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 #include <asm/sysreg.h> 14 15 static inline void set_my_cpu_offset(unsigned long off) 16 { 17 asm volatile(ALTERNATIVE("msr tpidr_el1, %0", 18 "msr tpidr_el2, %0", 19 ARM64_HAS_VIRT_HOST_EXTN) 20 :: "r" (off) : "memory"); 21 } 22 23 static inline unsigned long __hyp_my_cpu_offset(void) 24 { 25 /* 26 * Non-VHE hyp code runs with preemption disabled. No need to hazard 27 * the register access against barrier() as in __kern_my_cpu_offset. 28 */ 29 return read_sysreg(tpidr_el2); 30 } 31 32 static inline unsigned long __kern_my_cpu_offset(void) 33 { 34 unsigned long off; 35 36 /* 37 * We want to allow caching the value, so avoid using volatile and 38 * instead use a fake stack read to hazard against barrier(). 39 */ 40 asm(ALTERNATIVE("mrs %0, tpidr_el1", 41 "mrs %0, tpidr_el2", 42 ARM64_HAS_VIRT_HOST_EXTN) 43 : "=r" (off) : 44 "Q" (*(const unsigned long *)current_stack_pointer)); 45 46 return off; 47 } 48 49 #ifdef __KVM_NVHE_HYPERVISOR__ 50 #define __my_cpu_offset __hyp_my_cpu_offset() 51 #else 52 #define __my_cpu_offset __kern_my_cpu_offset() 53 #endif 54 55 #define PERCPU_RW_OPS(sz) \ 56 static inline unsigned long __percpu_read_##sz(void *ptr) \ 57 { \ 58 return READ_ONCE(*(u##sz *)ptr); \ 59 } \ 60 \ 61 static inline void __percpu_write_##sz(void *ptr, unsigned long val) \ 62 { \ 63 WRITE_ONCE(*(u##sz *)ptr, (u##sz)val); \ 64 } 65 66 #define __PERCPU_OP_CASE(w, sfx, name, sz, op_llsc, op_lse) \ 67 static inline void \ 68 __percpu_##name##_case_##sz(void *ptr, unsigned long val) \ 69 { \ 70 unsigned int loop; \ 71 u##sz tmp; \ 72 \ 73 asm volatile (ARM64_LSE_ATOMIC_INSN( \ 74 /* LL/SC */ \ 75 "1: ldxr" #sfx "\t%" #w "[tmp], %[ptr]\n" \ 76 #op_llsc "\t%" #w "[tmp], %" #w "[tmp], %" #w "[val]\n" \ 77 " stxr" #sfx "\t%w[loop], %" #w "[tmp], %[ptr]\n" \ 78 " cbnz %w[loop], 1b", \ 79 /* LSE atomics */ \ 80 #op_lse "\t%" #w "[val], %[ptr]\n" \ 81 __nops(3)) \ 82 : [loop] "=&r" (loop), [tmp] "=&r" (tmp), \ 83 [ptr] "+Q"(*(u##sz *)ptr) \ 84 : [val] "r" ((u##sz)(val))); \ 85 } 86 87 #define __PERCPU_RET_OP_CASE(w, sfx, name, sz, op_llsc, op_lse) \ 88 static inline u##sz \ 89 __percpu_##name##_return_case_##sz(void *ptr, unsigned long val) \ 90 { \ 91 unsigned int loop; \ 92 u##sz ret; \ 93 \ 94 asm volatile (ARM64_LSE_ATOMIC_INSN( \ 95 /* LL/SC */ \ 96 "1: ldxr" #sfx "\t%" #w "[ret], %[ptr]\n" \ 97 #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \ 98 " stxr" #sfx "\t%w[loop], %" #w "[ret], %[ptr]\n" \ 99 " cbnz %w[loop], 1b", \ 100 /* LSE atomics */ \ 101 #op_lse "\t%" #w "[val], %" #w "[ret], %[ptr]\n" \ 102 #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \ 103 __nops(2)) \ 104 : [loop] "=&r" (loop), [ret] "=&r" (ret), \ 105 [ptr] "+Q"(*(u##sz *)ptr) \ 106 : [val] "r" ((u##sz)(val))); \ 107 \ 108 return ret; \ 109 } 110 111 #define PERCPU_OP(name, op_llsc, op_lse) \ 112 __PERCPU_OP_CASE(w, b, name, 8, op_llsc, op_lse) \ 