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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 | /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_POWERPC_BOOK3S_32_KUP_H #define _ASM_POWERPC_BOOK3S_32_KUP_H #include <asm/bug.h> #include <asm/book3s/32/mmu-hash.h> #include <asm/mmu.h> #include <asm/synch.h> #ifndef __ASSEMBLY__ #ifdef CONFIG_PPC_KUAP #include <linux/sched.h> #define KUAP_NONE (~0UL) static __always_inline void kuap_lock_one(unsigned long addr) { mtsr(mfsr(addr) | SR_KS, addr); isync(); /* Context sync required after mtsr() */ } static __always_inline void kuap_unlock_one(unsigned long addr) { mtsr(mfsr(addr) & ~SR_KS, addr); isync(); /* Context sync required after mtsr() */ } static __always_inline void uaccess_begin_32s(unsigned long addr) { unsigned long tmp; asm volatile(ASM_MMU_FTR_IFSET( "mfsrin %0, %1;" "rlwinm %0, %0, 0, %2;" "mtsrin %0, %1;" "isync", "", %3) : "=&r"(tmp) : "r"(addr), "i"(~SR_KS), "i"(MMU_FTR_KUAP) : "memory"); } static __always_inline void uaccess_end_32s(unsigned long addr) { unsigned long tmp; asm volatile(ASM_MMU_FTR_IFSET( "mfsrin %0, %1;" "oris %0, %0, %2;" "mtsrin %0, %1;" "isync", "", %3) : "=&r"(tmp) : "r"(addr), "i"(SR_KS >> 16), "i"(MMU_FTR_KUAP) : "memory"); } static __always_inline void __kuap_save_and_lock(struct pt_regs *regs) { unsigned long kuap = current->thread.kuap; regs->kuap = kuap; if (unlikely(kuap == KUAP_NONE)) return; current->thread.kuap = KUAP_NONE; kuap_lock_one(kuap); } #define __kuap_save_and_lock __kuap_save_and_lock static __always_inline void kuap_user_restore(struct pt_regs *regs) { } static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap) { if (unlikely(kuap != KUAP_NONE)) { current->thread.kuap = KUAP_NONE; kuap_lock_one(kuap); } if (likely(regs->kuap == KUAP_NONE)) return; current->thread.kuap = regs->kuap; kuap_unlock_one(regs->kuap); } static __always_inline unsigned long __kuap_get_and_assert_locked(void) { unsigned long kuap = current->thread.kuap; WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != KUAP_NONE); return kuap; } #define __kuap_get_and_assert_locked __kuap_get_and_assert_locked static __always_inline void allow_user_access(void __user *to, const void __user *from, u32 size, unsigned long dir) { BUILD_BUG_ON(!__builtin_constant_p(dir)); if (!(dir & KUAP_WRITE)) return; current->thread.kuap = (__force u32)to; uaccess_begin_32s((__force u32)to); } static __always_inline void prevent_user_access(unsigned long dir) { u32 kuap = current->thread.kuap; BUILD_BUG_ON(!__builtin_constant_p(dir)); if (!(dir & KUAP_WRITE)) return; current->thread.kuap = KUAP_NONE; uaccess_end_32s(kuap); } static __always_inline unsigned long prevent_user_access_return(void) { unsigned long flags = current->thread.kuap; if (flags != KUAP_NONE) { current->thread.kuap = KUAP_NONE; uaccess_end_32s(flags); } return flags; } static __always_inline void restore_user_access(unsigned long flags) { if (flags != KUAP_NONE) { current->thread.kuap = flags; uaccess_begin_32s(flags); } } static __always_inline bool __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) { unsigned long kuap = regs->kuap; if (!is_write) return false; if (kuap == KUAP_NONE) return true; /* * If faulting address doesn't match unlocked segment, change segment. * In case of unaligned store crossing two segments, emulate store. */ if ((kuap ^ address) & 0xf0000000) { if (!(kuap & 0x0fffffff) && address > kuap - 4 && fix_alignment(regs)) { regs_add_return_ip(regs, 4); emulate_single_step(regs); } else { regs->kuap = address; } } return false; } #endif /* CONFIG_PPC_KUAP */ #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */ |