.
[    0.750283] rcu: 	RCU restricting CPUs from NR_CPUS=320 to nr_cpu_ids=128.
[    0.750284] rcu: 	RCU priority boosting: priority 1 delay 500 ms.
[    0.750285] 	Trampoline variant of Tasks RCU enabled.
[    0.750286] 	Rude variant of Tasks RCU enabled.
[    0.750286] 	Tracing variant of Tasks RCU enabled.
[    0.750287] rcu: RCU calculated value of scheduler-enlistment delay is 30 jiffies.
[    0.750288] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=128
[    0.754050] NR_IRQS: 20736, nr_irqs: 1448, preallocated irqs: 16
[    0.754473] rcu: srcu_init: Setting srcu_struct sizes to big.
[    0.754851] kfence: initialized - using 2097152 bytes for 255 objects at 0x(____ptrval____)-0x(____ptrval____)

TTY0中断初始化

[    0.755117] Console: colour dummy device 80x25
[    0.755120] printk: legacy console [tty0] enabled

初始化fpu等系统组件

[    0.755263] ACPI: Core revision 20230628
[    0.755845] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 133484882848 ns
[    0.755959] APIC: Switch to symmetric I/O mode setup
[    0.756295] x2apic enabled
[    0.756623] APIC: Switched APIC routing to: physical x2apic
[    0.758386] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[    0.758433] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x2e09c06b889, max_idle_ns: 440795314250 ns
[    0.758438] Calibrating delay loop (skipped) preset value.. 6390.94 BogoMIPS (lpj=10646307)
[    0.758943] x86/cpu: User Mode Instruction Prevention (UMIP) activated
[    0.759031] unchecked MSR access error: RDMSR from 0x852 at rIP: 0xffffffff89691387 (native_read_msr+0x7/0x40)
[    0.759037] Call Trace:
[    0.759039]  <TASK>
[    0.759041]  ? ex_handler_msr+0x121/0x130
[    0.759044]  ? fixup_exception+0x234/0x310
[    0.759045]  ? gp_try_fixup_and_notify+0x1e/0xc0
[    0.759048]  ? exc_general_protection+0x162/0x450
[    0.759052]  ? asm_exc_general_protection+0x26/0x30
[    0.759056]  ? native_read_msr+0x7/0x40
[    0.759058]  native_apic_msr_read+0x20/0x30
[    0.759061]  setup_APIC_eilvt+0x47/0x170
[    0.759065]  mce_amd_feature_init+0x47f/0x4f0
[    0.759068]  mcheck_cpu_init+0x19e/0x4a0
[    0.759071]  identify_cpu+0x3aa/0x600
[    0.759074]  arch_cpu_finalize_init+0x10/0x110
[    0.759078]  start_kernel+0x68f/0xaa0
[    0.759082]  x86_64_start_reservations+0x18/0x30
[    0.759085]  x86_64_start_kernel+0x96/0xa0
[    0.759087]  secondary_startup_64_no_verify+0x184/0x18b
[    0.759091]  </TASK>
[    0.759093] LVT offset 2 assigned for vector 0xf4
[    0.759094] [Firmware Bug]: cpu 0, try to use APIC520 (LVT offset 2) for vector 0xf4, but the register is already in use for vector 0x0 on this cpu
[    0.759112] Last level iTLB entries: 4KB 512, 2MB 512, 4MB 256
[    0.759114] Last level dTLB entries: 4KB 2048, 2MB 2048, 4MB 1024, 1GB 0
[    0.759117] Spectre V1 : Mitigation: usercopy/swapgs barriers and __user pointer sanitization
[    0.759119] Spectre V2 : Mitigation: Retpolines
[    0.759120] Spectre V2 : Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch
[    0.759120] Spectre V2 : Spectre v2 / SpectreRSB : Filling RSB on VMEXIT
[    0.759122] Spectre V2 : mitigation: Enabling conditional Indirect Branch Prediction Barrier
[    0.759123] Speculative Store Bypass: Vulnerable
[    0.759124] Speculative Return Stack Overflow: IBPB-extending microcode not applied!
[    0.759125] Speculative Return Stack Overflow: WARNING: See https://kernel.org/doc/html/latest/admin-guide/hw-vuln/srso.html for mitigation options.
[    0.759126] Speculative Return Stack Overflow: Vulnerable: Safe RET, no microcode
[    0.759175] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
[    0.759176] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
[    0.759177] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
[    0.759178] x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]:  256
[    0.759179] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'compacted' format.
[    0.786020] Freeing SMP alternatives memory: 40K
[    0.786025] pid_max: default: 131072 minimum: 1024
[    0.787375] ------------[ cut here ]------------
