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authorFrederic Weisbecker <fweisbec@gmail.com>2012-01-12 17:20:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:12 -0800
commit85bbddc37b2bf947a577d572b1c4c23bf829217f (patch)
tree07e483b13f93d6e5eb08d4423648a0812b41b3fe /tools
parent274343ad3e63c4dcee6744a75b5553940de4a0f6 (diff)
downloadlinux-linaro-stable-85bbddc37b2bf947a577d572b1c4c23bf829217f.tar.gz
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>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/Makefile2
-rw-r--r--tools/testing/selftests/breakpoints/Makefile20
-rw-r--r--tools/testing/selftests/breakpoints/breakpoint_test.c394
-rw-r--r--tools/testing/selftests/run_tests2
4 files changed, 416 insertions, 2 deletions
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 298a5c0c1ead..4ec84018cc13 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -1,4 +1,4 @@
-TARGETS =
+TARGETS = breakpoints
all:
for TARGET in $(TARGETS); do \
diff --git a/tools/testing/selftests/breakpoints/Makefile b/tools/testing/selftests/breakpoints/Makefile
new file mode 100644
index 000000000000..f362722cdce7
--- /dev/null
+++ b/tools/testing/selftests/breakpoints/Makefile
@@ -0,0 +1,20 @@
+# Taken from perf makefile
+uname_M := $(shell uname -m 2>/dev/null || echo not)
+ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/)
+ifeq ($(ARCH),i386)
+ ARCH := x86
+endif
+ifeq ($(ARCH),x86_64)
+ ARCH := x86
+endif
+
+
+all:
+ifeq ($(ARCH),x86)
+ gcc breakpoint_test.c -o run_test
+else
+ echo "Not an x86 target, can't build breakpoints selftests"
+endif
+
+clean:
+ rm -fr run_test
diff --git a/tools/testing/selftests/breakpoints/breakpoint_test.c b/tools/testing/selftests/breakpoints/breakpoint_test.c
new file mode 100644
index 000000000000..a0743f3b2b57
--- /dev/null
+++ b/tools/testing/selftests/breakpoints/breakpoint_test.c
@@ -0,0 +1,394 @@
+/*
+ * Copyright (C) 2011 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>
+ *
+ * Licensed under the terms of the GNU GPL License version 2
+ *
+ * Selftests for breakpoints (and more generally the do_debug() path) in x86.
+ */
+
+
+#include <sys/ptrace.h>
+#include <unistd.h>
+#include <stddef.h>
+#include <sys/user.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+
+/* Breakpoint access modes */
+enum {
+ BP_X = 1,
+ BP_RW = 2,
+ BP_W = 4,
+};
+
+static pid_t child_pid;
+
+/*
+ * Ensures the child and parent are always "talking" about
+ * the same test sequence. (ie: that we haven't forgotten
+ * to call check_trapped() somewhere).
+ */
+static int nr_tests;
+
+static void set_breakpoint_addr(void *addr, int n)
+{
+ int ret;
+
+ ret = ptrace(PTRACE_POKEUSER, child_pid,
+ offsetof(struct user, u_debugreg[n]), addr);
+ if (ret) {
+ perror("Can't set breakpoint addr\n");
+ exit(-1);
+ }
+}
+
+static void toggle_breakpoint(int n, int type, int len,
+ int local, int global, int set)
+{
+ int ret;
+
+ int xtype, xlen;
+ unsigned long vdr7, dr7;
+
+ switch (type) {
+ case BP_X:
+ xtype = 0;
+ break;
+ case BP_W:
+ xtype = 1;
+ break;
+ case BP_RW:
+ xtype = 3;
+ break;
+ }
+
+ switch (len) {
+ case 1:
+ xlen = 0;
+ break;
+ case 2:
+ xlen = 4;
+ break;
+ case 4:
+ xlen = 0xc;
+ break;
+ case 8:
+ xlen = 8;
+ break;
+ }
+
