1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2013 ARM Ltd.
4 */
5 #ifndef __ASM_PERCPU_H
6 #define __ASM_PERCPU_H
7
8 #include <linux/preempt.h>
9
10 #include <asm/alternative.h>
11 #include <asm/cmpxchg.h>
12 #include <asm/stack_pointer.h>
13
set_my_cpu_offset(unsigned long off)14 static inline void set_my_cpu_offset(unsigned long off)
15 {
16 asm volatile(ALTERNATIVE("msr tpidr_el1, %0",
17 "msr tpidr_el2, %0",
18 ARM64_HAS_VIRT_HOST_EXTN)
19 :: "r" (off) : "memory");
20 }
21
__hyp_my_cpu_offset(void)22 static inline unsigned long __hyp_my_cpu_offset(void)
23 {
24 /*
25 * Non-VHE hyp code runs with preemption disabled. No need to hazard
26 * the register access against barrier() as in __kern_my_cpu_offset.
27 */
28 return read_sysreg(tpidr_el2);
29 }
30
__kern_my_cpu_offset(void)31 static inline unsigned long __kern_my_cpu_offset(void)
32 {
33 unsigned long off;
34
35 /*
36 * We want to allow caching the value, so avoid using volatile and
37 * instead use a fake stack read to hazard against barrier().
38 */
39 asm(ALTERNATIVE("mrs %0, tpidr_el1",
40 "mrs %0, tpidr_el2",
41 ARM64_HAS_VIRT_HOST_EXTN)
42 : "=r" (off) :
43 "Q" (*(const unsigned long *)current_stack_pointer));
44
45 return off;
46 }
47
48 #ifdef __KVM_NVHE_HYPERVISOR__
49 #define __my_cpu_offset __hyp_my_cpu_offset()
50 #else
51 #define __my_cpu_offset __kern_my_cpu_offset()
52 #endif
53
54 #define PERCPU_RW_OPS(sz) \
55 static inline unsigned long __percpu_read_##sz(void *ptr) \
56 { \
57 return READ_ONCE(*(u##sz *)ptr); \
58 } \
59 \
60 static inline void __percpu_write_##sz(void *ptr, unsigned long val) \
61 { \
62 WRITE_ONCE(*(u##sz *)ptr, (u##sz)val); \
63 }
64
65 #define __PERCPU_OP_CASE(w, sfx, name, sz, op_llsc, op_lse) \
66 static inline void \
67 __percpu_##name##_case_##sz(void *ptr, unsigned long val) \
68 { \
69 unsigned int loop; \
70 u##sz tmp; \
71 \
72 asm volatile (ARM64_LSE_ATOMIC_INSN( \
73 /* LL/SC */ \
74 "1: ldxr" #sfx "\t%" #w "[tmp], %[ptr]\n" \
75 #op_llsc "\t%" #w "[tmp], %" #w "[tmp], %" #w "[val]\n" \
76 " stxr" #sfx "\t%w[loop], %" #w "[tmp], %[ptr]\n" \
77 " cbnz %w[loop], 1b", \
78 /* LSE atomics */ \
79 #op_lse "\t%" #w "[val], %[ptr]\n" \
80 __nops(3)) \
81 : [loop] "=&r" (loop), [tmp] "=&r" (tmp), \
82 [ptr] "+Q"(*(u##sz *)ptr) \
83 : [val] "r" ((u##sz)(val))); \
84 }
85
86 #define __PERCPU_RET_OP_CASE(w, sfx, name, sz, op_llsc, op_lse) \
87 static inline u##sz \
88 __percpu_##name##_return_case_##sz(void *ptr, unsigned long val) \
89 { \
90 unsigned int loop; \
91 u##sz ret; \
92 \
93 asm volatile (ARM64_LSE_ATOMIC_INSN( \
94 /* LL/SC */ \
95 "1: ldxr" #sfx "\t%" #w "[ret], %[ptr]\n" \
96 #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \
97 " stxr" #sfx "\t%w[loop], %" #w "[ret], %[ptr]\n" \
98 " cbnz %w[loop], 1b", \
99 /* LSE atomics */ \
100 #op_lse "\t%" #w "[val], %" #w "[ret], %[ptr]\n" \
101 #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \
