tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2013 ARM Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
16#ifndef __ASM_PERCPU_H
17#define __ASM_PERCPU_H
18
19#include <linux/preempt.h>
20
21#include <asm/alternative.h>
22#include <asm/cmpxchg.h>
23#include <asm/stack_pointer.h>
24
25static inline void set_my_cpu_offset(unsigned long off)
26{
27 asm volatile(ALTERNATIVE("msr tpidr_el1, %0",
28 "msr tpidr_el2, %0",
29 ARM64_HAS_VIRT_HOST_EXTN)
30 :: "r" (off) : "memory");
31}
32
33static inline unsigned long __my_cpu_offset(void)
34{
35 unsigned long off;
36
37 /*
38 * We want to allow caching the value, so avoid using volatile and
39 * instead use a fake stack read to hazard against barrier().
40 */
41 asm(ALTERNATIVE("mrs %0, tpidr_el1",
42 "mrs %0, tpidr_el2",
43 ARM64_HAS_VIRT_HOST_EXTN)
44 : "=r" (off) :
45 "Q" (*(const unsigned long *)current_stack_pointer));
46
47 return off;
48}
49#define __my_cpu_offset __my_cpu_offset()
50
51#define PERCPU_RW_OPS(sz) \
52static inline unsigned long __percpu_read_##sz(void *ptr) \
53{ \
54 return READ_ONCE(*(u##sz *)ptr); \
55} \
56 \
57static inline void __percpu_write_##sz(void *ptr, unsigned long val) \
58{ \
59 WRITE_ONCE(*(u##sz *)ptr, (u##sz)val); \
60}
61
62#define __PERCPU_OP_CASE(w, sfx, name, sz, op_llsc, op_lse) \
63static inline void \
64__percpu_##name##_case_##sz(void *ptr, unsigned long val) \
65{ \
66 unsigned int loop; \
67 u##sz tmp; \
68 \
69 asm volatile (ARM64_LSE_ATOMIC_INSN( \
70 /* LL/SC */ \
71 "1: ldxr" #sfx "\t%" #w "[tmp], %[ptr]\n" \
72 #op_llsc "\t%" #w "[tmp], %" #w "[tmp], %" #w "[val]\n" \
73 " stxr" #sfx "\t%w[loop], %" #w "[tmp], %[ptr]\n" \
74 " cbnz %w[loop], 1b", \
75 /* LSE atomics */ \
76 #op_lse "\t%" #w "[val], %[ptr]\n" \
77 __nops(3)) \
78 : [loop] "=&r" (loop), [tmp] "=&r" (tmp), \
79 [ptr] "+Q"(*(u##sz *)ptr) \
80 : [val] "r" ((u##sz)(val))); \
81}
82
83#define __PERCPU_RET_OP_CASE(w, sfx, name, sz, op_llsc, op_lse) \
84static inline u##sz \
85__percpu_##name##_return_case_##sz(void *ptr, unsigned long val) \
86{ \
87 unsigned int loop; \
88 u##sz ret; \
89 \
90 asm volatile (ARM64_LSE_ATOMIC_INSN( \
91 /* LL/SC */ \
92 "1: ldxr" #sfx "\t%" #w "[ret], %[ptr]\n" \
93 #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \
94 " stxr" #sfx "\t%w[loop], %" #w "[ret], %[ptr]\n" \
95 " cbnz %w[loop], 1b", \
96 /* LSE atomics */ \
97 #op_lse "\t%" #w "[val], %" #w "[ret], %[ptr]\n" \
98 #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \
99 __nops(2)) \
100 : [loop] "=&r" (loop), [ret] "=&r" (ret), \
101 [ptr] "+Q"(*(u##sz *)ptr) \
102 : [val] "r" ((u##sz)(val))); \
103 \
104 return ret; \
105}
106
107#define PERCPU_OP(name, op_llsc, op_lse) \
108 __PERCPU_OP_CASE(w, b, name, 8, op_llsc, op_lse) \
109 __PERCPU_OP_CASE(w, h, name, 16, op_llsc, op_lse) \
110 __PERCPU_OP_CASE(w, , name, 32, op_llsc, op_lse) \
111 __PERCPU_OP_CASE( , , name, 64, op_llsc, op_lse)
112
113#define PERCPU_RET_OP(name, op_llsc, op_lse) \
114 __PERCPU_RET_OP_CASE(w, b, name, 8, op_llsc, op_lse) \
115 __PERCPU_RET_OP_CASE(w, h, name, 16, op_llsc, op_lse) \
116 __PERCPU_RET_OP_CASE(w, , name, 32, op_llsc, op_lse) \
117 __PERCPU_RET_OP_CASE( , , name, 64, op_llsc, op_lse)
118
119PERCPU_RW_OPS(8)
120PERCPU_RW_OPS(16)
121PERCPU_RW_OPS(32)
122PERCPU_RW_OPS(64)
123PERCPU_OP(add, add, stadd)
124PERCPU_OP(andnot, bic, stclr)
125PERCPU_OP(or, orr, stset)
126PERCPU_RET_OP(add, add, ldadd)
127
128#undef PERCPU_RW_OPS
129#undef __PERCPU_OP_CASE
130#undef __PERCPU_RET_OP_CASE
131#undef PERCPU_OP
132#undef PERCPU_RET_OP
133
134/*
135 * It would be nice to avoid the conditional call into the scheduler when
136 * re-enabling preemption for preemptible kernels, but doing that in a way
137 * which builds inside a module would mean messing directly with the preempt
138 * count. If you do this, peterz and tglx will hunt you down.
