root/tools/perf/arch/x86/util/perf_regs.c

DEFINITIONS

1. sdt_init_op_regex
2. sdt_rename_register
3. arch_sdt_arg_parse_op
4. arch__intr_reg_mask

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <string.h>
   4 #include <regex.h>
   5 #include <linux/kernel.h>
   6 #include <linux/zalloc.h>
   7 
   8 #include "../../perf-sys.h"
   9 #include "../../util/perf_regs.h"
  10 #include "../../util/debug.h"
  11 #include "../../util/event.h"
  12 
  13 const struct sample_reg sample_reg_masks[] = {
  14         SMPL_REG(AX, PERF_REG_X86_AX),
  15         SMPL_REG(BX, PERF_REG_X86_BX),
  16         SMPL_REG(CX, PERF_REG_X86_CX),
  17         SMPL_REG(DX, PERF_REG_X86_DX),
  18         SMPL_REG(SI, PERF_REG_X86_SI),
  19         SMPL_REG(DI, PERF_REG_X86_DI),
  20         SMPL_REG(BP, PERF_REG_X86_BP),
  21         SMPL_REG(SP, PERF_REG_X86_SP),
  22         SMPL_REG(IP, PERF_REG_X86_IP),
  23         SMPL_REG(FLAGS, PERF_REG_X86_FLAGS),
  24         SMPL_REG(CS, PERF_REG_X86_CS),
  25         SMPL_REG(SS, PERF_REG_X86_SS),
  26 #ifdef HAVE_ARCH_X86_64_SUPPORT
  27         SMPL_REG(R8, PERF_REG_X86_R8),
  28         SMPL_REG(R9, PERF_REG_X86_R9),
  29         SMPL_REG(R10, PERF_REG_X86_R10),
  30         SMPL_REG(R11, PERF_REG_X86_R11),
  31         SMPL_REG(R12, PERF_REG_X86_R12),
  32         SMPL_REG(R13, PERF_REG_X86_R13),
  33         SMPL_REG(R14, PERF_REG_X86_R14),
  34         SMPL_REG(R15, PERF_REG_X86_R15),
  35 #endif
  36         SMPL_REG2(XMM0, PERF_REG_X86_XMM0),
  37         SMPL_REG2(XMM1, PERF_REG_X86_XMM1),
  38         SMPL_REG2(XMM2, PERF_REG_X86_XMM2),
  39         SMPL_REG2(XMM3, PERF_REG_X86_XMM3),
  40         SMPL_REG2(XMM4, PERF_REG_X86_XMM4),
  41         SMPL_REG2(XMM5, PERF_REG_X86_XMM5),
  42         SMPL_REG2(XMM6, PERF_REG_X86_XMM6),
  43         SMPL_REG2(XMM7, PERF_REG_X86_XMM7),
  44         SMPL_REG2(XMM8, PERF_REG_X86_XMM8),
  45         SMPL_REG2(XMM9, PERF_REG_X86_XMM9),
  46         SMPL_REG2(XMM10, PERF_REG_X86_XMM10),
  47         SMPL_REG2(XMM11, PERF_REG_X86_XMM11),
  48         SMPL_REG2(XMM12, PERF_REG_X86_XMM12),
  49         SMPL_REG2(XMM13, PERF_REG_X86_XMM13),
  50         SMPL_REG2(XMM14, PERF_REG_X86_XMM14),
  51         SMPL_REG2(XMM15, PERF_REG_X86_XMM15),
  52         SMPL_REG_END
  53 };
  54 
  55 struct sdt_name_reg {
  56         const char *sdt_name;
  57         const char *uprobe_name;
  58 };
  59 #define SDT_NAME_REG(n, m) {.sdt_name = "%" #n, .uprobe_name = "%" #m}
  60 #define SDT_NAME_REG_END {.sdt_name = NULL, .uprobe_name = NULL}
  61 
  62 static const struct sdt_name_reg sdt_reg_tbl[] = {
  63         SDT_NAME_REG(eax, ax),
  64         SDT_NAME_REG(rax, ax),
  65         SDT_NAME_REG(al,  ax),
  66         SDT_NAME_REG(ah,  ax),
  67         SDT_NAME_REG(ebx, bx),
  68         SDT_NAME_REG(rbx, bx),
  69         SDT_NAME_REG(bl,  bx),
  70         SDT_NAME_REG(bh,  bx),
  71         SDT_NAME_REG(ecx, cx),
  72         SDT_NAME_REG(rcx, cx),
  73         SDT_NAME_REG(cl,  cx),
  74         SDT_NAME_REG(ch,  cx),
  75         SDT_NAME_REG(edx, dx),
  76         SDT_NAME_REG(rdx, dx),
  77         SDT_NAME_REG(dl,  dx),
  78         SDT_NAME_REG(dh,  dx),