+ dr7 = ptrace(PTRACE_PEEKUSER, child_pid,
+ offsetof(struct user, u_debugreg[7]), 0);
+
+ vdr7 = (xlen | xtype) << 16;
+ vdr7 <<= 4 * n;
+
+ if (local) {
+ vdr7 |= 1 << (2 * n);
+ vdr7 |= 1 << 8;
+ }
+ if (global) {
+ vdr7 |= 2 << (2 * n);
+ vdr7 |= 1 << 9;
+ }
+
+ if (set)
+ dr7 |= vdr7;
+ else
+ dr7 &= ~vdr7;
+
+ ret = ptrace(PTRACE_POKEUSER, child_pid,
+ offsetof(struct user, u_debugreg[7]), dr7);
+ if (ret) {
+ perror("Can't set dr7");
+ exit(-1);
+ }
+}
+
+/* Dummy variables to test read/write accesses */
+static unsigned long long dummy_var[4];
+
+/* Dummy functions to test execution accesses */
+static void dummy_func(void) { }
+static void dummy_func1(void) { }
+static void dummy_func2(void) { }
+static void dummy_func3(void) { }
+
+static void (*dummy_funcs[])(void) = {
+ dummy_func,
+ dummy_func1,
+ dummy_func2,
+ dummy_func3,
+};
+
+static int trapped;
+
+static void check_trapped(void)
+{
+ /*
+ * If we haven't trapped, wake up the parent
+ * so that it notices the failure.
+ */
+ if (!trapped)
+ kill(getpid(), SIGUSR1);
+ trapped = 0;
+
+ nr_tests++;
+}
+
+static void write_var(int len)
+{
+ char *pcval; short *psval; int *pival; long long *plval;
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ switch (len) {
+ case 1:
+ pcval = (char *)&dummy_var[i];
+ *pcval = 0xff;
+ break;
+ case 2:
+ psval = (short *)&dummy_var[i];
+ *psval = 0xffff;
+ break;
+ case 4:
+ pival = (int *)&dummy_var[i];
+ *pival = 0xffffffff;
+ break;
+ case 8:
+ plval = (long long *)&dummy_var[i];
+ *plval = 0xffffffffffffffffLL;
+ break;
+ }
+ check_trapped();
+ }
+}
+
+static void read_var(int len)
+{
+ char cval; short sval; int ival; long long lval;
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ switch (len) {
+ case 1:
+ cval = *(char *)&dummy_var[i];
+ break;
+ case 2:
+ sval = *(short *)&dummy_var[i];
+ break;
+ case 4:
+ ival = *(int *)&dummy_var[i];
+ break;
+ case 8:
+ lval = *(long long *)&dummy_var[i];
+ break;
+ }
+ check_trapped();
+ }
+}
+
+/*
+ * Do the r/w/x accesses to trigger the breakpoints. And run
+ * the usual traps.
+ */
+static void trigger_tests(void)
+{
+ int len, local, global, i;
+ char val;
+ int ret;
+
+ ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);
+ if (ret) {
+ perror("Can't be traced?\n");
+ return;
+ }
+
+ /* Wake up father so that it sets up the first test */
+ kill(getpid(), SIGUSR1);
+
+ /* Test instruction breakpoints */
+ for (local = 0; local < 2; local++) {
+ for (global = 0; global < 2; global++) {
+ if (!local && !global)
+ continue;
+
+ for (i = 0; i < 4; i++) {
+ dummy_funcs[i]();
+ check_trapped();
+ }
+ }
+ }
+
+ /* Test write watchpoints */
+ for (len = 1; len <= sizeof(long); len <<= 1) {
+ for (local = 0; local < 2; local++) {
+ for (global = 0; global < 2; global++) {
+ if (!local && !global)
+ continue;
+ write_var(len);
+ }
+ }
+ }
+
+ /* Test read/write watchpoints (on read accesses) */
+ for (len = 1; len <= sizeof(long); len <<= 1) {
+ for (local = 0; local < 2; local++) {
+ for (global = 0; global < 2; global++) {
+ if (!local && !global)
+ continue;
+ read_var(len);
+ }
+ }
+ }
+
+ /* Icebp trap */
+ asm(".byte 0xf1\n");
+ check_trapped();
+
+ /* Int 3 trap */
+ asm("int $3\n");
+ check_trapped();
