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x86/cpa: use an undefined PTE bit for testing CPA 

Rather than using _PAGE_GLOBAL - which not all CPUs support - to test
CPA, use one of the reserved-for-software-use PTE flags instead.  This
allows CPA testing to work on CPUs which don't support PGD.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge 2008-07-01 16:46:37 -07:00 committed by Ingo Molnar
parent ef5e94af16
commit 5a654ba7a8
1 changed files with 13 additions and 8 deletions
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21
arch/x86/mm/pageattr-test.c
View File

@ -1,8 +1,8 @@
/*
* self test for change_page_attr.
*
* Clears the global bit on random pages in the direct mapping, then reverts
* and compares page tables forwards and afterwards.
* Clears the a test pte bit on random pages in the direct mapping,
* then reverts and compares page tables forwards and afterwards.
*/
#include <linux/bootmem.h>
#include <linux/kthread.h>
@ -32,6 +32,13 @@ enum {
GPS = (1<<30)
};
#define PAGE_TESTBIT __pgprot(_PAGE_UNUSED1)
static int pte_testbit(pte_t pte)
{
return pte_flags(pte) & _PAGE_UNUSED1;
}
struct split_state {
long lpg, gpg, spg, exec;
long min_exec, max_exec;
@ -165,15 +172,14 @@ static int pageattr_test(void)
continue;
}
err = change_page_attr_clear(addr[i], len[i],
__pgprot(_PAGE_GLOBAL));
err = change_page_attr_set(addr[i], len[i], PAGE_TESTBIT);
if (err < 0) {
printk(KERN_ERR "CPA %d failed %d\n", i, err);
failed++;
}
pte = lookup_address(addr[i], &level);
if (!pte || pte_global(*pte) || pte_huge(*pte)) {
if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
pte ? (u64)pte_val(*pte) : 0ULL);
failed++;
@ -198,14 +204,13 @@ static int pageattr_test(void)
failed++;
continue;
}
err = change_page_attr_set(addr[i], len[i],
__pgprot(_PAGE_GLOBAL));
err = change_page_attr_clear(addr[i], len[i], PAGE_TESTBIT);
if (err < 0) {
printk(KERN_ERR "CPA reverting failed: %d\n", err);
failed++;
}
pte = lookup_address(addr[i], &level);
if (!pte || !pte_global(*pte)) {
if (!pte || pte_testbit(*pte)) {
printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
failed++;