Messages in this thread |  | | Date | Mon, 16 Jun 2008 10:41:22 -0700 | From | "Yinghai Lu" <> | Subject | Re: [PATCH 4/8] x86 boot: allow overlapping ebda and efi memmap memory ranges |
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On Mon, Jun 16, 2008 at 10:37 AM, Paul Jackson <pj@sgi.com> wrote: > hpa, replying to pj: >> >> Would you recommend doing this with code in arch/x86/kernel/head.c, >> >> that did not invoke reserve_ebda_region() if efi_enabled was set? >> >> I disagree with it > > Ok - that's clear. > > So it would seem that I am getting conflicting advice. > > One person recommends code that only makes this safety reservation of > the ebda region in the non-EFI case: > > if (!efi_enabled) > reserve_ebda_region(); > > and the other recommends code that always makes this safety reservation, > and that handles the possible resulting overlap with the EFI memmap: > > if (!range_in_ebda_area(pmap, pmap + memmap.nr_map * memmap.desc_size)) > reserve_early(pmap, pmap + memmap.nr_map * memmap.desc_size, > "EFI memmap"); > > (The above code should be adjusted in light of Yinghai's suggestion > that it handle partial overlap.) > > The resolution of this conflict might be easy, however. > > I will readily accept that there exist some 'classic' PCs for which > we need to reserve a 'safe' ebda area. > > The question to me is this. Are there PCs which (1) need such a safety > reservation of an ebda area -and- (2) boot with EFI enabled? I am not > asking if there -could- be (in the abstract, there certainly is no law > of government or physics prohibiting such). Rather I am asking as a > practical matter if there is, or is likely to be, such PCs "in the wild."
like to see to make reserve_ebda_region() more smart like the old way when andi introduced ebda_size... instead of reserve 0x9000 to 0x100000 all the way.
YH
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