Find biggest page
Split out a handy function for finding the largest page the
architecture can map over a region.
Signed-Off-By: Ian Wienand <ianw@xxxxxxxxxxxxxxxxxx>
---
arch/ia64/mm/tlb.c | 43 +++++++++++++++++++++++--------------------
include/asm-ia64/tlb.h | 25 +++++++++++++++++++++++++
2 files changed, 48 insertions(+), 20 deletions(-)
Index: linux-2.6.17-rc3-lvhpt-v2-fresh/arch/ia64/mm/tlb.c
===================================================================
--- linux-2.6.17-rc3-lvhpt-v2-fresh.orig/arch/ia64/mm/tlb.c 2006-05-03 17:11:43.000000000 +1000
+++ linux-2.6.17-rc3-lvhpt-v2-fresh/arch/ia64/mm/tlb.c 2006-05-10 09:13:08.000000000 +1000
@@ -26,11 +26,10 @@
#include <asm/pal.h>
#include <asm/tlbflush.h>
#include <asm/dma.h>
+#include <asm/pgtable.h>
+#include <asm/tlb.h>
-static struct {
- unsigned long mask; /* mask of supported purge page-sizes */
- unsigned long max_bits; /* log2 of largest supported purge page-size */
-} purge;
+struct ia64_page_sizes_t ia64_page_sizes;
struct ia64_ctx ia64_ctx = {
.lock = SPIN_LOCK_UNLOCKED,
@@ -138,7 +137,6 @@
unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
- unsigned long size = end - start;
unsigned long nbits;
#ifndef CONFIG_SMP
@@ -148,12 +146,7 @@
}
#endif
- nbits = ia64_fls(size + 0xfff);
- while (unlikely (((1UL << nbits) & purge.mask) == 0) &&
- (nbits < purge.max_bits))
- ++nbits;
- if (nbits > purge.max_bits)
- nbits = purge.max_bits;
+ nbits = find_largest_page_size(end-start);
start &= ~((1UL << nbits) - 1);
preempt_disable();
@@ -173,19 +166,29 @@
}
EXPORT_SYMBOL(flush_tlb_range);
+/*
+ * We need this data early in the boot, so it gets called from
+ * setup_arch()
+ */
+void __devinit
+ia64_tlb_early_init (void)
+{
+ long status;
+ unsigned long tr_pgbits;
+
+ /* Setup valid page sizes for find_largest_page() */
+ if ((status = ia64_pal_vm_page_size(&tr_pgbits, &ia64_page_sizes.mask)) != 0) {
+ printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld;"
+ "defaulting to architected purge page-sizes.\n", status);
+ ia64_page_sizes.mask = 0x115557000UL;
+ }
+ ia64_page_sizes.max_bits = ia64_fls(ia64_page_sizes.mask);
+}
+
void __devinit
ia64_tlb_init (void)
{
ia64_ptce_info_t ptce_info;
- unsigned long tr_pgbits;
- long status;
-
- if ((status = ia64_pal_vm_page_size(&tr_pgbits, &purge.mask)) != 0) {
- printk(KERN_ERR "PAL_VM_PAGE_SIZE failed with status=%ld;"
- "defaulting to architected purge page-sizes.\n", status);
- purge.mask = 0x115557000UL;
- }
- purge.max_bits = ia64_fls(purge.mask);
ia64_get_ptce(&ptce_info);
local_cpu_data->ptce_base = ptce_info.base;
Index: linux-2.6.17-rc3-lvhpt-v2-fresh/include/asm-ia64/tlb.h
===================================================================
--- linux-2.6.17-rc3-lvhpt-v2-fresh.orig/include/asm-ia64/tlb.h 2006-05-03 17:11:43.000000000 +1000
+++ linux-2.6.17-rc3-lvhpt-v2-fresh/include/asm-ia64/tlb.h 2006-05-10 09:04:39.000000000 +1000
@@ -200,6 +200,31 @@
tlb->end_addr = address + PAGE_SIZE;
}
+/*
+ * Find an architecture suitable page size based big enough to map
+ * input size. Return the number of bits; i.e. (1 << nbits) is the
+ * page size in bytes.
+ */
+struct ia64_page_sizes_t {
+ unsigned long mask; /* mask of supported page-sizes */
+ unsigned long max_bits; /* log2 of largest supported page-size */
+};
+
+ /* initalised in ia64_tlb_init() from EFI */
+extern struct ia64_page_sizes_t ia64_page_sizes;
+
+static inline unsigned long
+find_largest_page_size(unsigned long size)
+{
+ int nbits = ia64_fls(size + 0xfff);
+ while (unlikely (((1UL << nbits) & ia64_page_sizes.mask) == 0) &&
+ (nbits < ia64_page_sizes.max_bits))
+ ++nbits;
+ if (nbits > ia64_page_sizes.max_bits)
+ nbits = ia64_page_sizes.max_bits;
+ return nbits;
+}
+
#define tlb_migrate_finish(mm) platform_tlb_migrate_finish(mm)
#define tlb_start_vma(tlb, vma) do { } while (0)
-
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