| Message ID | 1488782334-31000-1-git-send-email-eddie.cai.linux@gmail.com |
|---|---|
| State | Rejected |
| Delegated to: | Tom Rini |
| Headers | show |
On Mon, Mar 06, 2017 at 02:38:54PM +0800, Eddie Cai wrote: > scan_dev_for_boot_part will fail when there is no GPT table. So add auto write > GPT table if fail to get it. > > Signed-off-by: Eddie Cai <eddie.cai.linux@gmail.com> > --- > include/config_distro_bootcmd.h | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h > index 0e01e82..3be8ffa 100644 > --- a/include/config_distro_bootcmd.h > +++ b/include/config_distro_bootcmd.h > @@ -368,6 +368,14 @@ > "\0" \ > \ > "scan_dev_for_boot_part=" \ > + "part list ${devtype} ${devnum} -bootable test; " \ > + "if env exists test; then " \ > + "echo Found valid partition table; " \ > + "else " \ > + "echo No valid partition table, write the original partition table; " \ > + "gpt write ${devtype} ${devnum} ${partitions}; " \ > + "mmc rescan;" \ > + "fi;" \ > "part list ${devtype} ${devnum} -bootable devplist; " \ > "env exists devplist || setenv devplist 1; " \ > "for distro_bootpart in ${devplist}; do " \ Er, this feels rather risky to me. Why are we writing a table? How do we know it exists?
On Tue, Mar 07, 2017 at 08:29:52AM -0500, Tom Rini wrote: > On Mon, Mar 06, 2017 at 02:38:54PM +0800, Eddie Cai wrote: > > scan_dev_for_boot_part will fail when there is no GPT table. So add auto write > > GPT table if fail to get it. > > > > Signed-off-by: Eddie Cai <eddie.cai.linux@gmail.com> > > --- > > include/config_distro_bootcmd.h | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h > > index 0e01e82..3be8ffa 100644 > > --- a/include/config_distro_bootcmd.h > > +++ b/include/config_distro_bootcmd.h > > @@ -368,6 +368,14 @@ > > "\0" \ > > \ > > "scan_dev_for_boot_part=" \ > > + "part list ${devtype} ${devnum} -bootable test; " \ > > + "if env exists test; then " \ > > + "echo Found valid partition table; " \ > > + "else " \ > > + "echo No valid partition table, write the original partition table; " \ > > + "gpt write ${devtype} ${devnum} ${partitions}; " \ > > + "mmc rescan;" \ > > + "fi;" \ > > "part list ${devtype} ${devnum} -bootable devplist; " \ > > "env exists devplist || setenv devplist 1; " \ > > "for distro_bootpart in ${devplist}; do " \ > > Er, this feels rather risky to me. Why are we writing a table? How do > we know it exists? Please _never_ write a partition table as part of the default distro boot environment, and in particular not a GPT. The default boot environment should never perform any write access to storage media. Besides this general concern, writing a GPT regardless of whether a platform can actually use a GPT is a really bad idea as it will result in non-booting devices on certain platforms. An MBR-style partition table only uses the first sector, but GPT covers the first 34 512-bytes sectors of the medium and there are a number of systems that have their SPL inside this area, which means those are effectively dead after writing a GPT. One example for this are all sunxi-based systems on which the boot-ROM loads the SPL from sector 16 of the MMC device. Regards, Karsten
diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h index 0e01e82..3be8ffa 100644 --- a/include/config_distro_bootcmd.h +++ b/include/config_distro_bootcmd.h @@ -368,6 +368,14 @@ "\0" \ \ "scan_dev_for_boot_part=" \ + "part list ${devtype} ${devnum} -bootable test; " \ + "if env exists test; then " \ + "echo Found valid partition table; " \ + "else " \ + "echo No valid partition table, write the original partition table; " \ + "gpt write ${devtype} ${devnum} ${partitions}; " \ + "mmc rescan;" \ + "fi;" \ "part list ${devtype} ${devnum} -bootable devplist; " \ "env exists devplist || setenv devplist 1; " \ "for distro_bootpart in ${devplist}; do " \
scan_dev_for_boot_part will fail when there is no GPT table. So add auto write GPT table if fail to get it. Signed-off-by: Eddie Cai <eddie.cai.linux@gmail.com> --- include/config_distro_bootcmd.h | 8 ++++++++ 1 file changed, 8 insertions(+)