CODEWITHSUNDEEP
linux-kernelkernelembedded-linuxu-boot
Chagari Vamsi Reddy
Chagari Vamsi Reddy

Reputation: 31

Is there any way that uboot will know about the kernel boot status

Once the Uboot loads the Linux kernel image (ZImage) onto the ram, it invokes it (could be using bootz, bootm or some other commands based on the type of the kernel Image) and then the control goes to booting the kernel. Does the uboot will be informed about the kernel boot result?, means, whether the kernel booting went through completely or got stuck in the middle because of errors?.

I looked at do_bootz, do_bootm_states and boot_selected_os api's in the uboot src code to see if there is any way to know about the final kernel boot result, but I couldn't able to figured it out.

Details: U-boot Version: 2017.03-rc2 api's are available at: cmd/bootz.c and bootm.c files.

If any one in this community knows about it or have an idea about it, please explain to me or point me to the correct path.

Thanks in advance.

Regards Vamsi Chagari

Upvotes: 2

Views: 1113

Answers (1)

Xypron
Xypron

Reputation: 2483

After bootm, booti, bootz transfer control to the kernel the memory formerly used by U-Boot will be reused by the operating system. As U-Boot is no longer in memory it cannot be informed about the operating system status.

If you use the bootefi command the U-Boot implementation of the UEFI runtime services stays in memory while the operating system is starting. The UEFI services can be called by the operating system. These include services relating to variables. One use of UEFI variables is the definition of the boot sequence.

Unfortunately UEFI variables are not yet completetly implemented in U-Boot (as of version v2018.07). They currently cannot be accessed after exiting boot services.

Upvotes: 2

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