diff mbox series

[next,v2,2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.

Message ID bf92800b0c5445e2b2ca8c88e1f5e90f@AcuMS.aculab.com
State New
Headers
Series minmax: Relax type checks in min() and max(). |

Commit Message

David Laight July 28, 2023, 2:51 p.m. UTC 
  The type-check in min()/max() is there to stop unexpected results if a
negative value gets converted to a large unsigned value.
However it also rejects 'unsigned int' v 'unsigned long' compares
which are common and never problematc.

Replace the 'same type' check with a 'same signedness' check.

The new test isn't itself a compile time error, so use static_assert()
to report the error and give a meaningful error message.

Due to the way builtin_choose_expr() works detecting the error in the
'non-constant' side (where static_assert() can be used) also detects
errors when the arguments are constant.

Signed-off-by: David Laight <david.laight@aculab.com>
---
Changes for v2:
- #include <linux/build_bug.h> to fix 'um' build.
  This matches a separate commit from Andy.
- Do not delete __typecheck() - used outside this file.
- Use __builtin_choose_expr() in __clamp_once() to fix clang builds.

 include/linux/minmax.h | 60 +++++++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 30 deletions(-)

Comments

kernel test robot July 29, 2023, 2 a.m. UTC | #1 
Hi David,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master crng-random/master v6.5-rc3 next-20230728]
[cannot apply to next-20230728]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Laight/minmax-Add-min_unsigned-a-b-and-max_unsigned-a-b/20230728-225439
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/bf92800b0c5445e2b2ca8c88e1f5e90f%40AcuMS.aculab.com
patch subject: [PATCH next v2 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.
config: s390-randconfig-r044-20230728 (https://download.01.org/0day-ci/archive/20230729/202307290943.ODVeyeK6-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230729/202307290943.ODVeyeK6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307290943.ODVeyeK6-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from mm/percpu.c:73:
   In file included from include/linux/memblock.h:13:
   In file included from arch/s390/include/asm/dma.h:5:
   In file included from include/linux/io.h:13:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
                                                             ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
   #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
                                                        ^
   In file included from mm/percpu.c:73:
   In file included from include/linux/memblock.h:13:
   In file included from arch/s390/include/asm/dma.h:5:
   In file included from include/linux/io.h:13:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
   #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
                                                        ^
   In file included from mm/percpu.c:73:
   In file included from include/linux/memblock.h:13:
   In file included from arch/s390/include/asm/dma.h:5:
   In file included from include/linux/io.h:13:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> mm/percpu.c:3102:10: error: static assertion expression is not an integral constant expression
                   base = min(ptr, base);
                          ^~~~~~~~~~~~~~
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(min, x, y)
                           ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                   ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
           ^
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
                                    ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
                                                          ^~~~
   mm/percpu.c:3102:10: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(min, x, y)
                           ^
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                                 ^
   include/linux/minmax.h:23:3: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
            ^
   include/linux/compiler.h:237:32: note: expanded from macro 'is_signed_type'
   #define is_signed_type(type) (((type)(-1)) < (__force type)1)
                                  ^
   12 warnings and 1 error generated.
--
   In file included from mm/kmemleak.c:86:
   In file included from include/linux/memblock.h:13:
   In file included from arch/s390/include/asm/dma.h:5:
   In file included from include/linux/io.h:13:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
                                                             ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
   #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
                                                        ^
   In file included from mm/kmemleak.c:86:
   In file included from include/linux/memblock.h:13:
   In file included from arch/s390/include/asm/dma.h:5:
   In file included from include/linux/io.h:13:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
   #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
                                                        ^
   In file included from mm/kmemleak.c:86:
   In file included from include/linux/memblock.h:13:
   In file included from arch/s390/include/asm/dma.h:5:
   In file included from include/linux/io.h:13:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> mm/kmemleak.c:1389:10: error: static assertion expression is not an integral constant expression
                   next = min(start + MAX_SCAN_SIZE, end);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(min, x, y)
                           ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                   ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
           ^
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
                                    ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
                                                          ^~~~
   mm/kmemleak.c:1389:10: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(min, x, y)
                           ^
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                                 ^
   include/linux/minmax.h:23:3: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
            ^
   include/linux/compiler.h:237:32: note: expanded from macro 'is_signed_type'
   #define is_signed_type(type) (((type)(-1)) < (__force type)1)
                                  ^
   mm/kmemleak.c:1429:11: error: static assertion expression is not an integral constant expression
                           next = min(start + MAX_SCAN_SIZE, end);
                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(min, x, y)
                           ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                   ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
           ^
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
                                    ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
                                                          ^~~~
   mm/kmemleak.c:1429:11: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(min, x, y)
                           ^
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                                 ^
   include/linux/minmax.h:23:3: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
            ^
   include/linux/compiler.h:237:32: note: expanded from macro 'is_signed_type'
   #define is_signed_type(type) (((type)(-1)) < (__force type)1)
                                  ^
   12 warnings and 2 errors generated.
--
   In file included from crypto/skcipher.c:15:
   In file included from include/crypto/scatterwalk.h:18:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
                                                             ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
   #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
                                                        ^
   In file included from crypto/skcipher.c:15:
   In file included from include/crypto/scatterwalk.h:18:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
   #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
                                                        ^
   In file included from crypto/skcipher.c:15:
   In file included from include/crypto/scatterwalk.h:18:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> crypto/skcipher.c:80:9: error: static assertion expression is not an integral constant expression
           return max(start, end_page);
                  ^~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:74:19: note: expanded from macro 'max'
   #define max(x, y)       __careful_cmp(max, x, y)
                           ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                   ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
           ^
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
                                    ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
                                                          ^~~~
   crypto/skcipher.c:80:9: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
   include/linux/minmax.h:74:19: note: expanded from macro 'max'
   #define max(x, y)       __careful_cmp(max, x, y)
                           ^
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                                 ^
   include/linux/minmax.h:23:3: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
            ^
   include/linux/compiler.h:237:32: note: expanded from macro 'is_signed_type'
   #define is_signed_type(type) (((type)(-1)) < (__force type)1)
                                  ^
   12 warnings and 1 error generated.
..


