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, 7 insertions, 1 deletions

diff --git a/arch/tile/include/asm/pgtable_32.h b/arch/tile/include/asm/pgtable_32.h
index 53ec3488474..9f98529761f 100644
--- a/arch/tile/include/asm/pgtable_32.h
+++ b/arch/tile/include/asm/pgtable_32.h
@@ -24,6 +24,7 @@
 #define PGDIR_SIZE	HV_PAGE_SIZE_LARGE
 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
 #define PTRS_PER_PGD	(1 << (32 - PGDIR_SHIFT))
+#define SIZEOF_PGD	(PTRS_PER_PGD * sizeof(pgd_t))
 
 /*
  * The level-2 index is defined by the difference between the huge
@@ -33,6 +34,7 @@
  * this nomenclature is somewhat confusing.
  */
 #define PTRS_PER_PTE (1 << (HV_LOG2_PAGE_SIZE_LARGE - HV_LOG2_PAGE_SIZE_SMALL))
+#define SIZEOF_PTE	(PTRS_PER_PTE * sizeof(pte_t))
 
 #ifndef __ASSEMBLY__
 
@@ -94,7 +96,6 @@ static inline int pgd_addr_invalid(unsigned long addr)
  */
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
-#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 
 extern int ptep_test_and_clear_young(struct vm_area_struct *,
 				     unsigned long addr, pte_t *);
@@ -110,6 +111,11 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 	return pte;
 }
 
+static inline void __set_pmd(pmd_t *pmdp, pmd_t pmdval)
+{
+	set_pte(&pmdp->pud.pgd, pmdval.pud.pgd);
+}
+
 /* Create a pmd from a PTFN. */
 static inline pmd_t ptfn_pmd(unsigned long ptfn, pgprot_t prot)
 {