2009-04-09 22:12:13

by Pallipadi, Venkatesh

Subject: [patch 2/6] x86, PAT: Change order of cpa and free in set_memory_wb

To be free of aliasing due to races, set_memory_* interfaces should
follow ordering of reserving, changing memtype to UC/WC, changing
memtype back to WB followed by free.

Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Suresh Siddha <[email protected]>
---
arch/x86/mm/pageattr.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 1224865..38dc61f 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1007,15 +1007,19 @@ int _set_memory_wb(unsigned long addr, int numpages)

int set_memory_wb(unsigned long addr, int numpages)
{
+ int ret = _set_memory_wb(addr, numpages);
free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
-
- return _set_memory_wb(addr, numpages);
+ return ret;
}
EXPORT_SYMBOL(set_memory_wb);

int set_memory_array_wb(unsigned long *addr, int addrinarray)
{
int i;
+ int ret;
+
+ ret = change_page_attr_clear(addr, addrinarray,
+ __pgprot(_PAGE_CACHE_MASK), 1);

for (i = 0; i < addrinarray; i++) {
unsigned long start = __pa(addr[i]);
@@ -1028,8 +1032,7 @@ int set_memory_array_wb(unsigned long *addr, int addrinarray)
}
free_memtype(start, end);
}
- return change_page_attr_clear(addr, addrinarray,
- __pgprot(_PAGE_CACHE_MASK), 1);
+ return ret;
}
EXPORT_SYMBOL(set_memory_array_wb);

--
1.6.0.6

--

2009-04-10 12:35:08

by Pallipadi, Venkatesh

Subject: [tip:x86/pat] x86, PAT: Change order of cpa and free in set_memory_wb

Commit-ID: a5593e0b329a14dea41ea173380dbf1533de2bd2
Gitweb: http://git.kernel.org/tip/a5593e0b329a14dea41ea173380dbf1533de2bd2
Author: [email protected] <[email protected]>
AuthorDate: Thu, 9 Apr 2009 14:26:48 -0700
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 10 Apr 2009 13:55:46 +0200

x86, PAT: Change order of cpa and free in set_memory_wb

To be free of aliasing due to races, set_memory_* interfaces should
follow ordering of reserving, changing memtype to UC/WC, changing
memtype back to WB followed by free.

Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Suresh Siddha <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>


---
arch/x86/mm/pageattr.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index d71e1b6..d487eaa 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1021,15 +1021,19 @@ int _set_memory_wb(unsigned long addr, int numpages)

int set_memory_wb(unsigned long addr, int numpages)
{
+ int ret = _set_memory_wb(addr, numpages);
free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
-
- return _set_memory_wb(addr, numpages);
+ return ret;
}
EXPORT_SYMBOL(set_memory_wb);

int set_memory_array_wb(unsigned long *addr, int addrinarray)
{
int i;
+ int ret;
+
+ ret = change_page_attr_clear(addr, addrinarray,
+ __pgprot(_PAGE_CACHE_MASK), 1);

for (i = 0; i < addrinarray; i++) {
unsigned long start = __pa(addr[i]);
@@ -1042,8 +1046,7 @@ int set_memory_array_wb(unsigned long *addr, int addrinarray)
}
free_memtype(start, end);
}
- return change_page_attr_clear(addr, addrinarray,
- __pgprot(_PAGE_CACHE_MASK), 1);
+ return ret;
}
EXPORT_SYMBOL(set_memory_array_wb);