[U-Boot] [PATCH v2 1/3] efi_loader: rework fdt handling in distro boot script

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Tue, Oct 23, 2018 at 08:36:58AM +0100, Alexander Graf wrote:
> 
> 
> On 23.10.18 03:08, AKASHI Takahiro wrote:
> > On Mon, Oct 22, 2018 at 08:42:32AM +0100, Alexander Graf wrote:
> >>
> >>
> >> On 22.10.18 08:22, AKASHI Takahiro wrote:
> >>> On Mon, Oct 22, 2018 at 01:40:05PM +0900, AKASHI Takahiro wrote:
> >>>> The current scenario for default UEFI booting, scan_dev_for_efi, has
> >>>> several issues:
> >>>> * load dtb dynamically even if its loacation (device) is not the same
> >>>>   as BOOTEFI_NAME binary's, (reported by Alex)
> >>>> * invoke 'bootmgr' only if BOOTEFI_NAME binary does exit even though
> >>>>   'bootmgr' can and should work independently whether or not the binary
> >>>>   exist,
> >>>> * in addition, invoke 'bootmgr' with dynamically-loaded dtb.
> >>>>   This behavior is not expected. (reported by Alex)
> >>>> * always assume that a 'fdtfile' variable is defined,
> >>>>   ("test -e ${devtype} ${devnum}:${distro_bootpart} "${prefix}${efi_fdtfile}"
> >>>>   always returns true even if fdtfile is NULL with prefix=="/".)
> >>>> * redundantly check for 'fdt_addr_r' in boot_efi_binary
> >>>>
> >>>> In this patch, all the issues above are sorted out.
> >>>> Please note that the default behavior can be customized with:
> >>>> 	fdtfile: a dtb file name
> >>>> 	efi_dtb_prefixes: a list of paths for searching for a dtb file
> >>>>
> >>>> (this feature does work even without this patch.)
> >>>>
> >>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> >>>> ---
> >>>>  include/config_distro_bootcmd.h | 38 +++++++++++++++++----------------
> >>>>  1 file changed, 20 insertions(+), 18 deletions(-)
> >>>>
> >>>> diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
> >>>> index 373fee78a999..256698309eb9 100644
> >>>> --- a/include/config_distro_bootcmd.h
> >>>> +++ b/include/config_distro_bootcmd.h
> >>>> @@ -115,7 +115,7 @@
> >>>>   */
> >>>>  #define BOOTENV_EFI_SET_FDTFILE_FALLBACK                                  \
> >>>>  	"if test -z \"${fdtfile}\" -a -n \"${soc}\"; then "               \
> >>>> -	  "setenv efi_fdtfile ${soc}-${board}${boardver}.dtb; "           \
> >>>> +	  "efi_fdtfile=${soc}-${board}${boardver}.dtb; "           \
> >>>>  	"fi; "
> >>>>  #else
> >>>>  #define BOOTENV_EFI_SET_FDTFILE_FALLBACK
> >>>> @@ -124,26 +124,20 @@
> >>>>  
> >>>>  #define BOOTENV_SHARED_EFI                                                \
> >>>>  	"boot_efi_binary="                                                \
> >>>> -		"if fdt addr ${fdt_addr_r}; then "                        \
> >>>> -			"bootefi bootmgr ${fdt_addr_r};"                  \
> >>>> -		"else "                                                   \
> >>>> -			"bootefi bootmgr ${fdtcontroladdr};"              \
> >>>> -		"fi;"                                                     \
> >>>>  		"load ${devtype} ${devnum}:${distro_bootpart} "           \
> >>>>  			"${kernel_addr_r} efi/boot/"BOOTEFI_NAME"; "      \
> >>>> -		"if fdt addr ${fdt_addr_r}; then "                        \
> >>>> -			"bootefi ${kernel_addr_r} ${fdt_addr_r};"         \
> >>>> -		"else "                                                   \
> >>>> -			"bootefi ${kernel_addr_r} ${fdtcontroladdr};"     \
> >>>> -		"fi\0"                                                    \
> >>>> +		"bootefi ${kernel_addr_r} ${efi_fdt_addr};\0"		  \
> >>>>  	\
> >>>>  	"load_efi_dtb="                                                   \
> >>>> -		"load ${devtype} ${devnum}:${distro_bootpart} "           \
> >>>> -			"${fdt_addr_r} ${prefix}${efi_fdtfile}\0"         \
> >>>> +		"load ${devtype} ${devnum}:${distro_bootpart} "		  \
> >>>> +			"${fdt_addr_r} ${prefix}${efi_fdtfile}; "	  \
> >>>> +		"if fdt addr ${fdt_addr_r}; then "			  \
> >>>> +			"efi_fdt_addr=${fdt_addr_r}; "			  \
> >>>> +		"fi;\0"							  \
> >>>>  	\
> >>>>  	"efi_dtb_prefixes=/ /dtb/ /dtb/current/\0"                        \
> >>>> -	"scan_dev_for_efi="                                               \
> >>>> -		"setenv efi_fdtfile ${fdtfile}; "                         \
