On Wed, Nov 16, 2016 at 09:47:31PM +0000, David Howells wrote:
> Get the firmware's secure-boot status in the kernel boot wrapper and stash
> it somewhere that the main kernel image can find.
>
> Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> ---
>
> Documentation/x86/zero-page.txt | 2 ++
> arch/x86/boot/compressed/eboot.c | 35 +++++++++++++++++++++++++++++++++
> arch/x86/include/uapi/asm/bootparam.h | 3 ++-
> 3 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
> index 95a4d34af3fd..b8527c6b7646 100644
> --- a/Documentation/x86/zero-page.txt
> +++ b/Documentation/x86/zero-page.txt
> @@ -31,6 +31,8 @@ Offset Proto Name Meaning
> 1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below)
> 1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer
> (below)
> +1EB/001 ALL kbd_status Numlock is enabled
> +1EC/001 ALL secure_boot Secure boot is enabled in the firmware
> 1EF/001 ALL sentinel Used to detect broken bootloaders
> 290/040 ALL edd_mbr_sig_buffer EDD MBR signatures
> 2D0/A00 ALL e820_map E820 memory map table
> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
> index cc69e37548db..17b376596c96 100644
> --- a/arch/x86/boot/compressed/eboot.c
> +++ b/arch/x86/boot/compressed/eboot.c
> @@ -12,6 +12,7 @@
> #include <asm/efi.h>
> #include <asm/setup.h>
> #include <asm/desc.h>
> +#include <asm/bootparam_utils.h>
>
> #include "../string.h"
> #include "eboot.h"
> @@ -537,6 +538,36 @@ static void setup_efi_pci(struct boot_params *params)
> efi_call_early(free_pool, pci_handle);
> }
>
> +static int get_secure_boot(void)
> +{
This function is very similar to the existing efi_get_secureboot() in
drivers/firmware/efi/libstub/arm-stub.c.
Please avoid adding more duplicate code to the EFI stub and try to
reuse the existing code.
I suggest moving the existing efi_get_secureboot() to a new file
drivers/firmware/efi/libstub/secureboot.c which gets linked into
libstub, perhaps dependent on a new config option.
> + u8 sb, setup;
> + unsigned long datasize = sizeof(sb);
> + efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
> + efi_status_t status;
> +
> + status = efi_early->call((unsigned long)sys_table->runtime->get_variable,
> + L"SecureBoot", &var_guid, NULL, &datasize, &sb);
This doesn't work in mixed mode.
We already have the efi_call_early() macro to call boot services
in a manner that works across all arches and bitness variants.
In 4.10 there will be an efi_call_proto() macro to allow the same
for protocol calls:
http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?h=efi/core&id=3552fdf29f01
I suggest adding an efi_call_runtime() macro for arch- and bitness-
agnostic runtime services calls, like this:
#define efi_call_runtime(f, ...) \
__efi_early()->call(efi_table_attr(efi_runtime_services, f, \
__efi_early()->runtime_services), __VA_ARGS__)
For this to work you need to add a runtime_services attribute to struct
efi_config, this requires modifying head_32.S and head_64.S, use commit
0a637ee61247 ("x86/efi: Allow invocation of arbitrary boot services")
as a template.
If you define corresponding efi_call_runtime() macros for ARM, you
should indeed be able to share this function across arches.
Thanks,
Lukas
> +
> + if (status != EFI_SUCCESS)
> + return 0;
> +
> + if (sb == 0)
> + return 0;
> +
> +
> + status = efi_early->call((unsigned long)sys_table->runtime->get_variable,
> + L"SetupMode", &var_guid, NULL, &datasize,
> + &setup);
> +
> + if (status != EFI_SUCCESS)
> + return 0;
> +
> + if (setup == 1)
> + return 0;
> +
> + return 1;
> +}
> +
> static efi_status_t
> setup_uga32(void **uga_handle, unsigned long size, u32 *width, u32 *height)
> {
> @@ -1094,6 +1125,10 @@ struct boot_params *efi_main(struct efi_config *c,
> else
> setup_boot_services32(efi_early);
>
> + sanitize_boot_params(boot_params);
> +
> + boot_params->secure_boot = get_secure_boot();
> +
> setup_graphics(boot_params);
>
> setup_efi_pci(boot_params);
> diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
> index c18ce67495fa..2b3e5427097b 100644
> --- a/arch/x86/include/uapi/asm/bootparam.h
> +++ b/arch/x86/include/uapi/asm/bootparam.h
> @@ -134,7 +134,8 @@ struct boot_params {
> __u8 eddbuf_entries; /* 0x1e9 */
> __u8 edd_mbr_sig_buf_entries; /* 0x1ea */
> __u8 kbd_status; /* 0x1eb */
> - __u8 _pad5[3]; /* 0x1ec */
> + __u8 secure_boot; /* 0x1ec */
> + __u8 _pad5[2]; /* 0x1ed */
> /*
> * The sentinel is set to a nonzero value (0xff) in header.S.
> *
>
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