tools/testing/selftests/rseq/rseq-riscv.h

   1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
   2 /*
   3  * Select the instruction "csrw mhartid, x0" as the RSEQ_SIG. Unlike
   4  * other architectures, the ebreak instruction has no immediate field for
   5  * distinguishing purposes. Hence, ebreak is not suitable as RSEQ_SIG.
   6  * "csrw mhartid, x0" can also satisfy the RSEQ requirement because it
   7  * is an uncommon instruction and will raise an illegal instruction
   8  * exception when executed in all modes.
   9  */
  10 #include <endian.h>
  11
  12 #if defined(__BYTE_ORDER) ? (__BYTE_ORDER == __LITTLE_ENDIAN) : defined(__LITTLE_ENDIAN)
  13 #define RSEQ_SIG   0xf1401073  /* csrr mhartid, x0 */
  14 #else
  15 #error "Currently, RSEQ only supports Little-Endian version"
  16 #endif
  17
  18 #if __riscv_xlen == 64
  19 #define __REG_SEL(a, b) a
  20 #elif __riscv_xlen == 32
  21 #define __REG_SEL(a, b) b
  22 #endif
  23
  24 #define REG_L   __REG_SEL("ld ", "lw ")
  25 #define REG_S   __REG_SEL("sd ", "sw ")
  26
  27 #define RISCV_FENCE(p, s) \
  28         __asm__ __volatile__ ("fence " #p "," #s : : : "memory")
  29 #define rseq_smp_mb()   RISCV_FENCE(rw, rw)
  30 #define rseq_smp_rmb()  RISCV_FENCE(r, r)
  31 #define rseq_smp_wmb()  RISCV_FENCE(w, w)
  32 #define RSEQ_ASM_TMP_REG_1      "t6"
  33 #define RSEQ_ASM_TMP_REG_2      "t5"
  34 #define RSEQ_ASM_TMP_REG_3      "t4"
  35 #define RSEQ_ASM_TMP_REG_4      "t3"
  36
  37 #define rseq_smp_load_acquire(p)                                        \
  38 __extension__ ({                                                        \
  39         rseq_unqual_scalar_typeof(*(p)) ____p1 = RSEQ_READ_ONCE(*(p));  \
  40         RISCV_FENCE(r, rw);                                             \
  41         ____p1;                                                         \
  42 })
  43
  44 #define rseq_smp_acquire__after_ctrl_dep()      rseq_smp_rmb()
  45
  46 #define rseq_smp_store_release(p, v)                                    \
  47 do {                                                                    \
  48         RISCV_FENCE(rw, w);                                             \
  49         RSEQ_WRITE_ONCE(*(p), v);                                       \
  50 } while (0)
  51
  52 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip,        \
  53                                 post_commit_offset, abort_ip)           \
  54         ".pushsection   __rseq_cs, \"aw\"\n"                            \
  55         ".balign        32\n"                                           \
  56         __rseq_str(label) ":\n"                                         \
  57         ".long  " __rseq_str(version) ", " __rseq_str(flags) "\n"       \
  58         ".quad  " __rseq_str(start_ip) ", "                             \
  59                           __rseq_str(post_commit_offset) ", "           \
  60                           __rseq_str(abort_ip) "\n"                     \
  61         ".popsection\n\t"                                               \
  62         ".pushsection __rseq_cs_ptr_array, \"aw\"\n"                    \
  63         ".quad " __rseq_str(label) "b\n"                                \
  64         ".popsection\n"
  65
  66 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
  67         __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,               \
  68                                 ((post_commit_ip) - (start_ip)), abort_ip)
  69
  70 /*
  71  * Exit points of a rseq critical section consist of all instructions outside
  72  * of the critical section where a critical section can either branch to or
  73  * reach through the normal course of its execution. The abort IP and the
  74  * post-commit IP are already part of the __rseq_cs section and should not be
  75  * explicitly defined as additional exit points. Knowing all exit points is
  76  * useful to assist debuggers stepping over the critical section.
  77  */
  78 #define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)                   \
  79         ".pushsection __rseq_exit_point_array, \"aw\"\n"                \
  80         ".quad " __rseq_str(start_ip) ", " __rseq_str(exit_ip) "\n"     \
  81         ".popsection\n"
  82
  83 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)                \
  84         RSEQ_INJECT_ASM(1)                                              \
  85         "la     " RSEQ_ASM_TMP_REG_1 ", " __rseq_str(cs_label) "\n"     \
  86         REG_S   RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(rseq_cs) "]\n"     \
  87         __rseq_str(label) ":\n"
  88
  89 #define RSEQ_ASM_DEFINE_ABORT(label, abort_label)                       \
  90         "j      222f\n"                                                 \
  91         ".balign        4\n"                                            \
  92         ".long "        __rseq_str(RSEQ_SIG) "\n"                       \
  93         __rseq_str(label) ":\n"                                         \
  94         "j      %l[" __rseq_str(abort_label) "]\n"                      \
  95         "222:\n"
  96
  97 #define RSEQ_ASM_OP_STORE(value, var)                                   \
