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-rw-r--r--arch/arm64/mm/pgd.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c
new file mode 100644
index 000000000..4a64089e5
--- /dev/null
+++ b/arch/arm64/mm/pgd.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PGD allocation/freeing
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Catalin Marinas <catalin.marinas@arm.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+
+#include <asm/pgalloc.h>
+#include <asm/page.h>
+#include <asm/tlbflush.h>
+
+static struct kmem_cache *pgd_cache __ro_after_init;
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ gfp_t gfp = GFP_PGTABLE_USER;
+
+ if (PGD_SIZE == PAGE_SIZE)
+ return (pgd_t *)__get_free_page(gfp);
+ else
+ return kmem_cache_alloc(pgd_cache, gfp);
+}
+
+void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+ if (PGD_SIZE == PAGE_SIZE)
+ free_page((unsigned long)pgd);
+ else
+ kmem_cache_free(pgd_cache, pgd);
+}
+
+void __init pgtable_cache_init(void)
+{
+ if (PGD_SIZE == PAGE_SIZE)
+ return;
+
+#ifdef CONFIG_ARM64_PA_BITS_52
+ /*
+ * With 52-bit physical addresses, the architecture requires the
+ * top-level table to be aligned to at least 64 bytes.
+ */
+ BUILD_BUG_ON(PGD_SIZE < 64);
+#endif
+
+ /*
+ * Naturally aligned pgds required by the architecture.
+ */
+ pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
+ SLAB_PANIC, NULL);
+}