113 __PERCPU_OP_CASE(w, h, name, 16, op_llsc, op_lse) \ 114 __PERCPU_OP_CASE(w, , name, 32, op_llsc, op_lse) \ 115 __PERCPU_OP_CASE( , , name, 64, op_llsc, op_lse) 116 117 #define PERCPU_RET_OP(name, op_llsc, op_lse) \ 118 __PERCPU_RET_OP_CASE(w, b, name, 8, op_llsc, op_lse) \ 119 __PERCPU_RET_OP_CASE(w, h, name, 16, op_llsc, op_lse) \ 120 __PERCPU_RET_OP_CASE(w, , name, 32, op_llsc, op_lse) \ 121 __PERCPU_RET_OP_CASE( , , name, 64, op_llsc, op_lse) 122 123 PERCPU_RW_OPS(8) 124 PERCPU_RW_OPS(16) 125 PERCPU_RW_OPS(32) 126 PERCPU_RW_OPS(64) 127 PERCPU_OP(add, add, stadd) 128 PERCPU_OP(andnot, bic, stclr) 129 PERCPU_OP(or, orr, stset) 130 PERCPU_RET_OP(add, add, ldadd) 131 132 #undef PERCPU_RW_OPS 133 #undef __PERCPU_OP_CASE 134 #undef __PERCPU_RET_OP_CASE 135 #undef PERCPU_OP 136 #undef PERCPU_RET_OP 137 138 /* 139 * It would be nice to avoid the conditional call into the scheduler when 140 * re-enabling preemption for preemptible kernels, but doing that in a way 141 * which builds inside a module would mean messing directly with the preempt 142 * count. If you do this, peterz and tglx will hunt you down. 143 * 144 * Not to mention it'll break the actual preemption model for missing a 145 * preemption point when TIF_NEED_RESCHED gets set while preemption is 146 * disabled. 147 */ 148 149 #define _pcp_protect(op, pcp, ...) \ 150 ({ \ 151 preempt_disable_notrace(); \ 152 op(raw_cpu_ptr(&(pcp)), __VA_ARGS__); \ 153 preempt_enable_notrace(); \ 154 }) 155 156 #define _pcp_protect_return(op, pcp, args...) \ 157 ({ \ 158 typeof(pcp) __retval; \ 159 preempt_disable_notrace(); \ 160 __retval = (typeof(pcp))op(raw_cpu_ptr(&(pcp)), ##args); \ 161 preempt_enable_notrace(); \ 162 __retval; \ 163 }) 164 165 #define this_cpu_read_1(pcp) \ 166 _pcp_protect_return(__percpu_read_8, pcp) 167 #define this_cpu_read_2(pcp) \ 168 _pcp_protect_return(__percpu_read_16, pcp) 169 #define this_cpu_read_4(pcp) \ 170 _pcp_protect_return(__percpu_read_32, pcp) 171 #define this_cpu_read_8(pcp) \ 172 _pcp_protect_return(__percpu_read_64, pcp) 173 174 #define this_cpu_write_1(pcp, val) \ 175 _pcp_protect(__percpu_write_8, pcp, (unsigned long)val) 176 #define this_cpu_write_2(pcp, val) \ 177 _pcp_protect(__percpu_write_16, pcp, (unsigned long)val) 178 #define this_cpu_write_4(pcp, val) \ 179 _pcp_protect(__percpu_write_32, pcp, (unsigned long)val) 180 #define this_cpu_write_8(pcp, val) \ 181 _pcp_protect(__percpu_write_64, pcp, (unsigned long)val) 182 183 #define this_cpu_add_1(pcp, val) \ 184 _pcp_protect(__percpu_add_case_8, pcp, val) 185 #define this_cpu_add_2(pcp, val) \ 186 _pcp_protect(__percpu_add_case_16, pcp, val) 187 #define this_cpu_add_4(pcp, val) \ 188 _pcp_protect(__percpu_add_case_32, pcp, val) 189 #define this_cpu_add_8(pcp, val) \ 190 _pcp_protect(__percpu_add_case_64, pcp, val) 191 192 #define this_cpu_add_return_1(pcp, val) \ 193 _pcp_protect_return(__percpu_add_return_case_8, pcp, val) 