arch/powerpc/include/asm/kup.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_POWERPC_KUP_H_
   3 #define _ASM_POWERPC_KUP_H_
   4
   5 #define KUAP_READ       1
   6 #define KUAP_WRITE      2
   7 #define KUAP_READ_WRITE (KUAP_READ | KUAP_WRITE)
   8
   9 #ifndef __ASSEMBLY__
  10 #include <linux/types.h>
  11
  12 static __always_inline bool kuap_is_disabled(void);
  13 #endif
  14
  15 #ifdef CONFIG_PPC_BOOK3S_64
  16 #include <asm/book3s/64/kup.h>
  17 #endif
  18
  19 #ifdef CONFIG_PPC_8xx
  20 #include <asm/nohash/32/kup-8xx.h>
  21 #endif
  22
  23 #ifdef CONFIG_BOOKE_OR_40x
  24 #include <asm/nohash/kup-booke.h>
  25 #endif
  26
  27 #ifdef CONFIG_PPC_BOOK3S_32
  28 #include <asm/book3s/32/kup.h>
  29 #endif
  30
  31 #ifdef __ASSEMBLY__
  32 #ifndef CONFIG_PPC_KUAP
  33 .macro kuap_check_amr   gpr1, gpr2
  34 .endm
  35
  36 #endif
  37
  38 #else /* !__ASSEMBLY__ */
  39
  40 extern bool disable_kuep;
  41 extern bool disable_kuap;
  42
  43 #include <linux/pgtable.h>
  44
  45 void setup_kup(void);
  46 void setup_kuep(bool disabled);
  47
  48 #ifdef CONFIG_PPC_KUAP
  49 void setup_kuap(bool disabled);
  50
  51 static __always_inline bool kuap_is_disabled(void)
  52 {
  53         return !mmu_has_feature(MMU_FTR_KUAP);
  54 }
  55 #else
  56 static inline void setup_kuap(bool disabled) { }
  57
  58 static __always_inline bool kuap_is_disabled(void) { return true; }
  59
  60 static __always_inline bool
  61 __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
  62 {
  63         return false;
  64 }
  65
  66 static __always_inline void kuap_user_restore(struct pt_regs *regs) { }
  67 static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
  68
  69 /*
  70  * book3s/64/kup-radix.h defines these functions for the !KUAP case to flush
  71  * the L1D cache after user accesses. Only include the empty stubs for other
  72  * platforms.
  73  */
  74 #ifndef CONFIG_PPC_BOOK3S_64
  75 static __always_inline void allow_user_access(void __user *to, const void __user *from,
  76                                               unsigned long size, unsigned long dir) { }
  77 static __always_inline void prevent_user_access(unsigned long dir) { }
  78 static __always_inline unsigned long prevent_user_access_return(void) { return 0UL; }
  79 static __always_inline void restore_user_access(unsigned long flags) { }
  80 #endif /* CONFIG_PPC_BOOK3S_64 */
  81 #endif /* CONFIG_PPC_KUAP */
  82
  83 static __always_inline bool
  84 bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
  85 {
  86         if (kuap_is_disabled())
  87                 return false;
  88
  89         return __bad_kuap_fault(regs, address, is_write);
  90 }
  91
  92 static __always_inline void kuap_lock(void)
  93 {
  94 #ifdef __kuap_lock
  95         if (kuap_is_disabled())
  96                 return;
  97
  98         __kuap_lock();
  99 #endif
 100 }
 101
 102 static __always_inline void kuap_save_and_lock(struct pt_regs *regs)
 103 {
 104 #ifdef __kuap_save_and_lock
 105         if (kuap_is_disabled())
 106                 return;
 107
 108         __kuap_save_and_lock(regs);
 109 #endif
 110 }
 111
 112 static __always_inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
 113 {
 114         if (kuap_is_disabled())
 115                 return;
 116
 117         __kuap_kernel_restore(regs, amr);
 118 }
 119
 120 static __always_inline unsigned long kuap_get_and_assert_locked(void)
 121 {
 122 #ifdef __kuap_get_and_assert_locked
 123         if (!kuap_is_disabled())
 124                 return __kuap_get_and_assert_locked();
 125 #endif
 126         return 0;
 127 }
 128
 129 static __always_inline void kuap_assert_locked(void)
 130 {
 131         if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG))
 132                 kuap_get_and_assert_locked();
 133 }
 134
 135 static __always_inline void allow_read_from_user(const void __user *from, unsigned long size)
 136 {
 137         barrier_nospec();
 138         allow_user_access(NULL, from, size, KUAP_READ);
 139 }
 140
 141 static __always_inline void allow_write_to_user(void __user *to, unsigned long size)
 142 {
 143         allow_user_access(to, NULL, size, KUAP_WRITE);
 144 }
 145
 146 static __always_inline void allow_read_write_user(void __user *to, const void __user *from,
 147                                                   unsigned long size)
 148 {
 149         barrier_nospec();
 150         allow_user_access(to, from, size, KUAP_READ_WRITE);
 151 }
 152
 153 static __always_inline void prevent_read_from_user(const void __user *from, unsigned long size)
 154 {
 155         prevent_user_access(KUAP_READ);
 156 }
 157
 158 static __always_inline void prevent_write_to_user(void __user *to, unsigned long size)
 159 {
 160         prevent_user_access(KUAP_WRITE);
 161 }
 162
 163 static __always_inline void prevent_read_write_user(void __user *to, const void __user *from,
 164                                                     unsigned long size)
 165 {
 166         prevent_user_access(KUAP_READ_WRITE);
 167 }
 168
 169 static __always_inline void prevent_current_access_user(void)
 170 {
 171         prevent_user_access(KUAP_READ_WRITE);
 172 }
 173
 174 static __always_inline void prevent_current_read_from_user(void)
 175 {
 176         prevent_user_access(KUAP_READ);
 177 }
 178
 179 static __always_inline void prevent_current_write_to_user(void)
 180 {
 181         prevent_user_access(KUAP_WRITE);
 182 }
 183
 184 #endif /* !__ASSEMBLY__ */
 185
 186 #endif /* _ASM_POWERPC_KUAP_H_ */