cregit-Linux how code gets into the kernel

Release 4.14 tools/perf/arch/x86/util/perf_regs.c

// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <string.h>
#include <regex.h>

#include "../../perf.h"
#include "../../util/util.h"
#include "../../util/perf_regs.h"
#include "../../util/debug.h"


const struct sample_reg sample_reg_masks[] = {
	SMPL_REG(AX, PERF_REG_X86_AX),
	SMPL_REG(BX, PERF_REG_X86_BX),
	SMPL_REG(CX, PERF_REG_X86_CX),
	SMPL_REG(DX, PERF_REG_X86_DX),
	SMPL_REG(SI, PERF_REG_X86_SI),
	SMPL_REG(DI, PERF_REG_X86_DI),
	SMPL_REG(BP, PERF_REG_X86_BP),
	SMPL_REG(SP, PERF_REG_X86_SP),
	SMPL_REG(IP, PERF_REG_X86_IP),
	SMPL_REG(FLAGS, PERF_REG_X86_FLAGS),
	SMPL_REG(CS, PERF_REG_X86_CS),
	SMPL_REG(SS, PERF_REG_X86_SS),
#ifdef HAVE_ARCH_X86_64_SUPPORT
	SMPL_REG(R8, PERF_REG_X86_R8),
	SMPL_REG(R9, PERF_REG_X86_R9),
	SMPL_REG(R10, PERF_REG_X86_R10),
	SMPL_REG(R11, PERF_REG_X86_R11),
	SMPL_REG(R12, PERF_REG_X86_R12),
	SMPL_REG(R13, PERF_REG_X86_R13),
	SMPL_REG(R14, PERF_REG_X86_R14),
	SMPL_REG(R15, PERF_REG_X86_R15),
#endif
	SMPL_REG_END
};


struct sdt_name_reg {
	
const char *sdt_name;
	
const char *uprobe_name;
};

#define SDT_NAME_REG(n, m) {.sdt_name = "%" #n, .uprobe_name = "%" #m}

#define SDT_NAME_REG_END {.sdt_name = NULL, .uprobe_name = NULL}


static const struct sdt_name_reg sdt_reg_tbl[] = {
	SDT_NAME_REG(eax, ax),
	SDT_NAME_REG(rax, ax),
	SDT_NAME_REG(al,  ax),
	SDT_NAME_REG(ah,  ax),
	SDT_NAME_REG(ebx, bx),
	SDT_NAME_REG(rbx, bx),
	SDT_NAME_REG(bl,  bx),
	SDT_NAME_REG(bh,  bx),
	SDT_NAME_REG(ecx, cx),
	SDT_NAME_REG(rcx, cx),
	SDT_NAME_REG(cl,  cx),
	SDT_NAME_REG(ch,  cx),
	SDT_NAME_REG(edx, dx),
	SDT_NAME_REG(rdx, dx),
	SDT_NAME_REG(dl,  dx),
	SDT_NAME_REG(dh,  dx),
	SDT_NAME_REG(esi, si),
	SDT_NAME_REG(rsi, si),
	SDT_NAME_REG(sil, si),
	SDT_NAME_REG(edi, di),
	SDT_NAME_REG(rdi, di),
	SDT_NAME_REG(dil, di),
	SDT_NAME_REG(ebp, bp),
	SDT_NAME_REG(rbp, bp),
	SDT_NAME_REG(bpl, bp),
	SDT_NAME_REG(rsp, sp),
	SDT_NAME_REG(esp, sp),
	SDT_NAME_REG(spl, sp),

	/* rNN registers */
	SDT_NAME_REG(r8b,  r8),
	SDT_NAME_REG(r8w,  r8),
	SDT_NAME_REG(r8d,  r8),
	SDT_NAME_REG(r9b,  r9),
	SDT_NAME_REG(r9w,  r9),
	SDT_NAME_REG(r9d,  r9),
	SDT_NAME_REG(r10b, r10),
	SDT_NAME_REG(r10w, r10),
	SDT_NAME_REG(r10d, r10),
	SDT_NAME_REG(r11b, r11),
	SDT_NAME_REG(r11w, r11),
	SDT_NAME_REG(r11d, r11),
	SDT_NAME_REG(r12b, r12),
	SDT_NAME_REG(r12w, r12),
	SDT_NAME_REG(r12d, r12),
	SDT_NAME_REG(r13b, r13),
	SDT_NAME_REG(r13w, r13),
	SDT_NAME_REG(r13d, r13),
	SDT_NAME_REG(r14b, r14),
	SDT_NAME_REG(r14w, r14),
	SDT_NAME_REG(r14d, r14),
	SDT_NAME_REG(r15b, r15),
	SDT_NAME_REG(r15w, r15),
	SDT_NAME_REG(r15d, r15),
	SDT_NAME_REG_END,
};

/*
 * Perf only supports OP which is in  +/-NUM(REG)  form.
 * Here plus-minus sign, NUM and parenthesis are optional,
 * only REG is mandatory.
 *
 * SDT events also supports indirect addressing mode with a
 * symbol as offset, scaled mode and constants in OP. But
 * perf does not support them yet. Below are few examples.
 *
 * OP with scaled mode:
 *     (%rax,%rsi,8)
 *     10(%ras,%rsi,8)
 *
 * OP with indirect addressing mode:
 *     check_action(%rip)
 *     mp_+52(%rip)
 *     44+mp_(%rip)
 *
 * OP with constant values:
 *     $0
 *     $123
 *     $-1
 */

