[U-Boot] [PATCH v2 1/5] efi_loader: bootmgr: support BootNext and BootCurrent variable behavior

AKASHI Takahiro
2019-02-27T05:47:42Z

On Tue, Feb 26, 2019 at 07:57:26PM +0100, Heinrich Schuchardt wrote:
> On 1/15/19 3:54 AM, AKASHI Takahiro wrote:
> > See UEFI v2.7, section 3.1.2 for details of the specification.
> >
> > With my efitool command, you can try as the following:
> > => efi boot add 1 SHELL ...
> > => efi boot add 2 HELLO ...
> > => efi boot order 1 2
> > => efi bootmgr
> > (starting SHELL ...)
> > => efi boot next 2
> > => efi bootmgr
> > (starting HELLO ...)
> > => efi dumpvar
> > <snip ...>
> > BootCurrent: {boot,run}(blob)
> > 00000000: 02 00 ..
> > BootOrder: {boot,run}(blob)
> > 00000000: 01 00 02 00 ....
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > ---
> > lib/efi_loader/efi_bootmgr.c | 34 +++++++++++++++++++++++++++++++++-
> > 1 file changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
> > index a095df3f540b..6c5303736dc6 100644
> > --- a/lib/efi_loader/efi_bootmgr.c
> > +++ b/lib/efi_loader/efi_bootmgr.c
> > @@ -145,11 +145,21 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
> > efi_deserialize_load_option(&lo, load_option);
> >
> > if (lo.attributes & LOAD_OPTION_ACTIVE) {
> > + u32 attributes;
> > efi_status_t ret;
> >
> > debug("%s: trying to load \"%ls\" from %pD\n",
> > __func__, lo.label, lo.file_path);
> >
> > + attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
> > + EFI_VARIABLE_RUNTIME_ACCESS;
> > + size = sizeof(n);
> > + ret = rs->set_variable(L"BootCurrent",
> > + (efi_guid_t *)&efi_global_variable_guid,
>
> Use EFI_CALL().

Okay
But as I said somewhere else, it's quite annoying to me that
some efi_xxx requires EFI_CALL(), and others not.
There should have been consistent naming rules.

> Instead of dereferencing you could directly call
> efi_set_variable().

Yeah, given that this code is under lib/efi_loader, it may be natural
to use efi_set_variable(). But existing get_var() uses the same style of coding.

Do you want to change all of the call sites including get_var()?

> > + attributes, size, &n);
> > + if (ret != EFI_SUCCESS)
> > + goto error;
> > +
> > ret = efi_load_image_from_path(lo.file_path, &image);
> >
> > if (ret != EFI_SUCCESS)
> > @@ -173,16 +183,38 @@ error:
> > void *efi_bootmgr_load(struct efi_device_path **device_path,
> > struct efi_device_path **file_path)
> > {
> > - uint16_t *bootorder;
> > + u16 bootnext, *bootorder;
> > efi_uintn_t size;
> > void *image = NULL;
> > int i, num;
> > + efi_status_t ret;
> >
> > __efi_entry_check();
> >
> > bs = systab.boottime;
> > rs = systab.runtime;
> >
> > + /* get BootNext */
> > + size = sizeof(bootnext);
> > + ret = rs->get_variable(L"BootNext",
> > + (efi_guid_t *)&efi_global_variable_guid,
> > + NULL, &size, &bootnext);
>
> You could call efi_get_variable() directly instead of dereferencing rs.
> But anyway you have to use EFI_CALL().

Ditto

> > + if (!bootnext)
> > + goto run_list;
>
> Goto is acceptable for error handling. But otherwise I would rather
> avoid it.

Okay with another indentation.

> > +
> > + /* delete BootNext */
> > + ret = rs->set_variable(L"BootNext",
> > + (efi_guid_t *)&efi_global_variable_guid,
> > + 0, 0, &bootnext);
>
> EFI_CALL().

Thanks,
-Takahiro Akashi

> Best regards
>
> Heinrich
>
> > + if (ret != EFI_SUCCESS)
> > + goto error;
> > +
> > + image = try_load_entry(bootnext, device_path, file_path);
> > + if (image)
> > + goto error;
> > +
> > +run_list:
> > + /* BootOrder */
> > bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
> > if (!bootorder)
> > goto error;
> >
>