1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (C) 2020 ARM Ltd. 4 */ 5 #ifndef __ASM_MTE_H 6 #define __ASM_MTE_H 7 8 #include <asm/compiler.h> 9 #include <asm/mte-def.h> 10 11 #ifndef __ASSEMBLY__ 12 13 #include <linux/bitfield.h> 14 #include <linux/kasan-enabled.h> 15 #include <linux/page-flags.h> 16 #include <linux/sched.h> 17 #include <linux/types.h> 18 19 #include <asm/pgtable-types.h> 20 21 void mte_clear_page_tags(void *addr); 22 unsigned long mte_copy_tags_from_user(void *to, const void __user *from, 23 unsigned long n); 24 unsigned long mte_copy_tags_to_user(void __user *to, void *from, 25 unsigned long n); 26 int mte_save_tags(struct page *page); 27 void mte_save_page_tags(const void *page_addr, void *tag_storage); 28 bool mte_restore_tags(swp_entry_t entry, struct page *page); 29 void mte_restore_page_tags(void *page_addr, const void *tag_storage); 30 void mte_invalidate_tags(int type, pgoff_t offset); 31 void mte_invalidate_tags_area(int type); 32 void *mte_allocate_tag_storage(void); 33 void mte_free_tag_storage(char *storage); 34 35 #ifdef CONFIG_ARM64_MTE 36 37 /* track which pages have valid allocation tags */ 38 #define PG_mte_tagged PG_arch_2 39 40 void mte_zero_clear_page_tags(void *addr); 41 void mte_sync_tags(pte_t old_pte, pte_t pte); 42 void mte_copy_page_tags(void *kto, const void *kfrom); 43 void mte_thread_init_user(void); 44 void mte_thread_switch(struct task_struct *next); 45 void mte_suspend_enter(void); 46 long set_mte_ctrl(struct task_struct *task, unsigned long arg); 47 long get_mte_ctrl(struct task_struct *task); 48 int mte_ptrace_copy_tags(struct task_struct *child, long request, 49 unsigned long addr, unsigned long data); 50 size_t mte_probe_user_range(const char __user *uaddr, size_t size); 51 52 #else /* CONFIG_ARM64_MTE */ 53 54 /* unused if !CONFIG_ARM64_MTE, silence the compiler */ 55 #define PG_mte_tagged 0 56 57 static inline void mte_zero_clear_page_tags(void *addr) 58 { 59 } 60 static inline void mte_sync_tags(pte_t old_pte, pte_t pte) 61 { 62 } 63 static inline void mte_copy_page_tags(void *kto, const void *kfrom) 64 { 65 } 66 static inline void mte_thread_init_user(void) 67 { 68 } 69 static inline void mte_thread_switch(struct task_struct *next) 70 { 71 } 72 static inline void mte_suspend_enter(void) 73 { 74 } 75 static inline long set_mte_ctrl(struct task_struct *task, unsigned long arg) 76 { 77 return 0; 78 } 79 static inline long get_mte_ctrl(struct task_struct *task) 80 { 81 return 0; 82 } 83 static inline int mte_ptrace_copy_tags(struct task_struct *child, 84 long request, unsigned long addr, 85 unsigned long data) 86 { 87 return -EIO; 88 } 89 90 #endif /* CONFIG_ARM64_MTE */ 91 92 static inline void mte_disable_tco_entry(struct task_struct *task) 93 { 94 if (!system_supports_mte()) 95 return; 96 97 /* 98 * Re-enable tag checking (TCO set on exception entry). This is only 99 * necessary if MTE is enabled in either the kernel or the userspace 100 * task in synchronous or asymmetric mode (SCTLR_EL1.TCF0 bit 0 is set 101 * for both). With MTE disabled in the kernel and disabled or 102 * asynchronous in userspace, tag check faults (including in uaccesses) 103 * are not reported, therefore there is no need to re-enable checking. 104 * This is beneficial on microarchitectures where re-enabling TCO is 105 * expensive. 106 */ 107 if (kasan_hw_tags_enabled() || 108 (task->thread.sctlr_user & (1UL << SCTLR_EL1_TCF0_SHIFT))) 109 asm volatile(SET_PSTATE_TCO(0)); 110 } 111 112 #ifdef CONFIG_KASAN_HW_TAGS 113 /* Whether the MTE asynchronous mode is enabled. */ 114 DECLARE_STATIC_KEY_FALSE(mte_async_or_asymm_mode); 115 116 static inline bool system_uses_mte_async_or_asymm_mode(void) 117 { 118 return static_branch_unlikely(&mte_async_or_asymm_mode); 119 } 120 121 void mte_check_tfsr_el1(void); 122 123 static inline void mte_check_tfsr_entry(void) 124 { 125 if (!system_supports_mte()) 126 return; 127 128 mte_check_tfsr_el1(); 129 } 130 131 static inline void mte_check_tfsr_exit(void) 132 { 133 if (!system_supports_mte()) 134 return; 135 136 /* 137 * The asynchronous faults are sync'ed automatically with 138 * TFSR_EL1 on kernel entry but for exit an explicit dsb() 139 * is required. 140 */ 141 dsb(nsh); 142 isb(); 143 144 mte_check_tfsr_el1(); 145 } 146 #else 147 static inline bool system_uses_mte_async_or_asymm_mode(void) 148 { 149 return false; 150 } 151 static inline void mte_check_tfsr_el1(void) 152 { 153 } 154 static inline void mte_check_tfsr_entry(void) 155 { 156 } 157 static inline void mte_check_tfsr_exit(void) 158 { 159 } 160 #endif /* CONFIG_KASAN_HW_TAGS */ 161 162 #endif /* __ASSEMBLY__ */ 163 #endif /* __ASM_MTE_H */ 164