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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: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Jon Medhurst 2011-08-28 16:35:11 +01:00
parent 2c89240b63
commit 68f360e753
1 changed files with 99 additions and 4 deletions
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103
arch/arm/kernel/kprobes-test.c
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@ -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 @@ 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