102 __nops(2)) \
103 : [loop] "=&r" (loop), [ret] "=&r" (ret), \
104 [ptr] "+Q"(*(u##sz *)ptr) \
105 : [val] "r" ((u##sz)(val))); \
106 \
107 return ret; \
108 }
109
110 #define PERCPU_OP(name, op_llsc, op_lse) \
111 __PERCPU_OP_CASE(w, b, name, 8, op_llsc, op_lse) \
112 __PERCPU_OP_CASE(w, h, name, 16, op_llsc, op_lse) \
113 __PERCPU_OP_CASE(w, , name, 32, op_llsc, op_lse) \
114 __PERCPU_OP_CASE( , , name, 64, op_llsc, op_lse)
115
116 #define PERCPU_RET_OP(name, op_llsc, op_lse) \
117 __PERCPU_RET_OP_CASE(w, b, name, 8, op_llsc, op_lse) \
118 __PERCPU_RET_OP_CASE(w, h, name, 16, op_llsc, op_lse) \
119 __PERCPU_RET_OP_CASE(w, , name, 32, op_llsc, op_lse) \
120 __PERCPU_RET_OP_CASE( , , name, 64, op_llsc, op_lse)
121
122 PERCPU_RW_OPS(8)
123 PERCPU_RW_OPS(16)
124 PERCPU_RW_OPS(32)
125 PERCPU_RW_OPS(64)
126 PERCPU_OP(add, add, stadd)
127 PERCPU_OP(andnot, bic, stclr)
128 PERCPU_OP(or, orr, stset)
129 PERCPU_RET_OP(add, add, ldadd)
130
131 #undef PERCPU_RW_OPS
132 #undef __PERCPU_OP_CASE
133 #undef __PERCPU_RET_OP_CASE
134 #undef PERCPU_OP
135 #undef PERCPU_RET_OP
136
137 /*
138 * It would be nice to avoid the conditional call into the scheduler when
139 * re-enabling preemption for preemptible kernels, but doing that in a way
140 * which builds inside a module would mean messing directly with the preempt
141 * count. If you do this, peterz and tglx will hunt you down.
142 */
143 #define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2) \
144 ({ \
145 int __ret; \
146 preempt_disable_notrace(); \
147 __ret = cmpxchg_double_local( raw_cpu_ptr(&(ptr1)), \
148 raw_cpu_ptr(&(ptr2)), \
149 o1, o2, n1, n2); \
150 preempt_enable_notrace(); \
151 __ret; \
152 })
153
154 #define _pcp_protect(op, pcp, ...) \
155 ({ \
156 preempt_disable_notrace(); \
157 op(raw_cpu_ptr(&(pcp)), __VA_ARGS__); \
158 preempt_enable_notrace(); \
159 })
160
161 #define _pcp_protect_return(op, pcp, args...) \
162 ({ \
163 typeof(pcp) __retval; \
164 preempt_disable_notrace(); \
165 __retval = (typeof(pcp))op(raw_cpu_ptr(&(pcp)), ##args); \
166 preempt_enable_notrace(); \
167 __retval; \
168 })
169
170 #define this_cpu_read_1(pcp) \
171 _pcp_protect_return(__percpu_read_8, pcp)
172 #define this_cpu_read_2(pcp) \
173 _pcp_protect_return(__percpu_read_16, pcp)
174 #define this_cpu_read_4(pcp) \
175 _pcp_protect_return(__percpu_read_32, pcp)
176 #define this_cpu_read_8(pcp) \
177 _pcp_protect_return(__percpu_read_64, pcp)
178
179 #define this_cpu_write_1(pcp, val) \
180 _pcp_protect(__percpu_write_8, pcp, (unsigned long)val)
181 #define this_cpu_write_2(pcp, val) \
182 _pcp_protect(__percpu_write_16, pcp, (unsigned long)val)
183 #define this_cpu_write_4(pcp, val) \
184 _pcp_protect(__percpu_write_32, pcp, (unsigned long)val)
185 #define this_cpu_write_8(pcp, val) \
186 _pcp_protect(__percpu_write_64, pcp, (unsigned long)val)
187
188 #define this_cpu_add_1(pcp, val) \