vim +3102 mm/percpu.c

3c9a024fde58b08 Tejun Heo       2010-09-09  3022  
3c9a024fde58b08 Tejun Heo       2010-09-09  3023  #if defined(BUILD_EMBED_FIRST_CHUNK)
66c3a75772247c3 Tejun Heo       2009-03-10  3024  /**
66c3a75772247c3 Tejun Heo       2009-03-10  3025   * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
66c3a75772247c3 Tejun Heo       2009-03-10  3026   * @reserved_size: the size of reserved percpu area in bytes
4ba6ce250e406b2 Tejun Heo       2010-06-27  3027   * @dyn_size: minimum free size for dynamic allocation in bytes
c8826dd538602d7 Tejun Heo       2009-08-14  3028   * @atom_size: allocation atom size
c8826dd538602d7 Tejun Heo       2009-08-14  3029   * @cpu_distance_fn: callback to determine distance between cpus, optional
1ca3fb3abd2b615 Kefeng Wang     2022-01-19  3030   * @cpu_to_nd_fn: callback to convert cpu to it's node, optional
66c3a75772247c3 Tejun Heo       2009-03-10  3031   *
66c3a75772247c3 Tejun Heo       2009-03-10  3032   * This is a helper to ease setting up embedded first percpu chunk and
66c3a75772247c3 Tejun Heo       2009-03-10  3033   * can be called where pcpu_setup_first_chunk() is expected.
66c3a75772247c3 Tejun Heo       2009-03-10  3034   *
66c3a75772247c3 Tejun Heo       2009-03-10  3035   * If this function is used to setup the first chunk, it is allocated
23f917169ef157a Kefeng Wang     2022-01-19  3036   * by calling pcpu_fc_alloc and used as-is without being mapped into
c8826dd538602d7 Tejun Heo       2009-08-14  3037   * vmalloc area.  Allocations are always whole multiples of @atom_size
c8826dd538602d7 Tejun Heo       2009-08-14  3038   * aligned to @atom_size.
c8826dd538602d7 Tejun Heo       2009-08-14  3039   *
c8826dd538602d7 Tejun Heo       2009-08-14  3040   * This enables the first chunk to piggy back on the linear physical
c8826dd538602d7 Tejun Heo       2009-08-14  3041   * mapping which often uses larger page size.  Please note that this
c8826dd538602d7 Tejun Heo       2009-08-14  3042   * can result in very sparse cpu->unit mapping on NUMA machines thus
c8826dd538602d7 Tejun Heo       2009-08-14  3043   * requiring large vmalloc address space.  Don't use this allocator if
c8826dd538602d7 Tejun Heo       2009-08-14  3044   * vmalloc space is not orders of magnitude larger than distances
c8826dd538602d7 Tejun Heo       2009-08-14  3045   * between node memory addresses (ie. 32bit NUMA machines).
66c3a75772247c3 Tejun Heo       2009-03-10  3046   *
4ba6ce250e406b2 Tejun Heo       2010-06-27  3047   * @dyn_size specifies the minimum dynamic area size.
66c3a75772247c3 Tejun Heo       2009-03-10  3048   *
66c3a75772247c3 Tejun Heo       2009-03-10  3049   * If the needed size is smaller than the minimum or specified unit
23f917169ef157a Kefeng Wang     2022-01-19  3050   * size, the leftover is returned using pcpu_fc_free.
66c3a75772247c3 Tejun Heo       2009-03-10  3051   *
66c3a75772247c3 Tejun Heo       2009-03-10  3052   * RETURNS:
fb435d5233f8b6f Tejun Heo       2009-08-14  3053   * 0 on success, -errno on failure.
66c3a75772247c3 Tejun Heo       2009-03-10  3054   */
4ba6ce250e406b2 Tejun Heo       2010-06-27  3055  int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
c8826dd538602d7 Tejun Heo       2009-08-14  3056  				  size_t atom_size,
c8826dd538602d7 Tejun Heo       2009-08-14  3057  				  pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
23f917169ef157a Kefeng Wang     2022-01-19  3058  				  pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
66c3a75772247c3 Tejun Heo       2009-03-10  3059  {
c8826dd538602d7 Tejun Heo       2009-08-14  3060  	void *base = (void *)ULONG_MAX;
c8826dd538602d7 Tejun Heo       2009-08-14  3061  	void **areas = NULL;
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3062  	struct pcpu_alloc_info *ai;
93c76b6b2faaad7 zijun_hu        2016-10-05  3063  	size_t size_sum, areas_size;
93c76b6b2faaad7 zijun_hu        2016-10-05  3064  	unsigned long max_distance;
163fa23435cc9c7 Kefeng Wang     2019-07-03  3065  	int group, i, highest_group, rc = 0;
66c3a75772247c3 Tejun Heo       2009-03-10  3066  
c8826dd538602d7 Tejun Heo       2009-08-14  3067  	ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
c8826dd538602d7 Tejun Heo       2009-08-14  3068  				   cpu_distance_fn);
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3069  	if (IS_ERR(ai))
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3070  		return PTR_ERR(ai);
66c3a75772247c3 Tejun Heo       2009-03-10  3071  
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3072  	size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
c8826dd538602d7 Tejun Heo       2009-08-14  3073  	areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
fa8a7094ba1679b Tejun Heo       2009-06-22  3074  
26fb3dae0a1ec78 Mike Rapoport   2019-03-11  3075  	areas = memblock_alloc(areas_size, SMP_CACHE_BYTES);
c8826dd538602d7 Tejun Heo       2009-08-14  3076  	if (!areas) {
fb435d5233f8b6f Tejun Heo       2009-08-14  3077  		rc = -ENOMEM;
c8826dd538602d7 Tejun Heo       2009-08-14  3078  		goto out_free;
fa8a7094ba1679b Tejun Heo       2009-06-22  3079  	}
66c3a75772247c3 Tejun Heo       2009-03-10  3080  
9b7396624a7b503 zijun_hu        2016-10-05  3081  	/* allocate, copy and determine base address & max_distance */
9b7396624a7b503 zijun_hu        2016-10-05  3082  	highest_group = 0;
c8826dd538602d7 Tejun Heo       2009-08-14  3083  	for (group = 0; group < ai->nr_groups; group++) {
c8826dd538602d7 Tejun Heo       2009-08-14  3084  		struct pcpu_group_info *gi = &ai->groups[group];
c8826dd538602d7 Tejun Heo       2009-08-14  3085  		unsigned int cpu = NR_CPUS;
c8826dd538602d7 Tejun Heo       2009-08-14  3086  		void *ptr;
c8826dd538602d7 Tejun Heo       2009-08-14  3087  
c8826dd538602d7 Tejun Heo       2009-08-14  3088  		for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
c8826dd538602d7 Tejun Heo       2009-08-14  3089  			cpu = gi->cpu_map[i];
c8826dd538602d7 Tejun Heo       2009-08-14  3090  		BUG_ON(cpu == NR_CPUS);
c8826dd538602d7 Tejun Heo       2009-08-14  3091  
c8826dd538602d7 Tejun Heo       2009-08-14  3092  		/* allocate space for the whole group */
23f917169ef157a Kefeng Wang     2022-01-19  3093  		ptr = pcpu_fc_alloc(cpu, gi->nr_units * ai->unit_size, atom_size, cpu_to_nd_fn);
c8826dd538602d7 Tejun Heo       2009-08-14  3094  		if (!ptr) {
c8826dd538602d7 Tejun Heo       2009-08-14  3095  			rc = -ENOMEM;
