Skip to content

Commit

Permalink
asm-generic: make sparse happy with odd-sized put_unaligned_*()
Browse files Browse the repository at this point in the history
__put_unaligned_be24() and friends use implicit casts to convert
larger-sized data to bytes, which trips sparse truncation warnings when
the argument is a constant:

    CC [M]  drivers/input/touchscreen/hynitron_cstxxx.o
    CHECK   drivers/input/touchscreen/hynitron_cstxxx.c
  drivers/input/touchscreen/hynitron_cstxxx.c: note: in included file (through arch/x86/include/generated/asm/unaligned.h):
  include/asm-generic/unaligned.h:119:16: warning: cast truncates bits from constant value (aa01a0 becomes a0)
  include/asm-generic/unaligned.h:120:20: warning: cast truncates bits from constant value (aa01 becomes 1)
  include/asm-generic/unaligned.h:119:16: warning: cast truncates bits from constant value (ab00d0 becomes d0)
  include/asm-generic/unaligned.h:120:20: warning: cast truncates bits from constant value (ab00 becomes 0)

To avoid this let's mask off upper bits explicitly, the resulting code
should be exactly the same, but it will keep sparse happy.

Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/oe-kbuild-all/202401070147.gqwVulOn-lkp@intel.com/
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  • Loading branch information
Dmitry Torokhov authored and Linus Torvalds committed Jan 8, 2024
1 parent 0dd3ee3 commit 1ab33c0
Showing 1 changed file with 12 additions and 12 deletions.
24 changes: 12 additions & 12 deletions include/asm-generic/unaligned.h
Original file line number Diff line number Diff line change
@@ -104,9 +104,9 @@ static inline u32 get_unaligned_le24(const void *p)

static inline void __put_unaligned_be24(const u32 val, u8 *p)
{
*p++ = val >> 16;
*p++ = val >> 8;
*p++ = val;
*p++ = (val >> 16) & 0xff;
*p++ = (val >> 8) & 0xff;
*p++ = val & 0xff;
}

static inline void put_unaligned_be24(const u32 val, void *p)
@@ -116,9 +116,9 @@ static inline void put_unaligned_be24(const u32 val, void *p)

static inline void __put_unaligned_le24(const u32 val, u8 *p)
{
*p++ = val;
*p++ = val >> 8;
*p++ = val >> 16;
*p++ = val & 0xff;
*p++ = (val >> 8) & 0xff;
*p++ = (val >> 16) & 0xff;
}

static inline void put_unaligned_le24(const u32 val, void *p)
@@ -128,12 +128,12 @@ static inline void put_unaligned_le24(const u32 val, void *p)

static inline void __put_unaligned_be48(const u64 val, u8 *p)
{
*p++ = val >> 40;
*p++ = val >> 32;
*p++ = val >> 24;
*p++ = val >> 16;
*p++ = val >> 8;
*p++ = val;
*p++ = (val >> 40) & 0xff;
*p++ = (val >> 32) & 0xff;
*p++ = (val >> 24) & 0xff;
*p++ = (val >> 16) & 0xff;
*p++ = (val >> 8) & 0xff;
*p++ = val & 0xff;
}

static inline void put_unaligned_be48(const u64 val, void *p)

0 comments on commit 1ab33c0

Please sign in to comment.