Re: THE LINUX/I386 BOOT PROTOCOL - Breaking the 256 limit

From: H. Peter Anvin
Date: Tue Sep 06 2005 - 15:41:11 EST


Alon Bar-Lev wrote:

Hello Peter, I've written a reply before but got no response...

The idea of putting arguments in initramfs is not practical, since the whole idea is to have the same image of system and affecting its behavior using the boot loader...


No, you're wrong. The boot loader can synthesize an initramfs.

I would like to push forward the idea to extend the command-line size...

All we need for start is an updated version of the "THE LINUX/I386 BOOT PROTOCOL" document that states that in the 2.02+ protocol the boot loader should set cmd_line_ptr to a pointer to a null terminated string without any size restriction, specifying that the kernel will read as much as it can.

Already pushed to Andrew. I will follow it up with a patch to extend the command line, at least to 512.

After I get this update, I will try to work with GRUB and LILO so that they will fix their implementation. Currently they claim that they understand that they should truncate the string to 256.

After that I will provide my simple patch for setting the maximum size the kernel allocates in the configuration.

BTW: Do you know why the COMMAND_LINE_SIZE constant is located in two separate include files?

No, I don't. It could be because one is included from assembly code in the i386 architecture.

-hpa
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