c8826dd538602d7 Tejun Heo       2009-08-14  3096  			goto out_free_areas;
c8826dd538602d7 Tejun Heo       2009-08-14  3097  		}
f528f0b8e53d73b Catalin Marinas 2011-09-26  3098  		/* kmemleak tracks the percpu allocations separately */
a317ebccaa36099 Patrick Wang    2022-07-05  3099  		kmemleak_ignore_phys(__pa(ptr));
c8826dd538602d7 Tejun Heo       2009-08-14  3100  		areas[group] = ptr;
c8826dd538602d7 Tejun Heo       2009-08-14  3101  
c8826dd538602d7 Tejun Heo       2009-08-14 @3102  		base = min(ptr, base);
9b7396624a7b503 zijun_hu        2016-10-05  3103  		if (ptr > areas[highest_group])
9b7396624a7b503 zijun_hu        2016-10-05  3104  			highest_group = group;
9b7396624a7b503 zijun_hu        2016-10-05  3105  	}
9b7396624a7b503 zijun_hu        2016-10-05  3106  	max_distance = areas[highest_group] - base;
9b7396624a7b503 zijun_hu        2016-10-05  3107  	max_distance += ai->unit_size * ai->groups[highest_group].nr_units;
9b7396624a7b503 zijun_hu        2016-10-05  3108  
9b7396624a7b503 zijun_hu        2016-10-05  3109  	/* warn if maximum distance is further than 75% of vmalloc space */
9b7396624a7b503 zijun_hu        2016-10-05  3110  	if (max_distance > VMALLOC_TOTAL * 3 / 4) {
9b7396624a7b503 zijun_hu        2016-10-05  3111  		pr_warn("max_distance=0x%lx too large for vmalloc space 0x%lx\n",
9b7396624a7b503 zijun_hu        2016-10-05  3112  				max_distance, VMALLOC_TOTAL);
9b7396624a7b503 zijun_hu        2016-10-05  3113  #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
9b7396624a7b503 zijun_hu        2016-10-05  3114  		/* and fail if we have fallback */
9b7396624a7b503 zijun_hu        2016-10-05  3115  		rc = -EINVAL;
9b7396624a7b503 zijun_hu        2016-10-05  3116  		goto out_free_areas;
9b7396624a7b503 zijun_hu        2016-10-05  3117  #endif
42b64281453249d Tejun Heo       2012-04-27  3118  	}
42b64281453249d Tejun Heo       2012-04-27  3119  
42b64281453249d Tejun Heo       2012-04-27  3120  	/*
42b64281453249d Tejun Heo       2012-04-27  3121  	 * Copy data and free unused parts.  This should happen after all
42b64281453249d Tejun Heo       2012-04-27  3122  	 * allocations are complete; otherwise, we may end up with
42b64281453249d Tejun Heo       2012-04-27  3123  	 * overlapping groups.
42b64281453249d Tejun Heo       2012-04-27  3124  	 */
42b64281453249d Tejun Heo       2012-04-27  3125  	for (group = 0; group < ai->nr_groups; group++) {
42b64281453249d Tejun Heo       2012-04-27  3126  		struct pcpu_group_info *gi = &ai->groups[group];
42b64281453249d Tejun Heo       2012-04-27  3127  		void *ptr = areas[group];
66c3a75772247c3 Tejun Heo       2009-03-10  3128  
c8826dd538602d7 Tejun Heo       2009-08-14  3129  		for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
c8826dd538602d7 Tejun Heo       2009-08-14  3130  			if (gi->cpu_map[i] == NR_CPUS) {
c8826dd538602d7 Tejun Heo       2009-08-14  3131  				/* unused unit, free whole */
23f917169ef157a Kefeng Wang     2022-01-19  3132  				pcpu_fc_free(ptr, ai->unit_size);
c8826dd538602d7 Tejun Heo       2009-08-14  3133  				continue;
c8826dd538602d7 Tejun Heo       2009-08-14  3134  			}
c8826dd538602d7 Tejun Heo       2009-08-14  3135  			/* copy and return the unused part */
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3136  			memcpy(ptr, __per_cpu_load, ai->static_size);
23f917169ef157a Kefeng Wang     2022-01-19  3137  			pcpu_fc_free(ptr + size_sum, ai->unit_size - size_sum);
c8826dd538602d7 Tejun Heo       2009-08-14  3138  		}
66c3a75772247c3 Tejun Heo       2009-03-10  3139  	}
66c3a75772247c3 Tejun Heo       2009-03-10  3140  
c8826dd538602d7 Tejun Heo       2009-08-14  3141  	/* base address is now known, determine group base offsets */
6ea529a2037ce66 Tejun Heo       2009-09-24  3142  	for (group = 0; group < ai->nr_groups; group++) {
c8826dd538602d7 Tejun Heo       2009-08-14  3143  		ai->groups[group].base_offset = areas[group] - base;
6ea529a2037ce66 Tejun Heo       2009-09-24  3144  	}
c8826dd538602d7 Tejun Heo       2009-08-14  3145  
00206a69ee32f03 Matteo Croce    2019-03-18  3146  	pr_info("Embedded %zu pages/cpu s%zu r%zu d%zu u%zu\n",
00206a69ee32f03 Matteo Croce    2019-03-18  3147  		PFN_DOWN(size_sum), ai->static_size, ai->reserved_size,
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3148  		ai->dyn_size, ai->unit_size);
66c3a75772247c3 Tejun Heo       2009-03-10  3149  
163fa23435cc9c7 Kefeng Wang     2019-07-03  3150  	pcpu_setup_first_chunk(ai, base);
c8826dd538602d7 Tejun Heo       2009-08-14  3151  	goto out_free;
c8826dd538602d7 Tejun Heo       2009-08-14  3152  
c8826dd538602d7 Tejun Heo       2009-08-14  3153  out_free_areas:
c8826dd538602d7 Tejun Heo       2009-08-14  3154  	for (group = 0; group < ai->nr_groups; group++)
f851c8d8583891a Michael Holzheu 2013-09-17  3155  		if (areas[group])
23f917169ef157a Kefeng Wang     2022-01-19  3156  			pcpu_fc_free(areas[group],
c8826dd538602d7 Tejun Heo       2009-08-14  3157  				ai->groups[group].nr_units * ai->unit_size);
c8826dd538602d7 Tejun Heo       2009-08-14  3158  out_free:
fd1e8a1fe2b54df Tejun Heo       2009-08-14  3159  	pcpu_free_alloc_info(ai);
c8826dd538602d7 Tejun Heo       2009-08-14  3160  	if (areas)
4421cca0a3e4833 Mike Rapoport   2021-11-05  3161  		memblock_free(areas, areas_size);
fb435d5233f8b6f Tejun Heo       2009-08-14  3162  	return rc;
fa8a7094ba1679b Tejun Heo       2009-06-22  3163  }
3c9a024fde58b08 Tejun Heo       2010-09-09  3164  #endif /* BUILD_EMBED_FIRST_CHUNK */
d4b95f80399471e Tejun Heo       2009-07-04  3165
David Laight July 30, 2023, 2:55 p.m. UTC | #2 
From: kernel test robot
> Sent: 29 July 2023 03:01
> 
> kernel test robot noticed the following build errors:
> 
...)
> compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git
> 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
> reproduce: (https://download.01.org/0day-ci/archive/20230729/202307290943.ODVeyeK6-
> lkp@intel.com/reproduce)
> 
...
> >> mm/percpu.c:3102:10: error: static assertion expression is not an integral constant expression
>                    base = min(ptr, base);
>                           ^~~~~~~~~~~~~~
...                    ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
>            (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
>            ^
...
>    mm/percpu.c:3102:10: note: cast that performs the conversions of a reinterpret_cast is not allowed
> in a constant expression

