| Message ID | 20190918063837.8196-1-u.kleine-koenig@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | of: restore old handling of cells_name=NULL in of_*_phandle_with_args() | expand |
On 2019-09-18 08:38, Uwe Kleine-König wrote: > From: Uwe Kleine-König <uwe@kleine-koenig.org> > > Before commit e42ee61017f5 ("of: Let of_for_each_phandle fallback to > non-negative cell_count") the iterator functions calling > of_for_each_phandle assumed a cell count of 0 if cells_name was NULL. > This corner case was missed when implementing the fallback logic in > e42ee61017f5 and resulted in an endless loop. > > Restore the old behaviour of of_count_phandle_with_args() and > of_parse_phandle_with_args() and add a check to > of_phandle_iterator_init() to prevent a similar failure as a safety > precaution. of_parse_phandle_with_args_map() doesn't need a similar fix > as cells_name isn't NULL there. > > Affected drivers are: > - drivers/base/power/domain.c > - drivers/base/power/domain.c > - drivers/clk/ti/clk-dra7-atl.c > - drivers/hwmon/ibmpowernv.c > - drivers/i2c/muxes/i2c-demux-pinctrl.c > - drivers/iommu/mtk_iommu.c > - drivers/net/ethernet/freescale/fman/mac.c > - drivers/opp/of.c > - drivers/perf/arm_dsu_pmu.c > - drivers/regulator/of_regulator.c > - drivers/remoteproc/imx_rproc.c > - drivers/soc/rockchip/pm_domains.c > - sound/soc/fsl/imx-audmix.c > - sound/soc/fsl/imx-audmix.c > - sound/soc/meson/axg-card.c > - sound/soc/samsung/tm2_wm5110.c > - sound/soc/samsung/tm2_wm5110.c > > Thanks to Geert Uytterhoeven for reporting the issue, Peter Rosin for > helping pinpoint the actual problem and the testers for confirming this > fix. > > Fixes: e42ee61017f5 ("of: Let of_for_each_phandle fallback to non-negative cell_count") > Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> > Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > Hello, > > compared to the untested patch I sent yesterday I also fixed > of_parse_phandle_with_args which has three users that pass > cells_name=NULL. (i.e. drivers/clk/ti/clk-dra7-atl.c, > sound/soc/fsl/imx-audmix.c, sound/soc/samsung/tm2_wm5110.c) I didn't > look closely, but maybe these could be converted to use of_parse_phandle > as there are no arguments to be processed with no cells_name?! > > Best regards > Uwe > > drivers/of/base.c | 30 ++++++++++++++++++++++++++++-- > 1 file changed, 28 insertions(+), 2 deletions(-) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 2f25d2dfecfa..25ee07c0a3cd 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -1286,6 +1286,13 @@ int of_phandle_iterator_init(struct of_phandle_iterator *it, > > memset(it, 0, sizeof(*it)); > > + /* > + * one of cell_count or cells_name must be provided to determine the > + * argument length. > + */ > + if (cell_count < 0 && !cells_name) > + return -EINVAL; > + > list = of_get_property(np, list_name, &size); > if (!list) > return -ENOENT; > @@ -1512,10 +1519,17 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na > const char *cells_name, int index, > struct of_phandle_args *out_args) > { > + int cell_count = -1; > + > if (index < 0) > return -EINVAL; > - return __of_parse_phandle_with_args(np, list_name, cells_name, -1, > - index, out_args); > + > + /* If cells_name if NULL we assume a cell count of 0 */ > + if (!cells_name) > + cell_count = 0; > + > + return __of_parse_phandle_with_args(np, list_name, cells_name, > + cell_count, index, out_args); > } > EXPORT_SYMBOL(of_parse_phandle_with_args); > > @@ -1765,6 +1779,18 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na > struct of_phandle_iterator it; > int rc, cur_index = 0; > > + /* If cells_name is NULL we assume a cell count of 0 */ > + if (cells_name == NULL) { A couple of nits. I don't know if there are other considerations, but in the previous two hunks you use !cells_name instead of comparing explicitly with NULL. Personally, I find the shorter form more readable, and in the name of consistency bla bla... Also, the comment explaining this NULL-check didn't really make sense to me until I realized that knowing the cell count to be zero makes counting trivial. Something along those lines should perhaps be in the comment? But as I said, these are nits. Feel free to ignore. Cheers, Peter > + const __be32 *list; > + int size; > + > + list = of_get_property(np, list_name, &size); > + if (!list) > + return -ENOENT; > + > + return size / sizeof(*list); > + } > + > rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1); > if (rc) > return rc; >
diff --git a/drivers/of/base.c b/drivers/of/base.c index 2f25d2dfecfa..25ee07c0a3cd 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1286,6 +1286,13 @@ int of_phandle_iterator_init(struct of_phandle_iterator *it, memset(it, 0, sizeof(*it)); + /* + * one of cell_count or cells_name must be provided to determine the + * argument length. + */ + if (cell_count < 0 && !cells_name) + return -EINVAL; + list = of_get_property(np, list_name, &size); if (!list) return -ENOENT; @@ -1512,10 +1519,17 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na const char *cells_name, int index, struct of_phandle_args *out_args) { + int cell_count = -1; + if (index < 0) return -EINVAL; - return __of_parse_phandle_with_args(np, list_name, cells_name, -1, - index, out_args); + + /* If cells_name if NULL we assume a cell count of 0 */ + if (!cells_name) + cell_count = 0; + + return __of_parse_phandle_with_args(np, list_name, cells_name, + cell_count, index, out_args); } EXPORT_SYMBOL(of_parse_phandle_with_args); @@ -1765,6 +1779,18 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na struct of_phandle_iterator it; int rc, cur_index = 0; + /* If cells_name is NULL we assume a cell count of 0 */ + if (cells_name == NULL) { + const __be32 *list; + int size; + + list = of_get_property(np, list_name, &size); + if (!list) + return -ENOENT; + + return size / sizeof(*list); + } + rc = of_phandle_iterator_init(&it, np, list_name, cells_name, -1); if (rc) return rc;