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From: kernel test robot <lkp@intel.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: kbuild-all@lists.01.org, linux-kernel@vger.kernel.org,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: 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)'
Date: Thu, 16 Dec 2021 19:41:25 +0800	[thread overview]
Message-ID: <202112161929.ccx97Im9-lkp@intel.com> (raw)

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   2b14864acbaaf03d9c01982e243a84632524c3ac
commit: 2f78788b55baa3410b1ec91a576286abe1ad4d6a ilog2: improve ilog2 for constant arguments
date:   1 year ago
config: mips-randconfig-m031-20211216 (https://download.01.org/0day-ci/archive/20211216/202112161929.ccx97Im9-lkp@intel.com/config)
compiler: mips64-linux-gcc (GCC) 11.2.0

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

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:1681 iPTE_LW() warn: curly braces intended?
arch/mips/mm/tlbex.c:1713 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@imgtec.com>
:::::: CC: Ralf Baechle <ralf@linux-mips.org>

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

WARNING: multiple messages have this Message-ID (diff)
From: kernel test robot <lkp@intel.com>
To: kbuild-all@lists.01.org
Subject: 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)'
Date: Thu, 16 Dec 2021 19:41:25 +0800	[thread overview]
Message-ID: <202112161929.ccx97Im9-lkp@intel.com> (raw)

[-- Attachment #1: Type: text/plain, Size: 4019 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   2b14864acbaaf03d9c01982e243a84632524c3ac
commit: 2f78788b55baa3410b1ec91a576286abe1ad4d6a ilog2: improve ilog2 for constant arguments
date:   1 year ago
config: mips-randconfig-m031-20211216 (https://download.01.org/0day-ci/archive/20211216/202112161929.ccx97Im9-lkp(a)intel.com/config)
compiler: mips64-linux-gcc (GCC) 11.2.0

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

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:1681 iPTE_LW() warn: curly braces intended?
arch/mips/mm/tlbex.c:1713 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@imgtec.com>
:::::: CC: Ralf Baechle <ralf@linux-mips.org>

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

             reply	other threads:[~2021-12-16 11:42 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-16 11:41 kernel test robot [this message]
2021-12-16 11:41 ` 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)' kernel test robot
  -- strict thread matches above, loose matches on Subject: below --
2021-11-28  4:48 kernel test robot
2021-11-28  4:48 ` kernel test robot
2021-09-14 14:08 kernel test robot
2021-09-14 14:08 ` kernel test robot
2021-08-25 14:05 kernel test robot
2021-08-25 14:05 ` kernel test robot
2021-05-20 18:14 kernel test robot
2021-05-20 18:14 ` kernel test robot

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