That is a C++ error that seems to have crept into C.
The relevant definition is:

#define is_signed_type(type)  (((type)(-1)) < (type)1)

This seems to have been fixed in clang 16.0.0.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Nathan Chancellor July 30, 2023, 5:05 p.m. UTC | #3 
On Sun, Jul 30, 2023 at 02:55:50PM +0000, David Laight wrote:
> From: kernel test robot
> > Sent: 29 July 2023 03:01
> > 
> > kernel test robot noticed the following build errors:
> > 
> ...)
> > compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git
> > 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
> > reproduce: (https://download.01.org/0day-ci/archive/20230729/202307290943.ODVeyeK6-
> > lkp@intel.com/reproduce)
> > 
> ...
> > >> mm/percpu.c:3102:10: error: static assertion expression is not an integral constant expression
> >                    base = min(ptr, base);
> >                           ^~~~~~~~~~~~~~
> ...                    ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
> >    include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
> >            (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
> >            ^
> ...
> >    mm/percpu.c:3102:10: note: cast that performs the conversions of a reinterpret_cast is not allowed
> > in a constant expression
> 
> That is a C++ error that seems to have crept into C.
> The relevant definition is:
> 
> #define is_signed_type(type)  (((type)(-1)) < (type)1)
> 
> This seems to have been fixed in clang 16.0.0.

Indeed, it looks like

https://github.com/llvm/llvm-project/commit/a181de452df311d7647329120d05f4eb9c158b6c

fixed this as a result of the discussion at

https://github.com/llvm/llvm-project/issues/57687, which certainly makes
sense.

Cheers,
Nathan
David Laight July 30, 2023, 5:33 p.m. UTC | #4 
From: Nathan Chancellor
> Sent: 30 July 2023 18:06
> 
> On Sun, Jul 30, 2023 at 02:55:50PM +0000, David Laight wrote:
> > From: kernel test robot
> > > Sent: 29 July 2023 03:01
> > >
> > > kernel test robot noticed the following build errors:
> > >
> > ...)
> > > compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git
> > > 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
> > > reproduce: (https://download.01.org/0day-ci/archive/20230729/202307290943.ODVeyeK6-
> > > lkp@intel.com/reproduce)
> > >
> > ...
> > > >> mm/percpu.c:3102:10: error: static assertion expression is not an integral constant expression
> > >                    base = min(ptr, base);
> > >                           ^~~~~~~~~~~~~~
> > ...                    ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >    include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
> > >            (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
> > >            ^
> > ...
> > >    mm/percpu.c:3102:10: note: cast that performs the conversions of a reinterpret_cast is not allowed
> > > in a constant expression
> >
> > That is a C++ error that seems to have crept into C.
> > The relevant definition is:
> >
> > #define is_signed_type(type)  (((type)(-1)) < (type)1)
> >
> > This seems to have been fixed in clang 16.0.0.
> 
> Indeed, it looks like
> 
> https://github.com/llvm/llvm-project/commit/a181de452df311d7647329120d05f4eb9c158b6c
> 
> fixed this as a result of the discussion at
> 
> https://github.com/llvm/llvm-project/issues/57687, which certainly makes
> sense.