[    0.787377] CPA detected W^X violation: 8000000000000063 -> 0000000000000063 range: 0x000000000ff06000 - 0x000000000ff06fff PFN ff06
[    0.787424] WARNING: CPU: 0 PID: 0 at arch/x86/mm/pat/set_memory.c:645 __change_page_attr_set_clr+0xef8/0x1030
[    0.787431] Modules linked in:
[    0.787434] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.8.8-arch1-1 #1 6e5d9eb17edb3e2ef7f1d13e0aec4b6c1833b648
[    0.787437] Hardware name: VMware, Inc. VMware7,1/440BX Desktop Reference Platform, BIOS VMW71.00V.18452719.B64.2108091906 08/09/2021
[    0.787439] RIP: 0010:__change_page_attr_set_clr+0xef8/0x1030
[    0.787442] Code: 89 f9 48 89 c2 48 89 44 24 08 48 c7 c7 a8 85 c3 8a c6 05 85 49 f2 01 01 4c 8d 86 ff 0f 00 00 48 89 f1 4c 89 d6 e8 68 66 01 00 <0f> 0b 48 8b 44 24 08 e9 52 fc ff ff 4d 89 f3 48 8b 15 fa a1 63 01
[    0.787444] RSP: 0000:ffffffff8b403c68 EFLAGS: 00010282
[    0.787447] RAX: 0000000000000000 RBX: 000000000ff06063 RCX: ffff9a9dbfeee8a8
[    0.787449] RDX: 0000000000000000 RSI: 00000000ffff7fff RDI: 0000000000000001
[    0.787450] RBP: 800000000ff06063 R08: 0000000000000000 R09: ffffffff8b403af8
[    0.787452] R10: ffffffff8b403af0 R11: 0000000000000003 R12: ffffffff8bb55930
[    0.787454] R13: 0000000000000050 R14: 0000000000000001 R15: 000000000000ff06
[    0.787455] FS:  0000000000000000(0000) GS:ffff9a9db5e00000(0000) knlGS:0000000000000000
[    0.787457] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    0.787459] CR2: ffff9a9cafc03000 CR3: 000000012ee20000 CR4: 0000000000350ef0
[    0.787462] Call Trace:
[    0.787465]  <TASK>
[    0.787466]  ? __change_page_attr_set_clr+0xef8/0x1030
[    0.787469]  ? __warn+0x81/0x130
[    0.787474]  ? __change_page_attr_set_clr+0xef8/0x1030
[    0.787477]  ? report_bug+0x171/0x1a0
[    0.787481]  ? prb_read_valid+0x1b/0x30
[    0.787485]  ? srso_alias_return_thunk+0x5/0xfbef5
[    0.787489]  ? handle_bug+0x3c/0x80
[    0.787492]  ? exc_invalid_op+0x17/0x70
[    0.787495]  ? asm_exc_invalid_op+0x1a/0x20
[    0.787499]  ? __pfx_efi_update_mem_attr+0x10/0x10
[    0.787505]  ? __change_page_attr_set_clr+0xef8/0x1030
[    0.787508]  ? __change_page_attr_set_clr+0xef8/0x1030
[    0.787514]  ? __pfx_efi_update_mem_attr+0x10/0x10
[    0.787517]  kernel_map_pages_in_pgd+0xa7/0x110
[    0.787523]  efi_update_mappings+0x36/0xa0
[    0.787527]  ? __pfx_efi_update_mem_attr+0x10/0x10
[    0.787530]  efi_memattr_apply_permissions+0x20e/0x370
[    0.787537]  efi_enter_virtual_mode+0x212/0x4e0
[    0.787541]  start_kernel+0x973/0xaa0
[    0.787546]  x86_64_start_reservations+0x18/0x30
[    0.787556]  x86_64_start_kernel+0x96/0xa0
[    0.787559]  secondary_startup_64_no_verify+0x184/0x18b
[    0.787566]  </TASK>
[    0.787567] ---[ end trace 0000000000000000 ]---
[    0.787815] LSM: initializing lsm=capability,landlock,lockdown,yama,bpf,integrity
[    0.787853] landlock: Up and running.
[    0.787854] Yama: becoming mindful.
[    0.787860] LSM support for eBPF active
[    0.788205] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
[    0.788436] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes, linear)
[    0.789697] smpboot: CPU0: AMD Ryzen 7 5800H with Radeon Graphics (family: 0x19, model: 0x50, stepping: 0x0)
[    0.790536] RCU Tasks: Setting shift to 7 and lim to 1 rcu_task_cb_adjust=1.
[    0.790593] RCU Tasks Rude: Setting shift to 7 and lim to 1 rcu_task_cb_adjust=1.
[    0.790723] RCU Tasks Trace: Setting shift to 7 and lim to 1 rcu_task_cb_adjust=1.
[    0.790843] Performance Events: AMD PMU driver.
[    0.790906] ... version:                0
[    0.790907] ... bit width:              48
[    0.790908] ... generic registers:      4
[    0.790909] ... value mask:             0000ffffffffffff
[    0.790911] ... max period:             00007fffffffffff
[    0.790912] ... fixed-purpose events:   0
[    0.790913] ... event mask:             000000000000000f
[    0.791102] signal: max sigframe size: 1776
[    0.791185] rcu: Hierarchical SRCU implementation.
[    0.791187] rcu: 	Max phase no-delay instances is 1000.
[    0.793187] NMI watchdog: Enabled. Permanently consumes one hw-PMU counter.

