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[Xen-devel] Re: [bisected] Re: [PATCH 05 of 12] xen: add p2m mfn_list_list

Ingo Molnar wrote:
* Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

Subject: make page-aligned data and bss less fragile

Making a variable page-aligned by using __attribute__((section(".data.page_aligned"))) is fragile because if sizeof(variable) is not also a multiple of page size, it leaves variables in the remainder of the section unaligned.

This patch introduces two new qualifiers, __page_aligned_data and __page_aligned_bss to set the section *and* the alignment of variables. This makes page-aligned variables more robust because the linker will make sure they're aligned properly. Unfortunately it requires *all* page-aligned data to use these macros...

applied to -tip, thanks Jeremy. Created a new topic branch for the core bits of it: tip/build. Sam might want to pull from that topic branch eventually, once these changes pass testing in -tip.

Can you also drop "xen: fix early bootup crash on native hardware" and replace it with "x86: use __page_aligned_data/bss"? (Which seems to have been partially applied?)


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