Re: [PATCH v8 0/3] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory

Masayoshi Mizuma
2018-11-06T22:21:34Z

On Tue, Nov 06, 2018 at 09:45:11PM +0100, Borislav Petkov wrote:
> On Tue, Nov 06, 2018 at 02:36:38PM -0500, Masayoshi Mizuma wrote:
> > Yes, I think I can see what you are saying. However, I'm not sure how
> > I use the setup_data in legacy BIOS environment.
>
> What is "legacy BIOS environment" and what does that have to do with
> setup_data?

My proposed patch [1] is useful only for EFI environment. The patch
allocates a setup_date structure by efi_call_early() and store the
KASLR data into the memory area.

+static void setup_kaslr(struct boot_params *params)
+{
+ struct setup_data *kaslr_data = NULL;
+ struct setup_data *data;
+ unsigned long size;
+ efi_status_t status;
+
+ size = sizeof(struct setup_data) + sizeof(unsigned long long);
+
+ status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
+ size, (void **)&kaslr_data);

I'm not sure how I allocate such memory on no EFI environment.
Am I missing something...?

[1] https://lkml.kernel.org/r/20181022154204.kagmdb55jtoez4ca@gabell

Thanks,
Masa