#define SDT_OP_REGEX  "^([+\\-]?)([0-9]*)(\\(?)(%[a-z][a-z0-9]+)(\\)?)$"


static regex_t sdt_op_regex;


static int sdt_init_op_regex(void) { static int initialized; int ret = 0; if (initialized) return 0; ret = regcomp(&sdt_op_regex, SDT_OP_REGEX, REG_EXTENDED); if (ret < 0) { pr_debug4("Regex compilation error.\n"); return ret; } initialized = 1; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Ravi Bangoria5898.31%150.00%
Alexis Berlemont11.69%150.00%
Total59100.00%2100.00%

/* * Max x86 register name length is 5(ex: %r15d). So, 6th char * should always contain NULL. This helps to find register name * length using strlen, insted of maintaing one more variable. */ #define SDT_REG_NAME_SIZE 6 /* * The uprobe parser does not support all gas register names; * so, we have to replace them (ex. for x86_64: %rax -> %ax). * Note: If register does not require renaming, just copy * paste as it is, but don't leave it empty. */
static void sdt_rename_register(char *sdt_reg, int sdt_len, char *uprobe_reg) { int i = 0; for (i = 0; sdt_reg_tbl[i].sdt_name != NULL; i++) { if (!strncmp(sdt_reg_tbl[i].sdt_name, sdt_reg, sdt_len)) { strcpy(uprobe_reg, sdt_reg_tbl[i].uprobe_name); return; } } strncpy(uprobe_reg, sdt_reg, sdt_len); }

Contributors

PersonTokensPropCommitsCommitProp
Ravi Bangoria7286.75%150.00%
Alexis Berlemont1113.25%150.00%
Total83100.00%2100.00%


int arch_sdt_arg_parse_op(char *old_op, char **new_op) { char new_reg[SDT_REG_NAME_SIZE] = {0}; int new_len = 0, ret; /* * rm[0]: +/-NUM(REG) * rm[1]: +/- * rm[2]: NUM * rm[3]: ( * rm[4]: REG * rm[5]: ) */ regmatch_t rm[6]; /* * Max prefix length is 2 as it may contains sign(+/-) * and displacement 0 (Both sign and displacement 0 are * optional so it may be empty). Use one more character * to hold last NULL so that strlen can be used to find * prefix length, instead of maintaing one more variable. */ char prefix[3] = {0}; ret = sdt_init_op_regex(); if (ret < 0) return ret; /* * If unsupported OR does not match with regex OR * register name too long, skip it. */ if (strchr(old_op, ',') || strchr(old_op, '$') || regexec(&sdt_op_regex, old_op, 6, rm, 0) || rm[4].rm_eo - rm[4].rm_so > SDT_REG_NAME_SIZE) { pr_debug4("Skipping unsupported SDT argument: %s\n", old_op); return SDT_ARG_SKIP; } /* * Prepare prefix. * If SDT OP has parenthesis but does not provide * displacement, add 0 for displacement. * SDT Uprobe Prefix * ----------------------------- * +24(%rdi) +24(%di) + * 24(%rdi) +24(%di) + * %rdi %di * (%rdi) +0(%di) +0 * -80(%rbx) -80(%bx) - */ if (rm[3].rm_so != rm[3].rm_eo) { if (rm[1].rm_so != rm[1].rm_eo) prefix[0] = *(old_op + rm[1].rm_so); else if (rm[2].rm_so != rm[2].rm_eo) prefix[0] = '+'; else strncpy(prefix, "+0", 2); } /* Rename register */ sdt_rename_register(old_op + rm[4].rm_so, rm[4].rm_eo - rm[4].rm_so, new_reg); /* Prepare final OP which should be valid for uprobe_events */ new_len = strlen(prefix) + (rm[2].rm_eo - rm[2].rm_so) + (rm[3].rm_eo - rm[3].rm_so) + strlen(new_reg) + (rm[5].rm_eo - rm[5].rm_so) + 1; /* NULL */ *new_op = zalloc(new_len); if (!*new_op) return -ENOMEM; scnprintf(*new_op, new_len, "%.*s%.*s%.*s%.*s%.*s", strlen(prefix), prefix, (int)(rm[2].rm_eo - rm[2].rm_so), old_op + rm[2].rm_so, (int)(rm[3].rm_eo - rm[3].rm_so), old_op + rm[3].rm_so, strlen(new_reg), new_reg, (int)(rm[5].rm_eo - rm[5].rm_so), old_op + rm[5].rm_so); return SDT_ARG_VALID; }

Contributors

PersonTokensPropCommitsCommitProp
Ravi Bangoria36284.19%150.00%
Alexis Berlemont6815.81%150.00%
Total430100.00%2100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Ravi Bangoria78166.87%337.50%
Alexis Berlemont22219.01%112.50%
Stéphane Eranian16113.78%225.00%
Arnaldo Carvalho de Melo30.26%112.50%
Greg Kroah-Hartman10.09%112.50%
Total1168100.00%8100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.