From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/parisc/include/asm/pgalloc.h | 156 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 arch/parisc/include/asm/pgalloc.h

(limited to 'arch/parisc/include/asm/pgalloc.h')

diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
new file mode 100644
index 000000000..3a08eae33
--- /dev/null
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -0,0 +1,156 @@
+#ifndef _ASM_PGALLOC_H
+#define _ASM_PGALLOC_H
+
+#include <linux/gfp.h>
+#include <linux/mm.h>
+#include <linux/threads.h>
+#include <asm/processor.h>
+#include <asm/fixmap.h>
+
+#include <asm/cache.h>
+
+/* Allocate the top level pgd (page directory)
+ *
+ * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we
+ * allocate the first pmd adjacent to the pgd.  This means that we can
+ * subtract a constant offset to get to it.  The pmd and pgd sizes are
+ * arranged so that a single pmd covers 4GB (giving a full 64-bit
+ * process access to 8TB) so our lookups are effectively L2 for the
+ * first 4GB of the kernel (i.e. for all ILP32 processes and all the
+ * kernel for machines with under 4GB of memory) */
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,
+					       PGD_ALLOC_ORDER);
+	pgd_t *actual_pgd = pgd;
+
+	if (likely(pgd != NULL)) {
+		memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);
+#if CONFIG_PGTABLE_LEVELS == 3
+		actual_pgd += PTRS_PER_PGD;
+		/* Populate first pmd with allocated memory.  We mark it
+		 * with PxD_FLAG_ATTACHED as a signal to the system that this
+		 * pmd entry may not be cleared. */
+		__pgd_val_set(*actual_pgd, (PxD_FLAG_PRESENT | 
+				        PxD_FLAG_VALID | 
+					PxD_FLAG_ATTACHED) 
+			+ (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT));
+		/* The first pmd entry also is marked with _PAGE_GATEWAY as
+		 * a signal that this pmd may not be freed */
+		__pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
+#endif
+	}
+	return actual_pgd;
+}
+
+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+#if CONFIG_PGTABLE_LEVELS == 3
+	pgd -= PTRS_PER_PGD;
+#endif
+	free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);
+}
+
+#if CONFIG_PGTABLE_LEVELS == 3
+
+/* Three Level Page Table Support for pmd's */
+
+static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmd)
+{
+	__pgd_val_set(*pgd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) +
+		        (__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT));
+}
+
+static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+	pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT,
+					       PMD_ORDER);
+	if (pmd)
+		memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
+	return pmd;
+}
+
+static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
+{
+	if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
+		/*
+		 * This is the permanent pmd attached to the pgd;
+		 * cannot free it.
+		 * Increment the counter to compensate for the decrement
+		 * done by generic mm code.
+		 */
+		mm_inc_nr_pmds(mm);
+		return;
+	free_pages((unsigned long)pmd, PMD_ORDER);
+}
+
+#else
+
+/* Two Level Page Table Support for pmd's */
+
+/*
+ * allocating and freeing a pmd is trivial: the 1-entry pmd is
+ * inside the pgd, so has no extra memory associated with it.
+ */
+
+#define pmd_alloc_one(mm, addr)		({ BUG(); ((pmd_t *)2); })
+#define pmd_free(mm, x)			do { } while (0)
+#define pgd_populate(mm, pmd, pte)	BUG()
+
+#endif
+
+static inline void
+pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
+{
+#if CONFIG_PGTABLE_LEVELS == 3
+	/* preserve the gateway marker if this is the beginning of
+	 * the permanent pmd */
+	if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
+		__pmd_val_set(*pmd, (PxD_FLAG_PRESENT |
+				 PxD_FLAG_VALID |
+				 PxD_FLAG_ATTACHED) 
+			+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
+	else
+#endif
+		__pmd_val_set(*pmd, (PxD_FLAG_PRESENT | PxD_FLAG_VALID) 
+			+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT));
+}
+
+#define pmd_populate(mm, pmd, pte_page) \
+	pmd_populate_kernel(mm, pmd, page_address(pte_page))
+#define pmd_pgtable(pmd) pmd_page(pmd)
+
+static inline pgtable_t
+pte_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+	struct page *page = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
+	if (!page)
+		return NULL;
+	if (!pgtable_page_ctor(page)) {
+		__free_page(page);
+		return NULL;
+	}
+	return page;
+}
+
+static inline pte_t *
+pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr)
+{
+	pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
+	return pte;
+}
+
+static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
+{
+	free_page((unsigned long)pte);
+}
+
+static inline void pte_free(struct mm_struct *mm, struct page *pte)
+{
+	pgtable_page_dtor(pte);
+	pte_free_kernel(mm, page_address(pte));
+}
+
+#define check_pgt_cache()	do { } while (0)
+
+#endif
-- 
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