[U-Boot] [PATCH v2] cmd_bootm.c: Correct BOOTM_ERR_OVERLAP handling

[Tom Rini]

On Fri, Jun 28, 2013 at 02:41:49PM -0700, Simon Glass wrote:
> Hi Tom,
> 
> On Fri, Jun 28, 2013 at 1:25 PM, Tom Rini <trini at ti.com> wrote:
> 
> > With 35fc84fa1 [Refactor the bootm command to reduce code duplication]
> > we stopped checking the return value of bootm_load_os (unintentionally!)
> > and simply returned if we had a non-zero return value from the function.
> > This broke the valid case of a legacy image file of a single kernel
> > loaded into an overlapping memory area (the default way of booting
> > nearly all TI platforms).
> >
> > The best way to fix this problem in the new code is to make
> > bootm_load_os be the one to see if we have a problem with this, and if
> > it's fatal return BOOTM_ERR_RESET and if it's not BOOTM_ERR_OVERLAP, so
> > that we can avoid calling lmb_reserve() but continue with booting.  We
> > however still need to handle the other BOOTM_ERR values so re-work
> > do_bootm_states so that we have an error handler at the bottom we can
> > goto for problems from bootm_load_os, or problems from the other callers
> > (as the code was before).  Add a comment to do_bootm_states noting the
> > existing restriction on negative return values.
> >
> > Signed-off-by: Tom Rini <trini at ti.com>
> >
> > ---
> > Changes in v2:
> > - Rework so that only bootm_load_os and boot_selected_os head down into
> >   the err case code, and other errors simply return back to the caller.
> >   Fixes 'spl export'.
> > ---
> >  common/cmd_bootm.c |   65
> > ++++++++++++++++++++++++++++++----------------------
> >  1 file changed, 38 insertions(+), 27 deletions(-)
> >
> > diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
> > index ba0bcd4..3009ece 100644
> > --- a/common/cmd_bootm.c
> > +++ b/common/cmd_bootm.c
> > @@ -345,8 +345,10 @@ static int bootm_find_other(cmd_tbl_t *cmdtp, int
> > flag, int argc,
> >  #define BOOTM_ERR_RESET                -1
> >  #define BOOTM_ERR_OVERLAP      -2
> >  #define BOOTM_ERR_UNIMPLEMENTED        -3
> > -static int bootm_load_os(image_info_t os, ulong *load_end, int
> > boot_progress)
> > +static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end,
> > +               int boot_progress)
> >  {
> > +       image_info_t os = images->os;
> >         uint8_t comp = os.comp;
> >         ulong load = os.load;
> >         ulong blob_start = os.start;
> > @@ -464,7 +466,17 @@ static int bootm_load_os(image_info_t os, ulong
> > *load_end, int boot_progress)
> >                 debug("images.os.load = 0x%lx, load_end = 0x%lx\n", load,
> >                         *load_end);
> >
> > -               return BOOTM_ERR_OVERLAP;
> > +               /* Check what type of image this is. */
> > +               if (images->legacy_hdr_valid) {
> > +                       if (image_get_type(&images->legacy_hdr_os_copy)
> > +                                       == IH_TYPE_MULTI)
> > +                               puts("WARNING: legacy format multi
> > component image overwritten\n");
> > +                       return BOOTM_ERR_OVERLAP;
> > +               } else {
> > +                       puts("ERROR: new format image overwritten - must
> > RESET the board to recover\n");
> > +                       bootstage_error(BOOTSTAGE_ID_OVERWRITTEN);
> > +                       return BOOTM_ERR_RESET;
> > +               }
> >         }
> >
> >         return 0;
> > @@ -558,6 +570,10 @@ static int boot_selected_os(int argc, char * const
> > argv[], int state,
> >   * Note that if states contains more than one flag it MUST contain
> >   * BOOTM_STATE_START, since this handles and consumes the command line
> > args.
> >   *
> > + * Also note that aside from boot_os_fn functions and bootm_load_os no
> > other
> > + * functions we store the return value of in 'ret' may use a negative
> > return
> > + * value, without special handling.
> > + *
> >   * @param cmdtp                Pointer to bootm command table entry
> >   * @param flag         Command flags (CMD_FLAG_...)
> >   * @param argc         Number of subcommand arguments (0 = no arguments)
> > @@ -599,11 +615,15 @@ static int do_bootm_states(cmd_tbl_t *cmdtp, int
> > flag, int argc,
> >         if (!ret && (states & BOOTM_STATE_LOADOS)) {
> >                 ulong load_end;
> >
> > -               ret = bootm_load_os(images->os, &load_end, 0);
> > -               if (!ret) {
> > +               ret = bootm_load_os(images, &load_end, 0);
> > +               if (ret && ret != BOOTM_ERR_OVERLAP)
> > +                       goto err;
> > +
> > +               if (ret == 0)
> >                         lmb_reserve(&images->lmb, images->os.load,
> >                                     (load_end - images->os.load));
> > -               }
> > +               else if (ret == BOOTM_ERR_OVERLAP)
> > +                       ret = 0;
> >         }
> >
> >         /* Relocate the ramdisk */
> > @@ -660,34 +680,25 @@ static int do_bootm_states(cmd_tbl_t *cmdtp, int
> > flag, int argc,
> >         }
> >  #endif
> >         /* Now run the OS! We hope this doesn't return */
> > -       if (!ret && (states & BOOTM_STATE_OS_GO))
> > +       if (!ret && (states & BOOTM_STATE_OS_GO)) {
> >                 ret = boot_selected_os(argc, argv, BOOTM_STATE_OS_GO,
> >                                 images, boot_fn, &iflag);
> > +               if (ret)
> > +                       goto err;
> > +       }
> > +
> > +       return ret;
> >
> 
> Thanks for getting to the bottom of this.
> 
> Just a question here - should this fall through to display the error with
> the code below? For example if the subcommand is not supported...

Good point.  But we also aren't able to say what the subcommand is
anymore, so it's not as helpful, but we do need to say something.

I also don't want to leave things non-functional over the weekend, so
I'm pushing this version now, and we'll need another clean-up early next
week.  Thanks for spotting!

-- 
Tom
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