On Tue, Mar 06, 2007 at 09:42:04AM +0530, Vivek Goyal wrote: > On Mon, Mar 05, 2007 at 11:34:33PM +0100, Bernhard Walle wrote: > > This patch increases the kernel command line size for x86_64 and i386 > > to 2048 characters. This is necessary because with kernel 2.6.21 > > and newer, the kernel command line size has increased and kexec needs > > lot of command line space, so this solves some "command line overflow" > > problems. > > > > To be able to warn users running older kernels that the command line > > is too long (and don't wait that the kernel truncates it), the > > patch tries to get the kernel command line length from the kernel > > image that is loaded if possible by checking the length of the > > static array that holds the kernel command line when booting. > > > > It does not work for compressed images (bzImage). So kexing older bzImages > will never give you a warning message. > > Secondly, I think creating dependencies on kernel symbols is bad. Tomorrow > if kernel code changes, we are broken. The problem "crash" faces so often. > So we should create a well defined interface which can remain constant > even if kernel code changes. > > I personally think either there should be a way to specify command line > length supported in the image format (bzImage) or we should export it to > user space, lets say through /proc/ interface. > > Specifying max cmdline lenght in bzImage header helps because any bootloader > then take a clue and warn user about excessive command line length. > > Otherwise we can export something like /proc/max_cmdline_len on the lines > of /proc/cmdline. >
Thinking more about it. I think exporting it through /proc/ will work better. Extending bzImage format will help only bzImage but problem for ELF vmlniux will still persist, until we decide to append an ELF note to vmlinux. Thanks Vivek _______________________________________________ fastboot mailing list [email protected] https://lists.osdl.org/mailman/listinfo/fastboot