  79         SDT_NAME_REG(esi, si),
  80         SDT_NAME_REG(rsi, si),
  81         SDT_NAME_REG(sil, si),
  82         SDT_NAME_REG(edi, di),
  83         SDT_NAME_REG(rdi, di),
  84         SDT_NAME_REG(dil, di),
  85         SDT_NAME_REG(ebp, bp),
  86         SDT_NAME_REG(rbp, bp),
  87         SDT_NAME_REG(bpl, bp),
  88         SDT_NAME_REG(rsp, sp),
  89         SDT_NAME_REG(esp, sp),
  90         SDT_NAME_REG(spl, sp),
  91 
  92         /* rNN registers */
  93         SDT_NAME_REG(r8b,  r8),
  94         SDT_NAME_REG(r8w,  r8),
  95         SDT_NAME_REG(r8d,  r8),
  96         SDT_NAME_REG(r9b,  r9),
  97         SDT_NAME_REG(r9w,  r9),
  98         SDT_NAME_REG(r9d,  r9),
  99         SDT_NAME_REG(r10b, r10),
 100         SDT_NAME_REG(r10w, r10),
 101         SDT_NAME_REG(r10d, r10),
 102         SDT_NAME_REG(r11b, r11),
 103         SDT_NAME_REG(r11w, r11),
 104         SDT_NAME_REG(r11d, r11),
 105         SDT_NAME_REG(r12b, r12),
 106         SDT_NAME_REG(r12w, r12),
 107         SDT_NAME_REG(r12d, r12),
 108         SDT_NAME_REG(r13b, r13),
 109         SDT_NAME_REG(r13w, r13),
 110         SDT_NAME_REG(r13d, r13),
 111         SDT_NAME_REG(r14b, r14),
 112         SDT_NAME_REG(r14w, r14),
 113         SDT_NAME_REG(r14d, r14),
 114         SDT_NAME_REG(r15b, r15),
 115         SDT_NAME_REG(r15w, r15),
 116         SDT_NAME_REG(r15d, r15),
 117         SDT_NAME_REG_END,
 118 };
 119 
 120 /*
 121  * Perf only supports OP which is in  +/-NUM(REG)  form.
 122  * Here plus-minus sign, NUM and parenthesis are optional,
 123  * only REG is mandatory.
 124  *
 125  * SDT events also supports indirect addressing mode with a
 126  * symbol as offset, scaled mode and constants in OP. But
 127  * perf does not support them yet. Below are few examples.
 128  *
 129  * OP with scaled mode:
 130  *     (%rax,%rsi,8)
 131  *     10(%ras,%rsi,8)
 132  *
 133  * OP with indirect addressing mode:
 134  *     check_action(%rip)
 135  *     mp_+52(%rip)
 136  *     44+mp_(%rip)
 137  *
 138  * OP with constant values:
 139  *     $0
 140  *     $123
 141  *     $-1
 142  */
 143 #define SDT_OP_REGEX  "^([+\\-]?)([0-9]*)(\\(?)(%[a-z][a-z0-9]+)(\\)?)$"
 144 
 145 static regex_t sdt_op_regex;
 146 
 147 static int sdt_init_op_regex(void)
 148 {
 149         static int initialized;
 150         int ret = 0;
 151 
 152         if (initialized)
 153                 return 0;
 154 
 155         ret = regcomp(&sdt_op_regex, SDT_OP_REGEX, REG_EXTENDED);
 156         if (ret < 0) {
 157                 pr_debug4("Regex compilation error.\n");
 158                 return ret;
 159         }
 160 
 161         initialized = 1;
 162         return 0;
 163 }
 164 
 165 /*
 166  * Max x86 register name length is 5(ex: %r15d). So, 6th char
 167  * should always contain NULL. This helps to find register name
 168  * length using strlen, insted of maintaing one more variable.
 169  */
 170 #define SDT_REG_NAME_SIZE  6
 171 
 172 /*
 173  * The uprobe parser does not support all gas register names;
 174  * so, we have to replace them (ex. for x86_64: %rax -> %ax).
 175  * Note: If register does not require renaming, just copy
 176  * paste as it is, but don't leave it empty.