Annoyingly it also isn't a 'proper' compile time constant for pointers.
Wrapping as:
	__builtin_choose_expr(__is_constexpr(is_signed(type(x)), is_signed_type(x), 0)
fixes it for old clang and is also needed to fix the >= 0 check in 5/5.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
kernel test robot July 31, 2023, 9:43 p.m. UTC | #5 
Hi David,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master crng-random/master v6.5-rc4 next-20230731]
[cannot apply to next-20230728]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Laight/minmax-Add-min_unsigned-a-b-and-max_unsigned-a-b/20230728-225439
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/bf92800b0c5445e2b2ca8c88e1f5e90f%40AcuMS.aculab.com
patch subject: [PATCH next v2 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness.
config: powerpc-mpc5200_defconfig (https://download.01.org/0day-ci/archive/20230801/202308010559.SEtfkzQU-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce: (https://download.01.org/0day-ci/archive/20230801/202308010559.SEtfkzQU-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308010559.SEtfkzQU-lkp@intel.com/

All errors (new ones prefixed by >>):

   ^
   arch/powerpc/include/asm/io.h:610:56: note: expanded from macro '__do_insw'
   #define __do_insw(p, b, n)      readsw((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/gpu/drm/drm_modes.c:35:
   In file included from include/linux/fb.h:6:
   In file included from include/linux/kgdb.h:19:
   In file included from include/linux/kprobes.h:28:
   In file included from include/linux/ftrace.h:10:
   In file included from include/linux/trace_recursion.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:672:
   arch/powerpc/include/asm/io-defs.h:47:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insl, (unsigned long p, void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:669:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:101:1: note: expanded from here
   __do_insl
   ^
   arch/powerpc/include/asm/io.h:611:56: note: expanded from macro '__do_insl'
   #define __do_insl(p, b, n)      readsl((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/gpu/drm/drm_modes.c:35:
   In file included from include/linux/fb.h:6:
   In file included from include/linux/kgdb.h:19:
   In file included from include/linux/kprobes.h:28:
   In file included from include/linux/ftrace.h:10:
   In file included from include/linux/trace_recursion.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:672:
   arch/powerpc/include/asm/io-defs.h:49:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsb, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:669:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:103:1: note: expanded from here
   __do_outsb
   ^
   arch/powerpc/include/asm/io.h:612:58: note: expanded from macro '__do_outsb'
   #define __do_outsb(p, b, n)     writesb((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/gpu/drm/drm_modes.c:35:
   In file included from include/linux/fb.h:6:
   In file included from include/linux/kgdb.h:19:
   In file included from include/linux/kprobes.h:28:
   In file included from include/linux/ftrace.h:10:
   In file included from include/linux/trace_recursion.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:672:
   arch/powerpc/include/asm/io-defs.h:51:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsw, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:669:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:105:1: note: expanded from here
   __do_outsw
   ^
   arch/powerpc/include/asm/io.h:613:58: note: expanded from macro '__do_outsw'
   #define __do_outsw(p, b, n)     writesw((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from drivers/gpu/drm/drm_modes.c:35:
   In file included from include/linux/fb.h:6:
   In file included from include/linux/kgdb.h:19:
   In file included from include/linux/kprobes.h:28:
   In file included from include/linux/ftrace.h:10:
   In file included from include/linux/trace_recursion.h:5:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:672:
   arch/powerpc/include/asm/io-defs.h:53:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsl, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:669:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:107:1: note: expanded from here
   __do_outsl
   ^
   arch/powerpc/include/asm/io.h:614:58: note: expanded from macro '__do_outsl'
   #define __do_outsl(p, b, n)     writesl((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
>> drivers/gpu/drm/drm_modes.c:2474:15: error: static_assert expression is not an integral constant expression
                   extra_ptr = max(bpp_end_ptr, refresh_end_ptr);
                               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:74:19: note: expanded from macro 'max'
   #define max(x, y)       __careful_cmp(max, x, y)
                           ^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                   ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:23:2: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
           ^
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
   #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
                                    ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
   #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
                                                          ^~~~
   drivers/gpu/drm/drm_modes.c:2474:15: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
   include/linux/minmax.h:74:19: note: expanded from macro 'max'
   #define max(x, y)       __careful_cmp(max, x, y)
                           ^
   include/linux/minmax.h:40:3: note: expanded from macro '__careful_cmp'
                   __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
                   ^
   include/linux/minmax.h:33:17: note: expanded from macro '__cmp_once'
                   static_assert(__types_ok(x, y),         \
                                 ^
   include/linux/minmax.h:23:3: note: expanded from macro '__types_ok'
           (is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
            ^
   include/linux/compiler.h:237:32: note: expanded from macro 'is_signed_type'
   #define is_signed_type(type) (((type)(-1)) < (__force type)1)
                                  ^
   6 warnings and 1 error generated.


