From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Thu, 12 Jul 2018 12:42:05 +0000
Subject: [bug report] nds32: Loadable modules
Message-Id: <20180712124159.h7kqf2hamut2idhd@kili.mountain>
List-Id: <kernel-janitors.vger.kernel.org>
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To: kernel-janitors@vger.kernel.org

Hello Greentime Hu,

The patch c9a4a8da6baa: "nds32: Loadable modules" from Oct 25, 2017,
leads to the following static checker warning:

	./arch/nds32/kernel/module.c:43 do_reloc16()
	warn: should this be a bitwise negate mask?

./arch/nds32/kernel/module.c
    29  void do_reloc16(unsigned int val, unsigned int *loc, unsigned int val_mask,
    30                  unsigned int val_shift, unsigned int loc_mask,
    31                  unsigned int partial_in_place, unsigned int swap)
    32  {
    33          unsigned int tmp = 0, tmp2 = 0;
    34  
    35          __asm__ __volatile__("\tlhi.bi\t%0, [%2], 0\n"
    36                               "\tbeqz\t%3, 1f\n"
    37                               "\twsbh\t%0, %1\n"
    38                               "1:\n":"=r"(tmp):"0"(tmp), "r"(loc), "r"(swap)
    39              );
    40  
    41          tmp2 = tmp & loc_mask;
    42          if (partial_in_place) {
    43                  tmp &= (!loc_mask);
                                ^^^^^^^^^^
It looks like this should maybe be ~loc_mask?

    44                  tmp     45                      tmp2 | ((tmp + ((val & val_mask) >> val_shift)) & val_mask);
    46          } else {
    47                  tmp = tmp2 | ((val & val_mask) >> val_shift);
    48          }
    49  
    50          __asm__ __volatile__("\tbeqz\t%3, 2f\n"
    51                               "\twsbh\t%0, %1\n"
    52                               "2:\n"
    53                               "\tshi.bi\t%0, [%2], 0\n":"=r"(tmp):"0"(tmp),
    54                               "r"(loc), "r"(swap)
    55              );
    56  }
    57  
    58  void do_reloc32(unsigned int val, unsigned int *loc, unsigned int val_mask,
    59                  unsigned int val_shift, unsigned int loc_mask,
    60                  unsigned int partial_in_place, unsigned int swap)
    61  {
    62          unsigned int tmp = 0, tmp2 = 0;
    63  
    64          __asm__ __volatile__("\tlmw.bi\t%0, [%2], %0, 0\n"
    65                               "\tbeqz\t%3, 1f\n"
    66                               "\twsbh\t%0, %1\n"
    67                               "\trotri\t%0, %1, 16\n"
    68                               "1:\n":"=r"(tmp):"0"(tmp), "r"(loc), "r"(swap)
    69              );
    70  
    71          tmp2 = tmp & loc_mask;
    72          if (partial_in_place) {
    73                  tmp &= (!loc_mask);
                                ^^^^^^^^^
Same.

regards,
dan carpenter