[lkml]   [2010]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] Built kernel without -O2 option
On Mon, Nov 29, 2010 at 11:56:15AM +0800, Hui Zhu wrote:
>Now, there are a lot of ways to debug the Linux kernel with GDB, like
>qemu, kgtp or kgdb and so on.
>But the developer more like add a printk. It have a lot of reason, a big one is:
>(gdb) p ret
>$3 = <value optimized out>
>And the code execution order is not right.
>This is becuase the Kernel is bult with gcc -O2. Gcc will not
>generate enough debug message with file with -O2.
>So GDB cannot work very well with Linux kernel.
>So I make a patch that add a option in "Kernel hacking" called "Close
>GCC optimization". It will make kernel be built without -O2.
>I built and use it in i386 and x86_64. I will try to make it OK in other arch.

The problem is that some functions _have to_ be inlined and gcc without -O2
doesn't inline them. Have check all the cases? I doubt.

Also, what is size of vmlinux before applying your patch and after that?
Does it increase too much?

 \ /
  Last update: 2010-11-29 09:13    [W:0.130 / U:1.960 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site