[U-Boot] [RFC 3/8] efi_loader: bootmgr: return pointer and size of buffer in loading

[AKASHI Takahiro]

On Thu, Mar 21, 2019 at 12:41:06PM +0100, Heinrich Schuchardt wrote:
> On 3/5/19 6:53 AM, AKASHI Takahiro wrote:
> > We need to know the size of image loaded so as to be able to use
> > load_image() API at do_bootefi_exec() in a later patch.
> >
> > So change the interface of efi_bootmgr_load().
> >
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> > ---
> >  include/efi_loader.h         |  5 +++--
> >  lib/efi_loader/efi_bootmgr.c | 41 +++++++++++++++++++++---------------
> >  2 files changed, 27 insertions(+), 19 deletions(-)
> >
> > diff --git a/include/efi_loader.h b/include/efi_loader.h
> > index 47a51ddc9406..3f51116155ad 100644
> > --- a/include/efi_loader.h
> > +++ b/include/efi_loader.h
> > @@ -564,8 +564,9 @@ struct efi_load_option {
> >
> >  void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data);
> >  unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data);
> > -void *efi_bootmgr_load(struct efi_device_path **device_path,
> > -		       struct efi_device_path **file_path);
> > +efi_status_t efi_bootmgr_load(struct efi_device_path **device_path,
> > +			      struct efi_device_path **file_path,
> > +			      void **image, efi_uintn_t *size);
> >
> >  #else /* CONFIG_IS_ENABLED(EFI_LOADER) */
> >
> > diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
> > index 1575c5c09e46..38f3fa15f6ef 100644
> > --- a/lib/efi_loader/efi_bootmgr.c
> > +++ b/lib/efi_loader/efi_bootmgr.c
> > @@ -120,14 +120,17 @@ static void *get_var(u16 *name, const efi_guid_t *vendor,
> >   * if successful.  This checks that the EFI_LOAD_OPTION is active (enabled)
> >   * and that the specified file to boot exists.
> >   */
> > -static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
> > -			    struct efi_device_path **file_path)
> > +static efi_status_t try_load_entry(u16 n,
> > +				   struct efi_device_path **device_path,
> > +				   struct efi_device_path **file_path,
> > +				   void **image, efi_uintn_t *image_size)
> >  {
> >  	struct efi_load_option lo;
> >  	u16 varname[] = L"Boot0000";
> >  	u16 hexmap[] = L"0123456789ABCDEF";
> > -	void *load_option, *image = NULL;
> > +	void *load_option;
> >  	efi_uintn_t size;
> > +	efi_status_t ret;
> >
> >  	varname[4] = hexmap[(n & 0xf000) >> 12];
> >  	varname[5] = hexmap[(n & 0x0f00) >> 8];
> > @@ -136,18 +139,17 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
> >
> >  	load_option = get_var(varname, &efi_global_variable_guid, &size);
> >  	if (!load_option)
> > -		return NULL;
> > +		return EFI_LOAD_ERROR;
> >
> >  	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);
> >
> > -		ret = efi_load_image_from_path(lo.file_path, &image, &size);
> > +		ret = efi_load_image_from_path(lo.file_path, image, image_size);
> >
> 
> This call to efi_load_image_from_path() leads to duplication of logic.
> 
> Why don't we simply call EFI_CALL(efi_load_image())) here and if it
> succeeds return from efi_bootmgr_load()?

Make sense. It will make do_bootefi_exec() simpler.
This will also give us a reason why we have do_efibootmgr() apart
from do_boot_efi().

Thanks,
-Takahiro Akashi

> Best regards
> 
> Heinrich
> 
> >  		if (ret != EFI_SUCCESS)
> >  			goto error;
> > @@ -164,12 +166,14 @@ static void *try_load_entry(uint16_t n, struct efi_device_path **device_path,
> >
> >  		printf("Booting: %ls\n", lo.label);
> >  		efi_dp_split_file_path(lo.file_path, device_path, file_path);
> > +	} else {
> > +		ret = EFI_LOAD_ERROR;
> >  	}
> >
> >  error:
> >  	free(load_option);
> >
> > -	return image;
> > +	return ret;
> >  }
> >
> >  /*
> > @@ -177,12 +181,12 @@ error:
> >   * EFI variable, the available load-options, finding and returning
> >   * the first one that can be loaded successfully.
> >   */
> > -void *efi_bootmgr_load(struct efi_device_path **device_path,
> > -		       struct efi_device_path **file_path)
> > +efi_status_t efi_bootmgr_load(struct efi_device_path **device_path,
> > +			      struct efi_device_path **file_path,
> > +			      void **image, efi_uintn_t *image_size)
> >  {
> >  	u16 bootnext, *bootorder;
> >  	efi_uintn_t size;
> > -	void *image = NULL;
> >  	int i, num;
> >  	efi_status_t ret;
> >
> > @@ -201,9 +205,9 @@ void *efi_bootmgr_load(struct efi_device_path **device_path,
> >  					(efi_guid_t *)&efi_global_variable_guid,
> >  					0, 0, &bootnext));
> >  		if (ret == EFI_SUCCESS) {
> > -			image = try_load_entry(bootnext,
> > -					       device_path, file_path);
> > -			if (image)
> > +			ret = try_load_entry(bootnext, device_path, file_path,
> > +					     image, image_size);
> > +			if (ret == EFI_SUCCESS)
> >  				goto error;
> >  		}
> >  	}
> > @@ -212,19 +216,22 @@ void *efi_bootmgr_load(struct efi_device_path **device_path,
> >  	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
> >  	if (!bootorder) {
> >  		printf("BootOrder not defined\n");
> > +		ret = EFI_NOT_FOUND;
> >  		goto error;
> >  	}
> >
> >  	num = size / sizeof(uint16_t);
> >  	for (i = 0; i < num; i++) {
> > -		debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
> > -		image = try_load_entry(bootorder[i], device_path, file_path);
> > -		if (image)
> > +		debug("%s: trying to load Boot%04X\n", __func__,
> > +		      bootorder[i]);
> > +		ret = try_load_entry(bootorder[i], device_path, file_path,
> > +				     image, image_size);
> > +		if (ret == EFI_SUCCESS)
> >  			break;
> >  	}
> >
> >  	free(bootorder);
> >
> >  error:
> > -	return image;
> > +	return ret;
> >  }
> >
>