vim +2474 drivers/gpu/drm/drm_modes.c

a631bf30eb914a Maxime Ripard         2022-11-14  2334  
1794d257fa7bab Chris Wilson          2011-04-17  2335  /**
f5aabb978d1dcd Daniel Vetter         2014-01-23  2336   * drm_mode_parse_command_line_for_connector - parse command line modeline for connector
f5aabb978d1dcd Daniel Vetter         2014-01-23  2337   * @mode_option: optional per connector mode option
f5aabb978d1dcd Daniel Vetter         2014-01-23  2338   * @connector: connector to parse modeline for
f5aabb978d1dcd Daniel Vetter         2014-01-23  2339   * @mode: preallocated drm_cmdline_mode structure to fill out
1794d257fa7bab Chris Wilson          2011-04-17  2340   *
f5aabb978d1dcd Daniel Vetter         2014-01-23  2341   * This parses @mode_option command line modeline for modes and options to
1e84dadb2762cd Thomas Zimmermann     2023-02-09  2342   * configure the connector.
f5aabb978d1dcd Daniel Vetter         2014-01-23  2343   *
f5aabb978d1dcd Daniel Vetter         2014-01-23  2344   * This uses the same parameters as the fb modedb.c, except for an extra
dbd124f013a23d Daniel Vetter         2018-02-19  2345   * force-enable, force-enable-digital and force-disable bit at the end::
1794d257fa7bab Chris Wilson          2011-04-17  2346   *
1794d257fa7bab Chris Wilson          2011-04-17  2347   *	<xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m][eDd]
1794d257fa7bab Chris Wilson          2011-04-17  2348   *
1bf4e09227c345 Maxime Ripard         2019-06-19  2349   * Additionals options can be provided following the mode, using a comma to
1bf4e09227c345 Maxime Ripard         2019-06-19  2350   * separate each option. Valid options can be found in
bff9e34c678552 Mauro Carvalho Chehab 2019-07-15  2351   * Documentation/fb/modedb.rst.
1bf4e09227c345 Maxime Ripard         2019-06-19  2352   *
f5aabb978d1dcd Daniel Vetter         2014-01-23  2353   * The intermediate drm_cmdline_mode structure is required to store additional
2a97acd6376922 Yannick Guerrini      2015-03-04  2354   * options from the command line modline like the force-enable/disable flag.
f5aabb978d1dcd Daniel Vetter         2014-01-23  2355   *
f5aabb978d1dcd Daniel Vetter         2014-01-23  2356   * Returns:
f5aabb978d1dcd Daniel Vetter         2014-01-23  2357   * True if a valid modeline has been parsed, false otherwise.
1794d257fa7bab Chris Wilson          2011-04-17  2358   */
1794d257fa7bab Chris Wilson          2011-04-17  2359  bool drm_mode_parse_command_line_for_connector(const char *mode_option,
c0898fca3fce00 Arnd Bergmann         2019-06-28  2360  					       const struct drm_connector *connector,
1794d257fa7bab Chris Wilson          2011-04-17  2361  					       struct drm_cmdline_mode *mode)
1794d257fa7bab Chris Wilson          2011-04-17  2362  {
1794d257fa7bab Chris Wilson          2011-04-17  2363  	const char *name;
7b1cce760afe38 Hans de Goede         2019-11-18  2364  	bool freestanding = false, parse_extras = false;
1bf4e09227c345 Maxime Ripard         2019-06-19  2365  	unsigned int bpp_off = 0, refresh_off = 0, options_off = 0;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2366  	unsigned int mode_end = 0;
83e14ea3a64f00 Hans de Goede         2019-11-18  2367  	const char *bpp_ptr = NULL, *refresh_ptr = NULL, *extra_ptr = NULL;
83e14ea3a64f00 Hans de Goede         2019-11-18  2368  	const char *options_ptr = NULL;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2369  	char *bpp_end_ptr = NULL, *refresh_end_ptr = NULL;
a631bf30eb914a Maxime Ripard         2022-11-14  2370  	int len, ret;
1794d257fa7bab Chris Wilson          2011-04-17  2371  
d1fe276b5115f0 Hans de Goede         2019-11-18  2372  	memset(mode, 0, sizeof(*mode));
4e7a4a6fbdc669 Hans de Goede         2019-11-18  2373  	mode->panel_orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
4e7a4a6fbdc669 Hans de Goede         2019-11-18  2374  
d1fe276b5115f0 Hans de Goede         2019-11-18  2375  	if (!mode_option)
1794d257fa7bab Chris Wilson          2011-04-17  2376  		return false;
1794d257fa7bab Chris Wilson          2011-04-17  2377  
1794d257fa7bab Chris Wilson          2011-04-17  2378  	name = mode_option;
04fee895ef98ff Rolf Eike Beer        2011-06-15  2379  
90c258ba4a36f6 Maxime Ripard         2022-09-29  2380  	/* Locate the start of named options */
90c258ba4a36f6 Maxime Ripard         2022-09-29  2381  	options_ptr = strchr(name, ',');
90c258ba4a36f6 Maxime Ripard         2022-09-29  2382  	if (options_ptr)
90c258ba4a36f6 Maxime Ripard         2022-09-29  2383  		options_off = options_ptr - name;
90c258ba4a36f6 Maxime Ripard         2022-09-29  2384  	else
90c258ba4a36f6 Maxime Ripard         2022-09-29  2385  		options_off = strlen(name);
90c258ba4a36f6 Maxime Ripard         2022-09-29  2386  
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2387  	/* Try to locate the bpp and refresh specifiers, if any */
90c258ba4a36f6 Maxime Ripard         2022-09-29  2388  	bpp_ptr = strnchr(name, options_off, '-');
8b6e28ea0a51a7 Geert Uytterhoeven    2022-09-29  2389  	while (bpp_ptr && !isdigit(bpp_ptr[1]))
8b6e28ea0a51a7 Geert Uytterhoeven    2022-09-29  2390  		bpp_ptr = strnchr(bpp_ptr + 1, options_off, '-');
6a2d163756545a Hans de Goede         2019-11-18  2391  	if (bpp_ptr)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2392  		bpp_off = bpp_ptr - name;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2393  
90c258ba4a36f6 Maxime Ripard         2022-09-29  2394  	refresh_ptr = strnchr(name, options_off, '@');
7b1cce760afe38 Hans de Goede         2019-11-18  2395  	if (refresh_ptr)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2396  		refresh_off = refresh_ptr - name;
04fee895ef98ff Rolf Eike Beer        2011-06-15  2397  
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2398  	/* Locate the end of the name / resolution, and parse it */
1bf4e09227c345 Maxime Ripard         2019-06-19  2399  	if (bpp_ptr) {
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2400  		mode_end = bpp_off;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2401  	} else if (refresh_ptr) {
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2402  		mode_end = refresh_off;
1bf4e09227c345 Maxime Ripard         2019-06-19  2403  	} else if (options_ptr) {
1bf4e09227c345 Maxime Ripard         2019-06-19  2404  		mode_end = options_off;
cfb0881b8f621b Hans de Goede         2019-11-18  2405  		parse_extras = true;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2406  	} else {
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2407  		mode_end = strlen(name);
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2408  		parse_extras = true;
04fee895ef98ff Rolf Eike Beer        2011-06-15  2409  	}
04fee895ef98ff Rolf Eike Beer        2011-06-15  2410  
a631bf30eb914a Maxime Ripard         2022-11-14  2411  	if (!mode_end)
a631bf30eb914a Maxime Ripard         2022-11-14  2412  		return false;
3764137906a5ac Maxime Ripard         2019-08-27  2413  
a631bf30eb914a Maxime Ripard         2022-11-14  2414  	ret = drm_mode_parse_cmdline_named_mode(name, mode_end, mode);
a631bf30eb914a Maxime Ripard         2022-11-14  2415  	if (ret < 0)
a631bf30eb914a Maxime Ripard         2022-11-14  2416  		return false;
a631bf30eb914a Maxime Ripard         2022-11-14  2417  
a631bf30eb914a Maxime Ripard         2022-11-14  2418  	/*
a631bf30eb914a Maxime Ripard         2022-11-14  2419  	 * Having a mode that starts by a letter (and thus is named) and
