On 17.09.24 09:31, Anshuman Khandual wrote:
This changes platform's pmd_val() to access the pmd_t element directly like
other architectures rather than current pointer address based dereferencing
that prevents transition into pmdp_get().
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Guo Ren <guoren@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
arch/m68k/include/asm/page.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/m68k/include/asm/page.h b/arch/m68k/include/asm/page.h
index 8cfb84b49975..be3f2c2a656c 100644
--- a/arch/m68k/include/asm/page.h
+++ b/arch/m68k/include/asm/page.h
@@ -19,7 +19,7 @@
*/
#if !defined(CONFIG_MMU) || CONFIG_PGTABLE_LEVELS == 3
typedef struct { unsigned long pmd; } pmd_t;
-#define pmd_val(x) ((&x)->pmd)
+#define pmd_val(x) ((x).pmd)
#define __pmd(x) ((pmd_t) { (x) } )
#endif
Trying to understand what's happening here, I stumbled over
commit ef22d8abd876e805b604e8f655127de2beee2869
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Fri Jan 31 13:45:36 2020 +0100
m68k: mm: Restructure Motorola MMU page-table layout
The Motorola 68xxx MMUs, 040 (and later) have a fixed 7,7,{5,6}
page-table setup, where the last depends on the page-size selected (8k
vs 4k resp.), and head.S selects 4K pages. For 030 (and earlier) we
explicitly program 7,7,6 and 4K pages in %tc.
However, the current code implements this mightily weird. What it does
is group 16 of those (6 bit) pte tables into one 4k page to not waste
space. The down-side is that that forces pmd_t to be a 16-tuple
pointing to consecutive pte tables.
This breaks the generic code which assumes READ_ONCE(*pmd) will be
word sized.
Where we did
#if !defined(CONFIG_MMU) || CONFIG_PGTABLE_LEVELS == 3
-typedef struct { unsigned long pmd[16]; } pmd_t;
-#define pmd_val(x) ((&x)->pmd[0])
-#define __pmd(x) ((pmd_t) { { (x) }, })
+typedef struct { unsigned long pmd; } pmd_t;
+#define pmd_val(x) ((&x)->pmd)
+#define __pmd(x) ((pmd_t) { (x) } )
#endif
So I assume this should be fine
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
