1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_BOOK3S_32_KUP_H
3 #define _ASM_POWERPC_BOOK3S_32_KUP_H
4
5 #include <asm/bug.h>
6 #include <asm/book3s/32/mmu-hash.h>
7
8 #ifdef __ASSEMBLY__
9
10 .macro kuep_update_sr gpr1, gpr2 /* NEVER use r0 as gpr2 due to addis */
11 101: mtsrin \gpr1, \gpr2
12 addi \gpr1, \gpr1, 0x111 /* next VSID */
13 rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */
14 addis \gpr2, \gpr2, 0x1000 /* address of next segment */
15 bdnz 101b
16 isync
17 .endm
18
19 .macro kuep_lock gpr1, gpr2
20 #ifdef CONFIG_PPC_KUEP
21 li \gpr1, NUM_USER_SEGMENTS
22 li \gpr2, 0
23 mtctr \gpr1
24 mfsrin \gpr1, \gpr2
25 oris \gpr1, \gpr1, SR_NX@h /* set Nx */
26 kuep_update_sr \gpr1, \gpr2
27 #endif
28 .endm
29
30 .macro kuep_unlock gpr1, gpr2
31 #ifdef CONFIG_PPC_KUEP
32 li \gpr1, NUM_USER_SEGMENTS
33 li \gpr2, 0
34 mtctr \gpr1
35 mfsrin \gpr1, \gpr2
36 rlwinm \gpr1, \gpr1, 0, ~SR_NX /* Clear Nx */
37 kuep_update_sr \gpr1, \gpr2
38 #endif
39 .endm
40
41 #ifdef CONFIG_PPC_KUAP
42
43 .macro kuap_update_sr gpr1, gpr2, gpr3 /* NEVER use r0 as gpr2 due to addis */
44 101: mtsrin \gpr1, \gpr2
45 addi \gpr1, \gpr1, 0x111 /* next VSID */
46 rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */
47 addis \gpr2, \gpr2, 0x1000 /* address of next segment */
48 cmplw \gpr2, \gpr3
49 blt- 101b
50 isync
51 .endm
52
53 .macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
54 lwz \gpr2, KUAP(\thread)
55 rlwinm. \gpr3, \gpr2, 28, 0xf0000000
56 stw \gpr2, STACK_REGS_KUAP(\sp)
57 beq+ 102f
58 li \gpr1, 0
59 stw \gpr1, KUAP(\thread)
60 mfsrin \gpr1, \gpr2
61 oris \gpr1, \gpr1, SR_KS@h /* set Ks */
62 kuap_update_sr \gpr1, \gpr2, \gpr3
63 102:
64 .endm
65
66 .macro kuap_restore sp, current, gpr1, gpr2, gpr3
67 lwz \gpr2, STACK_REGS_KUAP(\sp)
68 rlwinm. \gpr3, \gpr2, 28, 0xf0000000
69 stw \gpr2, THREAD + KUAP(\current)
70 beq+ 102f
71 mfsrin \gpr1, \gpr2
72 rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */
73 kuap_update_sr \gpr1, \gpr2, \gpr3
74 102:
75 .endm
76
77 .macro kuap_check current, gpr
78 #ifdef CONFIG_PPC_KUAP_DEBUG
79 lwz \gpr, THREAD + KUAP(\current)
80 999: twnei \gpr, 0
81 EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
82 #endif
83 .endm
84
85 #endif /* CONFIG_PPC_KUAP */
86
87 #else /* !__ASSEMBLY__ */
88
89 #ifdef CONFIG_PPC_KUAP
90
91 #include <linux/sched.h>
92
kuap_update_sr(u32 sr,u32 addr,u32 end)93 static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
94 {
95 addr &= 0xf0000000; /* align addr to start of segment */
96 barrier(); /* make sure thread.kuap is updated before playing with SRs */
97 while (addr < end) {
98 mtsrin(sr, addr);
99 sr += 0x111; /* next VSID */
100 sr &= 0xf0ffffff; /* clear VSID overflow */
101 addr += 0x10000000; /* address of next segment */
102 }
103 isync(); /* Context sync required after mtsrin() */
104 }
105
allow_user_access(void __user * to,const void __user * from,u32 size,unsigned long dir)106 static __always_inline void allow_user_access(void __user *to, const void __user *from,
107 u32 size, unsigned long dir)
108 {
109 u32 addr, end;
110
111 BUILD_BUG_ON(!__builtin_constant_p(dir));
112 if (!(dir & KUAP_WRITE))
113 return;
114
115 addr = (__force u32)to;
116
117 if (!addr || addr >= TASK_SIZE || !size)
118 return;
119
120 end = min(addr + size, TASK_SIZE);
121 current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
122 kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */
123 }
124
prevent_user_access(void __user * to,const void __user * from,u32 size,unsigned long dir)125 static __always_inline void prevent_user_access(void __user *to, const void __user *from,
126 u32 size, unsigned long dir)
127 {
128 u32 addr = (__force u32)to;
129 u32 end = min(addr + size, TASK_SIZE);
130
131 BUILD_BUG_ON(!__builtin_constant_p(dir));
132 if (!(dir & KUAP_WRITE))
133 return;
134
135 if (!addr || addr >= TASK_SIZE || !size)
136 return;
137
138 current->thread.kuap = 0;
139 kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */
140 }
141
142 static inline bool
bad_kuap_fault(struct pt_regs * regs,unsigned long address,bool is_write)143 bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
144 {
145 unsigned long begin = regs->kuap & 0xf0000000;
146 unsigned long end = regs->kuap << 28;
147
148 if (!is_write)
149 return false;
150
151 return WARN(address < begin || address >= end,
152 "Bug: write fault blocked by segment registers !");
153 }
154
155 #endif /* CONFIG_PPC_KUAP */
156
157 #endif /* __ASSEMBLY__ */
158
159 #endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */
160