410 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2011 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>4 *5 * Selftests for breakpoints (and more generally the do_debug() path) in x86.6 */7 8 9#include <sys/ptrace.h>10#include <unistd.h>11#include <stddef.h>12#include <sys/user.h>13#include <stdio.h>14#include <stdlib.h>15#include <signal.h>16#include <sys/types.h>17#include <sys/wait.h>18#include <errno.h>19#include <string.h>20 21#include "../kselftest.h"22 23#define COUNT_ISN_BPS 424#define COUNT_WPS 425 26/* Breakpoint access modes */27enum {28 BP_X = 1,29 BP_RW = 2,30 BP_W = 4,31};32 33static pid_t child_pid;34 35/*36 * Ensures the child and parent are always "talking" about37 * the same test sequence. (ie: that we haven't forgotten38 * to call check_trapped() somewhere).39 */40static int nr_tests;41 42static void set_breakpoint_addr(void *addr, int n)43{44 int ret;45 46 ret = ptrace(PTRACE_POKEUSER, child_pid,47 offsetof(struct user, u_debugreg[n]), addr);48 if (ret)49 ksft_exit_fail_msg("Can't set breakpoint addr: %s\n",50 strerror(errno));51}52 53static void toggle_breakpoint(int n, int type, int len,54 int local, int global, int set)55{56 int ret;57 58 int xtype, xlen;59 unsigned long vdr7, dr7;60 61 switch (type) {62 case BP_X:63 xtype = 0;64 break;65 case BP_W:66 xtype = 1;67 break;68 case BP_RW:69 xtype = 3;70 break;71 }72 73 switch (len) {74 case 1:75 xlen = 0;76 break;77 case 2:78 xlen = 4;79 break;80 case 4:81 xlen = 0xc;82 break;83 case 8:84 xlen = 8;85 break;86 }87 88 dr7 = ptrace(PTRACE_PEEKUSER, child_pid,89 offsetof(struct user, u_debugreg[7]), 0);90 91 vdr7 = (xlen | xtype) << 16;92 vdr7 <<= 4 * n;93 94 if (local) {95 vdr7 |= 1 << (2 * n);96 vdr7 |= 1 << 8;97 }98 if (global) {99 vdr7 |= 2 << (2 * n);100 vdr7 |= 1 << 9;101 }102 103 if (set)104 dr7 |= vdr7;105 else106 dr7 &= ~vdr7;107 108 ret = ptrace(PTRACE_POKEUSER, child_pid,109 offsetof(struct user, u_debugreg[7]), dr7);110 if (ret) {111 ksft_print_msg("Can't set dr7: %s\n", strerror(errno));112 exit(-1);113 }114}115 116/* Dummy variables to test read/write accesses */117static unsigned long long dummy_var[4];118 119/* Dummy functions to test execution accesses */120static void dummy_func(void) { }121static void dummy_func1(void) { }122static void dummy_func2(void) { }123static void dummy_func3(void) { }124 125static void (*dummy_funcs[])(void) = {126 dummy_func,127 dummy_func1,128 dummy_func2,129 dummy_func3,130};131 132static int trapped;133 134static void check_trapped(void)135{136 /*137 * If we haven't trapped, wake up the parent138 * so that it notices the failure.139 */140 if (!trapped)141 kill(getpid(), SIGUSR1);142 trapped = 0;143 144 nr_tests++;145}146 147static void write_var(int len)148{149 char *pcval; short *psval; int *pival; long long *plval;150 int i;151 152 for (i = 0; i < 4; i++) {153 switch (len) {154 case 1:155 pcval = (char *)&dummy_var[i];156 *pcval = 0xff;157 break;158 case 2:159 psval = (short *)&dummy_var[i];160 *psval = 0xffff;161 break;162 case 4:163 pival = (int *)&dummy_var[i];164 *pival = 0xffffffff;165 break;166 case 8:167 plval = (long long *)&dummy_var[i];168 *plval = 0xffffffffffffffffLL;169 break;170 }171 check_trapped();172 }173}174 175static void read_var(int len)176{177 char cval; short sval; int ival; long long lval;178 int i;179 180 for (i = 0; i < 4; i++) {181 switch (len) {182 case 1:183 cval = *(char *)&dummy_var[i];184 break;185 case 2:186 sval = *(short *)&dummy_var[i];187 break;188 case 4:189 ival = *(int *)&dummy_var[i];190 break;191 case 8:192 lval = *(long long *)&dummy_var[i];193 break;194 }195 check_trapped();196 }197}198 199/*200 * Do the r/w/x accesses to trigger the breakpoints. And run201 * the usual traps.202 */203static void trigger_tests(void)204{205 int len, local, global, i;206 char val;207 int ret;208 209 ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);210 if (ret) {211 ksft_print_msg("Can't be traced? %s\n", strerror(errno));212 return;213 }214 215 /* Wake up father so that it sets up the first test */216 kill(getpid(), SIGUSR1);217 218 /* Test instruction breakpoints */219 for (local = 0; local < 2; local++) {220 for (global = 0; global < 2; global++) {221 if (!local && !global)222 continue;223 224 for (i = 0; i < COUNT_ISN_BPS; i++) {225 dummy_funcs[i]();226 check_trapped();227 }228 }229 }230 231 /* Test write watchpoints */232 for (len = 1; len <= sizeof(long); len <<= 1) {233 for (local = 0; local < 2; local++) {234 for (global = 0; global < 2; global++) {235 if (!local && !global)236 continue;237 write_var(len);238 }239 }240 }241 242 /* Test read/write watchpoints (on read accesses) */243 for (len = 1; len <= sizeof(long); len <<= 1) {244 for (local = 0; local < 2; local++) {245 for (global = 0; global < 2; global++) {246 if (!local && !global)247 continue;248 read_var(len);249 }250 }251 }252 253 /* Icebp trap */254 asm(".byte 0xf1\n");255 check_trapped();256 257 /* Int 3 trap */258 asm("int $3\n");259 check_trapped();260 261 kill(getpid(), SIGUSR1);262}263 264static void check_success(const char *msg)265{266 int child_nr_tests;267 int status;268 int ret;269 270 /* Wait for the child to SIGTRAP */271 wait(&status);272 273 ret = 0;274 275 if (WSTOPSIG(status) == SIGTRAP) {276 child_nr_tests = ptrace(PTRACE_PEEKDATA, child_pid,277 &nr_tests, 0);278 if (child_nr_tests == nr_tests)279 ret = 1;280 if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1))281 ksft_exit_fail_msg("Can't poke: %s\n", strerror(errno));282 }283 284 nr_tests++;285 286 if (ret)287 ksft_test_result_pass("%s", msg);288 else289 ksft_test_result_fail("%s", msg);290}291 292static void launch_instruction_breakpoints(char *buf, int local, int global)293{294 int i;295 296 for (i = 0; i < COUNT_ISN_BPS; i++) {297 set_breakpoint_addr(dummy_funcs[i], i);298 toggle_breakpoint(i, BP_X, 1, local, global, 1);299 ptrace(PTRACE_CONT, child_pid, NULL, 0);300 sprintf(buf, "Test breakpoint %d with local: %d global: %d\n",301 i, local, global);302 check_success(buf);303 toggle_breakpoint(i, BP_X, 1, local, global, 0);304 }305}306 307static void launch_watchpoints(char *buf, int mode, int len,308 int local, int global)309{310 const char *mode_str;311 int i;312 313 if (mode == BP_W)314 mode_str = "write";315 else316 mode_str = "read";317 318 for (i = 0; i < COUNT_WPS; i++) {319 set_breakpoint_addr(&dummy_var[i], i);320 toggle_breakpoint(i, mode, len, local, global, 1);321 ptrace(PTRACE_CONT, child_pid, NULL, 0);322 sprintf(buf,323 "Test %s watchpoint %d with len: %d local: %d global: %d\n",324 mode_str, i, len, local, global);325 check_success(buf);326 toggle_breakpoint(i, mode, len, local, global, 0);327 }328}329 330/* Set the breakpoints and check the child successfully trigger them */331static void launch_tests(void)332{333 char buf[1024];334 unsigned int tests = 0;335 int len, local, global, i;336 337 tests += 3 * COUNT_ISN_BPS;338 tests += sizeof(long) / 2 * 3 * COUNT_WPS;339 tests += sizeof(long) / 2 * 3 * COUNT_WPS;340 tests += 2;341 ksft_set_plan(tests);342 343 /* Instruction breakpoints */344 for (local = 0; local < 2; local++) {345 for (global = 0; global < 2; global++) {346 if (!local && !global)347 continue;348 launch_instruction_breakpoints(buf, local, global);349 }350 }351 352 /* Write watchpoint */353 for (len = 1; len <= sizeof(long); len <<= 1) {354 for (local = 0; local < 2; local++) {355 for (global = 0; global < 2; global++) {356 if (!local && !global)357 continue;358 launch_watchpoints(buf, BP_W, len,359 local, global);360 }361 }362 }363 364 /* Read-Write watchpoint */365 for (len = 1; len <= sizeof(long); len <<= 1) {366 for (local = 0; local < 2; local++) {367 for (global = 0; global < 2; global++) {368 if (!local && !global)369 continue;370 launch_watchpoints(buf, BP_RW, len,371 local, global);372 }373 }374 }375 376 /* Icebp traps */377 ptrace(PTRACE_CONT, child_pid, NULL, 0);378 check_success("Test icebp\n");379 380 /* Int 3 traps */381 ptrace(PTRACE_CONT, child_pid, NULL, 0);382 check_success("Test int 3 trap\n");383 384 ptrace(PTRACE_CONT, child_pid, NULL, 0);385}386 387int main(int argc, char **argv)388{389 pid_t pid;390 int ret;391 392 ksft_print_header();393 394 pid = fork();395 if (!pid) {396 trigger_tests();397 exit(0);398 }399 400 child_pid = pid;401 402 wait(NULL);403 404 launch_tests();405 406 wait(NULL);407 408 ksft_exit_pass();409}410