On Tue, Jan 15, 2008 at 12:09:50PM -0500, Neil Horman wrote: > On Tue, Jan 15, 2008 at 10:27:10AM -0500, Vivek Goyal wrote: > > On Mon, Jan 14, 2008 at 08:43:03AM -0500, Neil Horman wrote: > > > Hey all- > > > Regarding this bug: > > > http://bugzilla.kernel.org/show_bug.cgi?id=9641 > > > I'd like to look into putting together a patch for it, and wanted to > > > solicit comments for the best way to go about doing it. Currently I've got it > > > fixed up in the Red Hat tree by bumping COMMAND_LINE_SIZE to 2048 and > > > eliminating the reserved buffer of the x86_linux_faked_param_header, which works > > > well, but isn't backwards compatible as Bernhard pointed out. Given that extra > > > constraint, I thought it woudl e best to unify the command line and reserved > > > buffers in x86_linux_faked_param_header to one contiguour 2048 byte block and > > > maintain a separate variable that defines the command line length based on a > > > parsing of the UTS_VERSION. Does that sound reasonable to everyone, or is there > > > a better way that someone has in mind? > > > > > > > Hi Neil, > > > > Looking at UTS_VERSION and then deciding the command line length seems > > ok. > > > > When I look at inclue/asm-x86/bootparam.h in kernel, area starting from > > 0x2d0 to all the way up to 4K has been reserved for e820 maps and EDD buf. > > > > Does that mean newer boot loaders are putting command line outside of > > 4K page and only putting the pointer to cmdline in 4K page. If that's the > > case then we might have to do the same for kexec. > > > > That would seem to be the case yes, although it appears the kernel still > supports the old boot protocol if you want to restrict the command line length > to the old 256 chars (see copy_boot_data) > If that's the case then we probably should not be merging command_line and reserved area. Instead we might have to put command line somewhere else and pass the pointer to it in param page. If command line is with-in 256, then we can continue to pass it in param page. Thanks Vivek
