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libfdt: Correct fdt handling of overlays without fixups and base trees without symbols

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The fdt_overlay_apply() function purports to support the edge cases where
an overlay has no fixups to be applied, or a base tree which has no
symbols (the latter can only work if the former is also true).  However it
gets it wrong in a couple of small ways:

  * In the no fixups case, it doesn't fail immediately, but will attempt
    fdt_for_each_property_offset() giving -FDT_ERR_NOTFOUND as the node
    offset, which will fail.  Instead it should succeed immediately, since
    there's nothing to do.
  * In the case of no symbols, it again doesn't fail immediately.  However
    if there is an actual fixup it will fail with an unexpected error,
    because -FDT_ERR_NOTFOUND is passed to fdt_getprop() when attempting to
    look up the symbols.  We should instead return -FDT_ERR_NOTFOUND
    directly.

Both of these errors lead to the code returning misleading error codes in
failing cases.

[ DTC commit: 7d8ef6e1db9794f72805a0855f4f7f12fadd03d3 ]

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Acked-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
David Gibson 2016-12-20 15:58:44 +01:00 committed by Simon Glass
parent 70c1e0474a
commit 46743c412d
1 changed files with 6 additions and 1 deletions
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7
lib/libfdt/fdt_overlay.c
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@ -359,6 +359,9 @@ static int overlay_fixup_one_phandle(void *fdt, void *fdto,
int symbol_off, fixup_off;
int prop_len;
if (symbols_off < 0)
return symbols_off;
symbol_path = fdt_getprop(fdt, symbols_off, label,
&prop_len);
if (!symbol_path)
@ -492,7 +495,9 @@ static int overlay_fixup_phandles(void *fdt, void *fdto)
/* We can have overlays without any fixups */
fixups_off = fdt_path_offset(fdto, "/__fixups__");
if ((fixups_off < 0 && (fixups_off != -FDT_ERR_NOTFOUND)))
if (fixups_off == -FDT_ERR_NOTFOUND)
return 0; /* nothing to do */
if (fixups_off < 0)
return fixups_off;
/* And base DTs without symbols */