[PATCH] access gdtdesc on segment 0 unconditionally (Re: [PATCH] i386-qemu port)

[Robert Millan]

In this line of code in real_to_prot():

        DATA32  ADDR32  lgdt    %cs:gdtdesc

GAS generates an absolute address for `gdtdesc' (not relative to segment),
and so for the code to work %cs must be zero.  In current usage of
real_to_prot(), %cs is always zero because we jump to 0x0:0x82xx early on.

However, in other situations this is not possible.  On i386-qemu, before
moving to i386 mode the code we're running is in the 0xf0000-0x100000
range, which is inaccessible from segment 0.

This patch changes this to access gdtdesc from segment 0 unconditionally.

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."

cs_in_real_to_prot.diff
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