SMP机制初始化

[    0.800248] smp: Bringing up secondary CPUs ...
[    0.800841] smpboot: x86: Booting SMP configuration:
[    0.800843] .... node  #0, CPUs:          #1   #2   #3
。。。

DMA（也就是内存外存直通车机制）初始化

[    0.820223] DMA: preallocated 1024 KiB GFP_KERNEL pool for atomic allocations
[    0.821769] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA pool for atomic allocations
[    0.823306] DMA: preallocated 1024 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
[    0.823317] audit: initializing netlink subsys (disabled)
# 这里安排了为DMA提供多大内存映射！1MB大小

接入外设，初始化PCI总线上的一大堆设备：

[    0.835739] ACPI: Added _OSI(Module Device)
[    0.835741] ACPI: Added _OSI(Processor Device)
[    0.835742] ACPI: Added _OSI(3.0 _SCP Extensions)
[    0.835744] ACPI: Added _OSI(Processor Aggregator Device)
[    0.868436] ACPI: 1 ACPI AML tables successfully acquired and loaded
[    0.872132] ACPI: [Firmware Bug]: BIOS _OSI(Linux) query ignored
[    0.872143] ACPI: BIOS _OSI(Darwin) query ignored
[    0.875392] ACPI: _OSC evaluation for CPUs failed, trying _PDC
[    0.907570] ACPI: Interpreter enabled
[    0.907586] ACPI: PM: (supports S0 S1 S4 S5)
[    0.907588] ACPI: Using IOAPIC for interrupt routing
[    0.908436] PCI: ECAM [mem 0xe0000000-0xe7ffffff] (base 0xe0000000) for domain 0000 [bus 00-7f]
[    0.909374] PCI: ECAM [mem 0xe0000000-0xe7ffffff] reserved as ACPI motherboard resource
[    0.909386] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
[    0.909387] PCI: Using E820 reservations for host bridge windows
[    0.911491] ACPI: Enabled 4 GPEs in block 00 to 0F
[    1.192489] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-7f])
[    1.192498] acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI EDR HPX-Type3]
[    1.192627] acpi PNP0A03:00: _OSC: platform does not support [AER LTR DPC]
[    1.192968] acpi PNP0A03:00: _OSC: OS now controls [PCIeHotplug SHPCHotplug PME PCIeCapability]
[    1.194177] PCI host bridge to bus 0000:00
[    1.194180] pci_bus 0000:00: root bus resource [io  0x0d00-0xffff window]
[    1.194182] pci_bus 0000:00: root bus resource [io  0x0000-0x0cf7 window]
[    1.194184] pci_bus 0000:00: root bus resource [mem 0xfef00000-0xffdfffff window]
...

