[PATCH v2 02/10] ARM: kprobes: Add basic API tests

Tixy tixy at yxit.co.uk
Sat Sep 10 07:04:58 EDT 2011


From: Jon Medhurst <tixy at yxit.co.uk>

These test that the different kinds of probes can be successfully placed
into ARM and Thumb code and that the handlers are called correctly when
this code is executed.

Signed-off-by: Jon Medhurst <tixy at yxit.co.uk>
---
 arch/arm/kernel/Makefile       |    2 +
 arch/arm/kernel/kprobes-test.c |  340 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 342 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index f7887dc..c7cbd96 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -43,6 +43,8 @@ obj-$(CONFIG_KPROBES)		+= kprobes-thumb.o
 else
 obj-$(CONFIG_KPROBES)		+= kprobes-arm.o
 endif
+obj-$(CONFIG_ARM_KPROBES_TEST)	+= test-kprobes.o
+test-kprobes-objs		:= kprobes-test.o
 obj-$(CONFIG_ATAGS_PROC)	+= atags.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c
new file mode 100644
index 0000000..9fff044
--- /dev/null
+++ b/arch/arm/kernel/kprobes-test.c
@@ -0,0 +1,340 @@
+/*
+ * arch/arm/kernel/kprobes-test.c
+ *
+ * Copyright (C) 2011 Jon Medhurst <tixy at yxit.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+
+#include "kprobes.h"
+
+
+/*
+ * Test basic API
+ */
+
+static bool test_regs_ok;
+static int test_func_instance;
+static int pre_handler_called;
+static int post_handler_called;
+static int jprobe_func_called;
+static int kretprobe_handler_called;
+
+#define FUNC_ARG1 0x12345678
+#define FUNC_ARG2 0xabcdef
+
+
+#ifndef CONFIG_THUMB2_KERNEL
+
+long arm_func(long r0, long r1);
+
+static void __used __naked __arm_kprobes_test_func(void)
+{
+	__asm__ __volatile__ (
+		".arm					\n\t"
+		".type arm_func, %%function		\n\t"
+		"arm_func:				\n\t"
+		"adds	r0, r0, r1			\n\t"
+		"bx	lr				\n\t"
+		".code "NORMAL_ISA	 /* Back to Thumb if necessary */
+		: : : "r0", "r1", "cc"
+	);
+}
+
+#else /* CONFIG_THUMB2_KERNEL */
+
+long thumb16_func(long r0, long r1);
+long thumb32even_func(long r0, long r1);
+long thumb32odd_func(long r0, long r1);
+
+static void __used __naked __thumb_kprobes_test_funcs(void)
+{
+	__asm__ __volatile__ (
+		".type thumb16_func, %%function		\n\t"
+		"thumb16_func:				\n\t"
+		"adds.n	r0, r0, r1			\n\t"
+		"bx	lr				\n\t"
+
+		".align					\n\t"
+		".type thumb32even_func, %%function	\n\t"
+		"thumb32even_func:			\n\t"
+		"adds.w	r0, r0, r1			\n\t"
+		"bx	lr				\n\t"
+
+		".align					\n\t"
+		"nop.n					\n\t"
+		".type thumb32odd_func, %%function	\n\t"
+		"thumb32odd_func:			\n\t"
+		"adds.w	r0, r0, r1			\n\t"
+		"bx	lr				\n\t"
+
+		: : : "r0", "r1", "cc"
+	);
+}
+
+#endif /* CONFIG_THUMB2_KERNEL */
+
+
+static int call_test_func(long (*func)(long, long), bool check_test_regs)
+{
+	long ret;
+
+	++test_func_instance;
+	test_regs_ok = false;
+
+	ret = (*func)(FUNC_ARG1, FUNC_ARG2);
+	if (ret != FUNC_ARG1 + FUNC_ARG2) {
+		pr_err("FAIL: call_test_func: func returned %lx\n", ret);
+		return false;
+	}
+
+	if (check_test_regs && !test_regs_ok) {
+		pr_err("FAIL: test regs not OK\n");
+		return false;
+	}
+
+	return true;
+}
+
+static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	pre_handler_called = test_func_instance;
+	if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
+		test_regs_ok = true;
+	return 0;
+}
+
+static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
+				unsigned long flags)
+{
+	post_handler_called = test_func_instance;
+	if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
+		test_regs_ok = false;
+}
+
+static struct kprobe the_kprobe = {
+	.addr		= 0,
+	.pre_handler	= pre_handler,
+	.post_handler	= post_handler
+};
+
+static int test_kprobe(long (*func)(long, long))
+{
+	int ret;
+
+	the_kprobe.addr = (kprobe_opcode_t *)func;
+	ret = register_kprobe(&the_kprobe);
+	if (ret < 0) {
+		pr_err("FAIL: register_kprobe failed with %d\n", ret);
+		return ret;
+	}
+
+	ret = call_test_func(func, true);
+
+	unregister_kprobe(&the_kprobe);
+	the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
+
+	if (!ret)
+		return -EINVAL;
