> > Thanks for testing. In that case I will post this change, as I feel this > > should be > > fixed irrespective of my syscon patch. > > > > > But as Xiubo pointed in another mail, it may still cause other issues. > > > Looking at regmap.c, there're still some other places using the device > > pointer, e.g. > > > dev_xxx debug information and some tracepoints also take device pointer as > > > parameter(not sure if it will break if dev is NULL). > > > Another thing is that if dev is NULL, we may not be able to use regmap > > debugfs > > > feature which seems also not as our expected. > > > > > > > I would have preferred to check dev for NULL, as it's only at two places and > > we could > > still have debug prints for NULL dev, as normal pr_info instead of dev_info. > > > > But Xiubo also pointed out that his patch [1] which updates syscon binding > > information > > will be useless if we pass NULL dev in regmap_init_mmio, which he posted > > today, > > and it requires dev pointer in "regmap_get_val_endian" function to read DT > > property. > > > > [1]: [PATCH] mfd: syscon: binding: Add syscon endianness support > > https://lkml.org/lkml/2014/9/18/67 > > > > So instead of adding dummy device or creating device structure, I would > > prefer to get actual > > device pointer corresponding to "np" passed in of_syscon_register function > > as shown below: > > > > I wonder this may not work at early stage before the devices are populated > from device tree. > My initial understanding that one important thing for your patch is > to address this issue, isn't it? > Many people have asked for this feature before. > My boot log: ... of_platform_bus_create() - skipping /chosen, no compatible prop of_platform_bus_create() - skipping /aliases, no compatible prop of_platform_bus_create() - skipping /memory, no compatible prop of_platform_bus_create() - skipping /cpus, no compatible prop create child: /soc/smmu@1200000 create child: /soc/smmu@1280000 create child: /soc/smmu@1300000 create child: /soc/smmu@1380000 create child: /soc/interrupt-controller@1400000 create child: /soc/tzasc@1500000 of_platform_bus_create() - skipping /soc/tzasc@1500000, no compatible prop create child: /soc/ifc@1530000 create child: /soc/ifc@1530000/nor@0,0 create child: /soc/ifc@1530000/board-control@2,0 create child: /soc/dcfg@1ee0000 syscon 1ee0000.dcfg: regmap [mem 0x01ee0000-0x01eeffff] registered create child: /soc/quadspi@1550000 create child: /soc/esdhc@1560000 create child: /soc/scfg@1570000 create child: /soc/crypto@1700000 create child: /soc/sfp@1e80000 of_platform_bus_create() - skipping /soc/sfp@1e80000, no compatible prop create child: /soc/snvs@1e90000 of_platform_bus_create() - skipping /soc/snvs@1e90000, no compatible prop create child: /soc/serdes1@1ea0000 of_platform_bus_create() - skipping /soc/serdes1@1ea0000, no compatible prop create child: /soc/clocking@1ee1000 create child: /soc/rcpm@1ee2000 create child: /soc/dspi@2100000 create child: /soc/dspi@2110000 create child: /soc/i2c@2180000 create child: /soc/i2c@2190000 create child: /soc/i2c@21a0000 create child: /soc/serial@21c0500 create child: /soc/serial@21c0600 create child: /soc/serial@21d0500 create child: /soc/serial@21d0600 create child: /soc/gpio@2300000 create child: /soc/gpio@2310000 create child: /soc/gpio@2320000 create child: /soc/gpio@2330000 create child: /soc/uqe@2400000 create child: /soc/uqe@2400000/qeic@80 create child: /soc/uqe@2400000/ucc@2000 irq: no irq domain found for /soc/uqe@2400000/qeic@80 ! create child: /soc/uqe@2400000/ucc@2200 irq: no irq domain found for /soc/uqe@2400000/qeic@80 ! create child: /soc/uqe@2400000/muram@10000 create child: /soc/uqe@2400000/si@700 create child: /soc/uqe@2400000/siram@1000 create child: /soc/serial@2950000 create child: /soc/serial@2960000 create child: /soc/serial@2970000 create child: /soc/serial@2980000 create child: /soc/serial@2990000 create child: /soc/serial@29a0000 create child: /soc/ftm0_1@29d0000 create child: /soc/ftm@29f0000 of_platform_bus_create() - skipping /soc/ftm@29f0000, no compatible prop create child: /soc/ftm@2a00000 create child: /soc/ftm@2a10000 of_platform_bus_create() - skipping /soc/ftm@2a10000, no compatible prop create child: /soc/ftm@2a20000 of_platform_bus_create() - skipping /soc/ftm@2a20000, no compatible prop create child: /soc/ftm@2a30000 create child: /soc/ftm@2a40000 create child: /soc/wdog@2ad0000 create child: /soc/sai@2b60000 create child: /soc/edma@2c00000 create child: /soc/dcu@2ce0000 create child: /soc/mdio@2d24000 create child: /soc/ptp_clock@2d10e00 create child: /soc/ethernet@2d10000 create child: /soc/ethernet@2d50000 create child: /soc/ethernet@2d90000 create child: /soc/usb@8600000 create child: /soc/usb3@3100000 create child: /soc/can@2a70000 create child: /soc/can@2a80000 create child: /soc/can@2a90000 create child: /soc/can@2aa0000 create child: /soc/pcie@3400000 create child: /soc/pcie@3500000 create child: /dcsr@20000000/dcsr-epu@0 create child: /dcsr@20000000/dcsr-gdi@100000 create child: /dcsr@20000000/dcsr-dddi@120000 create child: /dcsr@20000000/dcsr-dcfg@220000 create child: /dcsr@20000000/dcsr-clock@221000 create child: /dcsr@20000000/dcsr-rcpm@222000 create child: /dcsr@20000000/dcsr-ccp@225000 create child: /dcsr@20000000/dcsr-fusectrl@226000 create child: /dcsr@20000000/dcsr-dap@300000 create child: /dcsr@20000000/dcsr-cstf@350000 create child: /dcsr@20000000/dcsr-a7rom@360000 create child: /dcsr@20000000/dcsr-a7cpu@370000 create child: /dcsr@20000000/dcsr-a7cti@378000 create child: /dcsr@20000000/dcsr-etm@37c000 create child: /dcsr@20000000/dcsr-hugorom@3a0000 create child: /dcsr@20000000/dcsr-etf@3a1000 create child: /dcsr@20000000/dcsr-etr@3a3000 create child: /dcsr@20000000/dcsr-cti@3a4000 create child: /dcsr@20000000/dcsr-atbrepl@3a8000 create child: /dcsr@20000000/dcsr-tsgen-ctrl@3a9000 create child: /dcsr@20000000/dcsr-tsgen-read@3aa000 create child: /regulators/regulator@0 ... As default the Linux will create all the platform device for each DT node, which Can be found from "drivers/of/platform.c". So we can get the pdev node using the specified DT node, and feel safe to use it as Pankaj's patch does. And also we must make sure that the 'syscon' DT nodes has the compatible prop. Thanks, BRs Xiubo > Regards > Dong Aisheng > > > ---- > > static struct syscon *of_syscon_register(struct device_node *np) > > { > > + struct platform_device *pdev; > > struct syscon *syscon; > > struct regmap *regmap; > > void __iomem *base; > > @@ -142,7 +144,11 @@ static struct syscon *of_syscon_register(struct > > device_node *np) > > if (!base) > > return ERR_PTR(-ENOMEM); > > > > - regmap = regmap_init_mmio(NULL, base, &syscon_regmap_config); > > + pdev = of_find_device_by_node(np); > > + if (!