diff options
| author |   Peter Zijlstra <peterz@infradead.org> | 2020-01-31 13:45:36 +0100 |
|---|---|---|
| committer |   Geert Uytterhoeven <geert@linux-m68k.org> | 2020-02-10 10:57:48 +0100 |
| commit | ef22d8abd876e805b604e8f655127de2beee2869 (patch) | |
| tree | d5a4ba746cf6d03a129d13183934f0a20dd1ee95 /arch/m68k/include/asm/pgtable_mm.h | |
| parent | m68k: mm: Move the pointer table allocator to motorola.c (diff) | |
| download | linux-dev-ef22d8abd876e805b604e8f655127de2beee2869.tar.xz linux-dev-ef22d8abd876e805b604e8f655127de2beee2869.zip | |
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.
Therefore implement a straight forward 7,7,6 3 level page-table setup,
with the addition (for 020/030) of (partial) large-page support. For
now this increases the memory footprint for pte-tables 15 fold.
Tested with ARAnyM/68040 emulation.
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://lore.kernel.org/r/20200131125403.711478295@infradead.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Diffstat (limited to 'arch/m68k/include/asm/pgtable_mm.h')
| -rw-r--r-- | arch/m68k/include/asm/pgtable_mm.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h index 2bf5c3501e78..f0e5167de834 100644 --- a/arch/m68k/include/asm/pgtable_mm.h +++ b/arch/m68k/include/asm/pgtable_mm.h @@ -36,7 +36,7 @@ /* PMD_SHIFT determines the size of the area a second-level page table can map */ #if CONFIG_PGTABLE_LEVELS == 3 -#define PMD_SHIFT 22 +#define PMD_SHIFT 18 #endif #define PMD_SIZE (1UL << PMD_SHIFT) #define PMD_MASK (~(PMD_SIZE-1)) @@ -67,8 +67,8 @@ #define PTRS_PER_PMD 1 #define PTRS_PER_PGD 1024 #else -#define PTRS_PER_PTE 1024 -#define PTRS_PER_PMD 8 +#define PTRS_PER_PTE 64 +#define PTRS_PER_PMD 128 #define PTRS_PER_PGD 128 #endif #define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE) @@ -76,8 +76,8 @@ /* Virtual address region for use by kernel_map() */ #ifdef CONFIG_SUN3 -#define KMAP_START 0x0DC00000 -#define KMAP_END 0x0E000000 +#define KMAP_START 0x0dc00000 +#define KMAP_END 0x0e000000 #elif defined(CONFIG_COLDFIRE) #define KMAP_START 0xe0000000 #define KMAP_END 0xf0000000 |