selftests: new x86 breakpoints selftest
Bring a first selftest in the relevant directory. This tests several combinations of breakpoints and watchpoints in x86, as well as icebp traps and int3 traps. Given the amount of breakpoint regressions we raised after we merged the generic breakpoint infrastructure, such selftest became necessary and can still serve today as a basis for new patches that touch the do_debug() path. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Frederic Weisbecker
Linus Torvalds
parent
274343ad3e
commit
85bbddc37b
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@ -1,4 +1,4 @@
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TARGETS =
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TARGETS = breakpoints
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all:
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for TARGET in $(TARGETS); do \
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@ -0,0 +1,20 @@
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# Taken from perf makefile
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uname_M := $(shell uname -m 2>/dev/null || echo not)
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ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/)
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ifeq ($(ARCH),i386)
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ARCH := x86
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endif
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ifeq ($(ARCH),x86_64)
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ARCH := x86
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endif
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all:
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ifeq ($(ARCH),x86)
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gcc breakpoint_test.c -o run_test
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else
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echo "Not an x86 target, can't build breakpoints selftests"
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endif
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clean:
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rm -fr run_test
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@ -0,0 +1,394 @@
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/*
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* Copyright (C) 2011 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>
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*
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* Licensed under the terms of the GNU GPL License version 2
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*
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* Selftests for breakpoints (and more generally the do_debug() path) in x86.
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*/
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#include <sys/ptrace.h>
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#include <unistd.h>
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#include <stddef.h>
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#include <sys/user.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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/* Breakpoint access modes */
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enum {
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BP_X = 1,
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BP_RW = 2,
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BP_W = 4,
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};
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static pid_t child_pid;
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/*
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* Ensures the child and parent are always "talking" about
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* the same test sequence. (ie: that we haven't forgotten
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* to call check_trapped() somewhere).
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*/
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static int nr_tests;
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static void set_breakpoint_addr(void *addr, int n)
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{
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int ret;
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ret = ptrace(PTRACE_POKEUSER, child_pid,
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offsetof(struct user, u_debugreg[n]), addr);
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if (ret) {
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perror("Can't set breakpoint addr\n");
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exit(-1);
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}
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}
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static void toggle_breakpoint(int n, int type, int len,
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int local, int global, int set)
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{
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int ret;
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int xtype, xlen;
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unsigned long vdr7, dr7;
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switch (type) {
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case BP_X:
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xtype = 0;
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break;
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case BP_W:
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xtype = 1;
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break;
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case BP_RW:
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xtype = 3;
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break;
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}
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switch (len) {
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case 1:
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xlen = 0;
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break;
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case 2:
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xlen = 4;
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break;
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case 4:
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xlen = 0xc;
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break;
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case 8:
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xlen = 8;
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break;
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}
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dr7 = ptrace(PTRACE_PEEKUSER, child_pid,
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offsetof(struct user, u_debugreg[7]), 0);
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vdr7 = (xlen | xtype) << 16;
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vdr7 <<= 4 * n;
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if (local) {
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vdr7 |= 1 << (2 * n);
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vdr7 |= 1 << 8;
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}
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if (global) {
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vdr7 |= 2 << (2 * n);
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vdr7 |= 1 << 9;
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}
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if (set)
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dr7 |= vdr7;
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else
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dr7 &= ~vdr7;
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ret = ptrace(PTRACE_POKEUSER, child_pid,
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offsetof(struct user, u_debugreg[7]), dr7);
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if (ret) {
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perror("Can't set dr7");
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exit(-1);
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}
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}
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/* Dummy variables to test read/write accesses */
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static unsigned long long dummy_var[4];
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/* Dummy functions to test execution accesses */
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static void dummy_func(void) { }
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static void dummy_func1(void) { }
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static void dummy_func2(void) { }
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static void dummy_func3(void) { }
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static void (*dummy_funcs[])(void) = {
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dummy_func,
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dummy_func1,
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dummy_func2,
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dummy_func3,
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};
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static int trapped;
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static void check_trapped(void)
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{
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/*
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* If we haven't trapped, wake up the parent
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* so that it notices the failure.
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*/
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if (!trapped)
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kill(getpid(), SIGUSR1);
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trapped = 0;
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nr_tests++;
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}
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static void write_var(int len)
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{
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char *pcval; short *psval; int *pival; long long *plval;
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int i;
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for (i = 0; i < 4; i++) {
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switch (len) {
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case 1:
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pcval = (char *)&dummy_var[i];
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*pcval = 0xff;
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break;
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case 2:
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psval = (short *)&dummy_var[i];
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*psval = 0xffff;
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break;
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case 4:
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pival = (int *)&dummy_var[i];
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*pival = 0xffffffff;
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break;
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case 8:
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plval = (long long *)&dummy_var[i];
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*plval = 0xffffffffffffffffLL;
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break;
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}
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check_trapped();
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}
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}
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static void read_var(int len)
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{
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char cval; short sval; int ival; long long lval;
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int i;
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for (i = 0; i < 4; i++) {
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switch (len) {
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case 1:
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cval = *(char *)&dummy_var[i];
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break;
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case 2:
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sval = *(short *)&dummy_var[i];
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break;
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case 4:
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ival = *(int *)&dummy_var[i];
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break;
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case 8:
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lval = *(long long *)&dummy_var[i];
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break;
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}
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check_trapped();
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}
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}
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/*
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* Do the r/w/x accesses to trigger the breakpoints. And run
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* the usual traps.