+	if (pre_handler_called != test_func_instance) {
+		pr_err("FAIL: kprobe pre_handler not called\n");
+		return -EINVAL;
+	}
+	if (post_handler_called != test_func_instance) {
+		pr_err("FAIL: kprobe post_handler not called\n");
+		return -EINVAL;
+	}
+	if (!call_test_func(func, false))
+		return -EINVAL;
+	if (pre_handler_called == test_func_instance ||
+				post_handler_called == test_func_instance) {
+		pr_err("FAIL: probe called after unregistering\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void __kprobes jprobe_func(long r0, long r1)
+{
+	jprobe_func_called = test_func_instance;
+	if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
+		test_regs_ok = true;
+	jprobe_return();
+}
+
+static struct jprobe the_jprobe = {
+	.entry		= jprobe_func,
+};
+
+static int test_jprobe(long (*func)(long, long))
+{
+	int ret;
+
+	the_jprobe.kp.addr = (kprobe_opcode_t *)func;
+	ret = register_jprobe(&the_jprobe);
+	if (ret < 0) {
+		pr_err("FAIL: register_jprobe failed with %d\n", ret);
+		return ret;
+	}
+
+	ret = call_test_func(func, true);
+
+	unregister_jprobe(&the_jprobe);
+	the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
+
+	if (!ret)
+		return -EINVAL;
+	if (jprobe_func_called != test_func_instance) {
+		pr_err("FAIL: jprobe handler function not called\n");
+		return -EINVAL;
+	}
+	if (!call_test_func(func, false))
+		return -EINVAL;
+	if (jprobe_func_called == test_func_instance) {
+		pr_err("FAIL: probe called after unregistering\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int __kprobes
+kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+	kretprobe_handler_called = test_func_instance;
+	if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
+		test_regs_ok = true;
+	return 0;
+}
+
+static struct kretprobe the_kretprobe = {
+	.handler	= kretprobe_handler,
+};
+
+static int test_kretprobe(long (*func)(long, long))
+{
+	int ret;
+
+	the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
+	ret = register_kretprobe(&the_kretprobe);
+	if (ret < 0) {
+		pr_err("FAIL: register_kretprobe failed with %d\n", ret);
+		return ret;
+	}
+
+	ret = call_test_func(func, true);
+
+	unregister_kretprobe(&the_kretprobe);
+	the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
+
+	if (!ret)
+		return -EINVAL;
+	if (kretprobe_handler_called != test_func_instance) {
+		pr_err("FAIL: kretprobe handler not called\n");
+		return -EINVAL;
+	}
+	if (!call_test_func(func, false))
+		return -EINVAL;
+	if (jprobe_func_called == test_func_instance) {
+		pr_err("FAIL: kretprobe called after unregistering\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int run_api_tests(long (*func)(long, long))
+{
+	int ret;
+
+	pr_info("    kprobe\n");
+	ret = test_kprobe(func);
+	if (ret < 0)
+		return ret;
+
+	pr_info("    jprobe\n");
+	ret = test_jprobe(func);
+	if (ret < 0)
+		return ret;
+
+	pr_info("    kretprobe\n");
+	ret = test_kretprobe(func);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+
+/*
+ * Top level test functions
+ */
+
+static int __init run_all_tests(void)
+{
+	int ret = 0;
+
+	pr_info("Begining kprobe tests...\n");
+
+#ifndef CONFIG_THUMB2_KERNEL
+
+	pr_info("Probe ARM code\n");
+	ret = run_api_tests(arm_func);
+	if (ret)
+		goto out;
+
+#else /* CONFIG_THUMB2_KERNEL */
+
+	pr_info("Probe 16-bit Thumb code\n");
+	ret = run_api_tests(thumb16_func);
+	if (ret)
+		goto out;
+
+	pr_info("Probe 32-bit Thumb code, even halfword\n");
+	ret = run_api_tests(thumb32even_func);
+	if (ret)
+		goto out;
+
+	pr_info("Probe 32-bit Thumb code, odd halfword\n");
+	ret = run_api_tests(thumb32odd_func);
+	if (ret)
+		goto out;
+
+#endif
+
+out:
+	if (ret == 0)
+		pr_info("Finished kprobe tests OK\n");
+	else
+		pr_err("kprobe tests failed\n");
+
+	return ret;
+}
+
+
+/*
+ * Module setup
+ */
+
+#ifdef MODULE
+
+static void __exit kprobe_test_exit(void)
+{
+}
+
+module_init(run_all_tests)
+module_exit(kprobe_test_exit)
+MODULE_LICENSE("GPL");
+
+#else /* !MODULE */
+
+late_initcall(run_all_tests);
+
+#endif
-- 
1.7.2.5




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