On Mon, Mar 10, 2014 at 02:33:41PM -0700, ron minnich wrote:
And locked out page zero. And we trap.
So, first question, can we move X86_BDA_BASE to somewhere other than 0x400? Anyone know?
The BIOS Data Area is not movable.
Jonathan Kollasch
Now you've just made me sad.
OK, given that in the beginning times we never supplied this little tidbit, who or what needs it? It looks like another memory turd whose time has gone.
ron
On Mon, Mar 10, 2014 at 2:41 PM, Jonathan A. Kollasch <jakllsch@kollasch.net
wrote:
On Mon, Mar 10, 2014 at 02:33:41PM -0700, ron minnich wrote:
And locked out page zero. And we trap.
So, first question, can we move X86_BDA_BASE to somewhere other than
0x400?
Anyone know?
The BIOS Data Area is not movable.
Jonathan Kollasch
On Mon, 2014-03-10 at 16:41 -0500, Jonathan A. Kollasch wrote:
On Mon, Mar 10, 2014 at 02:33:41PM -0700, ron minnich wrote:
And locked out page zero. And we trap.
So, first question, can we move X86_BDA_BASE to somewhere other than 0x400? Anyone know?
The BIOS Data Area is not movable.
The *physical* address of the BDA is not movable.
However there are no constraints on what its *virtual* address should be, while you're running in your own code with paging turned on.
Even if you generally have a 1:1 mapping of virt->phys addresses, you could still set up a mapping for the zero page at a different virtual address.
Good point.
On Wed, Mar 12, 2014 at 10:12 AM, David Woodhouse dwmw2@infradead.orgwrote:
On Mon, 2014-03-10 at 16:41 -0500, Jonathan A. Kollasch wrote:
On Mon, Mar 10, 2014 at 02:33:41PM -0700, ron minnich wrote:
And locked out page zero. And we trap.
So, first question, can we move X86_BDA_BASE to somewhere other than
0x400?
Anyone know?
The BIOS Data Area is not movable.
The *physical* address of the BDA is not movable.
However there are no constraints on what its *virtual* address should be, while you're running in your own code with paging turned on.
Even if you generally have a 1:1 mapping of virt->phys addresses, you could still set up a mapping for the zero page at a different virtual address.
-- dwmw2
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David Woodhouse -
Jonathan A. Kollasch -
ron minnich