[Fedora 17/19] bootparam: Pass acpi_rsdp pointer in bootparam

[Vivek Goyal]

On Wed, Sep 04, 2013 at 09:54:25PM +0000, Matthew Garrett wrote:
> On Wed, 2013-09-04 at 17:24 -0400, Vivek Goyal wrote:
> > Currently kexec does not enables EFI and its tables in second kernel. Hence
> > acpi rsdp root pointer is passed on command line. But secureboot does not trust
> > acpi_rsdp on command line as kernel can execute some of the code as retrieved
> > by following acpi_rsdp and root can modify command line. So in secureboot
> > mode we ignore acpi_rsdp on command line.
> 
> How does kexec know it's getting a trustworthy version of the acpi_rsdp
> pointer?

We get acpi_rsdp from /sys/firmware/efi/systab and assumption here is that
kexec is looking at right /proc/ and /sys to get that info.

Thanks
Vivek