Re: [PATCH v2] kdump: pass acpi_rsdp= to 2nd kernel for efi booting

Khalid Aziz
2012-10-23T13:33:24Z

On Mon, 2012-10-22 at 11:43 -0400, Vivek Goyal wrote:
> On Sat, Oct 20, 2012 at 08:06:23PM -0700, Eric W. Biederman wrote:
>
> [..]
> > It is the non-pure UEFI case where non-UEFI table scans work.
> >
> > Of course it puzzles me why we can't find the table via scanning memory
> > when running in a pure UEFI environment. Ah well that is a problem for
> > another day.
>
> I have the same question. Why can we find acpi tables by scaning in
> non-uefi case and why same is not possible in case of UEFI.

I had sent an explanation out on Friday but looks like my email got
stuck somewhere, and I don't see it on kexec list archive.

On a UEFI machine with CSM, kernel finds RSDP by searching through EBDA.
On a UEFI machine with no CSM, there is no EBDA I believe and kernel
fails to find RSDP. Here is the message I see on a UEFI machine with no
CSM:

ACPI BIOS Bug: Error: A valid RSDP was not found (20120913/tbxfroot-219)

--
Khalid