[PATCH 02/13] SPARC64: Fix D-cache corruption in mremap

Chris Wright
2006-06-20T11:49:38Z

[-- Attachment #1: sparc64-fix-d-cache-corruption-in-mremap.patch --]
[-- Type: text/plain, Size: 3073 bytes --]

-stable review patch. If anyone has any objections, please let us know.
------------------

From: David Miller <davem@davemloft.net>

If we move a mapping from one virtual address to another,
and this changes the virtual color of the mapping to those
pages, we can see corrupt data due to D-cache aliasing.

Check for and deal with this by overriding the move_pte()
macro. Set things up so that other platforms can cleanly
override the move_pte() macro too.

This long standing bug corrupts user memory, and in particular
has been notorious for corrupting Debian package database
files on sparc64 boxes.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

include/asm-generic/pgtable.h | 11 +----------
include/asm-mips/pgtable.h | 10 +++++++++-
include/asm-sparc64/pgtable.h | 17 +++++++++++++++++
3 files changed, 27 insertions(+), 11 deletions(-)

--- linux-2.6.16.21.orig/include/asm-generic/pgtable.h
+++ linux-2.6.16.21/include/asm-generic/pgtable.h
@@ -159,17 +159,8 @@ static inline void ptep_set_wrprotect(st
#define lazy_mmu_prot_update(pte) do { } while (0)
#endif

-#ifndef __HAVE_ARCH_MULTIPLE_ZERO_PAGE
+#ifndef __HAVE_ARCH_MOVE_PTE
#define move_pte(pte, prot, old_addr, new_addr) (pte)
-#else
-#define move_pte(pte, prot, old_addr, new_addr) \
-({ \
- pte_t newpte = (pte); \
- if (pte_present(pte) && pfn_valid(pte_pfn(pte)) && \
- pte_page(pte) == ZERO_PAGE(old_addr)) \
- newpte = mk_pte(ZERO_PAGE(new_addr), (prot)); \
- newpte; \
-})
#endif

/*
--- linux-2.6.16.21.orig/include/asm-mips/pgtable.h
+++ linux-2.6.16.21/include/asm-mips/pgtable.h
@@ -70,7 +70,15 @@ extern unsigned long zero_page_mask;
#define ZERO_PAGE(vaddr) \
(virt_to_page(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask)))

-#define __HAVE_ARCH_MULTIPLE_ZERO_PAGE
+#define __HAVE_ARCH_MOVE_PTE
+#define move_pte(pte, prot, old_addr, new_addr) \
+({ \
+ pte_t newpte = (pte); \
+ if (pte_present(pte) && pfn_valid(pte_pfn(pte)) && \
+ pte_page(pte) == ZERO_PAGE(old_addr)) \
+ newpte = mk_pte(ZERO_PAGE(new_addr), (prot)); \
+ newpte; \
+})

extern void paging_init(void);

--- linux-2.6.16.21.orig/include/asm-sparc64/pgtable.h
+++ linux-2.6.16.21/include/asm-sparc64/pgtable.h
@@ -335,6 +335,23 @@ static inline void set_pte_at(struct mm_
#define pte_clear(mm,addr,ptep) \
set_pte_at((mm), (addr), (ptep), __pte(0UL))

+#ifdef DCACHE_ALIASING_POSSIBLE
+#define __HAVE_ARCH_MOVE_PTE
+#define move_pte(pte, prot, old_addr, new_addr) \
+({ \
+ pte_t newpte = (pte); \
+ if (pte_present(pte)) { \
+ unsigned long this_pfn = pte_pfn(pte); \
+ \
+ if (pfn_valid(this_pfn) && \
+ (((old_addr) ^ (new_addr)) & (1 << 13))) \
+ flush_dcache_page_all(current->mm, \
+ pfn_to_page(this_pfn)); \
+ } \
+ newpte; \
+})
+#endif
+
extern pgd_t swapper_pg_dir[2048];
extern pmd_t swapper_low_pmd_dir[2048];

--