flush icache for ia64 take4.
This patch is against 2.6.23-rc1.
Changes V4 -> V5:
- removed sync_icache_dcache from do_wp_page() page reuse
case.
Changes v3 -> v4:
- avoid implementing flush_(i)cache_pages().
- added sync_icache_dcache() call.
- change Documentation/cachetlb.txt
Current ia64 kernel flushes icache by lazy_mmu_prot_update()
*after*
set_pte(). This is wrong. This patch removes
lazy_mmu_prot_update and
add sync_icache_dcache(). sync_icache_dcache() is called
before set_pte()
if necessary and synchronize icache with dcache (fc.i
instruction).
This patch fixes SIGILL problem on NFS/ia64.
About Icache-Dcache inconsistency in ia64
- When the cache line is modified, Icache and Dcache are
purged.
- When I-cache misses, I-cache will access just the lower
layer cache(memory).
Then, If the lower_layer_cache is not up-to-date, I-cache
will see
old information. For avoiding this case, Icache-Dcache
synchronization(fc.i)
is necessary. (Icache-Dcache synchronization means making
Dcache and lower
layer unified cache(memory) consistent.)
Details:
- In general, cache flushing macro are used for virtually
tagged caches.
IA64 has physically tagged caches but doesn't guarantee
consistency
between Icache and Dcache. So, new macro,
sync_icache_dcache() is added.
This is NO-OP in other archs.
- sync_icache_dcache() only works if pte is executable.
- sync_icache_dcache must be called before set_pte().
- A page which is consistent is marked as PG_arch_1.
About changes in generic codes:
- do_wp_page() ....need to sync newly copied page.
Here, lazy_mmu_prot_update() was done before
set_pte().
This was because someone mets SIGILL in
JAVA and small
fix was applied.
- do_anonymous_page() .... newly installed anon pages
doesn't contains any
instruction when set_pte() is executed,
icache-dcache
synchronization is not necessary.
- __do_fault() .... need to sync newly-installed page.
- handle_pte_fault() .... just changes access bit...then,
no need to sync.
- remove_migration_pte().... need to sync newly-installed
page.
- change_pte_range() .... need to sync icache-dcache. When
a user writes
instruction into the page and modifies protection to
be
executable, it should be synced.
- hugetlb_change_protection() .... Maybe cache will be
expired...but
it is safe to sync Icache before
set_pte().
- page_mkclean_one() .... no need to sync icache-dcache.
There is no page
contents modification. And there
is no protection
change.
Thanks to Zoltan Menyhart for his advices.
Signed-Off-By: KAMEZAWA Hiroyuki <kamezawa.hiroyu jp.fujitsu.com>
---
Documentation/cachetlb.txt | 11 +++++++----
arch/ia64/mm/init.c | 6 ++----
include/asm-generic/pgtable.h | 8 ++++----
include/asm-ia64/pgtable.h | 15 ++++++++++-----
mm/hugetlb.c | 3 +--
mm/memory.c | 7 ++-----
mm/migrate.c | 2 +-
mm/mprotect.c | 2 +-
mm/rmap.c | 1 -
9 files changed, 28 insertions(+), 27 deletions(-)
Index: linux-2.6.23-rc1.test/include/asm-generic/pgtable.h
============================================================
=======
---
linux-2.6.23-rc1.test.orig/include/asm-generic/pgtable.h
+++ linux-2.6.23-rc1.test/include/asm-generic/pgtable.h
-124,14
+124,14 static inline void ptep_set_wrprotect(st
#define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
#endif
-#ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
-#define lazy_mmu_prot_update(pte) do { } while (0)
-#endif
-
#ifndef __HAVE_ARCH_MOVE_PTE
#define move_pte(pte, prot, old_addr, new_addr) (pte)
#endif
+#ifndef __HAVE_ARCH_SYNC_ICACHE_DCACHE
+#define sync_icache_dcache(pte) do {} while (0)
+#endif
+
/*
* A facility to provide lazy MMU batching. This allows
PTE updates and
* page invalidations to be delayed until a call to leave
lazy MMU mode
Index: linux-2.6.23-rc1.test/include/asm-ia64/pgtable.h
============================================================
=======
--- linux-2.6.23-rc1.test.orig/include/asm-ia64/pgtable.h
+++ linux-2.6.23-rc1.test/include/asm-ia64/pgtable.h
-484,11
+484,17 extern struct page *zero_page_memmap_ptr
#endif
/*
- * IA-64 doesn't have any external MMU info: the page
tables contain all the necessary
- * information. However, we use this routine to take care
of any (delayed) i-cache
- * flushing that may be necessary.
