ARM: kprobes: Framework for instruction set test cases

On ARM we have to simulate/emulate CPU instructions in order to
singlestep them. This patch adds a framework which can be used to
construct test cases for different instruction forms. It is described in
detail in the in-source comments of kprobes-test.c

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 16:18:43 +01:00
parent 9eed179772
commit a43bc69b39
2 changed files with 1224 additions and 0 deletions

View File

@ -8,11 +8,180 @@
* published by the Free Software Foundation.
*/
/*
* TESTING METHODOLOGY
* -------------------
*
* The methodology used to test an ARM instruction 'test_insn' is to use
* inline assembler like:
*
* test_before: nop
* test_case: test_insn
* test_after: nop
*
* When the test case is run a kprobe is placed of each nop. The
* post-handler of the test_before probe is used to modify the saved CPU
* register context to that which we require for the test case. The
* pre-handler of the of the test_after probe saves a copy of the CPU
* register context. In this way we can execute test_insn with a specific
* register context and see the results afterwards.
*
* To actually test the kprobes instruction emulation we perform the above
* step a second time but with an additional kprobe on the test_case
* instruction itself. If the emulation is accurate then the results seen
* by the test_after probe will be identical to the first run which didn't
* have a probe on test_case.
*
* Each test case is run several times with a variety of variations in the
* flags value of stored in CPSR, and for Thumb code, different ITState.
*
* For instructions which can modify PC, a second test_after probe is used
* like this:
*
* test_before: nop
* test_case: test_insn
* test_after: nop
* b test_done
* test_after2: nop
* test_done:
*
* The test case is constructed such that test_insn branches to
* test_after2, or, if testing a conditional instruction, it may just
* continue to test_after. The probes inserted at both locations let us
* determine which happened. A similar approach is used for testing
* backwards branches...
*
* b test_before
* b test_done @ helps to cope with off by 1 branches
* test_after2: nop
* b test_done
* test_before: nop
* test_case: test_insn
* test_after: nop
* test_done:
*
* The macros used to generate the assembler instructions describe above
* are TEST_INSTRUCTION, TEST_BRANCH_F (branch forwards) and TEST_BRANCH_B
* (branch backwards). In these, the local variables numbered 1, 50, 2 and
* 99 represent: test_before, test_case, test_after2 and test_done.
*
* FRAMEWORK
* ---------
*
* Each test case is wrapped between the pair of macros TESTCASE_START and
* TESTCASE_END. As well as performing the inline assembler boilerplate,
* these call out to the kprobes_test_case_start() and
* kprobes_test_case_end() functions which drive the execution of the test
* case. The specific arguments to use for each test case are stored as
* inline data constructed using the various TEST_ARG_* macros. Putting
* this all together, a simple test case may look like:
*
* TESTCASE_START("Testing mov r0, r7")
* TEST_ARG_REG(7, 0x12345678) // Set r7=0x12345678
* TEST_ARG_END("")
* TEST_INSTRUCTION("mov r0, r7")
* TESTCASE_END
*
* Note, in practice the single convenience macro TEST_R would be used for this
* instead.
*
* The above would expand to assembler looking something like:
*
* @ TESTCASE_START
* bl __kprobes_test_case_start
* @ start of inline data...
* .ascii "mov r0, r7" @ text title for test case
* .byte 0
* .align 2
*
* @ TEST_ARG_REG
* .byte ARG_TYPE_REG
* .byte 7
* .short 0
* .word 0x1234567
*
* @ TEST_ARG_END
* .byte ARG_TYPE_END
* .byte TEST_ISA @ flags, including ISA being tested
* .short 50f-0f @ offset of 'test_before'
* .short 2f-0f @ offset of 'test_after2' (if relevent)
* .short 99f-0f @ offset of 'test_done'
* @ start of test case code...
* 0:
* .code TEST_ISA @ switch to ISA being tested
*
* @ TEST_INSTRUCTION
* 50: nop @ location for 'test_before' probe
* 1: mov r0, r7 @ the test case instruction 'test_insn'
* nop @ location for 'test_after' probe
*
* // TESTCASE_END
* 2:
* 99: bl __kprobes_test_case_end_##TEST_ISA
* .code NONMAL_ISA
*
* When the above is execute the following happens...
*
* __kprobes_test_case_start() is an assembler wrapper which sets up space
* for a stack buffer and calls the C function kprobes_test_case_start().
* This C function will do some initial processing of the inline data and
* setup some global state. It then inserts the test_before and test_after
* kprobes and returns a value which causes the assembler wrapper to jump
* to the start of the test case code, (local label '0').