139 */
140#define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2) \
141({ \
142 int __ret; \
143 preempt_disable_notrace(); \
144 __ret = cmpxchg_double_local( raw_cpu_ptr(&(ptr1)), \
145 raw_cpu_ptr(&(ptr2)), \
146 o1, o2, n1, n2); \
147 preempt_enable_notrace(); \
148 __ret; \
149})
150
151#define _pcp_protect(op, pcp, ...) \
152({ \
153 preempt_disable_notrace(); \
154 op(raw_cpu_ptr(&(pcp)), __VA_ARGS__); \
155 preempt_enable_notrace(); \
156})
157
158#define _pcp_protect_return(op, pcp, args...) \
159({ \
160 typeof(pcp) __retval; \
161 preempt_disable_notrace(); \
162 __retval = (typeof(pcp))op(raw_cpu_ptr(&(pcp)), ##args); \
163 preempt_enable_notrace(); \
164 __retval; \
165})
166
167#define this_cpu_read_1(pcp) \
168 _pcp_protect_return(__percpu_read_8, pcp)
169#define this_cpu_read_2(pcp) \
170 _pcp_protect_return(__percpu_read_16, pcp)
171#define this_cpu_read_4(pcp) \
172 _pcp_protect_return(__percpu_read_32, pcp)
173#define this_cpu_read_8(pcp) \
174 _pcp_protect_return(__percpu_read_64, pcp)
175
176#define this_cpu_write_1(pcp, val) \
177 _pcp_protect(__percpu_write_8, pcp, (unsigned long)val)
178#define this_cpu_write_2(pcp, val) \
179 _pcp_protect(__percpu_write_16, pcp, (unsigned long)val)
180#define this_cpu_write_4(pcp, val) \
181 _pcp_protect(__percpu_write_32, pcp, (unsigned long)val)
182#define this_cpu_write_8(pcp, val) \
183 _pcp_protect(__percpu_write_64, pcp, (unsigned long)val)
184
185#define this_cpu_add_1(pcp, val) \
186 _pcp_protect(__percpu_add_case_8, pcp, val)
187#define this_cpu_add_2(pcp, val) \
188 _pcp_protect(__percpu_add_case_16, pcp, val)
189#define this_cpu_add_4(pcp, val) \
190 _pcp_protect(__percpu_add_case_32, pcp, val)
191#define this_cpu_add_8(pcp, val) \
192 _pcp_protect(__percpu_add_case_64, pcp, val)
193
194#define this_cpu_add_return_1(pcp, val) \
195 _pcp_protect_return(__percpu_add_return_case_8, pcp, val)
196#define this_cpu_add_return_2(pcp, val) \
197 _pcp_protect_return(__percpu_add_return_case_16, pcp, val)
198#define this_cpu_add_return_4(pcp, val) \
199 _pcp_protect_return(__percpu_add_return_case_32, pcp, val)
200#define this_cpu_add_return_8(pcp, val) \
201 _pcp_protect_return(__percpu_add_return_case_64, pcp, val)
202
203#define this_cpu_and_1(pcp, val) \
204 _pcp_protect(__percpu_andnot_case_8, pcp, ~val)
205#define this_cpu_and_2(pcp, val) \
206 _pcp_protect(__percpu_andnot_case_16, pcp, ~val)
207#define this_cpu_and_4(pcp, val) \
208 _pcp_protect(__percpu_andnot_case_32, pcp, ~val)
209#define this_cpu_and_8(pcp, val) \
210 _pcp_protect(__percpu_andnot_case_64, pcp, ~val)
211
212#define this_cpu_or_1(pcp, val) \
213 _pcp_protect(__percpu_or_case_8, pcp, val)
214#define this_cpu_or_2(pcp, val) \
215 _pcp_protect(__percpu_or_case_16, pcp, val)
216#define this_cpu_or_4(pcp, val) \
217 _pcp_protect(__percpu_or_case_32, pcp, val)
218#define this_cpu_or_8(pcp, val) \
219 _pcp_protect(__percpu_or_case_64, pcp, val)
220
221#define this_cpu_xchg_1(pcp, val) \
222 _pcp_protect_return(xchg_relaxed, pcp, val)
223#define this_cpu_xchg_2(pcp, val) \
224 _pcp_protect_return(xchg_relaxed, pcp, val)
225#define this_cpu_xchg_4(pcp, val) \
226 _pcp_protect_return(xchg_relaxed, pcp, val)
227#define this_cpu_xchg_8(pcp, val) \
228 _pcp_protect_return(xchg_relaxed, pcp, val)
229
230#define this_cpu_cmpxchg_1(pcp, o, n) \
231 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
232#define this_cpu_cmpxchg_2(pcp, o, n) \
233 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
234#define this_cpu_cmpxchg_4(pcp, o, n) \
235 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
236#define this_cpu_cmpxchg_8(pcp, o, n) \
237 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n)
238
239#include <asm-generic/percpu.h>
240
241#endif /* __ASM_PERCPU_H */