+
+ kill(getpid(), SIGUSR1);
+}
+
+static void check_success(const char *msg)
+{
+ const char *msg2;
+ int child_nr_tests;
+ int status;
+
+ /* Wait for the child to SIGTRAP */
+ wait(&status);
+
+ msg2 = "Failed";
+
+ if (WSTOPSIG(status) == SIGTRAP) {
+ child_nr_tests = ptrace(PTRACE_PEEKDATA, child_pid,
+ &nr_tests, 0);
+ if (child_nr_tests == nr_tests)
+ msg2 = "Ok";
+ if (ptrace(PTRACE_POKEDATA, child_pid, &trapped, 1)) {
+ perror("Can't poke\n");
+ exit(-1);
+ }
+ }
+
+ nr_tests++;
+
+ printf("%s [%s]\n", msg, msg2);
+}
+
+static void launch_instruction_breakpoints(char *buf, int local, int global)
+{
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ set_breakpoint_addr(dummy_funcs[i], i);
+ toggle_breakpoint(i, BP_X, 1, local, global, 1);
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ sprintf(buf, "Test breakpoint %d with local: %d global: %d",
+ i, local, global);
+ check_success(buf);
+ toggle_breakpoint(i, BP_X, 1, local, global, 0);
+ }
+}
+
+static void launch_watchpoints(char *buf, int mode, int len,
+ int local, int global)
+{
+ const char *mode_str;
+ int i;
+
+ if (mode == BP_W)
+ mode_str = "write";
+ else
+ mode_str = "read";
+
+ for (i = 0; i < 4; i++) {
+ set_breakpoint_addr(&dummy_var[i], i);
+ toggle_breakpoint(i, mode, len, local, global, 1);
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ sprintf(buf, "Test %s watchpoint %d with len: %d local: "
+ "%d global: %d", mode_str, i, len, local, global);
+ check_success(buf);
+ toggle_breakpoint(i, mode, len, local, global, 0);
+ }
+}
+
+/* Set the breakpoints and check the child successfully trigger them */
+static void launch_tests(void)
+{
+ char buf[1024];
+ int len, local, global, i;
+
+ /* Instruction breakpoints */
+ for (local = 0; local < 2; local++) {
+ for (global = 0; global < 2; global++) {
+ if (!local && !global)
+ continue;
+ launch_instruction_breakpoints(buf, local, global);
+ }
+ }
+
+ /* Write watchpoint */
+ for (len = 1; len <= sizeof(long); len <<= 1) {
+ for (local = 0; local < 2; local++) {
+ for (global = 0; global < 2; global++) {
+ if (!local && !global)
+ continue;
+ launch_watchpoints(buf, BP_W, len,
+ local, global);
+ }
+ }
+ }
+
+ /* Read-Write watchpoint */
+ for (len = 1; len <= sizeof(long); len <<= 1) {
+ for (local = 0; local < 2; local++) {
+ for (global = 0; global < 2; global++) {
+ if (!local && !global)
+ continue;
+ launch_watchpoints(buf, BP_RW, len,
+ local, global);
+ }
+ }
+ }
+
+ /* Icebp traps */
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ check_success("Test icebp");
+
+ /* Int 3 traps */
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+ check_success("Test int 3 trap");
+
+ ptrace(PTRACE_CONT, child_pid, NULL, 0);
+}
+
+int main(int argc, char **argv)
+{
+ pid_t pid;
+ int ret;
+
+ pid = fork();
+ if (!pid) {
+ trigger_tests();
+ return 0;
+ }
+
+ child_pid = pid;
+
+ wait(NULL);
+
+ launch_tests();
+
+ wait(NULL);
+
+ return 0;
+}
diff --git a/tools/testing/selftests/run_tests b/tools/testing/selftests/run_tests
index 701960d9e531..320718a4e6bf 100644
--- a/tools/testing/selftests/run_tests
+++ b/tools/testing/selftests/run_tests
@@ -1,6 +1,6 @@
#!/bin/bash
-TARGETS=
+TARGETS=breakpoints
for TARGET in $TARGETS
do