[PATCH] m68k: Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, etc.

[PATCH] m68k: Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, etc.

[Wende Tan]

Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, `PTRS_PER_PMD`,
and `__PAGETABLE_PMD_FOLDED` when PGTABLE_LEVELS == 2 (i.e. SUN3 ||
COLDFIRE).  They have already been defined in
`asm-generic/pgtable-nopmd.h`.

See also https://lore.kernel.org/lkml/202107201907.lqC6B3dF-lkp@intel.com/#t

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Wende Tan <twd2.me@gmail.com>
---
 arch/m68k/include/asm/pgtable_mm.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h
index 143ba7de9bda..51653e8216a7 100644
--- a/arch/m68k/include/asm/pgtable_mm.h
+++ b/arch/m68k/include/asm/pgtable_mm.h
@@ -37,9 +37,9 @@
 /* PMD_SHIFT determines the size of the area a second-level page table can map */
 #if CONFIG_PGTABLE_LEVELS == 3
 #define PMD_SHIFT	18
-#endif
 #define PMD_SIZE	(1UL << PMD_SHIFT)
 #define PMD_MASK	(~(PMD_SIZE-1))
+#endif
 
 /* PGDIR_SHIFT determines what a third-level page table entry can map */
 #ifdef CONFIG_SUN3
@@ -58,13 +58,9 @@
  */
 #ifdef CONFIG_SUN3
 #define PTRS_PER_PTE   16
-#define __PAGETABLE_PMD_FOLDED 1
-#define PTRS_PER_PMD   1
 #define PTRS_PER_PGD   2048
 #elif defined(CONFIG_COLDFIRE)
 #define PTRS_PER_PTE	512
-#define __PAGETABLE_PMD_FOLDED 1
-#define PTRS_PER_PMD	1
 #define PTRS_PER_PGD	1024
 #else
 #define PTRS_PER_PTE	64
-- 
2.25.1

Re: [PATCH] m68k: Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, etc.

[Geert Uytterhoeven]

Hi Wende,

On Wed, Jul 21, 2021 at 12:44 PM Wende Tan <twd2.me@gmail.com> wrote:
> Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, `PTRS_PER_PMD`,
> and `__PAGETABLE_PMD_FOLDED` when PGTABLE_LEVELS == 2 (i.e. SUN3 ||
> COLDFIRE).  They have already been defined in
> `asm-generic/pgtable-nopmd.h`.

Thanks for your patch!

> See also https://lore.kernel.org/lkml/202107201907.lqC6B3dF-lkp@intel.com/#t

I'm a bit confused: is this a new issue introduced by the patch from
the above thread, or is this a pre-existing issue?
If the latter, do you know when it was introduced, and how to reproduce it?

> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Wende Tan <twd2.me@gmail.com>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] m68k: Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, etc.

[twd2]

On 2021/7/26 17:23, Geert Uytterhoeven wrote:
> Hi Wende,
>
> On Wed, Jul 21, 2021 at 12:44 PM Wende Tan <twd2.me@gmail.com> wrote:
>> Remove redefinitions of `PMD_SIZE`, `PMD_MASK`, `PTRS_PER_PMD`,
>> and `__PAGETABLE_PMD_FOLDED` when PGTABLE_LEVELS == 2 (i.e. SUN3 ||
>> COLDFIRE).  They have already been defined in
>> `asm-generic/pgtable-nopmd.h`.
> Thanks for your patch!
>
>> See also https://lore.kernel.org/lkml/202107201907.lqC6B3dF-lkp@intel.com/#t
> I'm a bit confused: is this a new issue introduced by the patch from
> the above thread, or is this a pre-existing issue?
> If the latter, do you know when it was introduced, and how to reproduce it?


I think this is a pre-existing issue, introduced in
commit 60e50f34b13e ("m68k: mm: use pgtable-nopXd instead of 4level-fixup") .
This commit replaced the usage of `4level-fixup.h` in `pgtable_mm.h` to
`pgtable-nop*d.h` and removed the redundent definition of `PMD_SHIFT` but
forgot to clean up other macros like `PMD_SIZE` (it should be moved into
the `#if` condition) [1].

And, GCC will not complain until two definitions of a macro with the same
name differ (as the above thread changes `1UL` to `_UL(1)`), hiding this
issue.

[1] https://github.com/torvalds/linux/commit/60e50f34b13e9e40763be12aa55f2144d8da514c#diff-9ec45948bad35c0e35d0c2d301a2a643336ff8fe2ee8ea3fff19d8f0bb948a46L34

Thanks.
Wende


>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Wende Tan <twd2.me@gmail.com>
> Gr{oetje,eeting}s,
>
>                         Geert
>