On Tue, Aug 16, 2016 at 12:19:42PM -0700, Yinghai Lu wrote: > On Mon, Aug 15, 2016 at 9:01 PM, Matt Mullins <mmull...@mmlx.us> wrote: > > > > This appears to have a negative effect on booting the Intel Edison > > platform, as > > it uses u-boot as its bootloader. u-boot does not copy the init_size > > parameter > > when booting a bzImage: it copies a fixed-size setup_header [1], and its > > definition of setup_header doesn't include the parameters beyond setup_data > > [2]. > > > > With a zero value for init_size, this calculates a %rsp value of > > 0x101ff9600. > > This causes the boot process to hard-stop at the immediately-following > > pushq, as > > this platform has no usable physical addresses above 4G. > > > > What are the options for getting this type of platform to function again? > > For > > now, kexec from a working Linux system does seem to be a work-around, but > > there > > appears to be other x86 hardware using u-boot: the chromium.org folks seem > > to be > > maintaining the u-boot x86 tree. > > > > [1] > > http://git.denx.de/?p=u-boot.git;a=blob;f=arch/x86/lib/zimage.c;h=1b33c771391f49ffe82864ff1582bdfd07e5e97d;hb=HEAD#l156 > > [2] > > http://git.denx.de/?p=u-boot.git;a=blob;f=arch/x86/include/asm/bootparam.h;h=140095117e5a2daef0a097c55f0ed10e08acc781;hb=HEAD#l24 > > Then should fix the u-boot about header_size assumption.
I was hoping to avoid that, since the Edison's u-boot is 10,000-line patch atop the upstream -- I don't trust myself to build and flash one quite yet. If this turned out to affect Chromebooks, I'd spend more effort pushing for a kernel fix, but it seems that ChromeOS has a different kernel load procedure and doesn't use "zboot". For now, I'll probably just keep a local patch that hard-codes a value large enough to decompress and launch the kernel. I may turn that local patch into something gated by a Kconfig eventually, in hopes that users of the other x86 u-boot platforms will see it in a "make oldconfig" run.
