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authorSuresh Siddha <suresh.b.siddha@intel.com>2009-10-28 18:46:58 -0800
committerIngo Molnar <mingo@elte.hu>2009-11-02 17:17:24 +0100
commite7d23dde9b7ebb575e2bcee2abefc9ec1e4adde9 (patch)
treee3c8683d149e29a2d3a6099ddcae4732d17d6b31
parent55ca3cc1746335bb6ef1d3894ddb6d0c729b3518 (diff)
x86_64, cpa: Use only text section in set_kernel_text_rw/ro
set_kernel_text_rw()/set_kernel_text_ro() are marking pages starting from _text to __start_rodata as RW or RO. With CONFIG_DEBUG_RODATA, there might be free pages (associated with padding the sections to 2MB large page boundary) between text and rodata sections that are given back to page allocator. So we should use only use the start (__text) and end (__stop___ex_table) of the text section in set_kernel_text_rw()/set_kernel_text_ro(). Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20091029024821.164525222@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/mm/init_64.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 4b507c08940..5198b9bb34e 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -700,7 +700,7 @@ int kernel_set_to_readonly;
void set_kernel_text_rw(void)
{
unsigned long start = PFN_ALIGN(_text);
- unsigned long end = PFN_ALIGN(__start_rodata);
+ unsigned long end = PFN_ALIGN(__stop___ex_table);
if (!kernel_set_to_readonly)
return;
@@ -708,13 +708,18 @@ void set_kernel_text_rw(void)
pr_debug("Set kernel text: %lx - %lx for read write\n",
start, end);
+ /*
+ * Make the kernel identity mapping for text RW. Kernel text
+ * mapping will always be RO. Refer to the comment in
+ * static_protections() in pageattr.c
+ */
set_memory_rw(start, (end - start) >> PAGE_SHIFT);
}
void set_kernel_text_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
- unsigned long end = PFN_ALIGN(__start_rodata);
+ unsigned long end = PFN_ALIGN(__stop___ex_table);
if (!kernel_set_to_readonly)
return;
@@ -722,6 +727,9 @@ void set_kernel_text_ro(void)
pr_debug("Set kernel text: %lx - %lx for read only\n",
start, end);
+ /*
+ * Set the kernel identity mapping for text RO.
+ */
set_memory_ro(start, (end - start) >> PAGE_SHIFT);
}