向linux kernel中添加cmdline的四种方式

在linux启动时候，串口log中会打印cmdline

1. [ 0.000000] c0 0 (swapper) Kernel command line: earlycon androidboot.selinux=permissive uart_dma keep_dbgclk_on clk_ignore_unused initrd=0xd0000000,38711808 rw crash_page=0x8f040000 initrd=/recoveryrc boot_reason=0x2000 ota_status=0x1001
   在linux启动完成后，通过 cat /proc/cmdline也是可以看到cmdline. 那么cmdline是如何添加的呢？

1、 在dts中的bootargs中添加

1. / {

2.  model = "xxx yyyyyyy FPGA";
   

3.  compatible = "xxx ,yyyyy-fpga", "xxx ,yyyyyy";
   

5.  chosen {
   

6.      /*
   

7.       * initrd parameters not set in dts file since the ramdisk.img size
   

8.       * need to check in uboot, and the initrd load address and size will
   

9.       * set in uboot stage.
   

10.      */
    

11.     bootargs = "earlycon androidboot.selinux=permissive uart_dma keep_dbgclk_on clk_ignore_unused";
    

12.     stdout-path = "serial0:115200";
    

13. };
    

14. …
15. }
    2、在BoardConfig中添加
    vim device/xxx/xxx_evb/BoardConfigCommon.mk
16. BOARD_KERNEL_CMDLINE += androidboot.selinux=enforcing androidboot.hardware=xxxxx_phone androidboot.dtbo_idx=0
    3、在uboot中添加
    vim u-boot/common/cmd_bootm.c
17. append_bootargs(“recovery=1”);
19. sprintf(dm_buf,“init=/init skip_initramfs rootwait root=/dev/dm-0 dm=“system none ro,0 1 android-verity /dev/mmcblk0p%d””,ret);
20. append_bootargs((const char *)dm_buf);

4、在android的Makefile中添加
vim build/core/Makefile

1. INTERNAL_KERNEL_CMDLINE := $(strip (BOARDKERNELCMDLINE)buildvariant=(BOARDK​ERNELC​MDLINE)buildvariant=(TARGET_BUILD_VARIANT)$(VERITY_KEYID))
2. ifdef INTERNAL_KERNEL_CMDLINE
3. INTERNAL_BOOTIMAGE_ARGS += --cmdline “$(INTERNAL_KERNEL_CMDLINE)”
4. endif
   
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