1 files changed, 79 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
new file mode 100644
index 000000000..48f8466a4
--- /dev/null
+++ b/arch/arm64/include/asm/mmu.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ */
+#ifndef __ASM_MMU_H
+#define __ASM_MMU_H
+
+#include <asm/cputype.h>
+
+#define MMCF_AARCH32	0x1	/* mm context flag for AArch32 executables */
+#define USER_ASID_BIT	48
+#define USER_ASID_FLAG	(UL(1) << USER_ASID_BIT)
+#define TTBR_ASID_MASK	(UL(0xffff) << 48)
+
+#ifndef __ASSEMBLY__
+
+#include <linux/refcount.h>
+#include <asm/cpufeature.h>
+
+typedef struct {
+	atomic64_t	id;
+#ifdef CONFIG_COMPAT
+	void		*sigpage;
+#endif
+	refcount_t	pinned;
+	void		*vdso;
+	unsigned long	flags;
+} mm_context_t;
+
+/*
+ * We use atomic64_read() here because the ASID for an 'mm_struct' can
+ * be reallocated when scheduling one of its threads following a
+ * rollover event (see new_context() and flush_context()). In this case,
+ * a concurrent TLBI (e.g. via try_to_unmap_one() and ptep_clear_flush())
+ * may use a stale ASID. This is fine in principle as the new ASID is
+ * guaranteed to be clean in the TLB, but the TLBI routines have to take
+ * care to handle the following race:
+ *
+ *    CPU 0                    CPU 1                          CPU 2
+ *
+ *    // ptep_clear_flush(mm)
+ *    xchg_relaxed(pte, 0)
+ *    DSB ISHST
+ *    old = ASID(mm)
+ *         |                                                  <rollover>
+ *         |                   new = new_context(mm)
+ *         \-----------------> atomic_set(mm->context.id, new)
+ *                             cpu_switch_mm(mm)
+ *                             // Hardware walk of pte using new ASID
+ *    TLBI(old)
+ *
+ * In this scenario, the barrier on CPU 0 and the dependency on CPU 1
+ * ensure that the page-table walker on CPU 1 *must* see the invalid PTE
+ * written by CPU 0.
+ */
+#define ASID(mm)	(atomic64_read(&(mm)->context.id) & 0xffff)
+
+static inline bool arm64_kernel_unmapped_at_el0(void)
+{
+	return cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0);
+}
+
+extern void arm64_memblock_init(void);
+extern void paging_init(void);
+extern void bootmem_init(void);
+extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
+extern void init_mem_pgprot(void);
+extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
+			       unsigned long virt, phys_addr_t size,
+			       pgprot_t prot, bool page_mappings_only);
+extern void *fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot);
+extern void mark_linear_text_alias_ro(void);
+extern bool kaslr_requires_kpti(void);
+
+#define INIT_MM_CONTEXT(name)	\
+	.pgd = init_pg_dir,
+
+#endif	/* !__ASSEMBLY__ */
+#endif