arch/x86/kernel/fpu/xstate.c:1117:7: warning: Local variable 'mask' shadows outer variable [shadowVariable]
From: kernel test robot
Date: Tue Apr 26 2022 - 08:25:30 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: d615b5416f8a1afeb82d13b238f8152c572d59c0
commit: 522e92743b35351bda1b6a9136560f833a9c2490 x86/fpu: Deduplicate copy_uabi_from_user/kernel_to_xstate()
date: 10 months ago
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
reproduce (cppcheck warning):
# apt-get install cppcheck
git checkout 522e92743b35351bda1b6a9136560f833a9c2490
cppcheck --quiet --enable=style,performance,portability --template=gcc FILE
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
cppcheck warnings: (new ones prefixed by >>)
>> arch/x86/kernel/fpu/xstate.c:1117:7: warning: Local variable 'mask' shadows outer variable [shadowVariable]
u64 mask = ((u64)1 << i);
^
arch/x86/kernel/fpu/xstate.c:1086:6: note: Shadowed declaration
u64 mask;
^
arch/x86/kernel/fpu/xstate.c:1117:7: note: Shadow variable
u64 mask = ((u64)1 << i);
^
vim +/mask +1117 arch/x86/kernel/fpu/xstate.c
947f4947cf00ea Thomas Gleixner 2021-06-23 1079
522e92743b3535 Thomas Gleixner 2021-06-23 1080
522e92743b3535 Thomas Gleixner 2021-06-23 1081 static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf,
522e92743b3535 Thomas Gleixner 2021-06-23 1082 const void __user *ubuf)
79fecc2b7506f2 Ingo Molnar 2017-09-23 1083 {
79fecc2b7506f2 Ingo Molnar 2017-09-23 1084 unsigned int offset, size;
80d8ae86b36791 Eric Biggers 2017-09-24 1085 struct xstate_header hdr;
522e92743b3535 Thomas Gleixner 2021-06-23 1086 u64 mask;
522e92743b3535 Thomas Gleixner 2021-06-23 1087 int i;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1088
79fecc2b7506f2 Ingo Molnar 2017-09-23 1089 offset = offsetof(struct xregs_state, header);
522e92743b3535 Thomas Gleixner 2021-06-23 1090 if (copy_from_buffer(&hdr, offset, sizeof(hdr), kbuf, ubuf))
522e92743b3535 Thomas Gleixner 2021-06-23 1091 return -EFAULT;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1092
5274e6c172c472 Fenghua Yu 2020-05-12 1093 if (validate_user_xstate_header(&hdr))
79fecc2b7506f2 Ingo Molnar 2017-09-23 1094 return -EINVAL;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1095
522e92743b3535 Thomas Gleixner 2021-06-23 1096 /* Validate MXCSR when any of the related features is in use */
522e92743b3535 Thomas Gleixner 2021-06-23 1097 mask = XFEATURE_MASK_FP | XFEATURE_MASK_SSE | XFEATURE_MASK_YMM;
522e92743b3535 Thomas Gleixner 2021-06-23 1098 if (hdr.xfeatures & mask) {
522e92743b3535 Thomas Gleixner 2021-06-23 1099 u32 mxcsr[2];
522e92743b3535 Thomas Gleixner 2021-06-23 1100
522e92743b3535 Thomas Gleixner 2021-06-23 1101 offset = offsetof(struct fxregs_state, mxcsr);
522e92743b3535 Thomas Gleixner 2021-06-23 1102 if (copy_from_buffer(mxcsr, offset, sizeof(mxcsr), kbuf, ubuf))
522e92743b3535 Thomas Gleixner 2021-06-23 1103 return -EFAULT;
