arch/powerpc/lib/sstep.c:1172:21: error: variable 'suffix' set but not used

From: kernel test robot
Date: Thu Oct 29 2020 - 14:00:45 EST


Hi Jordan,

FYI, the error/warning still remains.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 23859ae44402f4d935b9ee548135dd1e65e2cbf4
commit: 650b55b707fdfa764e9f2b81314d3eb4216fb962 powerpc: Add prefixed instructions to instruction data type
date: 5 months ago
config: powerpc-allnoconfig (attached as .config)
compiler: powerpc-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=650b55b707fdfa764e9f2b81314d3eb4216fb962
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 650b55b707fdfa764e9f2b81314d3eb4216fb962
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

arch/powerpc/lib/sstep.c: In function 'analyse_instr':
>> arch/powerpc/lib/sstep.c:1172:21: error: variable 'suffix' set but not used [-Werror=unused-but-set-variable]
1172 | unsigned int word, suffix;
| ^~~~~~
arch/powerpc/lib/sstep.c:1168:31: error: variable 'rc' set but not used [-Werror=unused-but-set-variable]
1168 | unsigned int opcode, ra, rb, rc, rd, spr, u;
| ^~
cc1: all warnings being treated as errors

vim +/suffix +1172 arch/powerpc/lib/sstep.c

1153
1154 /*
1155 * Decode an instruction, and return information about it in *op
1156 * without changing *regs.
1157 * Integer arithmetic and logical instructions, branches, and barrier
1158 * instructions can be emulated just using the information in *op.
1159 *
1160 * Return value is 1 if the instruction can be emulated just by
1161 * updating *regs with the information in *op, -1 if we need the
1162 * GPRs but *regs doesn't contain the full register set, or 0
1163 * otherwise.
1164 */
1165 int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
1166 struct ppc_inst instr)
1167 {
1168 unsigned int opcode, ra, rb, rc, rd, spr, u;
1169 unsigned long int imm;
1170 unsigned long int val, val2;
1171 unsigned int mb, me, sh;
> 1172 unsigned int word, suffix;
1173 long ival;
1174
1175 word = ppc_inst_val(instr);
1176 suffix = ppc_inst_suffix(instr);
1177
1178 op->type = COMPUTE;
1179
1180 opcode = ppc_inst_primary_opcode(instr);
1181 switch (opcode) {
1182 case 16: /* bc */
1183 op->type = BRANCH;
1184 imm = (signed short)(word & 0xfffc);
1185 if ((word & 2) == 0)
1186 imm += regs->nip;
1187 op->val = truncate_if_32bit(regs->msr, imm);
1188 if (word & 1)
1189 op->type |= SETLK;
1190 if (branch_taken(word, regs, op))
1191 op->type |= BRTAKEN;
1192 return 1;
1193 #ifdef CONFIG_PPC64
1194 case 17: /* sc */
1195 if ((word & 0xfe2) == 2)
1196 op->type = SYSCALL;
1197 else
1198 op->type = UNKNOWN;
1199 return 0;
1200 #endif
1201 case 18: /* b */
1202 op->type = BRANCH | BRTAKEN;
1203 imm = word & 0x03fffffc;
1204 if (imm & 0x02000000)
1205 imm -= 0x04000000;
1206 if ((word & 2) == 0)
1207 imm += regs->nip;
1208 op->val = truncate_if_32bit(regs->msr, imm);
1209 if (word & 1)
1210 op->type |= SETLK;
1211 return 1;
1212 case 19:
1213 switch ((word >> 1) & 0x3ff) {
1214 case 0: /* mcrf */
1215 op->type = COMPUTE + SETCC;
1216 rd = 7 - ((word >> 23) & 0x7);
1217 ra = 7 - ((word >> 18) & 0x7);
1218 rd *= 4;
1219 ra *= 4;
1220 val = (regs->ccr >> ra) & 0xf;
1221 op->ccval = (regs->ccr & ~(0xfUL << rd)) | (val << rd);
1222 return 1;
1223
1224 case 16: /* bclr */
1225 case 528: /* bcctr */
1226 op->type = BRANCH;
1227 imm = (word & 0x400)? regs->ctr: regs->link;
1228 op->val = truncate_if_32bit(regs->msr, imm);
1229 if (word & 1)
1230 op->type |= SETLK;
1231 if (branch_taken(word, regs, op))
1232 op->type |= BRTAKEN;
1233 return 1;
1234
1235 case 18: /* rfid, scary */
1236 if (regs->msr & MSR_PR)
1237 goto priv;
1238 op->type = RFI;
1239 return 0;
1240
1241 case 150: /* isync */
1242 op->type = BARRIER | BARRIER_ISYNC;
1243 return 1;
1244
1245 case 33: /* crnor */
1246 case 129: /* crandc */
1247 case 193: /* crxor */
1248 case 225: /* crnand */
1249 case 257: /* crand */
1250 case 289: /* creqv */
1251 case 417: /* crorc */
1252 case 449: /* cror */
1253 op->type = COMPUTE + SETCC;
1254 ra = (word >> 16) & 0x1f;
1255 rb = (word >> 11) & 0x1f;
1256 rd = (word >> 21) & 0x1f;
1257 ra = (regs->ccr >> (31 - ra)) & 1;
1258 rb = (regs->ccr >> (31 - rb)) & 1;
1259 val = (word >> (6 + ra * 2 + rb)) & 1;
1260 op->ccval = (regs->ccr & ~(1UL << (31 - rd))) |
1261 (val << (31 - rd));
1262 return 1;
1263 }
1264 break;
1265 case 31:
1266 switch ((word >> 1) & 0x3ff) {
1267 case 598: /* sync */
1268 op->type = BARRIER + BARRIER_SYNC;
1269 #ifdef __powerpc64__
1270 switch ((word >> 21) & 3) {
1271 case 1: /* lwsync */
1272 op->type = BARRIER + BARRIER_LWSYNC;
1273 break;
1274 case 2: /* ptesync */
1275 op->type = BARRIER + BARRIER_PTESYNC;
1276 break;
1277 }
1278 #endif
1279 return 1;
1280
1281 case 854: /* eieio */
1282 op->type = BARRIER + BARRIER_EIEIO;
1283 return 1;
1284 }
1285 break;
1286 }
1287
1288 /* Following cases refer to regs->gpr[], so we need all regs */
1289 if (!FULL_REGS(regs))
1290 return -1;
1291
1292 rd = (word >> 21) & 0x1f;
1293 ra = (word >> 16) & 0x1f;
1294 rb = (word >> 11) & 0x1f;
1295 rc = (word >> 6) & 0x1f;
1296
1297 switch (opcode) {
1298 #ifdef __powerpc64__
1299 case 2: /* tdi */
1300 if (rd & trap_compare(regs->gpr[ra], (short) word))
1301 goto trap;
1302 return 1;
1303 #endif
1304 case 3: /* twi */
1305 if (rd & trap_compare((int)regs->gpr[ra], (short) word))
1306 goto trap;
1307 return 1;
1308

---
0-DAY CI Kernel Test Service, Intel Corporation
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