Messages in this thread | | | Date | Mon, 14 Jan 2013 10:57:08 -0800 | Subject | Re: [PATCH v7u1 22/31] x86, boot: add fields to support load bzImage and ramdisk above 4G | From | Yinghai Lu <> |
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On Mon, Jan 14, 2013 at 9:49 AM, H. Peter Anvin <hpa@zytor.com> wrote: > On 01/13/2013 09:37 PM, Yinghai Lu wrote: >>> >>> >>> This is kinda missing from the mechanism of the sentinel and it should >>> be documented too. >> >> >> No, we should have too much duplicated info. >> > > That is not duplicating info... that is basic documentation. As you show in > the post further on, it took a very simple description, and it *is* a very > subtle thing that is inherently different from how the other fields operate.
please check if following is enough?
+ /* + * kernel have sentinel to set as 0xff in setup link scripts, + * so if bootloader just copy whole page from kernel image to + * get setup_header instead of clearing boot_param buffer and + * copying setup_header only, will leave sentinel as 0xff. + * With that, we can tell some fields in boot_param have + * invalid values, and we need to zero them in kernel. + */ + __u8 sentinel; /* 0x1ef */
> > It doesn't help that you didn't, despite repeated requests, implement what I > *asked for*, which is: > > If the sentinel is flagged, zero *all fields not explicitly set by the > broken versions of kexec*, not just your new "ext" fields.
other fields are pad* fields, so do we zero out them with memset with exact address? so next times, when someone change pad fields to other ext_*, they don't need to change code again here.
> > Yinghai, I understand you're frustrated, but please understand that Borislav > is not in any shape, way, or form "some guys that do not know the code well > keep sending comments out to waste others time". Rather, he has spent a > huge amount of time giving you an awful lot of good feedback A lot of them > have centered on documentation and code maintainability, both of which are > vitally important part of a long-lived codebase. > > Having someone doing line-by-line review of your code is enormously > time-consuming and not something most people enjoy doing. Borislav is doing > you -- and me -- a huge favor here.
yes.
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