Re: [PATCH v2 08/16] x86/efi: Carrying hibernation key by setup data

Matt Fleming
2015-08-21T12:40:34Z

On Tue, 11 Aug, at 02:16:28PM, Lee, Chun-Yi wrote:
> For forwarding hibernation key from EFI stub to boot kernel, this patch
> allocates setup data for carrying hibernation key, size and the status
> of efi operating.

This could do with some more information, and include that the key is
used to validate hibernate images.

But now that I think about it, is there a reason this patch hasn't
been merged with patch 6? The memory leak I mentioned in patch 6
becomes a non-issue in this one, so it would be good if these two
could be squashed together.

> Reviewed-by: Jiri Kosina <jkosina@suse.com>
> Tested-by: Jiri Kosina <jkosina@suse.com>
> Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
> ---
> arch/x86/boot/compressed/eboot.c | 26 +++++++++++++++++++++++---
> arch/x86/include/uapi/asm/bootparam.h | 1 +
> 2 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
> index 463aa9b..c838d09 100644
> --- a/arch/x86/boot/compressed/eboot.c
> +++ b/arch/x86/boot/compressed/eboot.c
> @@ -1394,18 +1394,22 @@ static void setup_hibernation_keys(struct boot_params *params)
> {
> unsigned long key_size;
> unsigned long attributes;
> + struct setup_data *setup_data, *hibernation_setup_data;
> struct hibernation_keys *keys;
> + unsigned long size = 0;
> efi_status_t status;

One thing to be aware of is that eboot.c has mainly used the
"reverse-christmas-tree" style of variable declarations, with longer
lines first, and shorter ones following. I haven't mentioned it before
because none of your changes seemed to be too different (and it's not
a tree-wide convention), but the above setup_data line goes a bit too
far.

Could you try and keep them ordered, longest line first?

>
> /* Allocate setup_data to carry keys */
> + size = sizeof(struct setup_data) + sizeof(struct hibernation_keys);
> status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
> - sizeof(struct hibernation_keys), &keys);
> + size, &hibernation_setup_data);
> if (status != EFI_SUCCESS) {
> efi_printk(sys_table, "Failed to alloc mem for hibernation keys\n");
> return;
> }
>
> - memset(keys, 0, sizeof(struct hibernation_keys));
> + memset(hibernation_setup_data, 0, size);
> + keys = (struct hibernation_keys *) hibernation_setup_data->data;
>
> status = efi_call_early(get_variable, HIBERNATION_KEY,
> &EFI_HIBERNATION_GUID, &attributes,
> @@ -1419,7 +1423,8 @@ static void setup_hibernation_keys(struct boot_params *params)
> if (status == EFI_SUCCESS) {
> efi_printk(sys_table, "Cleaned existing hibernation key\n");
> status = EFI_NOT_FOUND;
> - }
> + } else
> + goto clean_fail;

Please add braces for the 'else' clause. Also, please include a
comment stating that the reason you jump to the label instead of
returning is so that the EFI status error code can be recorded in
hibernation_setup_data.

> }
>
> if (status != EFI_SUCCESS) {
> @@ -1436,6 +1441,21 @@ static void setup_hibernation_keys(struct boot_params *params)
> if (status != EFI_SUCCESS)
> efi_printk(sys_table, "Failed to set hibernation key\n");
> }
> +
> +clean_fail:
> + hibernation_setup_data->type = SETUP_HIBERNATION_KEYS;
> + hibernation_setup_data->len = sizeof(struct hibernation_keys);
> + hibernation_setup_data->next = 0;
> + keys->hkey_status = efi_status_to_err(status);
> +
> + setup_data = (struct setup_data *)params->hdr.setup_data;
> + while (setup_data && setup_data->next)
> + setup_data = (struct setup_data *)setup_data->next;
> +
> + if (setup_data)
> + setup_data->next = (unsigned long)hibernation_setup_data;
> + else
> + params->hdr.setup_data = (unsigned long)hibernation_setup_data;

This label name is a little confusing because you reach it both when
the EFI boot variable was successfully created and when a bogus EFI
variable failed to be deleted, i.e. it's not always reached because of
a failure.

How about 'setup' or simply 'out' ?

--
Matt Fleming, Intel Open Source Technology Center