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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 | /* 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> #ifndef __ASSEMBLY__ #ifdef CONFIG_PPC_KUAP #include <linux/sched.h> static inline void kuap_update_sr(u32 sr, u32 addr, u32 end) { addr &= 0xf0000000; /* align addr to start of segment */ barrier(); /* make sure thread.kuap is updated before playing with SRs */ while (addr < end) { mtsr(sr, addr); sr += 0x111; /* next VSID */ sr &= 0xf0ffffff; /* clear VSID overflow */ addr += 0x10000000; /* address of next segment */ } isync(); /* Context sync required after mtsr() */ } static inline void kuap_save_and_lock(struct pt_regs *regs) { unsigned long kuap = current->thread.kuap; u32 addr = kuap & 0xf0000000; u32 end = kuap << 28; regs->kuap = kuap; if (unlikely(!kuap)) return; current->thread.kuap = 0; kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* Set Ks */ } static inline void kuap_user_restore(struct pt_regs *regs) { } static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap) { u32 addr = regs->kuap & 0xf0000000; u32 end = regs->kuap << 28; current->thread.kuap = regs->kuap; if (unlikely(regs->kuap == kuap)) return; kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */ } static 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 != 0); return kuap; } static inline void kuap_assert_locked(void) { kuap_get_and_assert_locked(); } static __always_inline void allow_user_access(void __user *to, const void __user *from, u32 size, unsigned long dir) { u32 addr, end; BUILD_BUG_ON(!__builtin_constant_p(dir)); BUILD_BUG_ON(dir & ~KUAP_READ_WRITE); if (!(dir & KUAP_WRITE)) return; addr = (__force u32)to; if (unlikely(addr >= TASK_SIZE || !size)) return; end = min(addr + size, TASK_SIZE); current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf); kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */ } static __always_inline void prevent_user_access(void __user *to, const void __user *from, u32 size, unsigned long dir) { u32 addr, end; BUILD_BUG_ON(!__builtin_constant_p(dir)); if (dir & KUAP_CURRENT_WRITE) { u32 kuap = current->thread.kuap; if (unlikely(!kuap)) return; addr = kuap & 0xf0000000; end = kuap << 28; } else if (dir & KUAP_WRITE) { addr = (__force u32)to; end = min(addr + size, TASK_SIZE); if (unlikely(addr >= TASK_SIZE || !size)) return; } else { return; } current->thread.kuap = 0; kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* set Ks */ } static inline unsigned long prevent_user_access_return(void) { unsigned long flags = current->thread.kuap; unsigned long addr = flags & 0xf0000000; unsigned long end = flags << 28; void __user *to = (__force void __user *)addr; if (flags) prevent_user_access(to, to, end - addr, KUAP_READ_WRITE); return flags; } static inline void restore_user_access(unsigned long flags) { unsigned long addr = flags & 0xf0000000; unsigned long end = flags << 28; void __user *to = (__force void __user *)addr; if (flags) allow_user_access(to, to, end - addr, KUAP_READ_WRITE); } static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) { unsigned long begin = regs->kuap & 0xf0000000; unsigned long end = regs->kuap << 28; return is_write && (address < begin || address >= end); } #endif /* CONFIG_PPC_KUAP */ #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */ |