sh: page table alloc cleanups and page fault optimizations.

Cleanup of page table allocators, using generic folded PMD and PUD
helpers. TLB flushing operations are moved to a more sensible spot.

The page fault handler is also optimized slightly, we no longer waste
cycles on IRQ disabling for flushing of the page from the ITLB, since
we're already under CLI protection by the initial exception handler.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 53 insertions, 27 deletions

diff --git a/include/asm-sh/pgtable.h b/include/asm-sh/pgtable.h
index 40d41a78041e..9728b58f7c13 100644
--- a/include/asm-sh/pgtable.h
+++ b/include/asm-sh/pgtable.h
@@ -1,42 +1,42 @@
-#ifndef __ASM_SH_PGTABLE_H
-#define __ASM_SH_PGTABLE_H
-
-#include <asm-generic/4level-fixup.h>
-
 /*
+ * This file contains the functions and defines necessary to modify and
+ * use the SuperH page table tree.
+ *
  * Copyright (C) 1999 Niibe Yutaka
- * Copyright (C) 2002, 2003, 2004 Paul Mundt
+ * Copyright (C) 2002 - 2005 Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file "COPYING" in the main directory of this
+ * archive for more details.
  */
+#ifndef __ASM_SH_PGTABLE_H
+#define __ASM_SH_PGTABLE_H
 
-#include <asm/pgtable-2level.h>
+#include <asm-generic/pgtable-nopmd.h>
+#include <asm/page.h>
+
+#define PTRS_PER_PGD            1024
 
-/*
- * This file contains the functions and defines necessary to modify and use
- * the SuperH page table tree.
- */
 #ifndef __ASSEMBLY__
-#include <asm/processor.h>
 #include <asm/addrspace.h>
 #include <asm/fixmap.h>
-#include <linux/threads.h>
 
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 extern void paging_init(void);
 
 /*
- * Basically we have the same two-level (which is the logical three level
- * Linux page table layout folded) page tables as the i386.
- */
-
-/*
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
  */
-extern unsigned long empty_zero_page[1024];
+extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 
 #endif /* !__ASSEMBLY__ */
 
+/* traditional two-level paging structure */
+#define PGDIR_SHIFT     22
+#define PTRS_PER_PMD    1
+#define PTRS_PER_PTE    1024
 #define PMD_SIZE        (1UL << PMD_SHIFT)
 #define PMD_MASK        (~(PMD_SIZE-1))
 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
@@ -47,7 +47,6 @@ extern unsigned long empty_zero_page[1024];
 
 #define PTE_PHYS_MASK   0x1ffff000
 
-#ifndef __ASSEMBLY__
 /*
  * First 1MB map is used by fixed purpose.
  * Currently only 4-enty (16kB) is used (see arch/sh/mm/cache.c)
@@ -65,7 +64,7 @@ extern unsigned long empty_zero_page[1024];
 #define _PAGE_SZ1       0x080  /* SZ1-bit : Size of page (on SH-4) */
 #define _PAGE_PRESENT   0x100  /* V-bit   : page is valid */
 #define _PAGE_PROTNONE  0x200  /* software: if not present  */
-#define _PAGE_ACCESSED  0x400  /* software: page referenced */
+#define _PAGE_ACCESSED  0x400  /* software: page referenced */
 #define _PAGE_U0_SHARED 0x800  /* software: page is shared in user space */
 
 #define _PAGE_FILE      _PAGE_WT  /* software: pagecache or swap? */
@@ -83,7 +82,6 @@ extern unsigned long empty_zero_page[1024];
 #define _PAGE_PCC_ATR8  0x60000000      /* Attribute Memory space, 8 bit bus */
 #define _PAGE_PCC_ATR16 0x60000001      /* Attribute Memory space, 6 bit bus */
 
-
 /* Mask which drop software flags
  * We also drop WT bit since it is used for _PAGE_FILE
  * bit in this implementation.
@@ -115,6 +113,8 @@ extern unsigned long empty_zero_page[1024];
 #define _KERNPG_TABLE   (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
 #define _PAGE_CHG_MASK  (PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | _PAGE_DIRTY | _PAGE_SHARED)
 
+#ifndef __ASSEMBLY__
+
 #ifdef CONFIG_MMU
 #define PAGE_NONE       __pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE |_PAGE_ACCESSED | _PAGE_FLAGS_HARD)
 #define PAGE_SHARED     __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_CACHABLE |_PAGE_ACCESSED | _PAGE_SHARED | _PAGE_FLAGS_HARD)
@@ -137,12 +137,13 @@ extern unsigned long empty_zero_page[1024];
 #define PAGE_KERNEL_PCC         __pgprot(0)
 #endif
 
+#endif /* __ASSEMBLY__ */
+
 /*
  * As i386 and MIPS, SuperH can't do page protection for execute, and
  * considers that the same as a read.  Also, write permissions imply
- * read permissions. This is the closest we can get..  
+ * read permissions. This is the closest we can get..
  */
-
 #define __P000  PAGE_NONE
 #define __P001  PAGE_READONLY
 #define __P010  PAGE_COPY
@@ -161,6 +162,26 @@ extern unsigned long empty_zero_page[1024];
 #define __S110  PAGE_SHARED
 #define __S111  PAGE_SHARED
 
+#ifndef __ASSEMBLY__
+
+/*
+ * Certain architectures need to do special things when PTEs
+ * within a page table are directly modified.  Thus, the following
+ * hook is made available.
+ */
+#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
+#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
+
+/*
+ * (pmds are folded into pgds so this doesn't get actually called,
+ * but the define is needed for a generic inline function.)
+ */
+#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
+
+#define pte_pfn(x)              ((unsigned long)(((x).pte >> PAGE_SHIFT)))
+#define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
+#define pfn_pmd(pfn, prot)      __pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
+
 #define pte_none(x)     (!pte_val(x))
 #define pte_present(x)  (pte_val(x) & (_PAGE_PRESENT | _PAGE_PROTNONE))
 #define pte_clear(mm,addr,xp)   do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)
@@ -171,7 +192,7 @@ extern unsigned long empty_zero_page[1024];
 #define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
 
 #define pages_to_mb(x)  ((x) >> (20-PAGE_SHIFT))
-#define pte_page(x)     phys_to_page(pte_val(x)&PTE_PHYS_MASK)
+#define pte_page(x)     phys_to_page(pte_val(x)&PTE_PHYS_MASK)
 
 /*
  * The following only work if pte_present() is true.
@@ -248,6 +269,11 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 #define pte_unmap(pte)          do { } while (0)
 #define pte_unmap_nested(pte)   do { } while (0)
 
+#define pte_ERROR(e) \
+        printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
+#define pgd_ERROR(e) \
+        printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
+
 struct vm_area_struct;
 extern void update_mmu_cache(struct vm_area_struct * vma,
                              unsigned long address, pte_t pte);
@@ -272,8 +298,6 @@ extern void update_mmu_cache(struct vm_area_struct * vma,
 
 typedef pte_t *pte_addr_t;
 
-#endif /* !__ASSEMBLY__ */
-
 #define kern_addr_valid(addr)   (1)
 
 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)         \
@@ -301,5 +325,7 @@ extern pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t
 
 #include <asm-generic/pgtable.h>
 
+#endif /* !__ASSEMBLY__ */
+
 #endif /* __ASM_SH_PAGE_H */