Re: [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation

kernel test robot
2021-04-20T21:22:28Z

[-- Attachment #1: Type: text/plain, Size: 4789 bytes --]

Hi Liam,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on arm64/for-next/core]
[also build test WARNING on arm-perf/for-next/perf xlnx/master arm/for-next soc/for-next kvmarm/next linus/master v5.12-rc8 next-20210420]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url: https://github.com/0day-ci/linux/commits/Liam-Howlett/arm64-armv8_deprecated-Fix-swp_handler-signal-generation/20210421-005252
base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-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://github.com/0day-ci/linux/commit/96a011695861072d32851ba3a104b19106955869
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Liam-Howlett/arm64-armv8_deprecated-Fix-swp_handler-signal-generation/20210421-005252
git checkout 96a011695861072d32851ba3a104b19106955869
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arm64

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

All warnings (new ones prefixed by >>):

arch/arm64/kernel/armv8_deprecated.c: In function 'swp_handler':
>> arch/arm64/kernel/armv8_deprecated.c:418:11: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
418 | else if (res = -ENXIO) /* Unaligned pointer */
| ^~~

vim +418 arch/arm64/kernel/armv8_deprecated.c

365
366 /*
367 * swp_handler logs the id of calling process, dissects the instruction, sanity
368 * checks the memory location, calls emulate_swpX for the actual operation and
369 * deals with fixup/error handling before returning
370 */
371 static int swp_handler(struct pt_regs *regs, u32 instr)
372 {
373 u32 destreg, data, type, address = 0;
374 const void __user *user_ptr;
375 int rn, rt2, res = 0;
376
377 perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
378
379 type = instr & TYPE_SWPB;
380
381 switch (aarch32_check_condition(instr, regs->pstate)) {
382 case ARM_OPCODE_CONDTEST_PASS:
383 break;
384 case ARM_OPCODE_CONDTEST_FAIL:
385 /* Condition failed - return to next instruction */
386 goto ret;
387 case ARM_OPCODE_CONDTEST_UNCOND:
388 /* If unconditional encoding - not a SWP, undef */
389 return -EFAULT;
390 default:
391 return -EINVAL;
392 }
393
394 rn = aarch32_insn_extract_reg_num(instr, A32_RN_OFFSET);
395 rt2 = aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET);
396
397 address = (u32)regs->user_regs.regs[rn];
398 data = (u32)regs->user_regs.regs[rt2];
399 destreg = aarch32_insn_extract_reg_num(instr, A32_RT_OFFSET);
400
401 pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n",
402 rn, address, destreg,
403 aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET), data);
404
405 /* Check access in reasonable access range for both SWP and SWPB */
406 user_ptr = (const void __user *)(unsigned long)(address & ~3);
407 if (!access_ok(user_ptr, 4)) {
408 pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n",
409 address);
410 goto e_access;
411 }
412
413 res = emulate_swpX(address, &data, type);
414 if (!res)
415 regs->user_regs.regs[destreg] = data;
416 else if (res == -EFAULT)
417 goto e_fault;
> 418 else if (res = -ENXIO) /* Unaligned pointer */
419 goto e_align;
420
421 ret:
422 if (type == TYPE_SWPB)
423 trace_instruction_emulation("swpb", regs->pc);
424 else
425 trace_instruction_emulation("swp", regs->pc);
426
427 pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n",
428 current->comm, (unsigned long)current->pid, regs->pc);
429
430 arm64_skip_faulting_instruction(regs, 4);
431 return 0;
432
433 e_fault:
434 pr_debug("SWP{B} emulation: access caused memory abort!\n");
435 arm64_notify_segfault(address);
436 return 0;
437
438 e_align:
439 e_access:
440 force_signal_inject(SIGSEGV, SEGV_ACCERR, address, 0);
441 return 0;
442 }
443

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 76777 bytes --]