+ * IA-64 doesn't guarantee Icache is consistent with
Dcache. For ensure
+ * Icache consistency, we have to synchronize them before
setting pte
+ * as an executable pte.
*/
-extern void lazy_mmu_prot_update (pte_t pte);
+extern void __sync_icache_dcache(pte_t pte);
+static inline void sync_icache_dcache(pte_t pte) {
+ if (pte_exec(pte))
+ __sync_icache_dcache(pte);
+}
+#define __HAVE_ARCH_SYNC_ICACHE_DCACHE
+
#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
/*
-578,7
+584,6 extern void lazy_mmu_prot_update (pte_t
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
#define __HAVE_ARCH_PTE_SAME
#define __HAVE_ARCH_PGD_OFFSET_GATE
-#define __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
#ifndef CONFIG_PGTABLE_4
#include <asm-generic/pgtable-nopud.h>
Index: linux-2.6.23-rc1.test/Documentation/cachetlb.txt
============================================================
=======
--- linux-2.6.23-rc1.test.orig/Documentation/cachetlb.txt
+++ linux-2.6.23-rc1.test/Documentation/cachetlb.txt
-133,11
+133,14 changes occur:
The ia64 sn2 platform is one example of a platform
that uses this interface.
-8) void lazy_mmu_prot_update(pte_t pte)
- This interface is called whenever the protection on
- any user PTEs change. This interface provides a
notification
- to architecture specific code to take appropriate action.
+8) void sync_icache_dcache(pte_t pte)
+ This interface is used for synchronize icache and dcache.
+ Even if the cache is physically tagged, some archs
doesn't
+ guarantee consistency between I-cache and D-cache. In such
arch,
+ we need to synchronize I-cache and D-cache before
installing
+ executable pages.
+ This is used only for ia64 now.
Next, we have the cache flushing interfaces. In general,
when Linux
is changing an existing virtual-->physical mapping to a
new value,
Index: linux-2.6.23-rc1.test/mm/memory.c
============================================================
=======
--- linux-2.6.23-rc1.test.orig/mm/memory.c
+++ linux-2.6.23-rc1.test/mm/memory.c
-1699,7
+1699,6 static int do_wp_page(struct mm_struct *
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
if (ptep_set_access_flags(vma, address, page_table,
entry,1)) {
update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
}
ret |= VM_FAULT_WRITE;
goto unlock;
-1741,7
+1740,7 gotten:
flush_cache_page(vma, address, pte_pfn(orig_pte));
entry = mk_pte(new_page, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- lazy_mmu_prot_update(entry);
+ sync_icache_dcache(entry);
/*
* Clear the pte entry and flush it first, before
updating the
* pte with the new entry. This will avoid a race
condition
-2286,7
+2285,6 static int do_anonymous_page(struct mm_s
/* No need to invalidate - it was non-present before */
update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
unlock:
pte_unmap_unlock(page_table, ptl);
return 0;
-2419,6
+2417,7 static int __do_fault(struct mm_struct *
if (likely(pte_same(*page_table, orig_pte))) {
flush_icache_page(vma, page);
entry = mk_pte(page, vma->vm_page_prot);
+ sync_icache_dcache(entry);
if (flags & FAULT_FLAG_WRITE)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
set_pte_at(mm, address, page_table, entry);
-2437,7
+2436,6 static int __do_fault(struct mm_struct *
/* no need to invalidate: a not-present page won't be
cached */
