x86/boot: efistub: Assign global boot_params variable

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.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org

drivers/firmware/efi/libstub/x86-stub.c

@@ -818,6 +818,8 @@ void __noreturn efi_stub_entry(efi_handle_t handle,
 	unsigned long kernel_entry;
 	efi_status_t status;
 
+	boot_params_ptr = 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)