(&pdev->dev)) > > + return ERR_PTR(-ENODEV); > > + > > + regmap = regmap_init_mmio(&pdev->dev, base, &syscon_regmap_config); > > if (IS_ERR(regmap)) { > > pr_err("regmap init failed\n"); > > return ERR_CAST(regmap); > > ------- > > > > I have tested this in linux-next and it works well. In this way there won't > > be any issues of > > dereferencing NULL pointer in regmap.c and at the same time, if DT has > > {big,little}-endian > > optional property in syscon device node, it will be taken care. > > > > So I would wait for Arnd's opinion about above mentioned changes and then > > post a new > > change after addressing Arnd's minor comment along with this fix in next > > revision. > > > > > > Thanks, > > Pankaj Dubey > > > Maybe we could consider create device structure for each syscon compatible > > device in > > > syscon driver in of_syscon_register in first time which seems to be > > reasonable. > > > > > > Regards > > > Dong Aisheng > > > > > > > -------------------------------------------- > > > > Subject: [PATCH] regmap: fix NULL pointer dereference in > > > > regmap_get_val_endian > > > > > > > > Recent commits for getting reg endianess causing NULL pointer > > > > dereference if dev is passed NULL in regmap_init_mmio. This patch > > > > fixes this issue, and allows to parse reg endianess only if dev and > > > > dev->of_node exist. > > > > > > > > Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx> > > > > --- > > > > drivers/base/regmap/regmap.c | 23 ++++++++++++++--------- > > > > 1 file changed, 14 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/drivers/base/regmap/regmap.c > > > > b/drivers/base/regmap/regmap.c index f2281af..455a877 100644 > > > > --- a/drivers/base/regmap/regmap.c > > > > +++ b/drivers/base/regmap/regmap.c > > > > @@ -477,7 +477,7 @@ static enum regmap_endian > > > > regmap_get_val_endian(struct device *dev, > > > > const struct regmap_bus *bus, > > > > const struct regmap_config *config) > > { > > > > - struct device_node *np = dev->of_node; > > > > + struct device_node *np; > > > > enum regmap_endian endian; > > > > > > > > /* Retrieve the endianness specification from the regmap config > */ > > > > @@ -487,15 +487,20 @@ static enum regmap_endian > > > > regmap_get_val_endian(struct device *dev, > > > > if (endian != REGMAP_ENDIAN_DEFAULT) > > > > return endian; > > > > > > > > - /* Parse the device's DT node for an endianness specification */ > > > > - if (of_property_read_bool(np, "big-endian")) > > > > - endian = REGMAP_ENDIAN_BIG; > > > > - else if (of_property_read_bool(np, "little-endian")) > > > > - endian = REGMAP_ENDIAN_LITTLE; > > > > + /* If the dev and dev->of_node exist try to get endianness from > DT > > > > */ > > > > + if (dev && dev->of_node) { > > > > + np = dev->of_node; > > > > > > > > - /* If the endianness was specified in DT, use that */ > > > > - if (endian != REGMAP_ENDIAN_DEFAULT) > > > > - return endian; > > > > + /* Parse the device's DT node for an endianness > > > > specification */ > > > > + if (of_property_read_bool(np, "big-endian")) > > > > + endian = REGMAP_ENDIAN_BIG; > > > > + else if (of_property_read_bool(np, "little-endian")) > > > > + endian = REGMAP_ENDIAN_LITTLE; > > > > + > > > > + /* If the endianness was specified in DT, use that */ > > > > + if (endian != REGMAP_ENDIAN_DEFAULT) > > > > + return endian; > > > > + } > > > > > > > > /* Retrieve the endianness specification from the bus config */ > > > > if (bus && bus->val_format_endian_default) > > > > -- > > > > > > > > Thanks, > > > > Pankaj Dubey > > > > > > > > > Regards > > > > > Dong Aisheng > > > > > > > > > > > > > > > > > Thanks, > > > > > > Pankaj Dubey > > > > > > > > > > > > > Regards > > > > > > > Dong Aisheng > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > > > > linux-arm-kernel mailing list > > > > > > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > > > > > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > > > > > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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