再一次排查内存，APIC和PIC总线设备映射了一些内存到RAM上，这就要求我们务必再一次排查内存

[    1.659318] e820: reserve RAM buffer [mem 0x0c2c6018-0x0fffffff]
[    1.659336] e820: reserve RAM buffer [mem 0x0e609018-0x0fffffff]
[    1.659338] e820: reserve RAM buffer [mem 0x0e60b018-0x0fffffff]
[    1.659339] e820: reserve RAM buffer [mem 0x0e656000-0x0fffffff]
[    1.659341] e820: reserve RAM buffer [mem 0x0efab000-0x0fffffff]
[    1.659342] e820: reserve RAM buffer [mem 0x0efbd000-0x0fffffff]
[    1.659343] e820: reserve RAM buffer [mem 0x0fee6000-0x0fffffff]

开始注册IRQ，你熟悉的

[    1.422344] ACPI: PCI: Interrupt link LNKA configured for IRQ 0
[    1.422346] ACPI: PCI: Interrupt link LNKA disabled # 顺手disable了！这个时候内核还在初始化
[    1.422428] ACPI: PCI: Interrupt link LNKB configured for IRQ 0
[    1.422430] ACPI: PCI: Interrupt link LNKB disabled
[    1.422508] ACPI: PCI: Interrupt link LNKC configured for IRQ 0
[    1.422510] ACPI: PCI: Interrupt link LNKC disabled
[    1.422591] ACPI: PCI: Interrupt link LNKD configured for IRQ 0
[    1.422594] ACPI: PCI: Interrupt link LNKD disabled

并行的，初始化网络子系统

[    1.720347] NET: Registered PF_INET protocol family
[    1.722277] IP idents hash table entries: 131072 (order: 8, 1048576 bytes, linear)
[    1.737287] tcp_listen_portaddr_hash hash table entries: 4096 (order: 4, 65536 bytes, linear)
[    1.737307] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear)
[    1.737335] TCP established hash table entries: 65536 (order: 7, 524288 bytes, linear)
[    1.741297] TCP bind hash table entries: 65536 (order: 9, 2097152 bytes, linear)
[    1.741392] TCP: Hash tables configured (established 65536 bind 65536)
[    1.742373] MPTCP token hash table entries: 8192 (order: 5, 196608 bytes, linear)
[    1.742400] UDP hash table entries: 4096 (order: 5, 131072 bytes, linear)
[    1.742617] UDP-Lite hash table entries: 4096 (order: 5, 131072 bytes, linear)

很多常见的协议这里就开始初始化工作了！这里初始化的是哈希表，干嘛的？之后网络服务分配端口用的！端口从这些hash table中取出来！

初始化挂载文件系统：感谢我的一位大爹推介，我给root挂的是Brtfs，不是Ext4文件系统（），这里可以看到它把文件系统挂载在了sda3硬盘分区上，而且校验机制是32为CRC循环校验码

[    3.278244] Btrfs loaded, zoned=yes, fsverity=yes
[    3.321572] BTRFS: device label ArchLinux devid 1 transid 3897 /dev/sda3 scanned by mount (191)
[    3.322361] BTRFS info (device sda3): first mount of filesystem c6ae9e8b-6dd3-4a7b-99bf-fcedbd6ab74c
[    3.322370] BTRFS info (device sda3): using crc32c (crc32c-intel) checksum algorithm 
[    3.322374] BTRFS info (device sda3): using free-space-tree

Systemd开始工作：

[    3.485381] systemd[1]: systemd 255.5-3-arch running in system mode (+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBFDISK +PCRE2 +PWQUALITY +P11KIT +QRENCODE +TPM2 +BZIP2 +LZ4 +XZ +ZLIB +ZSTD +BPF_FRAMEWORK +XKBCOMMON +UTMP -SYSVINIT default-hierarchy=unified)
[    3.485385] systemd[1]: Detected virtualization vmware.
[    3.485444] systemd[1]: Detected architecture x86-64.
[    3.487031] systemd[1]: Hostname set to <ArchLinux>.
[    3.920722] systemd[1]: bpf-lsm: LSM BPF program attached
[    4.211409] systemd[1]: Queued start job for default target Graphical Interface.
[    4.258091] systemd[1]: Created slice Slice /system/dirmngr.
[    4.258751] systemd[1]: Created slice Slice /system/getty.
[    4.259320] systemd[1]: Created slice Slice /system/gpg-agent.
[    4.259910] systemd[1]: Created slice Slice /system/gpg-agent-browser.
[    4.260527] systemd[1]: Created slice Slice /system/gpg-agent-extra.
[    4.261419] systemd[1]: Created slice Slice /system/gpg-agent-ssh.
[    4.262026] systemd[1]: Created slice Slice /system/keyboxd.
[    4.262596] systemd[1]: Created slice Slice /system/modprobe.
[    4.263159] systemd[1]: Created slice User and Session Slice.
[    4.263275] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[    4.263462] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point.
[    4.263503] systemd[1]: Expecting device /dev/disk/by-
...

