1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_BOOK3S_32_KUP_H
3 #define _ASM_POWERPC_BOOK3S_32_KUP_H
5 #include <asm/book3s/32/mmu-hash.h>
9 .macro kuep_update_sr gpr1, gpr2 /* NEVER use r0 as gpr2 due to addis */
10 101: mtsrin \gpr1, \gpr2
11 addi \gpr1, \gpr1, 0x111 /* next VSID */
12 rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */
13 addis \gpr2, \gpr2, 0x1000 /* address of next segment */
18 .macro kuep_lock gpr1, gpr2
19 #ifdef CONFIG_PPC_KUEP
20 li \gpr1, NUM_USER_SEGMENTS
24 oris \gpr1, \gpr1, SR_NX@h /* set Nx */
25 kuep_update_sr \gpr1, \gpr2
29 .macro kuep_unlock gpr1, gpr2
30 #ifdef CONFIG_PPC_KUEP
31 li \gpr1, NUM_USER_SEGMENTS
35 rlwinm \gpr1, \gpr1, 0, ~SR_NX /* Clear Nx */
36 kuep_update_sr \gpr1, \gpr2
40 #ifdef CONFIG_PPC_KUAP
42 .macro kuap_update_sr gpr1, gpr2, gpr3 /* NEVER use r0 as gpr2 due to addis */
43 101: mtsrin \gpr1, \gpr2
44 addi \gpr1, \gpr1, 0x111 /* next VSID */
45 rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */
46 addis \gpr2, \gpr2, 0x1000 /* address of next segment */
52 .macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
53 lwz \gpr2, KUAP(\thread)
54 rlwinm. \gpr3, \gpr2, 28, 0xf0000000
55 stw \gpr2, STACK_REGS_KUAP(\sp)
58 stw \gpr1, KUAP(\thread)
60 oris \gpr1, \gpr1, SR_KS@h /* set Ks */
61 kuap_update_sr \gpr1, \gpr2, \gpr3
65 .macro kuap_restore sp, current, gpr1, gpr2, gpr3
66 lwz \gpr2, STACK_REGS_KUAP(\sp)
67 rlwinm. \gpr3, \gpr2, 28, 0xf0000000
68 stw \gpr2, THREAD + KUAP(\current)
71 rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */
72 kuap_update_sr \gpr1, \gpr2, \gpr3
76 .macro kuap_check current, gpr
77 #ifdef CONFIG_PPC_KUAP_DEBUG
78 lwz \gpr, KUAP(thread)
80 EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
84 #endif /* CONFIG_PPC_KUAP */
86 #else /* !__ASSEMBLY__ */
88 #ifdef CONFIG_PPC_KUAP
90 #include <linux/sched.h>
92 static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
94 addr &= 0xf0000000; /* align addr to start of segment */
95 barrier(); /* make sure thread.kuap is updated before playing with SRs */
98 sr += 0x111; /* next VSID */
99 sr &= 0xf0ffffff; /* clear VSID overflow */
100 addr += 0x10000000; /* address of next segment */
102 isync(); /* Context sync required after mtsrin() */
105 static __always_inline void allow_user_access(void __user *to, const void __user *from,
106 u32 size, unsigned long dir)
110 BUILD_BUG_ON(!__builtin_constant_p(dir));
111 BUILD_BUG_ON(dir == KUAP_CURRENT);
113 if (!(dir & KUAP_WRITE))
116 addr = (__force u32)to;
118 if (unlikely(addr >= TASK_SIZE || !size))
121 end = min(addr + size, TASK_SIZE);
123 current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
124 kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */
127 static __always_inline void prevent_user_access(void __user *to, const void __user *from,
128 u32 size, unsigned long dir)
132 BUILD_BUG_ON(!__builtin_constant_p(dir));
134 if (dir == KUAP_CURRENT) {
135 u32 kuap = current->thread.kuap;
140 addr = kuap & 0xf0000000;
142 } else if (dir & KUAP_WRITE) {
143 addr = (__force u32)to;
144 end = min(addr + size, TASK_SIZE);
146 if (unlikely(addr >= TASK_SIZE || !size))
152 current->thread.kuap = 0;
153 kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */
156 static inline unsigned long prevent_user_access_return(void)
158 unsigned long flags = current->thread.kuap;
159 unsigned long addr = flags & 0xf0000000;
160 unsigned long end = flags << 28;
161 void __user *to = (__force void __user *)addr;
164 prevent_user_access(to, to, end - addr, KUAP_READ_WRITE);
169 static inline void restore_user_access(unsigned long flags)
171 unsigned long addr = flags & 0xf0000000;
172 unsigned long end = flags << 28;
173 void __user *to = (__force void __user *)addr;
176 allow_user_access(to, to, end - addr, KUAP_READ_WRITE);
180 bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
182 unsigned long begin = regs->kuap & 0xf0000000;
183 unsigned long end = regs->kuap << 28;
188 return WARN(address < begin || address >= end,
189 "Bug: write fault blocked by segment registers !");
192 #endif /* CONFIG_PPC_KUAP */
194 #endif /* __ASSEMBLY__ */
196 #endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */