arch/arm64/include/asm/percpu.h

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