[git pull] x86 fixes

Ingo Molnar
2009-02-20T14:19:21Z

Linus,

Please pull the latest x86-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git x86-fixes-for-linus

this includes the fix for the PMD permission bug that Steve
found, and a VMI fix.

Thanks,

Ingo

------------------>
Alok N Kataria (1):
x86, vmi: TSC going backwards check in vmi clocksource

Ingo Molnar (1):
x86: use the right protections for split-up pagetables

arch/x86/kernel/vmiclock_32.c | 5 ++++-
arch/x86/mm/pageattr.c | 15 +++++----------
2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/vmiclock_32.c b/arch/x86/kernel/vmiclock_32.c
index c4c1f9e..bde106c 100644
--- a/arch/x86/kernel/vmiclock_32.c
+++ b/arch/x86/kernel/vmiclock_32.c
@@ -283,10 +283,13 @@ void __devinit vmi_time_ap_init(void)
#endif

/** vmi clocksource */
+static struct clocksource clocksource_vmi;

static cycle_t read_real_cycles(void)
{
- return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL);
+ cycle_t ret = (cycle_t)vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL);
+ return ret >= clocksource_vmi.cycle_last ?
+ ret : clocksource_vmi.cycle_last;
}

static struct clocksource clocksource_vmi = {
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 8ca0d85..7be47d1 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -508,18 +508,13 @@ static int split_large_page(pte_t *kpte, unsigned long address)
#endif

/*
- * Install the new, split up pagetable. Important details here:
+ * Install the new, split up pagetable.
*
- * On Intel the NX bit of all levels must be cleared to make a
- * page executable. See section 4.13.2 of Intel 64 and IA-32
- * Architectures Software Developer's Manual).
- *
- * Mark the entry present. The current mapping might be
- * set to not present, which we preserved above.
+ * We use the standard kernel pagetable protections for the new
+ * pagetable protections, the actual ptes set above control the
+ * primary protection behavior:
*/
- ref_prot = pte_pgprot(pte_mkexec(pte_clrhuge(*kpte)));
- pgprot_val(ref_prot) |= _PAGE_PRESENT;
- __set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
+ __set_pmd_pte(kpte, address, mk_pte(base, __pgprot(_KERNPG_TABLE)));
base = NULL;