 177  */
 178 static void sdt_rename_register(char *sdt_reg, int sdt_len, char *uprobe_reg)
 179 {
 180         int i = 0;
 181 
 182         for (i = 0; sdt_reg_tbl[i].sdt_name != NULL; i++) {
 183                 if (!strncmp(sdt_reg_tbl[i].sdt_name, sdt_reg, sdt_len)) {
 184                         strcpy(uprobe_reg, sdt_reg_tbl[i].uprobe_name);
 185                         return;
 186                 }
 187         }
 188 
 189         strncpy(uprobe_reg, sdt_reg, sdt_len);
 190 }
 191 
 192 int arch_sdt_arg_parse_op(char *old_op, char **new_op)
 193 {
 194         char new_reg[SDT_REG_NAME_SIZE] = {0};
 195         int new_len = 0, ret;
 196         /*
 197          * rm[0]:  +/-NUM(REG)
 198          * rm[1]:  +/-
 199          * rm[2]:  NUM
 200          * rm[3]:  (
 201          * rm[4]:  REG
 202          * rm[5]:  )
 203          */
 204         regmatch_t rm[6];
 205         /*
 206          * Max prefix length is 2 as it may contains sign(+/-)
 207          * and displacement 0 (Both sign and displacement 0 are
 208          * optional so it may be empty). Use one more character
 209          * to hold last NULL so that strlen can be used to find
 210          * prefix length, instead of maintaing one more variable.
 211          */
 212         char prefix[3] = {0};
 213 
 214         ret = sdt_init_op_regex();
 215         if (ret < 0)
 216                 return ret;
 217 
 218         /*
 219          * If unsupported OR does not match with regex OR
 220          * register name too long, skip it.
 221          */
 222         if (strchr(old_op, ',') || strchr(old_op, '$') ||
 223             regexec(&sdt_op_regex, old_op, 6, rm, 0)   ||
 224             rm[4].rm_eo - rm[4].rm_so > SDT_REG_NAME_SIZE) {
 225                 pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);
 226                 return SDT_ARG_SKIP;
 227         }
 228 
 229         /*
 230          * Prepare prefix.
 231          * If SDT OP has parenthesis but does not provide
 232          * displacement, add 0 for displacement.
 233          *     SDT         Uprobe     Prefix
 234          *     -----------------------------
 235          *     +24(%rdi)   +24(%di)   +
 236          *     24(%rdi)    +24(%di)   +
 237          *     %rdi        %di
 238          *     (%rdi)      +0(%di)    +0
 239          *     -80(%rbx)   -80(%bx)   -
 240          */
 241         if (rm[3].rm_so != rm[3].rm_eo) {
 242                 if (rm[1].rm_so != rm[1].rm_eo)
 243                         prefix[0] = *(old_op + rm[1].rm_so);
 244                 else if (rm[2].rm_so != rm[2].rm_eo)
 245                         prefix[0] = '+';
 246                 else
 247                         scnprintf(prefix, sizeof(prefix), "+0");
 248         }
 249 
 250         /* Rename register */
 251         sdt_rename_register(old_op + rm[4].rm_so, rm[4].rm_eo - rm[4].rm_so,
 252                             new_reg);
 253 
 254         /* Prepare final OP which should be valid for uprobe_events */
 255         new_len = strlen(prefix)              +
 256                   (rm[2].rm_eo - rm[2].rm_so) +
 257                   (rm[3].rm_eo - rm[3].rm_so) +
 258                   strlen(new_reg)             +
 259                   (rm[5].rm_eo - rm[5].rm_so) +
 260                   1;                                    /* NULL */
 261 
 262         *new_op = zalloc(new_len);
 263         if (!*new_op)
 264                 return -ENOMEM;
 265 
 266         scnprintf(*new_op, new_len, "%.*s%.*s%.*s%.*s%.*s",
 267                   strlen(prefix), prefix,
 268                   (int)(rm[2].rm_eo - rm[2].rm_so), old_op + rm[2].rm_so,
 269                   (int)(rm[3].rm_eo - rm[3].rm_so), old_op + rm[3].rm_so,
 270                   strlen(new_reg), new_reg,
 271                   (int)(rm[5].rm_eo - rm[5].rm_so), old_op + rm[5].rm_so);
 272 
 273         return SDT_ARG_VALID;
 274 }
 275 
 276 uint64_t arch__intr_reg_mask(void)
 277 {
 278         struct perf_event_attr attr = {
 279                 .type                   = PERF_TYPE_HARDWARE,
 280                 .config                 = PERF_COUNT_HW_CPU_CYCLES,
 281                 .sample_type            = PERF_SAMPLE_REGS_INTR,
 282                 .sample_regs_intr       = PERF_REG_EXTENDED_MASK,
 283                 .precise_ip             = 1,
 284                 .disabled               = 1,
 285                 .exclude_kernel         = 1,
 286         };
 287         int fd;
 288         /*
 289          * In an unnamed union, init it here to build on older gcc versions
 290          */
 291         attr.sample_period = 1;
 292 
 293         event_attr_init(&attr);
 294 
 295         fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
 296         if (fd != -1) {
 297                 close(fd);
 298                 return (PERF_REG_EXTENDED_MASK | PERF_REGS_MASK);
 299         }
 300 
 301         return PERF_REGS_MASK;
 302 }