| Summary: | Building a mipsel kernel format vmlinuz (+ gzip + initrd) generates non-compressed, non-bootable image | ||
|---|---|---|---|
| Product: | buildroot | Reporter: | Alexander Enchevich <a.enchevich> |
| Component: | Other | Assignee: | unassigned |
| Status: | RESOLVED WONTFIX | ||
| Severity: | major | CC: | a.enchevich, buildroot |
| Priority: | P5 | ||
| Version: | 2017.02 | ||
| Target Milestone: | --- | ||
| Hardware: | PC | ||
| OS: | Linux | ||
| Host: | Target: | ||
| Build: | |||
| Attachments: |
My buildroot's .config file
Kernel .config file Buildroot defconfig Kernel's defconfig patch kernel to compile with buildroot's gcc 4.8.x Enable kernel gzip compression |
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Created attachment 7381 [details]
Kernel .config file
Reading the above perhaps a quick clarification is in order to help understand why I believe the vmlinuz produced by buildroot is significantly smaller then it should be (and hence, IMO, is missing the initial ram disk): Good vmlinuZ (from Broadcom): compressed: 6 MB uncompressed: 13 MB Good vmlinuX (from buildroot): compressed: 9 MB uncompressed: 21 MB BAD vmlinuZ (from buildroot): compressed: 9 MB (8.8) uncompressed: 9 MB (8.7) Created attachment 7386 [details]
Buildroot defconfig
Created attachment 7391 [details]
Kernel's defconfig
The git repo for Broadcom's stblinux 3.3 is https://github.com/Broadcom/stblinux-3.3.git. However it can not be used as a git URL directly because the kernel is not at the top level but dir down. The version I used is latest at time of filing this bug (tag: stblinux-3.3-4.2). To make this kernel compile with the standard buildroot gcc compiler and binutils I made a patch, because there was a problem with binutils > v.2.24.51 not being able to mix hard- and softfloat FPU mode/instructions. Also the the gzip compression option was ignored, for which there is also patch. Created attachment 7396 [details]
patch kernel to compile with buildroot's gcc 4.8.x
Created attachment 7401 [details]
Enable kernel gzip compression
Could you reproduce this problem with a MIPS defconfig available in the upstream Linux kernel? I personally really don't want to debug stuff deep down in the Broadcom BSP. The original contributor never came back with a way to reproduce the problem with a reasonable kernel version (i.e not the Broadcom BSP), so let's mark the bug as WONTFIX. Do not hesitate to reopen with an easier way to reproduce the problem. Thanks! |
Created attachment 7376 [details] My buildroot's .config file I have sources + images provided by Broadcom for their 7362a0 set top box boards. The kernel image there is has initrd linked in and is: $ ls -l -rw-r--r-- 1 me users 5669240 Sep 20 17:52 vmlinuz-initrd-7362a0 $ file vmlinuz-initrd-7362a0 vmlinuz-initrd-7362a0: gzip compressed data, last modified: Wed Sep 20 14:52:20 2017, max compression, from Unix So the vmlinuz that works is about 5.7MB, gzipped, with the initrd. = = = When I try generating a vmlinuz kernel in buildroot, however, I am getting a file which is ELF and DOES NOT have the initrd and can not be booted: -rw-r--r-- 1 me users 8814700 Oct 31 14:04 vmlinuz-from-BR2 $ file vmlinuz-from-BR2 vmlinuz-from-BR2: ELF 32-bit LSB executable, MIPS, MIPS32 version 1 (SYSV), statically linked, stripped The reasons I am saying that initrd is not linked in, is because: a) the vmlinuz image dies very early during the TFTP transfer (packet 8 or 9). b) because I also tried compiling a vmlinux image+initrd. That one is about 21MB and about 8.8MB stripped and gzipped. I tried booting the gzipped vmlinux and it works fine. I do not yet know the reason why it is so much bigger than Broadcom's original vmlinuz image, but I suppose it is because I linked in various packages to play with - DirectFB, SDL, SDL2, etc... = = = So firstly, it seems that the option 'initial RAM filesystem linked into linux kernel' from the Filesystem images menu is ignored in the case of vmlinuz. Secondly, I was expecting a gzipped data (not and ELF binary) when option 'Kernel compression format (gzip compression)' is selected (regardless of vmlinux/vmlinuz).