194 #define this_cpu_add_return_2(pcp, val) \ 195 _pcp_protect_return(__percpu_add_return_case_16, pcp, val) 196 #define this_cpu_add_return_4(pcp, val) \ 197 _pcp_protect_return(__percpu_add_return_case_32, pcp, val) 198 #define this_cpu_add_return_8(pcp, val) \ 199 _pcp_protect_return(__percpu_add_return_case_64, pcp, val) 200 201 #define this_cpu_and_1(pcp, val) \ 202 _pcp_protect(__percpu_andnot_case_8, pcp, ~val) 203 #define this_cpu_and_2(pcp, val) \ 204 _pcp_protect(__percpu_andnot_case_16, pcp, ~val) 205 #define this_cpu_and_4(pcp, val) \ 206 _pcp_protect(__percpu_andnot_case_32, pcp, ~val) 207 #define this_cpu_and_8(pcp, val) \ 208 _pcp_protect(__percpu_andnot_case_64, pcp, ~val) 209 210 #define this_cpu_or_1(pcp, val) \ 211 _pcp_protect(__percpu_or_case_8, pcp, val) 212 #define this_cpu_or_2(pcp, val) \ 213 _pcp_protect(__percpu_or_case_16, pcp, val) 214 #define this_cpu_or_4(pcp, val) \ 215 _pcp_protect(__percpu_or_case_32, pcp, val) 216 #define this_cpu_or_8(pcp, val) \ 217 _pcp_protect(__percpu_or_case_64, pcp, val) 218 219 #define this_cpu_xchg_1(pcp, val) \ 220 _pcp_protect_return(xchg_relaxed, pcp, val) 221 #define this_cpu_xchg_2(pcp, val) \ 222 _pcp_protect_return(xchg_relaxed, pcp, val) 223 #define this_cpu_xchg_4(pcp, val) \ 224 _pcp_protect_return(xchg_relaxed, pcp, val) 225 #define this_cpu_xchg_8(pcp, val) \ 226 _pcp_protect_return(xchg_relaxed, pcp, val) 227 228 #define this_cpu_cmpxchg_1(pcp, o, n) \ 229 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) 230 #define this_cpu_cmpxchg_2(pcp, o, n) \ 231 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) 232 #define this_cpu_cmpxchg_4(pcp, o, n) \ 233 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) 234 #define this_cpu_cmpxchg_8(pcp, o, n) \ 235 _pcp_protect_return(cmpxchg_relaxed, pcp, o, n) 236 237 #define this_cpu_cmpxchg64(pcp, o, n) this_cpu_cmpxchg_8(pcp, o, n) 238 239 #define this_cpu_cmpxchg128(pcp, o, n) \ 240 ({ \ 241 typedef typeof(pcp) pcp_op_T__; \ 242 u128 old__, new__, ret__; \ 243 pcp_op_T__ *ptr__; \ 244 old__ = o; \ 245 new__ = n; \ 246 preempt_disable_notrace(); \ 247 ptr__ = raw_cpu_ptr(&(pcp)); \ 248 ret__ = cmpxchg128_local((void *)ptr__, old__, new__); \ 249 preempt_enable_notrace(); \ 250 ret__; \ 251 }) 252 253 #ifdef __KVM_NVHE_HYPERVISOR__ 254 extern unsigned long __hyp_per_cpu_offset(unsigned int cpu); 255 #define __per_cpu_offset 256 #define per_cpu_offset(cpu) __hyp_per_cpu_offset((cpu)) 257 #endif 258 259 #include <asm-generic/percpu.h> 260 261 /* Redefine macros for nVHE hyp under DEBUG_PREEMPT to avoid its dependencies. */ 262 #if defined(__KVM_NVHE_HYPERVISOR__) && defined(CONFIG_DEBUG_PREEMPT) 263 #undef this_cpu_ptr 264 #define this_cpu_ptr raw_cpu_ptr 265 #undef __this_cpu_read 266 #define __this_cpu_read raw_cpu_read 267 #undef __this_cpu_write 268 #define __this_cpu_write raw_cpu_write 269 #endif 270 271 #endif /* __ASM_PERCPU_H */ 272