*
* When the test case code executes, the test_before probe will be hit and
* test_before_post_handler will call setup_test_context(). This fills the
* stack buffer and CPU registers with a test pattern and then processes
* the test case arguments. In our example there is one TEST_ARG_REG which
* indicates that R7 should be loaded with the value 0x12345678.
*
* When the test_before probe ends, the test case continues and executes
* the "mov r0, r7" instruction. It then hits the test_after probe and the
* pre-handler for this (test_after_pre_handler) will save a copy of the
* CPU register context. This should now have R0 holding the same value as
* R7.
*
* Finally we get to the call to __kprobes_test_case_end_{32,16}. This is
* an assembler wrapper which switches back to the ISA used by the test
* code and calls the C function kprobes_test_case_end().
*
* For each run through the test case, test_case_run_count is incremented
* by one. For even runs, kprobes_test_case_end() saves a copy of the
* register and stack buffer contents from the test case just run. It then
* inserts a kprobe on the test case instruction 'test_insn' and returns a
* value to cause the test case code to be re-run.
*
* For odd numbered runs, kprobes_test_case_end() compares the register and
* stack buffer contents to those that were saved on the previous even
* numbered run (the one without the kprobe on test_insn). These should be
* the same if the kprobe instruction simulation routine is correct.
*
* The pair of test case runs is repeated with different combinations of
* flag values in CPSR and, for Thumb, different ITState. This is
* controlled by test_context_cpsr().
*
* BUILDING TEST CASES
* -------------------
*
*
* As an aid to building test cases, the stack buffer is initialised with
* some special values:
*
* [SP+13*4] Contains SP+120. This can be used to test instructions
* which load a value into SP.
*
* [SP+15*4] When testing branching instructions using TEST_BRANCH_{F,B},
* this holds the target address of the branch, 'test_after2'.
* This can be used to test instructions which load a PC value
* from memory.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include "kprobes.h"
#include "kprobes-test.h"
/*
@ -273,6 +442,677 @@ static int run_api_tests(long (*func)(long, long))
}
/*
* Framework for instruction set test cases
*/
void __naked __kprobes_test_case_start(void)
{
__asm__ __volatile__ (
"stmdb sp!, {r4-r11} \n\t"
"sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
"bic r0, lr, #1 @ r0 = inline title string \n\t"
"mov r1, sp \n\t"
"bl kprobes_test_case_start \n\t"
"bx r0 \n\t"
);
}
#ifndef CONFIG_THUMB2_KERNEL
void __naked __kprobes_test_case_end_32(void)
{
__asm__ __volatile__ (
"mov r4, lr \n\t"
"bl kprobes_test_case_end \n\t"
"cmp r0, #0 \n\t"
"movne pc, r0 \n\t"
"mov r0, r4 \n\t"
"add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
"ldmia sp!, {r4-r11} \n\t"
"mov pc, r0 \n\t"
);
}
#else /* CONFIG_THUMB2_KERNEL */
void __naked __kprobes_test_case_end_16(void)
{
__asm__ __volatile__ (
"mov r4, lr \n\t"
"bl kprobes_test_case_end \n\t"
"cmp r0, #0 \n\t"
"bxne r0 \n\t"
"mov r0, r4 \n\t"
"add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
"ldmia sp!, {r4-r11} \n\t"
"bx r0 \n\t"
);
}
void __naked __kprobes_test_case_end_32(void)
{
__asm__ __volatile__ (
".arm \n\t"
"orr lr, lr, #1 @ will return to Thumb code \n\t"
"ldr pc, 1f \n\t"
"1: \n\t"
".word __kprobes_test_case_end_16 \n\t"
);
}
#endif
int kprobe_test_flags;
int kprobe_test_cc_position;
static int test_try_count;
static int test_pass_count;
static int test_fail_count;
static struct pt_regs initial_regs;
static struct pt_regs expected_regs;
static struct pt_regs result_regs;
static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
static const char *current_title;
static struct test_arg *current_args;
static u32 *current_stack;
static uintptr_t current_branch_target;
static uintptr_t current_code_start;
static kprobe_opcode_t current_instruction;
#define TEST_CASE_PASSED -1
#define TEST_CASE_FAILED -2
static int test_case_run_count;
static bool test_case_is_thumb;
static int test_instance;
/*
* We ignore the state of the imprecise abort disable flag (CPSR.A) because this
* can change randomly as the kernel doesn't take care to preserve or initialise
* this across context switches. Also, with Security Extentions, the flag may
* not be under control of the kernel; for this reason we ignore the state of
* the FIQ disable flag CPSR.F as well.
