Re: [linux-next:master 10352/10516] include/linux/mm.h:101:35: error: 'MAX_PHYSMEM_BITS' undeclared

["Huang, Ying" <ying.huang@intel.com>]

Andrew Morton <akpm@linux-foundation.org> writes:

> On Tue, 10 Sep 2024 09:33:48 +0800 kernel test robot <lkp@intel.com> wrote:
>
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head:   100cc857359b5d731407d1038f7e76cd0e871d94
>> commit: 5f445800cbdfc4b4185d496a43dfd78df63d2265 [10352/10516] Merge branch 'mm-everything' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
>> config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20240910/202409100913.RxkfrKU6-lkp@intel.com/config)
>> compiler: m68k-linux-gcc (GCC) 14.1.0
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240910/202409100913.RxkfrKU6-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/202409100913.RxkfrKU6-lkp@intel.com/
>> 
>> All errors (new ones prefixed by >>):
>> 
>>    In file included from include/linux/ioport.h:15,
>>                     from kernel/resource.c:15:
>>    kernel/resource.c: In function 'gfr_start':
>> >> include/linux/mm.h:101:35: error: 'MAX_PHYSMEM_BITS' undeclared (first use in this function)
>>      101 | # define PHYSMEM_END    ((1ULL << MAX_PHYSMEM_BITS) - 1)
>>          |                                   ^~~~~~~~~~~~~~~~
>>    include/linux/minmax.h:93:38: note: in definition of macro '__cmp_once_unique'
>>       93 |         ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); })
>>          |                                      ^
>
> Thanks. "resource, kunit: add test case for region_intersects" is the culprit.

Yes.  Although the definition in include/linux/mm.h introduced in

  commit ea72ce5da228 ("x86/kaslr: Expose and use the end of the physical memory address space")

doesn't compile on m68k.  There are no users of PHYSMEM_END before patch
"resource, kunit: add test case for region_intersects".  This can be
fixed via the following patch.

---------------------------------8<--------------------------------------
From 00d176e0cd07e3df1ea37a5e56ca576c819b585a Mon Sep 17 00:00:00 2001
From: Huang Ying <ying.huang@intel.com>
Date: Tue, 10 Sep 2024 13:20:40 +0800
Subject: [PATCH] mm: fix PHYSMEM_END build error on m68k

0Day build system reported build error on m68k architecture for missing
the definition of MAX_PHYSMEM_BITS when defining PHYSMEM_END.  Fixed it
via making PHYSMEM_END definition depends on MAX_PHYSMEM_BITS definition
conditionally.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202409100913.RxkfrKU6-lkp@intel.com/
---
 include/linux/mm.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 147073601716..62bb7e7e0a17 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -98,7 +98,11 @@ extern int mmap_rnd_compat_bits __read_mostly;
 #endif
 
 #ifndef PHYSMEM_END
-# define PHYSMEM_END	((1ULL << MAX_PHYSMEM_BITS) - 1)
+# ifdef MAX_PHYSMEM_BITS
+#  define PHYSMEM_END		((1ULL << MAX_PHYSMEM_BITS) - 1)
+# else
+#  define PHYSMEM_END		(-1ULL)
+# endif
 #endif
 
 #include <asm/page.h>
-- 
2.39.2