powerpc/mm: Split hash MMU specific hugepage code into a new file

This patch separates the parts of hugetlbpage.c which are inherently
specific to the hash MMU into a new hugelbpage-hash64.c file.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 167 insertions, 0 deletions

diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
new file mode 100644
index 000000000000..1508ffc1e1e1
--- /dev/null
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -0,0 +1,167 @@
+/*
+ * PPC64 Huge TLB Page Support for hash based MMUs (POWER4 and later)
+ *
+ * Copyright (C) 2003 David Gibson, IBM Corporation.
+ *
+ * Based on the IA-32 version:
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/cacheflush.h>
+#include <asm/machdep.h>
+
+/*
+ * Called by asm hashtable.S for doing lazy icache flush
+ */
+static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
+					pte_t pte, int trap, unsigned long sz)
+{
+	struct page *page;
+	int i;
+
+	if (!pfn_valid(pte_pfn(pte)))
+		return rflags;
+
+	page = pte_page(pte);
+
+	/* page is dirty */
+	if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
+		if (trap == 0x400) {
+			for (i = 0; i < (sz / PAGE_SIZE); i++)
+				__flush_dcache_icache(page_address(page+i));
+			set_bit(PG_arch_1, &page->flags);
+		} else {
+			rflags |= HPTE_R_N;
+		}
+	}
+	return rflags;
+}
+
+int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
+		     pte_t *ptep, unsigned long trap, int local, int ssize,
+		     unsigned int shift, unsigned int mmu_psize)
+{
+	unsigned long old_pte, new_pte;
+	unsigned long va, rflags, pa, sz;
+	long slot;
+	int err = 1;
+
+	BUG_ON(shift != mmu_psize_defs[mmu_psize].shift);
+
+	/* Search the Linux page table for a match with va */
+	va = hpt_va(ea, vsid, ssize);
+
+	/*
+	 * Check the user's access rights to the page.  If access should be
+	 * prevented then send the problem up to do_page_fault.
+	 */
+	if (unlikely(access & ~pte_val(*ptep)))
+		goto out;
+	/*
+	 * At this point, we have a pte (old_pte) which can be used to build
+	 * or update an HPTE. There are 2 cases:
+	 *
+	 * 1. There is a valid (present) pte with no associated HPTE (this is
+	 *	the most common case)
+	 * 2. There is a valid (present) pte with an associated HPTE. The
+	 *	current values of the pp bits in the HPTE prevent access
+	 *	because we are doing software DIRTY bit management and the
+	 *	page is currently not DIRTY.
+	 */
+
+
+	do {
+		old_pte = pte_val(*ptep);
+		if (old_pte & _PAGE_BUSY)
+			goto out;
+		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
+	} while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
+					 old_pte, new_pte));
+
+	rflags = 0x2 | (!(new_pte & _PAGE_RW));
+	/* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
+	rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
+	sz = ((1UL) << shift);
+	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		/* No CPU has hugepages but lacks no execute, so we
+		 * don't need to worry about that case */
+		rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
+						       trap, sz);
+
+	/* Check if pte already has an hpte (case 2) */
+	if (unlikely(old_pte & _PAGE_HASHPTE)) {
+		/* There MIGHT be an HPTE for this pte */
+		unsigned long hash, slot;
+
+		hash = hpt_hash(va, shift, ssize);
+		if (old_pte & _PAGE_F_SECOND)
+			hash = ~hash;
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += (old_pte & _PAGE_F_GIX) >> 12;
+
+		if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_psize,
+					 ssize, local) == -1)
+			old_pte &= ~_PAGE_HPTEFLAGS;
+	}
+
+	if (likely(!(old_pte & _PAGE_HASHPTE))) {
+		unsigned long hash = hpt_hash(va, shift, ssize);
+		unsigned long hpte_group;
+
+		pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
+
+repeat:
+		hpte_group = ((hash & htab_hash_mask) *
+			      HPTES_PER_GROUP) & ~0x7UL;
+
+		/* clear HPTE slot informations in new PTE */
+#ifdef CONFIG_PPC_64K_PAGES
+		new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0;
+#else
+		new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
+#endif
+		/* Add in WIMG bits */
+		rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
+				      _PAGE_COHERENT | _PAGE_GUARDED));
+
+		/* Insert into the hash table, primary slot */
+		slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
+					  mmu_psize, ssize);
+
+		/* Primary is full, try the secondary */
+		if (unlikely(slot == -1)) {
+			hpte_group = ((~hash & htab_hash_mask) *
+				      HPTES_PER_GROUP) & ~0x7UL;
+			slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
+						  HPTE_V_SECONDARY,
+						  mmu_psize, ssize);
+			if (slot == -1) {
+				if (mftb() & 0x1)
+					hpte_group = ((hash & htab_hash_mask) *
+						      HPTES_PER_GROUP)&~0x7UL;
+
+				ppc_md.hpte_remove(hpte_group);
+				goto repeat;
+                        }
+		}
+
+		if (unlikely(slot == -2))
+			panic("hash_huge_page: pte_insert failed\n");
+
+		new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
+	}
+
+	/*
+	 * No need to use ldarx/stdcx here
+	 */
+	*ptep = __pte(new_pte & ~_PAGE_BUSY);
+
+	err = 0;
+
+ out:
+	return err;
+}