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

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (32 commits)
  x86: add MAP_STACK mmap flag
  x86: fix section mismatch warning - spp_getpage()
  x86: change init_gdt to update the gdt via write_gdt, rather than a direct write.
  x86-64: fix overlap of modules and fixmap areas
  x86, geode-mfgpt: check IRQ before using MFGPT as clocksource
  x86, acpi: cleanup, temp_stack is used only when CONFIG_SMP is set
  x86: fix spin_is_contended()
  x86, nmi: clean UP NMI watchdog failure message
  x86, NMI: fix watchdog failure message
  x86: fix /proc/meminfo DirectMap
  x86: fix readb() et al compile error with gcc-3.2.3
  arch/x86/Kconfig: clean up, experimental adjustement
  x86: invalidate caches before going into suspend
  x86, perfctr: don't use CCCR_OVF_PMI1 on Pentium 4Ds
  x86, AMD IOMMU: initialize dma_ops after sysfs registration
  x86m AMD IOMMU: cleanup: replace LOW_U32 macro with generic lower_32_bits
  x86, AMD IOMMU: initialize device table properly
  x86, AMD IOMMU: use status bit instead of memory write-back for completion wait
  x86: silence mmconfig printk
  x86, msr: fix NULL pointer deref due to msr_open on nonexistent CPUs
  ...

1 files changed, 23 insertions, 0 deletions

diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 5f58da4..4df3e2f 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -728,6 +728,29 @@ extern unsigned long		boot_option_idle_override;
 extern unsigned long		idle_halt;
 extern unsigned long		idle_nomwait;
 
+/*
+ * on systems with caches, caches must be flashed as the absolute
+ * last instruction before going into a suspended halt.  Otherwise,
+ * dirty data can linger in the cache and become stale on resume,
+ * leading to strange errors.
+ *
+ * perform a variety of operations to guarantee that the compiler
+ * will not reorder instructions.  wbinvd itself is serializing
+ * so the processor will not reorder.
+ *
+ * Systems without cache can just go into halt.
+ */
+static inline void wbinvd_halt(void)
+{
+	mb();
+	/* check for clflush to determine if wbinvd is legal */
+	if (cpu_has_clflush)
+		asm volatile("cli; wbinvd; 1: hlt; jmp 1b" : : : "memory");
+	else
+		while (1)
+			halt();
+}
+
 extern void enable_sep_cpu(void);
 extern int sysenter_setup(void);