tile: support CONFIG_PREEMPT

This change adds support for CONFIG_PREEMPT (full kernel preemption).
In addition to the core support, this change includes a number
of places where we fix up uses of smp_processor_id() and per-cpu
variables.  I also eliminate the PAGE_HOME_HERE and PAGE_HOME_UNKNOWN
values for page homing, as it turns out they weren't being used.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

2 files changed, 18 insertions, 11 deletions

diff --git a/arch/tile/include/asm/homecache.h b/arch/tile/include/asm/homecache.h
index 7b7771328642..49d19dfc0630 100644
--- a/arch/tile/include/asm/homecache.h
+++ b/arch/tile/include/asm/homecache.h
@@ -44,16 +44,8 @@ struct zone;
  */
 #define PAGE_HOME_INCOHERENT -3
 
-#if CHIP_HAS_CBOX_HOME_MAP()
 /* Home for the page is distributed via hash-for-home. */
 #define PAGE_HOME_HASH -4
-#endif
-
-/* Homing is unknown or unspecified.  Not valid for page_home(). */
-#define PAGE_HOME_UNKNOWN -5
-
-/* Home on the current cpu.  Not valid for page_home(). */
-#define PAGE_HOME_HERE -6
 
 /* Support wrapper to use instead of explicit hv_flush_remote(). */
 extern void flush_remote(unsigned long cache_pfn, unsigned long cache_length,
diff --git a/arch/tile/include/asm/irqflags.h b/arch/tile/include/asm/irqflags.h
index c96f9bbb760d..71af5747874d 100644
--- a/arch/tile/include/asm/irqflags.h
+++ b/arch/tile/include/asm/irqflags.h
@@ -124,6 +124,12 @@
 DECLARE_PER_CPU(unsigned long long, interrupts_enabled_mask);
 #define INITIAL_INTERRUPTS_ENABLED (1ULL << INT_MEM_ERROR)
 
+#ifdef CONFIG_DEBUG_PREEMPT
+/* Due to inclusion issues, we can't rely on <linux/smp.h> here. */
+extern unsigned int debug_smp_processor_id(void);
+# define smp_processor_id() debug_smp_processor_id()
+#endif
+
 /* Disable interrupts. */
 #define arch_local_irq_disable() \
 	interrupt_mask_set_mask(LINUX_MASKABLE_INTERRUPTS)
@@ -132,9 +138,18 @@ DECLARE_PER_CPU(unsigned long long, interrupts_enabled_mask);
 #define arch_local_irq_disable_all() \
 	interrupt_mask_set_mask(-1ULL)
 
+/*
+ * Read the set of maskable interrupts.
+ * We avoid the preemption warning here via __this_cpu_ptr since even
+ * if irqs are already enabled, it's harmless to read the wrong cpu's
+ * enabled mask.
+ */
+#define arch_local_irqs_enabled() \
+	(*__this_cpu_ptr(&interrupts_enabled_mask))
+
 /* Re-enable all maskable interrupts. */
 #define arch_local_irq_enable() \
-	interrupt_mask_reset_mask(__get_cpu_var(interrupts_enabled_mask))
+	interrupt_mask_reset_mask(arch_local_irqs_enabled())
 
 /* Disable or enable interrupts based on flag argument. */
 #define arch_local_irq_restore(disabled) do { \
@@ -161,7 +176,7 @@ DECLARE_PER_CPU(unsigned long long, interrupts_enabled_mask);
 
 /* Prevent the given interrupt from being enabled next time we enable irqs. */
 #define arch_local_irq_mask(interrupt) \
-	(__get_cpu_var(interrupts_enabled_mask) &= ~(1ULL << (interrupt)))
+	this_cpu_and(interrupts_enabled_mask, ~(1ULL << (interrupt)))
 
 /* Prevent the given interrupt from being enabled immediately. */
 #define arch_local_irq_mask_now(interrupt) do { \
@@ -171,7 +186,7 @@ DECLARE_PER_CPU(unsigned long long, interrupts_enabled_mask);
 
 /* Allow the given interrupt to be enabled next time we enable irqs. */
 #define arch_local_irq_unmask(interrupt) \
-	(__get_cpu_var(interrupts_enabled_mask) |= (1ULL << (interrupt)))
+	this_cpu_or(interrupts_enabled_mask, (1ULL << (interrupt)))
 
 /* Allow the given interrupt to be enabled immediately, if !irqs_disabled. */
 #define arch_local_irq_unmask_now(interrupt) do { \