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x86: mark the .rodata section also NX 

The .rodata section shouldn't just be read-only,
but also non-executable. This is free since we've broken
up the 2MB page already anyway.

also update test_nx to check for this.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Arjan van de Ven 2008-02-06 22:39:45 +01:00 committed by Ingo Molnar
parent a57dae3aa4
commit 984bb80d94
2 changed files with 9 additions and 2 deletions
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2
arch/x86/kernel/test_nx.c
View File

@ -139,7 +139,6 @@ static int test_NX(void)
* Until then, don't run them to avoid too many people getting scared
* by the error message
*/
#if 0
#ifdef CONFIG_DEBUG_RODATA
/* Test 3: Check if the .rodata section is executable */
@ -152,6 +151,7 @@ static int test_NX(void)
}
#endif
#if 0
/* Test 4: Check if the .data section of a module is executable */
if (test_address(&test_data)) {
printk(KERN_ERR "test_nx: .data section is executable\n");

9
arch/x86/mm/init_64.c
View File

@ -591,10 +591,17 @@ void mark_rodata_ro(void)
if (end <= start)
return;
set_memory_ro(start, (end - start) >> PAGE_SHIFT);
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
set_memory_ro(start, (end - start) >> PAGE_SHIFT);
/*
* The rodata section (but not the kernel text!) should also be
* not-executable.
*/
start = ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
set_memory_nx(start, (end - start) >> PAGE_SHIFT);
rodata_test();