189 _pcp_protect(__percpu_add_case_8, pcp, val)
190 #define this_cpu_add_2(pcp, val) \
191 _pcp_protect(__percpu_add_case_16, pcp, val)
192 #define this_cpu_add_4(pcp, val) \
193 _pcp_protect(__percpu_add_case_32, pcp, val)
194 #define this_cpu_add_8(pcp, val) \
195 _pcp_protect(__percpu_add_case_64, pcp, val)
196
197 #define this_cpu_add_return_1(pcp, val) \
198 _pcp_protect_return(__percpu_add_return_case_8, pcp, val)
199 #define this_cpu_add_return_2(pcp, val) \
200 _pcp_protect_return(__percpu_add_return_case_16, pcp, val)
201 #define this_cpu_add_return_4(pcp, val) \
202 _pcp_protect_return(__percpu_add_return_case_32, pcp, val)
203 #define this_cpu_add_return_8(pcp, val) \
204 _pcp_protect_return(__percpu_add_return_case_64, pcp, val)
205
206 #define this_cpu_and_1(pcp, val) \
207 _pcp_protect(__percpu_andnot_case_8, pcp, ~val)
208 #define this_cpu_and_2(pcp, val) \
209 _pcp_protect(__percpu_andnot_case_16, pcp, ~val)
210 #define this_cpu_and_4(pcp, val) \
211 _pcp_protect(__percpu_andnot_case_32, pcp, ~val)
212 #define this_cpu_and_8(pcp, val) \
213 _pcp_protect(__percpu_andnot_case_64, pcp, ~val)
214
215 #define this_cpu_or_1(pcp, val) \
216 _pcp_protect(__percpu_or_case_8, pcp, val)
217 #define this_cpu_or_2(pcp, val) \
218 _pcp_protect(__percpu_or_case_16, pcp, val)
219 #define this_cpu_or_4(pcp, val) \
220 _pcp_protect(__percpu_or_case_32, pcp, val)
221 #define this_cpu_or_8(pcp, val) \
222 _pcp_protect(__percpu_or_case_64, pcp, val)
223
224 #define this_cpu_xchg_1(pcp, val) \
225 _pcp_protect_return(xchg_relaxed, pcp, val)
226 #define this_cpu_xchg_2(pcp, val) \
227 _pcp_protect_return(xchg_relaxed, pcp, val)
228 #define this_cpu_xchg_4(pcp, val) \
229 _pcp_protect_return(xchg_relaxed, pcp, val)
230 #define this_cpu_xchg_8(pcp, val) \
231 _pcp_protect_return(xchg_relaxed, pcp, val)
232
233 #define this_cpu_cmpxchg_1(pcp, o, n) \
234 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
235 #define this_cpu_cmpxchg_2(pcp, o, n) \
236 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
237 #define this_cpu_cmpxchg_4(pcp, o, n) \
238 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
239 #define this_cpu_cmpxchg_8(pcp, o, n) \
240 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
241
242 #ifdef __KVM_NVHE_HYPERVISOR__
243 extern unsigned long __hyp_per_cpu_offset(unsigned int cpu);
244 #define __per_cpu_offset
245 #define per_cpu_offset(cpu) __hyp_per_cpu_offset((cpu))
246 #endif
247
248 #include <asm-generic/percpu.h>
249
250 /* Redefine macros for nVHE hyp under DEBUG_PREEMPT to avoid its dependencies. */
251 #if defined(__KVM_NVHE_HYPERVISOR__) && defined(CONFIG_DEBUG_PREEMPT)
252 #undef this_cpu_ptr
253 #define this_cpu_ptr raw_cpu_ptr
254 #undef __this_cpu_read
255 #define __this_cpu_read raw_cpu_read
256 #undef __this_cpu_write
257 #define __this_cpu_write raw_cpu_write
258 #endif
259
260 #endif /* __ASM_PERCPU_H */
261