Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 68f360e7 authored by Jon Medhurst's avatar Jon Medhurst
Browse files

ARM: kprobes: Add decoding table self-consistency tests 



These check that the bitmask and match value used in the decoding tables
are self consistent.

Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent 2c89240b

arch/arm/kernel/kprobes-test.c

+99 −4
Original line number Diff line number Diff line
@@ -442,6 +442,92 @@ static int run_api_tests(long (*func)(long, long)) 
}





/*

 * Decoding table self-consistency tests

 */



static const int decode_struct_sizes[NUM_DECODE_TYPES] = {

	[DECODE_TYPE_TABLE]	= sizeof(struct decode_table),

	[DECODE_TYPE_CUSTOM]	= sizeof(struct decode_custom),

	[DECODE_TYPE_SIMULATE]	= sizeof(struct decode_simulate),

	[DECODE_TYPE_EMULATE]	= sizeof(struct decode_emulate),

	[DECODE_TYPE_OR]	= sizeof(struct decode_or),

	[DECODE_TYPE_REJECT]	= sizeof(struct decode_reject)

};



static int table_iter(const union decode_item *table,

			int (*fn)(const struct decode_header *, void *),

			void *args)

{

	const struct decode_header *h = (struct decode_header *)table;

	int result;



	for (;;) {

		enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;



		if (type == DECODE_TYPE_END)

			return 0;



		result = fn(h, args);

		if (result)

			return result;



		h = (struct decode_header *)

			((uintptr_t)h + decode_struct_sizes[type]);



	}

}



static int table_test_fail(const struct decode_header *h, const char* message)

{



	pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",

					message, h->mask.bits, h->value.bits);

	return -EINVAL;

}



struct table_test_args {

	const union decode_item *root_table;

	u32			parent_mask;

	u32			parent_value;

};



static int table_test_fn(const struct decode_header *h, void *args)

{

	struct table_test_args *a = (struct table_test_args *)args;

	enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;



	if (h->value.bits & ~h->mask.bits)

		return table_test_fail(h, "Match value has bits not in mask");



	if ((h->mask.bits & a->parent_mask) != a->parent_mask)

		return table_test_fail(h, "Mask has bits not in parent mask");



	if ((h->value.bits ^ a->parent_value) & a->parent_mask)

		return table_test_fail(h, "Value is inconsistent with parent");



	if (type == DECODE_TYPE_TABLE) {

		struct decode_table *d = (struct decode_table *)h;

		struct table_test_args args2 = *a;

		args2.parent_mask = h->mask.bits;

		args2.parent_value = h->value.bits;

		return table_iter(d->table.table, table_test_fn, &args2);

	}



	return 0;

}



static int table_test(const union decode_item *table)

{

	struct table_test_args args = {

		.root_table	= table,

		.parent_mask	= 0,

		.parent_value	= 0

	};

	return table_iter(args.root_table, table_test_fn, &args);

}





/*

 * Framework for instruction set test cases

 */
@@ -1117,8 +1203,15 @@ static uintptr_t __used kprobes_test_case_end(void) 
 * Top level test functions

 */



static int run_test_cases(void (*tests)(void))

static int run_test_cases(void (*tests)(void), const union decode_item *table)

{

	int ret;



	pr_info("    Check decoding tables\n");

	ret = table_test(table);

	if (ret)

		return ret;



	pr_info("    Run test cases\n");

	tests();
@@ -1140,7 +1233,7 @@ static int __init run_all_tests(void) 
		goto out;



	pr_info("ARM instruction simulation\n");

	ret = run_test_cases(kprobe_arm_test_cases);

	ret = run_test_cases(kprobe_arm_test_cases, kprobe_decode_arm_table);

	if (ret)

		goto out;
@@ -1162,12 +1255,14 @@ static int __init run_all_tests(void) 
		goto out;



	pr_info("16-bit Thumb instruction simulation\n");

	ret = run_test_cases(kprobe_thumb16_test_cases);

	ret = run_test_cases(kprobe_thumb16_test_cases,

				kprobe_decode_thumb16_table);

	if (ret)

		goto out;



	pr_info("32-bit Thumb instruction simulation\n");

	ret = run_test_cases(kprobe_thumb32_test_cases);

	ret = run_test_cases(kprobe_thumb32_test_cases,

				kprobe_decode_thumb32_table);

	if (ret)

		goto out;

#endif