LXR linux/arch/arm64/include/asm/mmu.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Copyright (C) 2012 ARM Ltd.
   4 */
   5#ifndef __ASM_MMU_H
   6#define __ASM_MMU_H
   7
   8#include <asm/cputype.h>
   9
  10#define MMCF_AARCH32    0x1     /* mm context flag for AArch32 executables */
  11#define USER_ASID_BIT   48
  12#define USER_ASID_FLAG  (UL(1) << USER_ASID_BIT)
  13#define TTBR_ASID_MASK  (UL(0xffff) << 48)
  14
  15#define BP_HARDEN_EL2_SLOTS 4
  16
  17#ifndef __ASSEMBLY__
  18
  19typedef struct {
  20        atomic64_t      id;
  21        void            *vdso;
  22        unsigned long   flags;
  23} mm_context_t;
  24
  25/*
  26 * This macro is only used by the TLBI code, which cannot race with an
  27 * ASID change and therefore doesn't need to reload the counter using
  28 * atomic64_read.
  29 */
  30#define ASID(mm)        ((mm)->context.id.counter & 0xffff)
  31
  32static inline bool arm64_kernel_unmapped_at_el0(void)
  33{
  34        return IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) &&
  35               cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0);
  36}
  37
  38static inline bool arm64_kernel_use_ng_mappings(void)
  39{
  40        bool tx1_bug;
  41
  42        /* What's a kpti? Use global mappings if we don't know. */
  43        if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0))
  44                return false;
  45
  46        /*
  47         * Note: this function is called before the CPU capabilities have
  48         * been configured, so our early mappings will be global. If we
  49         * later determine that kpti is required, then
  50         * kpti_install_ng_mappings() will make them non-global.
  51         */
  52        if (arm64_kernel_unmapped_at_el0())
  53                return true;
  54
  55        if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
  56                return false;
  57
  58        /*
  59         * KASLR is enabled so we're going to be enabling kpti on non-broken
  60         * CPUs regardless of their susceptibility to Meltdown. Rather
  61         * than force everybody to go through the G -> nG dance later on,
  62         * just put down non-global mappings from the beginning.
  63         */
  64        if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
  65                tx1_bug = false;
  66#ifndef MODULE
  67        } else if (!static_branch_likely(&arm64_const_caps_ready)) {
  68                extern const struct midr_range cavium_erratum_27456_cpus[];
  69
  70                tx1_bug = is_midr_in_range_list(read_cpuid_id(),
  71                                                cavium_erratum_27456_cpus);
  72#endif
  73        } else {
  74                tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456);
  75        }
  76
  77        return !tx1_bug && kaslr_offset() > 0;
  78}
  79
  80typedef void (*bp_hardening_cb_t)(void);
  81
  82struct bp_hardening_data {
  83        int                     hyp_vectors_slot;
  84        bp_hardening_cb_t       fn;
  85};
  86
  87#if (defined(CONFIG_HARDEN_BRANCH_PREDICTOR) || \
  88     defined(CONFIG_HARDEN_EL2_VECTORS))
  89extern char __bp_harden_hyp_vecs_start[], __bp_harden_hyp_vecs_end[];
  90extern atomic_t arm64_el2_vector_last_slot;
  91#endif  /* CONFIG_HARDEN_BRANCH_PREDICTOR || CONFIG_HARDEN_EL2_VECTORS */
  92
  93#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
  94DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
  95
  96static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void)
  97{
  98        return this_cpu_ptr(&bp_hardening_data);
  99}
 100
 101static inline void arm64_apply_bp_hardening(void)
 102{
 103        struct bp_hardening_data *d;
 104
 105        if (!cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR))
 106                return;
 107
 108        d = arm64_get_bp_hardening_data();
 109        if (d->fn)
 110                d->fn();
 111}
 112#else
 113static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void)
 114{
 115        return NULL;
 116}
 117
 118static inline void arm64_apply_bp_hardening(void)       { }
 119#endif  /* CONFIG_HARDEN_BRANCH_PREDICTOR */
 120
 121extern void arm64_memblock_init(void);
 122extern void paging_init(void);
 123extern void bootmem_init(void);
 124extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
 125extern void init_mem_pgprot(void);
 126extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 127                               unsigned long virt, phys_addr_t size,
 128                               pgprot_t prot, bool page_mappings_only);
 129extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
 130extern void mark_linear_text_alias_ro(void);
 131
 132#define INIT_MM_CONTEXT(name)   \
 133        .pgd = init_pg_dir,
 134
 135#endif  /* !__ASSEMBLY__ */
 136#endif
 137