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*/
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static void trigger_tests(void)
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{
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int len, local, global, i;
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char val;
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int ret;
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ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);
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if (ret) {
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perror("Can't be traced?\n");
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return;
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}
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/* Wake up father so that it sets up the first test */
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kill(getpid(), SIGUSR1);
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/* Test instruction breakpoints */
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for (local = 0; local < 2; local++) {
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for (global = 0; global < 2; global++) {
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if (!local && !global)
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continue;
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for (i = 0; i < 4; i++) {
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dummy_funcs[i]();
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check_trapped();
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}
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}
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}
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/* Test write watchpoints */
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for (len = 1; len <= sizeof(long); len <<= 1) {
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for (local = 0; local < 2; local++) {
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for (global = 0; global < 2; global++) {
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if (!local && !global)
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continue;
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write_var(len);
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}
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}
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}
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/* Test read/write watchpoints (on read accesses) */
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for (len = 1; len <= sizeof(long); len <<= 1) {
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for (local = 0; local < 2; local++) {
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for (global = 0; global < 2; global++) {
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if (!local && !global)
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continue;
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read_var(len);
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}
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}
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}
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/* Icebp trap */
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asm(".byte 0xf1\n");
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check_trapped();
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/* Int 3 trap */
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asm("int $3\n");
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check_trapped();
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kill(getpid(), SIGUSR1);
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}
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static void check_success(const char *msg)
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{
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const char *msg2;
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int child_nr_tests;
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int status;
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/* Wait for the child to SIGTRAP */
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wait(&status);
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msg2 = "Failed";
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if (WSTOPSIG(status) == SIGTRAP) {
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child_nr_tests = ptrace(PTRACE_PEEKDATA, child_pid,
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&nr_tests, 0);
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if (child_nr_tests == nr_tests)
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msg2 = "Ok";
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if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1)) {
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perror("Can't poke\n");
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exit(-1);
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}
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}
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nr_tests++;
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printf("%s [%s]\n", msg, msg2);
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}
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static void launch_instruction_breakpoints(char *buf, int local, int global)
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{
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int i;
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for (i = 0; i < 4; i++) {
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set_breakpoint_addr(dummy_funcs[i], i);
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toggle_breakpoint(i, BP_X, 1, local, global, 1);
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ptrace(PTRACE_CONT, child_pid, NULL, 0);
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sprintf(buf, "Test breakpoint %d with local: %d global: %d",
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i, local, global);
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check_success(buf);
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toggle_breakpoint(i, BP_X, 1, local, global, 0);
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}
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}
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static void launch_watchpoints(char *buf, int mode, int len,
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int local, int global)
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{
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const char *mode_str;
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int i;
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if (mode == BP_W)
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mode_str = "write";
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else
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mode_str = "read";
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for (i = 0; i < 4; i++) {
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set_breakpoint_addr(&dummy_var[i], i);
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toggle_breakpoint(i, mode, len, local, global, 1);
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ptrace(PTRACE_CONT, child_pid, NULL, 0);
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sprintf(buf, "Test %s watchpoint %d with len: %d local: "
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"%d global: %d", mode_str, i, len, local, global);
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check_success(buf);
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toggle_breakpoint(i, mode, len, local, global, 0);
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}
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}
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/* Set the breakpoints and check the child successfully trigger them */
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static void launch_tests(void)
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{
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char buf[1024];
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int len, local, global, i;
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/* Instruction breakpoints */
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for (local = 0; local < 2; local++) {
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for (global = 0; global < 2; global++) {
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if (!local && !global)
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continue;
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launch_instruction_breakpoints(buf, local, global);
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}
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}
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/* Write watchpoint */
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for (len = 1; len <= sizeof(long); len <<= 1) {
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for (local = 0; local < 2; local++) {
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for (global = 0; global < 2; global++) {
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if (!local && !global)
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continue;
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launch_watchpoints(buf, BP_W, len,
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local, global);
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}
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}
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}
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/* Read-Write watchpoint */
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for (len = 1; len <= sizeof(long); len <<= 1) {
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for (local = 0; local < 2; local++) {
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for (global = 0; global < 2; global++) {
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if (!local && !global)
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continue;
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launch_watchpoints(buf, BP_RW, len,
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local, global);
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}
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}
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}
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/* Icebp traps */
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ptrace(PTRACE_CONT, child_pid, NULL, 0);
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check_success("Test icebp");
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/* Int 3 traps */
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ptrace(PTRACE_CONT, child_pid, NULL, 0);
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check_success("Test int 3 trap");
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ptrace(PTRACE_CONT, child_pid, NULL, 0);
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}
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int main(int argc, char **argv)
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{
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pid_t pid;
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int ret;
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pid = fork();
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if (!pid) {
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trigger_tests();
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return 0;
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}
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child_pid = pid;
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wait(NULL);
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launch_tests();
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wait(NULL);
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return 0;
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}
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@ -1,6 +1,6 @@
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#!/bin/bash
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TARGETS=
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TARGETS=breakpoints
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for TARGET in $TARGETS
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do
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