522e92743b3535 Thomas Gleixner 2021-06-23 1104
522e92743b3535 Thomas Gleixner 2021-06-23 1105 /* Reserved bits in MXCSR must be zero. */
522e92743b3535 Thomas Gleixner 2021-06-23 1106 if (mxcsr[0] & ~mxcsr_feature_mask)
947f4947cf00ea Thomas Gleixner 2021-06-23 1107 return -EINVAL;
947f4947cf00ea Thomas Gleixner 2021-06-23 1108
522e92743b3535 Thomas Gleixner 2021-06-23 1109 /* SSE and YMM require MXCSR even when FP is not in use. */
522e92743b3535 Thomas Gleixner 2021-06-23 1110 if (!(hdr.xfeatures & XFEATURE_MASK_FP)) {
522e92743b3535 Thomas Gleixner 2021-06-23 1111 xsave->i387.mxcsr = mxcsr[0];
522e92743b3535 Thomas Gleixner 2021-06-23 1112 xsave->i387.mxcsr_mask = mxcsr[1];
522e92743b3535 Thomas Gleixner 2021-06-23 1113 }
522e92743b3535 Thomas Gleixner 2021-06-23 1114 }
522e92743b3535 Thomas Gleixner 2021-06-23 1115
79fecc2b7506f2 Ingo Molnar 2017-09-23 1116 for (i = 0; i < XFEATURE_MAX; i++) {
79fecc2b7506f2 Ingo Molnar 2017-09-23 @1117 u64 mask = ((u64)1 << i);
79fecc2b7506f2 Ingo Molnar 2017-09-23 1118
b89eda482d7849 Eric Biggers 2017-09-24 1119 if (hdr.xfeatures & mask) {
07baeb04f37c95 Sebastian Andrzej Siewior 2019-04-03 1120 void *dst = __raw_xsave_addr(xsave, i);
79fecc2b7506f2 Ingo Molnar 2017-09-23 1121
79fecc2b7506f2 Ingo Molnar 2017-09-23 1122 offset = xstate_offsets[i];
79fecc2b7506f2 Ingo Molnar 2017-09-23 1123 size = xstate_sizes[i];
79fecc2b7506f2 Ingo Molnar 2017-09-23 1124
522e92743b3535 Thomas Gleixner 2021-06-23 1125 if (copy_from_buffer(dst, offset, size, kbuf, ubuf))
522e92743b3535 Thomas Gleixner 2021-06-23 1126 return -EFAULT;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1127 }
79fecc2b7506f2 Ingo Molnar 2017-09-23 1128 }
79fecc2b7506f2 Ingo Molnar 2017-09-23 1129
79fecc2b7506f2 Ingo Molnar 2017-09-23 1130 /*
79fecc2b7506f2 Ingo Molnar 2017-09-23 1131 * The state that came in from userspace was user-state only.
79fecc2b7506f2 Ingo Molnar 2017-09-23 1132 * Mask all the user states out of 'xfeatures':
79fecc2b7506f2 Ingo Molnar 2017-09-23 1133 */
8ab22804efefea Fenghua Yu 2020-05-12 1134 xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1135
79fecc2b7506f2 Ingo Molnar 2017-09-23 1136 /*
79fecc2b7506f2 Ingo Molnar 2017-09-23 1137 * Add back in the features that came in from userspace:
79fecc2b7506f2 Ingo Molnar 2017-09-23 1138 */
b89eda482d7849 Eric Biggers 2017-09-24 1139 xsave->header.xfeatures |= hdr.xfeatures;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1140
79fecc2b7506f2 Ingo Molnar 2017-09-23 1141 return 0;
79fecc2b7506f2 Ingo Molnar 2017-09-23 1142 }
79fecc2b7506f2 Ingo Molnar 2017-09-23 1143
:::::: The code at line 1117 was first introduced by commit
:::::: 79fecc2b7506f29fb91becc65e8788e5ae7eba9f x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate()
:::::: TO: Ingo Molnar <mingo@xxxxxxxxxx>
:::::: CC: Ingo Molnar <mingo@xxxxxxxxxx>
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