arch/tile: support 4KB page size as well as 64KB

The Tilera architecture traditionally supports 64KB page sizes
to improve TLB utilization and improve performance when the
hardware is being used primarily to run a single application.

For more generic server scenarios, it can be beneficial to run
with 4KB page sizes, so this commit allows that to be specified
(by modifying the arch/tile/include/hv/pagesize.h header).

As part of this change, we also re-worked the PTE management
slightly so that PTE writes all go through a __set_pte() function
where we can do some additional validation.  The set_pte_order()
function was eliminated since the "order" argument wasn't being used.

One bug uncovered was in the PCI DMA code, which wasn't properly
flushing the specified range.  This was benign with 64KB pages,
but with 4KB pages we were getting some larger flushes wrong.

The per-cpu memory reservation code also needed updating to
conform with the newer percpu stuff; before it always chose 64KB,
and that was always correct, but with 4KB granularity we now have
to pay closer attention and reserve the amount of memory that will
be requested when the percpu code starts allocating.

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

1 files changed, 11 insertions, 23 deletions

diff --git a/arch/tile/include/asm/page.h b/arch/tile/include/asm/page.h
index 7979a45..3eb5352 100644
--- a/arch/tile/include/asm/page.h
+++ b/arch/tile/include/asm/page.h
@@ -16,10 +16,11 @@
 #define _ASM_TILE_PAGE_H
 
 #include <linux/const.h>
+#include <hv/pagesize.h>
 
 /* PAGE_SHIFT and HPAGE_SHIFT determine the page sizes. */
-#define PAGE_SHIFT	16
-#define HPAGE_SHIFT	24
+#define PAGE_SHIFT	HV_LOG2_PAGE_SIZE_SMALL
+#define HPAGE_SHIFT	HV_LOG2_PAGE_SIZE_LARGE
 
 #define PAGE_SIZE	(_AC(1, UL) << PAGE_SHIFT)
 #define HPAGE_SIZE	(_AC(1, UL) << HPAGE_SHIFT)
@@ -29,25 +30,18 @@
 
 #ifdef __KERNEL__
 
-#include <hv/hypervisor.h>
-#include <arch/chip.h>
-
 /*
- * The {,H}PAGE_SHIFT values must match the HV_LOG2_PAGE_SIZE_xxx
- * definitions in <hv/hypervisor.h>.  We validate this at build time
- * here, and again at runtime during early boot.  We provide a
- * separate definition since userspace doesn't have <hv/hypervisor.h>.
- *
- * Be careful to distinguish PAGE_SHIFT from HV_PTE_INDEX_PFN, since
- * they are the same on i386 but not TILE.
+ * If the Kconfig doesn't specify, set a maximum zone order that
+ * is enough so that we can create huge pages from small pages given
+ * the respective sizes of the two page types.  See <linux/mmzone.h>.
  */
-#if HV_LOG2_PAGE_SIZE_SMALL != PAGE_SHIFT
-# error Small page size mismatch in Linux
-#endif
-#if HV_LOG2_PAGE_SIZE_LARGE != HPAGE_SHIFT
-# error Huge page size mismatch in Linux
+#ifndef CONFIG_FORCE_MAX_ZONEORDER
+#define CONFIG_FORCE_MAX_ZONEORDER (HPAGE_SHIFT - PAGE_SHIFT + 1)
 #endif
 
+#include <hv/hypervisor.h>
+#include <arch/chip.h>
+
 #ifndef __ASSEMBLY__
 
 #include <linux/types.h>
@@ -81,12 +75,6 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
  * Hypervisor page tables are made of the same basic structure.
  */
 
-typedef __u64 pteval_t;
-typedef __u64 pmdval_t;
-typedef __u64 pudval_t;
-typedef __u64 pgdval_t;
-typedef __u64 pgprotval_t;
-
 typedef HV_PTE pte_t;
 typedef HV_PTE pgd_t;
 typedef HV_PTE pgprot_t;