  98         REG_S   "%[" __rseq_str(value) "], %[" __rseq_str(var) "]\n"
  99
 100 #define RSEQ_ASM_OP_CMPEQ(var, expect, label)                           \
 101         REG_L   RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(var) "]\n"         \
 102         "bne    " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(expect) "] ,"    \
 103                   __rseq_str(label) "\n"
 104
 105 #define RSEQ_ASM_OP_CMPEQ32(var, expect, label)                         \
 106         "lw     " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(var) "]\n"       \
 107         "bne    " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(expect) "] ,"    \
 108                   __rseq_str(label) "\n"
 109
 110 #define RSEQ_ASM_OP_CMPNE(var, expect, label)                           \
 111         REG_L   RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(var) "]\n"         \
 112         "beq    " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(expect) "] ,"    \
 113                   __rseq_str(label) "\n"
 114
 115 #define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label)              \
 116         RSEQ_INJECT_ASM(2)                                              \
 117         RSEQ_ASM_OP_CMPEQ32(current_cpu_id, cpu_id, label)
 118
 119 #define RSEQ_ASM_OP_R_LOAD(var)                                         \
 120         REG_L   RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(var) "]\n"
 121
 122 #define RSEQ_ASM_OP_R_STORE(var)                                        \
 123         REG_S   RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(var) "]\n"
 124
 125 #define RSEQ_ASM_OP_R_LOAD_OFF(offset)                                  \
 126         "add    " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(offset) "], "    \
 127                  RSEQ_ASM_TMP_REG_1 "\n"                                \
 128         REG_L   RSEQ_ASM_TMP_REG_1 ", (" RSEQ_ASM_TMP_REG_1 ")\n"
 129
 130 #define RSEQ_ASM_OP_R_ADD(count)                                        \
 131         "add    " RSEQ_ASM_TMP_REG_1 ", " RSEQ_ASM_TMP_REG_1            \
 132                 ", %[" __rseq_str(count) "]\n"
 133
 134 #define RSEQ_ASM_OP_FINAL_STORE(value, var, post_commit_label)          \
 135         RSEQ_ASM_OP_STORE(value, var)                                   \
 136         __rseq_str(post_commit_label) ":\n"
 137
 138 #define RSEQ_ASM_OP_FINAL_STORE_RELEASE(value, var, post_commit_label)  \
 139         "fence  rw, w\n"                                                \
 140         RSEQ_ASM_OP_STORE(value, var)                                   \
 141         __rseq_str(post_commit_label) ":\n"
 142
 143 #define RSEQ_ASM_OP_R_FINAL_STORE(var, post_commit_label)               \
 144         REG_S   RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(var) "]\n"         \
 145         __rseq_str(post_commit_label) ":\n"
 146
 147 #define RSEQ_ASM_OP_R_BAD_MEMCPY(dst, src, len)                         \
 148         "beqz   %[" __rseq_str(len) "], 333f\n"                         \
 149         "mv     " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(len) "]\n"       \
 150         "mv     " RSEQ_ASM_TMP_REG_2 ", %[" __rseq_str(src) "]\n"       \
 151         "mv     " RSEQ_ASM_TMP_REG_3 ", %[" __rseq_str(dst) "]\n"       \
 152         "222:\n"                                                        \
 153         "lb     " RSEQ_ASM_TMP_REG_4 ", 0(" RSEQ_ASM_TMP_REG_2 ")\n"    \
 154         "sb     " RSEQ_ASM_TMP_REG_4 ", 0(" RSEQ_ASM_TMP_REG_3 ")\n"    \
 155         "addi   " RSEQ_ASM_TMP_REG_1 ", " RSEQ_ASM_TMP_REG_1 ", -1\n"   \
 156         "addi   " RSEQ_ASM_TMP_REG_2 ", " RSEQ_ASM_TMP_REG_2 ", 1\n"    \
 157         "addi   " RSEQ_ASM_TMP_REG_3 ", " RSEQ_ASM_TMP_REG_3 ", 1\n"    \
 158         "bnez   " RSEQ_ASM_TMP_REG_1 ", 222b\n"                         \
 159         "333:\n"
 160
 161 #define RSEQ_ASM_OP_R_DEREF_ADDV(ptr, off, post_commit_label)           \
 162         "mv     " RSEQ_ASM_TMP_REG_1 ", %[" __rseq_str(ptr) "]\n"       \
 163         RSEQ_ASM_OP_R_ADD(off)                                          \
 164         REG_L     RSEQ_ASM_TMP_REG_1 ", 0(" RSEQ_ASM_TMP_REG_1 ")\n"    \
 165         RSEQ_ASM_OP_R_ADD(inc)                                          \
 166         __rseq_str(post_commit_label) ":\n"
 167
 168 /* Per-cpu-id indexing. */
 169
 170 #define RSEQ_TEMPLATE_CPU_ID
 171 #define RSEQ_TEMPLATE_MO_RELAXED
 172 #include "rseq-riscv-bits.h"
 173 #undef RSEQ_TEMPLATE_MO_RELAXED
 174
 175 #define RSEQ_TEMPLATE_MO_RELEASE
 176 #include "rseq-riscv-bits.h"
 177 #undef RSEQ_TEMPLATE_MO_RELEASE
 178 #undef RSEQ_TEMPLATE_CPU_ID
 179
 180 /* Per-mm-cid indexing. */
 181
 182 #define RSEQ_TEMPLATE_MM_CID
 183 #define RSEQ_TEMPLATE_MO_RELAXED
 184 #include "rseq-riscv-bits.h"
 185 #undef RSEQ_TEMPLATE_MO_RELAXED
 186
 187 #define RSEQ_TEMPLATE_MO_RELEASE
 188 #include "rseq-riscv-bits.h"
 189 #undef RSEQ_TEMPLATE_MO_RELEASE
 190 #undef RSEQ_TEMPLATE_MM_CID
 191
 192 /* APIs which are not based on cpu ids. */
 193
 194 #define RSEQ_TEMPLATE_CPU_ID_NONE
 195 #define RSEQ_TEMPLATE_MO_RELAXED
 196 #include "rseq-riscv-bits.h"
 197 #undef RSEQ_TEMPLATE_MO_RELAXED
 198 #undef RSEQ_TEMPLATE_CPU_ID_NONE