*/
#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
static unsigned long test_check_cc(int cc, unsigned long cpsr)
{
unsigned long temp;
switch (cc) {
case 0x0: /* eq */
return cpsr & PSR_Z_BIT;
case 0x1: /* ne */
return (~cpsr) & PSR_Z_BIT;
case 0x2: /* cs */
return cpsr & PSR_C_BIT;
case 0x3: /* cc */
return (~cpsr) & PSR_C_BIT;
case 0x4: /* mi */
return cpsr & PSR_N_BIT;
case 0x5: /* pl */
return (~cpsr) & PSR_N_BIT;
case 0x6: /* vs */
return cpsr & PSR_V_BIT;
case 0x7: /* vc */
return (~cpsr) & PSR_V_BIT;
case 0x8: /* hi */
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return cpsr & PSR_C_BIT;
case 0x9: /* ls */
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return (~cpsr) & PSR_C_BIT;
case 0xa: /* ge */
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return (~cpsr) & PSR_N_BIT;
case 0xb: /* lt */
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return cpsr & PSR_N_BIT;
case 0xc: /* gt */
temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return (~temp) & PSR_N_BIT;
case 0xd: /* le */
temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return temp & PSR_N_BIT;
case 0xe: /* al */
case 0xf: /* unconditional */
return true;
}
BUG();
return false;
}
static int is_last_scenario;
static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
static int memory_needs_checking;
static unsigned long test_context_cpsr(int scenario)
{
unsigned long cpsr;
probe_should_run = 1;
/* Default case is that we cycle through 16 combinations of flags */
cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
cpsr |= (scenario & 0xf) << 16; /* GE flags */
cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
if (!test_case_is_thumb) {
/* Testing ARM code */
probe_should_run = test_check_cc(current_instruction >> 28, cpsr) != 0;
if (scenario == 15)
is_last_scenario = true;
} else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
/* Testing Thumb code without setting ITSTATE */
if (kprobe_test_cc_position) {
int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
probe_should_run = test_check_cc(cc, cpsr) != 0;
}
if (scenario == 15)
is_last_scenario = true;
} else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
/* Testing Thumb code with all combinations of ITSTATE */
unsigned x = (scenario >> 4);
unsigned cond_base = x % 7; /* ITSTATE<7:5> */
unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
if (mask > 0x1f) {
/* Finish by testing state from instruction 'itt al' */
cond_base = 7;
mask = 0x4;
if ((scenario & 0xf) == 0xf)
is_last_scenario = true;
}
cpsr |= cond_base << 13; /* ITSTATE<7:5> */
cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
} else {
/* Testing Thumb code with several combinations of ITSTATE */
switch (scenario) {
case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
cpsr = 0x00000800;
probe_should_run = 0;
break;
case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
cpsr = 0xf0007800;
probe_should_run = 0;
break;
case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
cpsr = 0x00009800;
break;
case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
cpsr = 0xf0002800;
is_last_scenario = true;
break;
}
}
return cpsr;
}
static void setup_test_context(struct pt_regs *regs)
{
int scenario = test_case_run_count>>1;
unsigned long val;
struct test_arg *args;
int i;
is_last_scenario = false;
memory_needs_checking = false;
/* Initialise test memory on stack */
val = (scenario & 1) ? VALM : ~VALM;
for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
current_stack[i] = val + (i << 8);
/* Put target of branch on stack for tests which load PC from memory */
if (current_branch_target)
current_stack[15] = current_branch_target;
/* Put a value for SP on stack for tests which load SP from memory */
current_stack[13] = (u32)current_stack + 120;
/* Initialise register values to their default state */
val = (scenario & 2) ? VALR : ~VALR;
for (i = 0; i < 13; ++i)
regs->uregs[i] = val ^ (i << 8);
regs->ARM_lr = val ^ (14 << 8);
regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
regs->ARM_cpsr |= test_context_cpsr(scenario);
/* Perform testcase specific register setup */
args = current_args;
for (; args[0].type != ARG_TYPE_END; ++args)
switch (args[0].type) {
case ARG_TYPE_REG: {
struct test_arg_regptr *arg =
(struct test_arg_regptr *)args;
regs->uregs[arg->reg] = arg->val;
break;
}
case ARG_TYPE_PTR: {
struct test_arg_regptr *arg =
(struct test_arg_regptr *)args;
regs->uregs[arg->reg] =
(unsigned long)current_stack + arg->val;
memory_needs_checking = true;
break;
}
case ARG_TYPE_MEM: {
struct test_arg_mem *arg = (struct test_arg_mem *)args;
current_stack[arg->index] = arg->val;
break;
}
default:
break;
}
}
struct test_probe {
struct kprobe kprobe;
bool registered;
int hit;
};
static void unregister_test_probe(struct test_probe *probe)
{
if (probe->registered) {