这里开始就是启动守护进程来观察剩下的子系统的建立：比如说文件系统的彻底初始化，网络子系统的彻底初始化

[    4.263527] systemd[1]: Reached target Login Prompts.	# 登录脚本获取
[    4.263537] systemd[1]: Reached target Local Integrity Protected Volumes.
[    4.263553] systemd[1]: Reached target Remote File Systems.
[    4.263559] systemd[1]: Reached target Slice Units.
[    4.263575] systemd[1]: Reached target Local Verity Protected Volumes.
[    4.263645] systemd[1]: Listening on Device-mapper event daemon FIFOs.
[    4.266006] systemd[1]: Listening on Process Core Dump Socket.
[    4.266159] systemd[1]: Listening on Journal Socket (/dev/log).
[    4.266275] systemd[1]: Listening on Journal Socket.
[    4.266305] systemd[1]: TPM2 PCR Extension (Varlink) was skipped because of an unmet condition check (ConditionSecurity=measured-uki).
[    4.267123] systemd[1]: Listening on udev Control Socket. # udev程序开始工作：udev管理设备接入的
[    4.267225] systemd[1]: Listening on udev Kernel Socket.
[    4.267324] systemd[1]: Listening on User Database Manager Socket.
[    4.269352] systemd[1]: Mounting Huge Pages File System...
[    4.271193] systemd[1]: Mounting POSIX Message Queue File System...
[    4.272566] systemd[1]: Mounting Kernel Debug File System...
[    4.275675] systemd[1]: Mounting Kernel Trace File System...
[    4.277280] systemd[1]: Starting Create List of Static Device Nodes...

内核模块挂载功能的初始化，已经注册的模块的初始化

[    4.278792] systemd[1]: Starting Load Kernel Module configfs... # 开始初始化内核模块挂载初始化
[    4.282344] systemd[1]: Starting Load Kernel Module dm_mod...
[    4.287784] systemd[1]: Starting Load Kernel Module drm...
[    4.291169] systemd[1]: Starting Load Kernel Module fuse...
[    4.295357] systemd[1]: Starting Load Kernel Module loop...
[    4.300246] systemd[1]: Starting Journal Service...
[    4.303957] systemd[1]: Starting Load Kernel Modules...
[    4.303970] systemd[1]: TPM2 PCR Machine ID Measurement was skipped because of an unmet condition check (ConditionSecurity=measured-uki).
[    4.311843] device-mapper: uevent: version 1.0.3
[    4.311964] loop: module loaded
[    4.312243] systemd[1]: Starting Remount Root and Kernel File Systems...
[    4.312276] systemd[1]: TPM2 SRK Setup (Early) was skipped because of an unmet condition check (ConditionSecurity=measured-uki).
[    4.312986] device-mapper: ioctl: 4.48.0-ioctl (2023-03-01) initialised: dm-devel@redhat.com
[    4.314481] systemd[1]: Starting Coldplug All udev Devices...
[    4.317552] systemd[1]: Starting Virtual Console Setup...
[    4.319302] systemd[1]: Mounted Huge Pages File System.
[    4.319416] systemd[1]: Mounted POSIX Message Queue File System.
[    4.319518] systemd[1]: Mounted Kernel Debug File System.
[    4.319620] systemd[1]: Mounted Kernel Trace File System.
[    4.319938] systemd[1]: Finished Create List of Static Device Nodes.
[    4.320293] systemd[1]: modprobe@configfs.service: Deactivated successfully.
[    4.320449] systemd[1]: Finished Load Kernel Module configfs.
[    4.320851] systemd[1]: modprobe@dm_mod.service: Deactivated successfully.
[    4.321003] systemd[1]: Finished Load Kernel Module dm_mod.
[    4.321329] systemd[1]: modprobe@drm.service: Deactivated successfully.
[    4.321523] systemd[1]: Finished Load Kernel Module drm.
[    4.321818] systemd[1]: modprobe@fuse.service: Deactivated successfully.
[    4.321968] systemd[1]: Finished Load Kernel Module fuse.
[    4.322270] systemd[1]: modprobe@loop.service: Deactivated successfully.
[    4.322431] systemd[1]: Finished Load Kernel Module loop.
[    4.322464] systemd-journald[246]: Collecting audit messages is disabled.
[    4.327584] systemd[1]: Mounting FUSE Control File System...
[    4.331144] systemd[1]: Mounting Kernel Configuration File System...
[    4.331197] systemd[1]: Repartition Root Disk was skipped because no trigger condition checks were met.
[    4.333564] BTRFS info (device sda3: state M): use zstd compression, level 3

