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* [pci:controller/imx6 2/2] drivers/pci/controller/dwc/pci-imx6.c:1116:11: warning: variable 'sid' is used uninitialized whenever 'if' condition is false
@ 2025-01-15  7:19 kernel test robot
  2025-01-15 21:03 ` Bjorn Helgaas
  0 siblings, 1 reply; 2+ messages in thread
From: kernel test robot @ 2025-01-15  7:19 UTC (permalink / raw)
  To: Frank Li
  Cc: llvm, oe-kbuild-all, linux-pci, Krzysztof Wilczyński,
	Bjorn Helgaas

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git controller/imx6
head:   bc92494deb1c40f7336ca645c3815f19a5d0e2af
commit: d02f7572cb39c962d0e432f57a267a844d164b4f [2/2] PCI: imx6: Add IOMMU and ITS MSI support for i.MX95
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20250115/202501151501.d4MgHDRq-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250115/202501151501.d4MgHDRq-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501151501.d4MgHDRq-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/pci/controller/dwc/pci-imx6.c:19:
   In file included from include/linux/module.h:19:
   In file included from include/linux/elf.h:6:
   In file included from arch/s390/include/asm/elf.h:181:
   In file included from arch/s390/include/asm/mmu_context.h:11:
   In file included from arch/s390/include/asm/pgalloc.h:18:
   In file included from include/linux/mm.h:2223:
   include/linux/vmstat.h:504:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     504 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     505 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:511:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     511 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     512 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:524:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     524 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     525 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
>> drivers/pci/controller/dwc/pci-imx6.c:1116:11: warning: variable 'sid' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
    1116 |         else if (!err_m)
         |                  ^~~~~~
   drivers/pci/controller/dwc/pci-imx6.c:1119:41: note: uninitialized use occurs here
    1119 |         return imx_pcie_add_lut(imx_pcie, rid, sid);
         |                                                ^~~
   drivers/pci/controller/dwc/pci-imx6.c:1116:7: note: remove the 'if' if its condition is always true
    1116 |         else if (!err_m)
         |              ^~~~~~~~~~~
    1117 |                 sid = sid_m & IMX95_SID_MASK;
   drivers/pci/controller/dwc/pci-imx6.c:1044:9: note: initialize the variable 'sid' to silence this warning
    1044 |         u32 sid;
         |                ^
         |                 = 0
   5 warnings generated.


vim +1116 drivers/pci/controller/dwc/pci-imx6.c

  1035	
  1036	static int imx_pcie_enable_device(struct pci_host_bridge *bridge,
  1037					  struct pci_dev *pdev)
  1038	{
  1039		struct imx_pcie *imx_pcie = to_imx_pcie(to_dw_pcie_from_pp(bridge->sysdata));
  1040		u32 sid_i, sid_m, rid = pci_dev_id(pdev);
  1041		struct device_node *target;
  1042		struct device *dev;
  1043		int err_i, err_m;
  1044		u32 sid;
  1045	
  1046		dev = imx_pcie->pci->dev;
  1047	
  1048		target = NULL;
  1049		err_i = of_map_id(dev->of_node, rid, "iommu-map", "iommu-map-mask",
  1050				  &target, &sid_i);
  1051		if (target) {
  1052			of_node_put(target);
  1053		} else {
  1054			/*
  1055			 * "target == NULL && err_i == 0" means RID out of map range.
  1056			 * Use 1:1 map RID to streamID. Hardware can't support this
  1057			 * because the streamID is only 6 bits
  1058			 */
  1059			err_i = -EINVAL;
  1060		}
  1061	
  1062		target = NULL;
  1063		err_m = of_map_id(dev->of_node, rid, "msi-map", "msi-map-mask",
  1064				  &target, &sid_m);
  1065	
  1066		/*
  1067		 *   err_m      target
  1068		 *	0	NULL		RID out of range. Use 1:1 map RID to
  1069		 *				streamID, Current hardware can't
  1070		 *				support it, so return -EINVAL.
  1071		 *      != 0    NULL		msi-map does not exist, use built-in MSI
  1072		 *	0	!= NULL		Get correct streamID from RID
  1073		 *	!= 0	!= NULL		Invalid combination
  1074		 */
  1075		if (!err_m && !target)
  1076			return -EINVAL;
  1077		else if (target)
  1078			of_node_put(target); /* Find streamID map entry for RID in msi-map */
  1079	
  1080		/*
  1081		 * msi-map        iommu-map
  1082		 *   N                N            DWC MSI Ctrl
  1083		 *   Y                Y            ITS + SMMU, require the same SID
  1084		 *   Y                N            ITS
  1085		 *   N                Y            DWC MSI Ctrl + SMMU
  1086		 */
  1087		if (err_i && err_m)
  1088			return 0;
  1089	
  1090		if (!err_i && !err_m) {
  1091			/*
  1092			 *	    Glue Layer
  1093			 *          <==========>
  1094			 * ┌─────┐                  ┌──────────┐
  1095			 * │ LUT │ 6-bit streamID   │          │
  1096			 * │     │─────────────────►│  MSI     │
  1097			 * └─────┘   2-bit ctrl ID  │          │
  1098			 *             ┌───────────►│          │
  1099			 *  (i.MX95)   │            │          │
  1100			 *  00 PCIe0   │            │          │
  1101			 *  01 ENETC   │            │          │
  1102			 *  10 PCIe1   │            │          │
  1103			 *             │            └──────────┘
  1104			 * The MSI glue layer auto adds 2 bits controller ID ahead of
  1105			 * streamID, so mask these 2 bits to get streamID. The
  1106			 * IOMMU glue layer doesn't do that.
  1107			 */
  1108			if (sid_i != (sid_m & IMX95_SID_MASK)) {
  1109				dev_err(dev, "iommu-map and msi-map entries mismatch!\n");
  1110				return -EINVAL;
  1111			}
  1112		}
  1113	
  1114		if (!err_i)
  1115			sid = sid_i;
> 1116		else if (!err_m)
  1117			sid = sid_m & IMX95_SID_MASK;
  1118	
  1119		return imx_pcie_add_lut(imx_pcie, rid, sid);
  1120	}
  1121	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

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2025-01-15  7:19 [pci:controller/imx6 2/2] drivers/pci/controller/dwc/pci-imx6.c:1116:11: warning: variable 'sid' is used uninitialized whenever 'if' condition is false kernel test robot
2025-01-15 21:03 ` Bjorn Helgaas

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