of: address: Preserve the flags portion on 1:1 dma-ranges mapping

commit 7f05e20b989ac33c9c0f8c2028ec0a566493548f upstream.

A missing or empty dma-ranges in a DT node implies a 1:1 mapping for dma
translations. In this specific case, the current behaviour is to zero out
the entire specifier so that the translation could be carried on as an
offset from zero. This includes address specifier that has flags (e.g.
PCI ranges).

Once the flags portion has been zeroed, the translation chain is broken
since the mapping functions will check the upcoming address specifier
against mismatching flags, always failing the 1:1 mapping and its entire
purpose of always succeeding.

Set to zero only the address portion while passing the flags through.

Fixes: dbbdee94734b ("of/address: Merge all of the bus translation code")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
Tested-by: Herve Codina <herve.codina@bootlin.com>
Link: https://lore.kernel.org/r/e51ae57874e58a9b349c35e2e877425ebc075d7a.1732441813.git.andrea.porta@suse.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 286f0c161e332f29d84921455c6e1aeb52275a7f..b3479586bd4d3572021bc4c682e280ec8d7386fd 100644 (file)
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -455,7 +455,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus,
        }
        if (ranges == NULL || rlen == 0) {
                offset = of_read_number(addr, na);
-               memset(addr, 0, pna * 4);
+               /* set address to zero, pass flags through */
+               memset(addr + pbus->flag_cells, 0, (pna - pbus->flag_cells) * 4);
                pr_debug("empty ranges; 1:1 translation\n");
                goto finish;
        }