# Re: \[PATCH V38 15/29\] acpi: Ignore acpi\_rsdp kernel param when the kernel has been locked down

- From: Borislav Petkov \<bp@alien8.de\>
- Date: 2019-08-14 17:46:49 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2019/08/5688246
- Thread: https://ratatoskr.run/linux-security-module/2019/08/5681185/t.md

```text
On Wed, Aug 14, 2019 at 10:14:54AM -0700, Matthew Garrett wrote:
> We explicitly don't want to pay attention to the acpi_rsdp kernel
> parameter in early boot except for the case of finding the SRAT table,
> and we only need that if CONFIG_RANDOMIZE_BASE and
> CONFIG_MEMORY_HOTREMOVE are set. However, we *do* want to tell the
> actual kernel where the RSDP is if we found it via some other means,
> so we can't just clear the boot parameters value.

Ok.

> The kernel proper will parse the command line again and will then (if
> lockdown isn't enabled) override the actual value we passed up in boot
> params.

Yeah, ok, I see what you're doing there. AFAICT, you do that in

setup_arch->acpi_boot_table_init-> ... -> acpi_os_get_root_pointer()

I hope nothing needs it earlier because then we'll have to restructure
again...

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.
```