tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: d0ee23f9d78be5531c4b055ea424ed0b489dfe9b commit: 2f78788b55baa3410b1ec91a576286abe1ad4d6a ilog2: improve ilog2 for constant arguments date: 9 months ago config: mips-randconfig-m031-20210914 (attached as .config) compiler: mips-linux-gcc (GCC) 11.2.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; New smatch warnings: arch/mips/mm/tlbex.c:2599 check_pabits() warn: always true condition '(fillbits >= ((__builtin_constant_p(0)) ?(((0) < 2) ?0:63 - __builtin_clzll(0)):((4 <= 4)) ?__ilog2_u32(0):__ilog2_u64(0))) => (0-u32max >= 0)' Old smatch warnings: arch/mips/mm/tlbex.c:1741 iPTE_SW() warn: inconsistent indenting vim +2599 arch/mips/mm/tlbex.c c5b367835cfc7a Steven J. Hill 2015-02-26 2569 00bf1c691d082c Paul Burton 2015-09-22 2570 static void check_pabits(void) 00bf1c691d082c Paul Burton 2015-09-22 2571 { 00bf1c691d082c Paul Burton 2015-09-22 2572 unsigned long entry; 00bf1c691d082c Paul Burton 2015-09-22 2573 unsigned pabits, fillbits; 00bf1c691d082c Paul Burton 2015-09-22 2574 00bf1c691d082c Paul Burton 2015-09-22 2575 if (!cpu_has_rixi || !_PAGE_NO_EXEC) { 00bf1c691d082c Paul Burton 2015-09-22 2576 /* 00bf1c691d082c Paul Burton 2015-09-22 2577 * We'll only be making use of the fact that we can rotate bits 00bf1c691d082c Paul Burton 2015-09-22 2578 * into the fill if the CPU supports RIXI, so don't bother 00bf1c691d082c Paul Burton 2015-09-22 2579 * probing this for CPUs which don't. 00bf1c691d082c Paul Burton 2015-09-22 2580 */ 00bf1c691d082c Paul Burton 2015-09-22 2581 return; 00bf1c691d082c Paul Burton 2015-09-22 2582 } 00bf1c691d082c Paul Burton 2015-09-22 2583 00bf1c691d082c Paul Burton 2015-09-22 2584 write_c0_entrylo0(~0ul); 00bf1c691d082c Paul Burton 2015-09-22 2585 back_to_back_c0_hazard(); 00bf1c691d082c Paul Burton 2015-09-22 2586 entry = read_c0_entrylo0(); 00bf1c691d082c Paul Burton 2015-09-22 2587 00bf1c691d082c Paul Burton 2015-09-22 2588 /* clear all non-PFN bits */ 00bf1c691d082c Paul Burton 2015-09-22 2589 entry &= ~((1 << MIPS_ENTRYLO_PFN_SHIFT) - 1); 00bf1c691d082c Paul Burton 2015-09-22 2590 entry &= ~(MIPS_ENTRYLO_RI | MIPS_ENTRYLO_XI); 00bf1c691d082c Paul Burton 2015-09-22 2591 00bf1c691d082c Paul Burton 2015-09-22 2592 /* find a lower bound on PABITS, and upper bound on fill bits */ 00bf1c691d082c Paul Burton 2015-09-22 2593 pabits = fls_long(entry) + 6; 00bf1c691d082c Paul Burton 2015-09-22 2594 fillbits = max_t(int, (int)BITS_PER_LONG - pabits, 0); 00bf1c691d082c Paul Burton 2015-09-22 2595 00bf1c691d082c Paul Burton 2015-09-22 2596 /* minus the RI & XI bits */ 00bf1c691d082c Paul Burton 2015-09-22 2597 fillbits -= min_t(unsigned, fillbits, 2); 00bf1c691d082c Paul Burton 2015-09-22 2598 00bf1c691d082c Paul Burton 2015-09-22 @2599 if (fillbits >= ilog2(_PAGE_NO_EXEC)) 00bf1c691d082c Paul Burton 2015-09-22 2600 fill_includes_sw_bits = true; 00bf1c691d082c Paul Burton 2015-09-22 2601 00bf1c691d082c Paul Burton 2015-09-22 2602 pr_debug("Entry* registers contain %u fill bits\n", fillbits); 00bf1c691d082c Paul Burton 2015-09-22 2603 } 00bf1c691d082c Paul Burton 2015-09-22 2604 :::::: The code at line 2599 was first introduced by commit :::::: 00bf1c691d082c1945fdba032c03a9a82e9e7e61 MIPS: tlbex: Avoid placing software PTE bits in Entry* PFN fields :::::: TO: Paul Burton <paul.burton(a)imgtec.com&gt; :::::: CC: Ralf Baechle <ralf(a)linux-mips.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org