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[linuxsh-dev] Changes for cache function
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From: NIIBE Y. <gn...@m1...> - 2001-08-06 09:21:17
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OK, with this patch, I've finally got reliable implementation. Some
clean up is still needed, but I think that all the bugs are gone.
I've changed the logic to defer the actual flusing. I've introduced,
PG_mapped_with_alias flag. This flag will be set at update_mmu_cache,
if it maps with the address of alias. We can do this, because all the
vma areas are aligned to 16KB. The flag will be cleard when the PTE gets
cleared.
* include/asm-sh/pgtable.h (PG_mapped_with_alias): New macro.
(PG_dcache_dirty: Deleted.
(ptep_get_and_clear, ptep_test_and_clear_young,
ptep_test_and_clear_dirty, ptep_set_wrprotect, ptep_mkdirty,
pte_same): Define here (was: included by <asm-generic/pgtable.h>).
* arch/sh/mm/cache-sh4.c (flush_dcache_page): New implementation.
Check if it's mapped or not.
(ptep_get_and_clear): New function (was: generic implementation).
* arch/sh/mm/fault.c (update_mmu_cache): Flush the cache when
it's mapped at first, and mark the page as it's mapped.
Bug fix: check the page is VALID or not.
* arch/sh/mm/cache-sh4.c (CACHE_ALIAS): Moved to ...
* include/asm-sh/pgtable.h (CACHE_ALIAS): ... here.
Index: arch/sh/mm/cache-sh4.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/mm/cache-sh4.c,v
retrieving revision 1.10
diff -u -p -r1.10 cache-sh4.c
--- arch/sh/mm/cache-sh4.c 2001/08/06 02:19:56 1.10
+++ arch/sh/mm/cache-sh4.c 2001/08/06 09:05:45
@@ -41,9 +41,6 @@
#define CACHE_IC_NUM_ENTRIES 256
#define CACHE_OC_NUM_ENTRIES 512
-/* Page is 4K, OC size is 16K, there are four lines. */
-#define CACHE_ALIAS 0x00003000
-
static void __init
detect_cpu_and_cache_system(void)
{
@@ -206,7 +203,7 @@ void __flush_cache_page(unsigned long ph
unsigned long addr, data;
unsigned long flags;
- phys|=CACHE_VALID;
+ phys |= CACHE_VALID;
save_and_cli(flags);
jump_to_P2();
@@ -274,19 +271,10 @@ void __flush_icache_page(unsigned long u
* Write back & invalidate the I/D-cache of the page.
* (To avoid "alias" issues)
*/
-void flush_dcache_page(struct page *pg)
+void flush_dcache_page(struct page *page)
{
- if (!pg->mapping
- || pg->mapping->i_mmap || pg->mapping->i_mmap_shared) {
- unsigned long phys;
-
- phys = PHYSADDR(page_address(pg));
- if (pg->mapping)
- __flush_cache_page(phys, 1);
- else
- __flush_cache_page(phys, 0);
- } else
- set_bit(PG_dcache_dirty, &pg->flags);
+ if (test_bit(PG_mapped_with_alias, &page->flags))
+ __flush_cache_page(PHYSADDR(page_address(page)), 1);
}
void flush_cache_all(void)
@@ -535,4 +523,18 @@ void copy_user_page(void *to, void *from
pte_clear(pte);
up(&p3map_sem[(address & CACHE_ALIAS)>>12]);
}
+}
+
+pte_t ptep_get_and_clear(pte_t *ptep)
+{
+ pte_t pte = *ptep;
+
+ if (!pte_not_present(pte)) {
+ struct page *page = pte_page(pte);
+ if (VALID_PAGE(page)&&
+ (!page->mapping || !(page->mapping->i_mmap_shared)))
+ __clear_bit(PG_mapped_with_alias, &page->flags);
+ }
+ pte_clear(ptep);
+ return pte;
}
Index: arch/sh/mm/fault.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/mm/fault.c,v