> >>>> +	"set_efi_fdt_addr="						  \
> >>>> +		"efi_fdtfile=${fdtfile}; "                         \
> >>>>  		BOOTENV_EFI_SET_FDTFILE_FALLBACK                          \
> >>>>  		"for prefix in ${efi_dtb_prefixes}; do "                  \
> >>>>  			"if test -e ${devtype} "                          \
> >>>> @@ -151,19 +145,26 @@
> >>>>  					"${prefix}${efi_fdtfile}; then "  \
> >>>>  				"run load_efi_dtb; "                      \
> >>>>  			"fi;"                                             \
> >>>> -		"done;"                                                   \
> >>>> +		"done;\0"                                                   \
> >>>> +	\
> >>>> +	"scan_dev_for_efi="                                               \
> >>>>  		"if test -e ${devtype} ${devnum}:${distro_bootpart} "     \
> >>>>  					"efi/boot/"BOOTEFI_NAME"; then "  \
> >>>>  				"echo Found EFI removable media binary "  \
> >>>>  					"efi/boot/"BOOTEFI_NAME"; "       \
> >>>> +				"efi_fdt_addr=${fdtcontroladdr}; "	  \
> >>>> +				"if test -n \"${fdtfile}\"; then "	  \
> >>>> +					"run set_efi_fdt_addr; "	  \
> >>>> +				"fi; "					  \
> >>>>  				"run boot_efi_binary; "                   \
> >>>>  				"echo EFI LOAD FAILED: continuing...; "   \
> >>>> -		"fi; "                                                    \
> >>>> -		"setenv efi_fdtfile\0"
> >>>> +		"fi;\0"
> >>>>  #define SCAN_DEV_FOR_EFI "run scan_dev_for_efi;"
> >>>> +#define BOOT_EFI_BOOT_MANAGER "bootefi bootmgr;"
> >>>>  #else
> >>>>  #define BOOTENV_SHARED_EFI
> >>>>  #define SCAN_DEV_FOR_EFI
> >>>> +#define BOOT_EFI_BOOT_MANAGER
> >>>>  #endif
> >>>>  
> >>>>  #ifdef CONFIG_SATA
> >>>> @@ -409,6 +410,7 @@
> >>>>  	BOOT_TARGET_DEVICES(BOOTENV_DEV)                                  \
> >>>>  	\
> >>>>  	"distro_bootcmd=" BOOTENV_SET_SCSI_NEED_INIT                      \
> >>>> +		BOOT_EFI_BOOT_MANAGER					  \
> >>>
> >>> The last-minute change may have introduced a problem.
> >>> By moving "bootmgr" from scan_dev_for_efi" to here,
> >>> grub fails to start a grub.cfg menu, saying
> >>>   "error: no such device: /.disk/info."
> >>>
> >>> Do you have any ideas?
> >>
> >> I would guess that bootmgr doesn't set the loaded image target correctly
> >> and before it just happened to work because there was a load command
> >> before the bootmgr command?
> > 
> > The root cause was that efi_init_obj_list(), particularly efi_disk_register(),
> > is executed only once.
> > In my case, efi bootmgr is called before "usb start" in scan_dev_for_efi,
> > and any USB devices will not be added to efi object list forever.
> > Therefore, later on, grub itself can start but cannot detect/access its own
> > boot device (USB mass storage) via efi interface.
> > 
> > I think we can fix this problem in several ways:
> > 1. run all 'device-scanning' commands, like "usb start" and "scsi scan,"
> >    before calling bootmgr in distro_bootcmd,
> 
> This would work, though it's slightly complicated - hm :/.
> 
> > 2. modify efi_obj_init_list() to check and register newly-detected devices,
> 
> That won't work, because then efibootmgr won't be able to boot from USB, no?
> 
> > 3. add a device to efi object list dynamically whenever a 'device-scanning'
> >    command detects one,
> 
> Same here I assume.
> 
> > 4. search and check for a device on-the-fly with each efi device path
> >    (or handle?) specified in efi interface
> 
> That won't work either, because we simply don't initialize USB in the
> efibootmgr case, so there won't be anything on the fly ;).
> 
> > 
> > What do you think?
> 
> I guess one of your options above mentions this and I just missed it,
> but I think we'll have to find out what to initialize in the efibootmgr
> command based on the device path we're trying to execute and then
> initialize that respective subsystem.
> 
> So if we see that the device path involves USB, we need to run "usb
> start" from within the efibootmgr code.

I don't think that this behavior is consistent with other U-boot commands.
For example, "load usb 0:1 ..." doesn't work unless we run "usb start"
first. Efi bootmgr should not be an exception.

-Takahiro Akashi

> 
> Alex