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";
    
  4. chosen {
    
  5.     /*
    
  6.      * initrd parameters not set in dts file since the ramdisk.img size
    
  7.      * need to check in uboot, and the initrd load address and size will
    
  8.      * set in uboot stage.
    
  9.      */
    
  10.     bootargs = "earlycon androidboot.selinux=permissive uart_dma keep_dbgclk_on clk_ignore_unused";
    
  11.     stdout-path = "serial0:115200";
    
  12. };
    
  13. ......
  14. } 2、在BoardConfig中添加 vim device/xxx/xxx_evb/BoardConfigCommon.mk
  15. 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
  16. append_bootargs("recovery=1");
  17. sprintf(dm_buf,"init=/init skip_initramfs rootwait root=/dev/dm-0 dm="system none ro,0 1 android-verity /dev/mmcblk0p%d"",ret);
  18. append_bootargs((const char *)dm_buf);

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

  1. INTERNAL_KERNEL_CMDLINE := $(strip $(BOARD_KERNEL_CMDLINE) buildvariant=$(TARGET_BUILD_VARIANT) $(VERITY_KEYID))
  2. ifdef INTERNAL_KERNEL_CMDLINE
  3. INTERNAL_BOOTIMAGE_ARGS += --cmdline "$(INTERNAL_KERNEL_CMDLINE)"
  4. endif image.png 《ARMv8/ARMv9架构学习系列课程》全系列,共计52节课,超16h的视频课程