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 199