On Mon, 16 Oct 2023 at 18:46, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
>
> From: Ard Biesheuvel <ardb@xxxxxxxxxx>
>
> Now that the x86 EFI stub calls into some APIs exposed by the
> decompressor (e.g., kaslr_get_random_long()), it is necessary to ensure
> that the global boot_params variable is set correctly before doing so.
>
> Note that the decompressor and the kernel proper carry conflicting
> declarations for the global variable 'boot_params' so refer to it via an
> alias to work around this.
>
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> ---
> drivers/firmware/efi/libstub/x86-stub.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> index 3bfc59637dd1..51407207ded5 100644
> --- a/drivers/firmware/efi/libstub/x86-stub.c
> +++ b/drivers/firmware/efi/libstub/x86-stub.c
> @@ -812,12 +812,15 @@ void __noreturn efi_stub_entry(efi_handle_t handle,
> efi_system_table_t *sys_table_arg,
> struct boot_params *boot_params)
> {
> + extern struct boot_params *bpp asm("boot_params");
I am getting hatemail from the bots about this extern declaration, so
I will move that into x86-stub.h.
Unless anyone minds, I'll queue this up and send it to Linus myself
via the EFI fixes branch.
> efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
> struct setup_header *hdr = &boot_params->hdr;
> const struct linux_efi_initrd *initrd = NULL;
> unsigned long kernel_entry;
> efi_status_t status;
>
> + bpp = boot_params;
> +
> efi_system_table = sys_table_arg;
> /* Check if we were booted by the EFI firmware */
> if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
> --
> 2.42.0.655.g421f12c284-goog
>