a631bf30eb914a Maxime Ripard         2022-11-14  2420  	 * an at-sign (used to specify a refresh rate) is disallowed.
a631bf30eb914a Maxime Ripard         2022-11-14  2421  	 */
a631bf30eb914a Maxime Ripard         2022-11-14  2422  	if (ret && refresh_ptr)
a631bf30eb914a Maxime Ripard         2022-11-14  2423  		return false;
3764137906a5ac Maxime Ripard         2019-08-27  2424  
7b1cce760afe38 Hans de Goede         2019-11-18  2425  	/* No named mode? Check for a normal mode argument, e.g. 1024x768 */
7b1cce760afe38 Hans de Goede         2019-11-18  2426  	if (!mode->specified && isdigit(name[0])) {
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2427  		ret = drm_mode_parse_cmdline_res_mode(name, mode_end,
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2428  						      parse_extras,
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2429  						      connector,
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2430  						      mode);
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2431  		if (ret)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2432  			return false;
7b1cce760afe38 Hans de Goede         2019-11-18  2433  
1794d257fa7bab Chris Wilson          2011-04-17  2434  		mode->specified = true;
7b1cce760afe38 Hans de Goede         2019-11-18  2435  	}
7b1cce760afe38 Hans de Goede         2019-11-18  2436  
7b1cce760afe38 Hans de Goede         2019-11-18  2437  	/* No mode? Check for freestanding extras and/or options */
7b1cce760afe38 Hans de Goede         2019-11-18  2438  	if (!mode->specified) {
7b1cce760afe38 Hans de Goede         2019-11-18  2439  		unsigned int len = strlen(mode_option);
7b1cce760afe38 Hans de Goede         2019-11-18  2440  
7b1cce760afe38 Hans de Goede         2019-11-18  2441  		if (bpp_ptr || refresh_ptr)
7b1cce760afe38 Hans de Goede         2019-11-18  2442  			return false; /* syntax error */
7b1cce760afe38 Hans de Goede         2019-11-18  2443  
7b1cce760afe38 Hans de Goede         2019-11-18  2444  		if (len == 1 || (len >= 2 && mode_option[1] == ','))
7b1cce760afe38 Hans de Goede         2019-11-18  2445  			extra_ptr = mode_option;
7b1cce760afe38 Hans de Goede         2019-11-18  2446  		else
7b1cce760afe38 Hans de Goede         2019-11-18  2447  			options_ptr = mode_option - 1;
7b1cce760afe38 Hans de Goede         2019-11-18  2448  
7b1cce760afe38 Hans de Goede         2019-11-18  2449  		freestanding = true;
7b1cce760afe38 Hans de Goede         2019-11-18  2450  	}
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2451  
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2452  	if (bpp_ptr) {
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2453  		ret = drm_mode_parse_cmdline_bpp(bpp_ptr, &bpp_end_ptr, mode);
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2454  		if (ret)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2455  			return false;
6a2d163756545a Hans de Goede         2019-11-18  2456  
6a2d163756545a Hans de Goede         2019-11-18  2457  		mode->bpp_specified = true;
1794d257fa7bab Chris Wilson          2011-04-17  2458  	}
1794d257fa7bab Chris Wilson          2011-04-17  2459  
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2460  	if (refresh_ptr) {
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2461  		ret = drm_mode_parse_cmdline_refresh(refresh_ptr,
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2462  						     &refresh_end_ptr, mode);
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2463  		if (ret)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2464  			return false;
6a2d163756545a Hans de Goede         2019-11-18  2465  
6a2d163756545a Hans de Goede         2019-11-18  2466  		mode->refresh_specified = true;
1794d257fa7bab Chris Wilson          2011-04-17  2467  	}
1794d257fa7bab Chris Wilson          2011-04-17  2468  
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2469  	/*
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2470  	 * Locate the end of the bpp / refresh, and parse the extras
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2471  	 * if relevant
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2472  	 */
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2473  	if (bpp_ptr && refresh_ptr)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19 @2474  		extra_ptr = max(bpp_end_ptr, refresh_end_ptr);
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2475  	else if (bpp_ptr)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2476  		extra_ptr = bpp_end_ptr;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2477  	else if (refresh_ptr)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2478  		extra_ptr = refresh_end_ptr;
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2479  
c2ed3e94190181 Hans de Goede         2019-11-18  2480  	if (extra_ptr) {
c2ed3e94190181 Hans de Goede         2019-11-18  2481  		if (options_ptr)
c2ed3e94190181 Hans de Goede         2019-11-18  2482  			len = options_ptr - extra_ptr;
c2ed3e94190181 Hans de Goede         2019-11-18  2483  		else
c2ed3e94190181 Hans de Goede         2019-11-18  2484  			len = strlen(extra_ptr);
3aeeb13d899627 Maxime Ripard         2019-06-19  2485  
7b1cce760afe38 Hans de Goede         2019-11-18  2486  		ret = drm_mode_parse_cmdline_extra(extra_ptr, len, freestanding,
3aeeb13d899627 Maxime Ripard         2019-06-19  2487  						   connector, mode);
3aeeb13d899627 Maxime Ripard         2019-06-19  2488  		if (ret)
3aeeb13d899627 Maxime Ripard         2019-06-19  2489  			return false;
1bf4e09227c345 Maxime Ripard         2019-06-19  2490  	}
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2491  
1bf4e09227c345 Maxime Ripard         2019-06-19  2492  	if (options_ptr) {
739b200c2edcaa Hans de Goede         2019-11-18  2493  		ret = drm_mode_parse_cmdline_options(options_ptr + 1,
7b1cce760afe38 Hans de Goede         2019-11-18  2494  						     freestanding,
1bf4e09227c345 Maxime Ripard         2019-06-19  2495  						     connector, mode);
1bf4e09227c345 Maxime Ripard         2019-06-19  2496  		if (ret)
e08ab74bd4c7a5 Maxime Ripard         2019-06-19  2497  			return false;
1794d257fa7bab Chris Wilson          2011-04-17  2498  	}
1794d257fa7bab Chris Wilson          2011-04-17  2499  
1794d257fa7bab Chris Wilson          2011-04-17  2500  	return true;
1794d257fa7bab Chris Wilson          2011-04-17  2501  }
1794d257fa7bab Chris Wilson          2011-04-17  2502  EXPORT_SYMBOL(drm_mode_parse_command_line_for_connector);
1794d257fa7bab Chris Wilson          2011-04-17  2503
David Laight Aug. 1, 2023, 8:45 a.m. UTC | #6 
From: kernel test robot
> Sent: 31 July 2023 22:44
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on akpm-mm/mm-everything]
> [also build test ERROR on linus/master crng-random/master v6.5-rc4 next-20230731]
> [cannot apply to next-20230728]
...
> compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git
> f28c006a5895fc0e329fe15fead81e37457cb1d1)
> reproduce: (https://download.01.org/0day-ci/archive/20230801/202308010559.SEtfkzQU-
> lkp@intel.com/reproduce)
> 
....
> >> drivers/gpu/drm/drm_modes.c:2474:15: error: static_assert expression is not an integral constant
> expression
>                    extra_ptr = max(bpp_end_ptr, refresh_end_ptr);
>                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is really a bug in clang - fixed in 16.0.0.
In C (but probably not C++) '(void *)1' should be a compile-time constant.
Will be fixed in v3 of the patch.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
diff mbox series

