1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_BOOK3S_32_KUP_H
3 #define _ASM_POWERPC_BOOK3S_32_KUP_H
6 #include <asm/book3s/32/mmu-hash.h>
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 */
19 .macro kuep_lock gpr1, gpr2
20 #ifdef CONFIG_PPC_KUEP
21 li \gpr1, NUM_USER_SEGMENTS
25 oris \gpr1, \gpr1, SR_NX@h /* set Nx */
26 kuep_update_sr \gpr1, \gpr2
30 .macro kuep_unlock gpr1, gpr2
31 #ifdef CONFIG_PPC_KUEP
32 li \gpr1, NUM_USER_SEGMENTS
36 rlwinm \gpr1, \gpr1, 0, ~SR_NX /* Clear Nx */
37 kuep_update_sr \gpr1, \gpr2
41 #ifdef CONFIG_PPC_KUAP
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 */
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)
59 stw \gpr1, KUAP(\thread)
61 oris \gpr1, \gpr1, SR_KS@h /* set Ks */
62 kuap_update_sr \gpr1, \gpr2, \gpr3
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)
72 rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */
73 kuap_update_sr \gpr1, \gpr2, \gpr3
77 .macro kuap_check current, gpr
78 #ifdef CONFIG_PPC_KUAP_DEBUG
79 lwz \gpr, THREAD + KUAP(\current)
81 EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
85 #endif /* CONFIG_PPC_KUAP */
87 #else /* !__ASSEMBLY__ */
89 #ifdef CONFIG_PPC_KUAP
91 #include <linux/sched.h>
93 static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
95 addr &= 0xf0000000; /* align addr to start of segment */
96 barrier(); /* make sure thread.kuap is updated before playing with SRs */
99 sr += 0x111; /* next VSID */
100 sr &= 0xf0ffffff; /* clear VSID overflow */
101 addr += 0x10000000; /* address of next segment */
103 isync(); /* Context sync required after mtsrin() */
106 static __always_inline void allow_user_access(void __user *to, const void __user *from,
107 u32 size, unsigned long dir)
111 BUILD_BUG_ON(!__builtin_constant_p(dir));
112 BUILD_BUG_ON(dir & ~KUAP_READ_WRITE);
114 if (!(dir & KUAP_WRITE))
117 addr = (__force u32)to;
119 if (unlikely(addr >= TASK_SIZE || !size))
122 end = min(addr + size, TASK_SIZE);
124 current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
125 kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */
128 static __always_inline void prevent_user_access(void __user *to, const void __user *from,
129 u32 size, unsigned long dir)
133 BUILD_BUG_ON(!__builtin_constant_p(dir));
135 if (dir & KUAP_CURRENT_WRITE) {
136 u32 kuap = current->thread.kuap;
141 addr = kuap & 0xf0000000;
143 } else if (dir & KUAP_WRITE) {
144 addr = (__force u32)to;
145 end = min(addr + size, TASK_SIZE);
147 if (unlikely(addr >= TASK_SIZE || !size))
153 current->thread.kuap = 0;
154 kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */
157 static inline unsigned long prevent_user_access_return(void)
159 unsigned long flags = current->thread.kuap;
160 unsigned long addr = flags & 0xf0000000;
161 unsigned long end = flags << 28;
162 void __user *to = (__force void __user *)addr;
165 prevent_user_access(to, to, end - addr, KUAP_READ_WRITE);
170 static inline void restore_user_access(unsigned long flags)
172 unsigned long addr = flags & 0xf0000000;
173 unsigned long end = flags << 28;
174 void __user *to = (__force void __user *)addr;
177 allow_user_access(to, to, end - addr, KUAP_READ_WRITE);
181 bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
183 unsigned long begin = regs->kuap & 0xf0000000;
184 unsigned long end = regs->kuap << 28;
189 return WARN(address < begin || address >= end,
190 "Bug: write fault blocked by segment registers !");
193 #endif /* CONFIG_PPC_KUAP */
195 #endif /* __ASSEMBLY__ */
197 #endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */