[PATCH v2 07/10] ARM: kprobes: Add decoding table self-consistency tests
Tixy
tixy at yxit.co.uk
Sat Sep 10 07:05:03 EDT 2011
From: Jon Medhurst <tixy at yxit.co.uk>
These check that the bitmask and match value used in the decoding tables
are self consistent.
Signed-off-by: Jon Medhurst <tixy at yxit.co.uk>
---
arch/arm/kernel/kprobes-test.c | 103 ++++++++++++++++++++++++++++++++++++++--
1 files changed, 99 insertions(+), 4 deletions(-)
diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c
index 1e7cdda..74a3a34 100644
--- a/arch/arm/kernel/kprobes-test.c
+++ b/arch/arm/kernel/kprobes-test.c
@@ -443,6 +443,92 @@ 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 @@ end:
* 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
--
1.7.2.5
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