最后的最后，我们使用已经初始化完成的设备管理子系统接入诸如声卡，网卡，蓝牙等设备

[    5.160970] e1000: Intel(R) PRO/1000 Network Driver
[    5.160973] e1000: Copyright (c) 1999-2006 Intel Corporation.
[    5.161298] e1000 0000:02:01.0: enabling device (0110 -> 0113)
[    5.166576] Guest personality initialized and is active
[    5.166621] VMCI host device registered (name=vmci, major=10, minor=123)
[    5.166623] Initialized host personality
# 声卡
[    5.199128] input: PC Speaker as /devices/platform/pcspkr/input/input4
[    5.252008] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input6
[    5.252656] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input5
[    5.327777] cryptd: max_cpu_qlen set to 1000
[    5.370835] Bluetooth: Core ver 2.22
[    5.370927] NET: Registered PF_BLUETOOTH protocol family
# 蓝牙
[    5.370929] Bluetooth: HCI device and connection manager initialized
[    5.370933] Bluetooth: HCI socket layer initialized
[    5.370935] Bluetooth: L2CAP socket layer initialized
[    5.370939] Bluetooth: SCO socket layer initialized
[    5.375620] AVX2 version of gcm_enc/dec engaged.
[    5.376048] AES CTR mode by8 optimization enabled
[    5.424872] snd_ens1371 0000:02:02.0: enabling device (0000 -> 0001)
[    5.430767] usbcore: registered new interface driver btusb
[    5.478456] Bluetooth: hci0: unexpected cc 0x0c12 length: 2 < 3
[    5.478467] Bluetooth: hci0: Opcode 0x0c12 failed: -38
# 抓到的网卡配置，可以ifconfig查看
[    5.613099] e1000 0000:02:01.0 eth0: (PCI:66MHz:32-bit) 00:0c:29:dc:f5:a8
[    5.613109] e1000 0000:02:01.0 eth0: Intel(R) PRO/1000 Network Connection
[    5.623326] e1000 0000:02:01.0 ens33: renamed from eth0
[    5.654147] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
[    6.446371] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[    6.451480] Bridge firewalling registered
[    6.555526] Initializing XFRM netlink socket
[   74.611975] systemd-journald[246]: /var/log/journal/deaaebab639c462183f85623319ae5fc/user-1000.journal: Journal file uses a different sequence number ID, rotating.
[  273.008400] systemd[1]: systemd 255.5-4-arch running in system mode (+PAM +AUDIT -SELINUX -APPARMOR -IMA +SMACK +SECCOMP +GCRYPT +GNUTLS +OPENSSL +ACL +BLKID +CURL +ELFUTILS +FIDO2 +IDN2 -IDN +IPTC +KMOD +LIBCRYPTSETUP +LIBFDISK +PCRE2 +PWQUALITY +P11KIT +QRENCODE +TPM2 +BZIP2 +LZ4 +XZ +ZLIB +ZSTD +BPF_FRAMEWORK +XKBCOMMON +UTMP -SYSVINIT default-hierarchy=unified)
[  273.008505] systemd[1]: Detected virtualization vmware.
[  273.008596] systemd[1]: Detected architecture x86-64.
[  273.424093] systemd[1]: bpf-lsm: LSM BPF program attached
[  352.419139] perf: interrupt took too long (2590 > 2500), lowering kernel.perf_event_max_sample_rate to 77100
[  390.817032] perf: interrupt took too long (3500 > 3237), lowering kernel.perf_event_max_sample_rate to 57000
[  527.871009] perf: interrupt took too long (4415 > 4375), lowering kernel.perf_event_max_sample_rate to 45300

到此位置，整个系统初始化完成，可以登录了！

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