retrieving revision 1.44
diff -u -p -r1.44 fault.c
--- arch/sh/mm/fault.c 2001/07/18 04:27:38 1.44
+++ arch/sh/mm/fault.c 2001/08/06 09:05:45
@@ -290,15 +290,15 @@ void update_mmu_cache(struct vm_area_str
return;
#if defined(__SH4__)
- page = pte_page(pte);
-
- if (__test_and_clear_bit(PG_dcache_dirty, &page->flags))
- if (page->mapping) {
- unsigned long phys;
- /* Physical address of this page */
- phys = PHYSADDR(pte_val(pte)&PAGE_MASK);
+ if ((address ^ pte_val(pte)) & CACHE_ALIAS) {
+ page = pte_page(pte);
+ if (VALID_PAGE(page) &&
+ !test_bit(PG_mapped_with_alias, &page->flags)) {
+ unsigned long phys = pte_val(pte) & PTE_PHYS_MASK;
__flush_cache_page(phys, 1);
+ set_bit(PG_mapped_with_alias, &page->flags);
}
+ }
#endif
save_and_cli(flags);
Index: include/asm-sh/pgtable.h
===================================================================
RCS file: /cvsroot/linuxsh/kernel/include/asm-sh/pgtable.h,v
retrieving revision 1.40
diff -u -p -r1.40 pgtable.h
--- include/asm-sh/pgtable.h 2001/08/05 01:54:18 1.40
+++ include/asm-sh/pgtable.h 2001/08/06 09:05:47
@@ -75,6 +75,11 @@ extern void __flush_icache_page(unsigned
/* Initialization of P3 area for copy_user_page */
extern void p3_cache_init(void);
+
+#define PG_mapped_with_alias PG_arch_1
+
+/* We provide our own get_unmapped_area to avoid cache alias issue */
+#define HAVE_ARCH_UNMAPPED_AREA
#endif
/*
@@ -290,9 +295,60 @@ extern void update_mmu_cache(struct vm_a
*
* We just can use generic implementation, as SuperH has no SMP feature.
* (We needed atomic implementation for SMP)
+ *
*/
-#include <asm-generic/pgtable.h>
+#if defined(__SH4__)
+/* Page is 4K, OC size is 16K, there are four lines. */
+#define CACHE_ALIAS 0x00003000
+/*
+ * For SH-4, we have our own implementation for ptep_get_and_clear
+ */
+extern pte_t ptep_get_and_clear(pte_t *ptep);
+#else
+static inline pte_t ptep_get_and_clear(pte_t *ptep)
+{
+ pte_t pte = *ptep;
+ pte_clear(ptep);
+ return pte;
+}
+#endif
+
+/*
+ * Following functions are same as generic ones.
+ */
+static inline int ptep_test_and_clear_young(pte_t *ptep)
+{
+ pte_t pte = *ptep;
+ if (!pte_young(pte))
+ return 0;
+ set_pte(ptep, pte_mkold(pte));
+ return 1;
+}
+
+static inline int ptep_test_and_clear_dirty(pte_t *ptep)
+{
+ pte_t pte = *ptep;
+ if (!pte_dirty(pte))
+ return 0;
+ set_pte(ptep, pte_mkclean(pte));
+ return 1;
+}
+
+static inline void ptep_set_wrprotect(pte_t *ptep)
+{
+ pte_t old_pte = *ptep;
+ set_pte(ptep, pte_wrprotect(old_pte));
+}
+
+static inline void ptep_mkdirty(pte_t *ptep)
+{
+ pte_t old_pte = *ptep;
+ set_pte(ptep, pte_mkdirty(old_pte));
+}
+
+#define pte_same(A,B) (pte_val(A) == pte_val(B))
+
#endif /* !__ASSEMBLY__ */
/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
@@ -300,12 +356,5 @@ extern void update_mmu_cache(struct vm_a
#define kern_addr_valid(addr) (1)
#define io_remap_page_range remap_page_range
-
-#if defined(__SH4__)
-#define PG_dcache_dirty PG_arch_1
-
-/* We provide our own get_unmapped_area to avoid cache alias issue */
-#define HAVE_ARCH_UNMAPPED_AREA
-#endif
#endif /* __ASM_SH_PAGE_H */
--
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