1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_KUP_BOOKE_H_
3 #define _ASM_POWERPC_KUP_BOOKE_H_
4
5 #include <asm/bug.h>
6 #include <asm/mmu.h>
7
8 #ifdef CONFIG_PPC_KUAP
9
10 #ifdef __ASSEMBLY__
11
12 .macro kuap_check_amr gpr1, gpr2
13 .endm
14
15 #else
16
17 #include <linux/sched.h>
18
19 #include <asm/reg.h>
20
21 static __always_inline void __kuap_lock(void)
22 {
23 mtspr(SPRN_PID, 0);
24 isync();
25 }
26 #define __kuap_lock __kuap_lock
27
28 static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
29 {
30 regs->kuap = mfspr(SPRN_PID);
31 mtspr(SPRN_PID, 0);
32 isync();
33 }
34 #define __kuap_save_and_lock __kuap_save_and_lock
35
36 static __always_inline void kuap_user_restore(struct pt_regs *regs)
37 {
38 if (kuap_is_disabled())
39 return;
40
41 mtspr(SPRN_PID, current->thread.pid);
42
43 /* Context synchronisation is performed by rfi */
44 }
45
46 static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
47 {
48 if (regs->kuap)
49 mtspr(SPRN_PID, current->thread.pid);
50
51 /* Context synchronisation is performed by rfi */
52 }
53
54 #ifdef CONFIG_PPC_KUAP_DEBUG
55 static __always_inline unsigned long __kuap_get_and_assert_locked(void)
56 {
57 WARN_ON_ONCE(mfspr(SPRN_PID));
58
59 return 0;
60 }
61 #define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
62 #endif
63
64 static __always_inline void uaccess_begin_booke(unsigned long val)
65 {
66 asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
67 "i"(SPRN_PID), "r"(val), "i"(MMU_FTR_KUAP) : "memory");
68 }
69
70 static __always_inline void uaccess_end_booke(void)
71 {
72 asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
73 "i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory");
74 }
75
76 static __always_inline void allow_user_access(void __user *to, const void __user *from,
77 unsigned long size, unsigned long dir)
78 {
79 uaccess_begin_booke(current->thread.pid);
80 }
81
82 static __always_inline void prevent_user_access(unsigned long dir)
83 {
84 uaccess_end_booke();
85 }
86
87 static __always_inline unsigned long prevent_user_access_return(void)
88 {
89 unsigned long flags = mfspr(SPRN_PID);
90
91 uaccess_end_booke();
92
93 return flags;
94 }
95
96 static __always_inline void restore_user_access(unsigned long flags)
97 {
98 if (flags)
99 uaccess_begin_booke(current->thread.pid);
100 }
101
102 static __always_inline bool
103 __bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
104 {
105 return !regs->kuap;
106 }
107
108 #endif /* !__ASSEMBLY__ */
109
110 #endif /* CONFIG_PPC_KUAP */
111
112 #endif /* _ASM_POWERPC_KUP_BOOKE_H_ */
113
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