update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
} else {
if (anon)
page_cache_release(page);
-2611,7
+2609,6 static inline int handle_pte_fault(struc
entry = pte_mkyoung(entry);
if (ptep_set_access_flags(vma, address, pte, entry,
write_access)) {
update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
} else {
/*
* This is needed only for protection faults but the arch
code
Index: linux-2.6.23-rc1.test/mm/migrate.c
============================================================
=======
--- linux-2.6.23-rc1.test.orig/mm/migrate.c
+++ linux-2.6.23-rc1.test/mm/migrate.c
-173,6
+173,7 static void remove_migration_pte(struct
if (is_write_migration_entry(entry))
pte = pte_mkwrite(pte);
flush_cache_page(vma, addr, pte_pfn(pte));
+ sync_icache_dcache(pte);
set_pte_at(mm, addr, ptep, pte);
if (PageAnon(new))
-182,7
+183,6 static void remove_migration_pte(struct
/* No need to invalidate - it was non-present before */
update_mmu_cache(vma, addr, pte);
- lazy_mmu_prot_update(pte);
out:
pte_unmap_unlock(ptep, ptl);
Index: linux-2.6.23-rc1.test/mm/hugetlb.c
============================================================
=======
--- linux-2.6.23-rc1.test.orig/mm/hugetlb.c
+++ linux-2.6.23-rc1.test/mm/hugetlb.c
-352,7
+352,6 static void set_huge_ptep_writable(struc
entry = pte_mkwrite(pte_mkdirty(*ptep));
if (ptep_set_access_flags(vma, address, ptep, entry, 1))
{
update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
}
}
-704,8
+703,8 void hugetlb_change_protection(struct vm
if (!pte_none(*ptep)) {
pte = huge_ptep_get_and_clear(mm, address, ptep);
pte = pte_mkhuge(pte_modify(pte, newprot));
+ sync_icache_dcache(pte);
set_huge_pte_at(mm, address, ptep, pte);
- lazy_mmu_prot_update(pte);
}
}
spin_unlock(&mm->page_table_lock);
Index: linux-2.6.23-rc1.test/arch/ia64/mm/init.c
============================================================
=======
--- linux-2.6.23-rc1.test.orig/arch/ia64/mm/init.c
+++ linux-2.6.23-rc1.test/arch/ia64/mm/init.c
-54,15
+54,13 struct page *zero_page_memmap_ptr; /* ma
EXPORT_SYMBOL(zero_page_memmap_ptr);
void
-lazy_mmu_prot_update (pte_t pte)
+__sync_icache_dcache (pte_t pte)
{
unsigned long addr;
struct page *page;
unsigned long order;
- if (!pte_exec(pte))
- return; /* not an executable page... */
-
+ BUG_ON(!pte_exec(pte));
page = pte_page(pte);
addr = (unsigned long) page_address(page);
Index: linux-2.6.23-rc1.test/mm/mprotect.c
============================================================
=======
--- linux-2.6.23-rc1.test.orig/mm/mprotect.c
+++ linux-2.6.23-rc1.test/mm/mprotect.c
-52,8
+52,8 static void change_pte_range(struct mm_s
*/
if (dirty_accountable && pte_dirty(ptent))
ptent = pte_mkwrite(ptent);
+ sync_icache_dcache(ptent);
set_pte_at(mm, addr, pte, ptent);
- lazy_mmu_prot_update(ptent);
#ifdef CONFIG_MIGRATION
} else if (!pte_file(oldpte)) {
swp_entry_t entry = pte_to_swp_entry(oldpte);
Index: linux-2.6.23-rc1.test/mm/rmap.c
============================================================
=======
--- linux-2.6.23-rc1.test.orig/mm/rmap.c
+++ linux-2.6.23-rc1.test/mm/rmap.c
-436,7
+436,6 static int page_mkclean_one(struct page
entry = pte_wrprotect(entry);
entry = pte_mkclean(entry);
set_pte_at(mm, address, pte, entry);
- lazy_mmu_prot_update(entry);
ret = 1;
}
-
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