Bug 12320

Summary: Enable multiple kernels and multiple kernel command lines in systemd-boot, grub-efi menu
Product: [Build System, Metadata & Runtime] OE-Core Reporter: Tim Orling <tim.orling>
Component: coreAssignee: Unassigned <unassigned>
Status: NEW --- QA Contact:
Severity: enhancement    
Priority: Medium CC: bluelightning, meta.mr.watcher, meta.watcher, randy.macleod
Version: 2.5   
Target Milestone: 6.99   
Hardware: x86   
OS: Multiple   
Whiteboard:
OS type for building Yocto: --- Type of Regression: ---
Verified: Documentation change: Yes (doc changes required)
Bug Depends on: 11363    
Bug Blocks:    

Description Tim Orling 2017-11-08 03:54:00 UTC 
The multiple-kernel built and deployed in one image from BZ#11363 leads to the next enhancement request: 
enabling multiple kernels in systemd-boot or grub-efi (or other) boot menu. 

This is fairly common in mainline Linux distributions and an increasingly frequent request from our customers, especially during development and integration.

In addition to enabling the multiple kernels, while we are at it we should enable multiple kernel command lines in the menu (different options for the same kernel binary).

An example use case is to compare latency/performance of (1) "standard" (e.g. 4.9.47), (2)"stable preempt_rt" (e.g. 4.9.47-rt37) and (3) "rt-devel" (e.g. 4.13.10-rt3) kernels (different binaries) without and with (4,5,6) debug enabled (command line argument).

The three kernels (1,2,3) should be discoverable at image creation time (using, e.g. KERNEL_PACKAGE_NAME[]) and the boot menu should be able to be "auto" populated. The additional command line argument entries (4,5,6) would clearly need to be manually configured by a different mechanism.
Comment 1 Tim Orling 2020-03-12 16:05:21 UTC 
The kernels and the kernel modules need to be installed into the EFI System Partition (ESP) [1], so that they are available early in booting. The current implementation from BZ#11363 indeed allows multiple kernels to be installed into the rootfs, but they are not available until after the system has booted and mounted that partition.

[1] https://en.wikipedia.org/wiki/EFI_system_partition
Comment 2 Randy MacLeod 2023-10-24 14:24:19 UTC 
Bulk move from 4.99 or 0.00 to 5.99