Patch

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 531860e9cc55..cb126853f2be 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -2,6 +2,7 @@ 
 #ifndef _LINUX_MINMAX_H
 #define _LINUX_MINMAX_H
 
+#include <linux/build_bug.h>
 #include <linux/const.h>
 
 /*
@@ -9,9 +10,8 @@ 
  *
  * - avoid multiple evaluations of the arguments (so side-effects like
  *   "x++" happen only once) when non-constant.
- * - perform strict type-checking (to generate warnings instead of
- *   nasty runtime surprises). See the "unnecessary" pointer comparison
- *   in __typecheck().
+ * - perform signed v unsigned type-checking (to generate compile
+ *   errors instead of nasty runtime surprises).
  * - retain result as a constant expressions when called with only
  *   constant expressions (to avoid tripping VLA warnings in stack
  *   allocation usage).
@@ -19,23 +19,25 @@ 
 #define __typecheck(x, y) \
 	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
 
-#define __no_side_effects(x, y) \
-		(__is_constexpr(x) && __is_constexpr(y))
+#define __types_ok(x, y) \
+	(is_signed_type(typeof(x)) == is_signed_type(typeof(y)))
 
-#define __safe_cmp(x, y) \
-		(__typecheck(x, y) && __no_side_effects(x, y))
+#define __cmp_op_min <
+#define __cmp_op_max >
 
-#define __cmp(x, y, op)	((x) op (y) ? (x) : (y))
+#define __cmp(op, x, y)	((x) __cmp_op_##op (y) ? (x) : (y))
 
-#define __cmp_once(x, y, unique_x, unique_y, op) ({	\
+#define __cmp_once(op, x, y, unique_x, unique_y) ({	\
 		typeof(x) unique_x = (x);		\
 		typeof(y) unique_y = (y);		\
-		__cmp(unique_x, unique_y, op); })
+		static_assert(__types_ok(x, y),		\
+			#op "(" #x ", " #y ") signedness error, fix types or consider " #op "_unsigned() before " #op "_t()"); \
+		__cmp(op, unique_x, unique_y); })
 
-#define __careful_cmp(x, y, op) \
-	__builtin_choose_expr(__safe_cmp(x, y), \
-		__cmp(x, y, op), \
-		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
+#define __careful_cmp(op, x, y)					\
+	__builtin_choose_expr(__is_constexpr((x) - (y)),	\
+		__cmp(op, x, y),				\
+		__cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
 
 #define __clamp(val, lo, hi)	\
 	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
@@ -44,17 +46,15 @@ 
 		typeof(val) unique_val = (val);				\
 		typeof(lo) unique_lo = (lo);				\
 		typeof(hi) unique_hi = (hi);				\
+		static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
+				(lo) <= (hi), true),					\
+			"clamp() low limit " #lo " greater than high limit " #hi);	\
+		static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
+		static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
 		__clamp(unique_val, unique_lo, unique_hi); })
 
-#define __clamp_input_check(lo, hi)					\
-        (BUILD_BUG_ON_ZERO(__builtin_choose_expr(			\
-                __is_constexpr((lo) > (hi)), (lo) > (hi), false)))
-
 #define __careful_clamp(val, lo, hi) ({					\
-	__clamp_input_check(lo, hi) +					\
-	__builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) && \
-			      __typecheck(hi, lo) && __is_constexpr(val) && \
-			      __is_constexpr(lo) && __is_constexpr(hi),	\
+	__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),	\
 		__clamp(val, lo, hi),					\
 		__clamp_once(val, lo, hi, __UNIQUE_ID(__val),		\
 			     __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
@@ -64,14 +64,14 @@ 
  * @x: first value
  * @y: second value
  */
-#define min(x, y)	__careful_cmp(x, y, <)
+#define min(x, y)	__careful_cmp(min, x, y)
 
 /**
  * max - return maximum of two values of the same or compatible types
  * @x: first value
  * @y: second value
  */
-#define max(x, y)	__careful_cmp(x, y, >)
+#define max(x, y)	__careful_cmp(max, x, y)
 
 /**
  * min_unsigned - return minimum of two non-negative values
@@ -79,16 +79,16 @@ 
  * @x: first value
  * @y: second value
  */
-#define min_unsigned(x, y)	\
-	__careful_cmp((x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull, <)
+#define min_unsigned(x, y) \
+	__careful_cmp(min, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
 
 /**
  * max_unsigned - return maximum of two non-negative values
  * @x: first value
  * @y: second value
  */
-#define max_unsigned(x, y)	\
-	__careful_cmp((x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull, >)
+#define max_unsigned(x, y) \
+	__careful_cmp(max, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
 
 /**
  * min3 - return minimum of three values
@@ -140,7 +140,7 @@ 
  * @x: first value
  * @y: second value
  */
-#define min_t(type, x, y)	__careful_cmp((type)(x), (type)(y), <)
+#define min_t(type, x, y)	__careful_cmp(min, (type)(x), (type)(y))
 
 /**
  * max_t - return maximum of two values, using the specified type
@@ -148,7 +148,7 @@ 
  * @x: first value
  * @y: second value
  */
-#define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)
+#define max_t(type, x, y)	__careful_cmp(max, (type)(x), (type)(y))
 
 /**
  * clamp_t - return a value clamped to a given range using a given type