Messages in this thread | | | Date | Sat, 24 Nov 2012 21:50:01 -0800 | Subject | Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImage and ramdisk high | From | Yinghai Lu <> |
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On Sat, Nov 24, 2012 at 4:11 PM, Yinghai Lu <yinghai@kernel.org> wrote: > On Sat, Nov 24, 2012 at 4:04 PM, H. Peter Anvin <hpa@zytor.com> wrote: >> >> It sounds like we are leaning toward some form of the sentinel hack, which >> means we need an enumerated list of things that should *not* be zeroed if >> the sentinel is present. >> >> The option of declaring the list frozen makes me a bit nervous, because it >> isn't clear that we don't already have fields that will be misinterpreted by >> the kernel if filled in from the file. > > USE_EXT_BOOT_PARAMS bit in xloadflags should work.
new kexec will clean around bit around setup head, and set that bit, if it is not with real_mode entry.
32bit and 64bit entry: old kernel has no idea of this bit, and still use old ramdisk_image, cmd_line_ptr in setup header. new kernel will check that bit before it use ext_ramdisk_image, and ext_cmd_line_ptr.
old kexec and new kernel is safe too, because that bit is not set, new kernel will not use ex_...
later all new kernel need to check USE_EXT_BOOT_PARAMS bit for all new added field in boot_params.
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