From 5a654ba7a88d90483d0f0586297ea9075d755fc8 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 1 Jul 2008 16:46:37 -0700 Subject: [PATCH] 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 Cc: Stephen Tweedie Cc: Eduardo Habkost Cc: Mark McLoughlin Signed-off-by: Ingo Molnar --- arch/x86/mm/pageattr-test.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c index 75f1b109aae8..0dcd42eb94e6 100644 --- a/arch/x86/mm/pageattr-test.c +++ b/arch/x86/mm/pageattr-test.c @@ -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 #include @@ -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++; -- 2.20.1