unregister_kprobe(&probe->kprobe);
probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
}
probe->registered = false;
}
static int register_test_probe(struct test_probe *probe)
{
int ret;
if (probe->registered)
BUG();
ret = register_kprobe(&probe->kprobe);
if (ret >= 0) {
probe->registered = true;
probe->hit = -1;
}
return ret;
}
static int __kprobes
test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
container_of(p, struct test_probe, kprobe)->hit = test_instance;
return 0;
}
static void __kprobes
test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
unsigned long flags)
{
setup_test_context(regs);
initial_regs = *regs;
initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
}
static int __kprobes
test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
container_of(p, struct test_probe, kprobe)->hit = test_instance;
return 0;
}
static int __kprobes
test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
return 0; /* Already run for this test instance */
result_regs = *regs;
result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
/* Undo any changes done to SP by the test case */
regs->ARM_sp = (unsigned long)current_stack;
container_of(p, struct test_probe, kprobe)->hit = test_instance;
return 0;
}
static struct test_probe test_before_probe = {
.kprobe.pre_handler = test_before_pre_handler,
.kprobe.post_handler = test_before_post_handler,
};
static struct test_probe test_case_probe = {
.kprobe.pre_handler = test_case_pre_handler,
};
static struct test_probe test_after_probe = {
.kprobe.pre_handler = test_after_pre_handler,
};
static struct test_probe test_after2_probe = {
.kprobe.pre_handler = test_after_pre_handler,
};
static void test_case_cleanup(void)
{
unregister_test_probe(&test_before_probe);
unregister_test_probe(&test_case_probe);
unregister_test_probe(&test_after_probe);
unregister_test_probe(&test_after2_probe);
}
static void print_registers(struct pt_regs *regs)
{
pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
pr_err("cpsr %08lx\n", regs->ARM_cpsr);
}
static void print_memory(u32 *mem, size_t size)
{
int i;
for (i = 0; i < size / sizeof(u32); i += 4)
pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
mem[i+2], mem[i+3]);
}
static size_t expected_memory_size(u32 *sp)
{
size_t size = sizeof(expected_memory);
int offset = (uintptr_t)sp - (uintptr_t)current_stack;
if (offset > 0)
size -= offset;
return size;
}
static void test_case_failed(const char *message)
{
test_case_cleanup();
pr_err("FAIL: %s\n", message);
pr_err("FAIL: Test %s\n", current_title);
pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
}
static unsigned long next_instruction(unsigned long pc)
{
#ifdef CONFIG_THUMB2_KERNEL
if ((pc & 1) && !is_wide_instruction(*(u16 *)(pc - 1)))
return pc + 2;
else
#endif
return pc + 4;
}
static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
{
struct test_arg *args;
struct test_arg_end *end_arg;
unsigned long test_code;
args = (struct test_arg *)PTR_ALIGN(title + strlen(title) + 1, 4);
current_title = title;
current_args = args;
current_stack = stack;
++test_try_count;
while (args->type != ARG_TYPE_END)
++args;
end_arg = (struct test_arg_end *)args;
test_code = (unsigned long)(args + 1); /* Code starts after args */
test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
if (test_case_is_thumb)
test_code |= 1;
current_code_start = test_code;
current_branch_target = 0;
if (end_arg->branch_offset != end_arg->end_offset)
current_branch_target = test_code + end_arg->branch_offset;
test_code += end_arg->code_offset;
test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
test_code = next_instruction(test_code);
test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
if (test_case_is_thumb) {
u16 *p = (u16 *)(test_code & ~1);
current_instruction = p[0];
if (is_wide_instruction(current_instruction)) {
current_instruction <<= 16;
current_instruction |= p[1];
}
} else {
current_instruction = *(u32 *)test_code;
}
if (current_title[0] == '.')
verbose("%s\n", current_title);
else
verbose("%s\t@ %0*x\n", current_title,
test_case_is_thumb ? 4 : 8,
current_instruction);
test_code = next_instruction(test_code);
test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
if (!test_case_is_thumb ||
is_wide_instruction(current_instruction)) {
test_case_failed("expected 16-bit instruction");
goto fail;
}
} else {
if (test_case_is_thumb &&
!is_wide_instruction(current_instruction)) {
test_case_failed("expected 32-bit instruction");
goto fail;
}
}
if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
if (register_test_probe(&test_case_probe) < 0)
goto pass;
test_case_failed("registered probe for unsupported instruction");
goto fail;
}
if (end_arg->flags & ARG_FLAG_SUPPORTED) {
if (register_test_probe(&test_case_probe) >= 0)
goto pass;
test_case_failed("couldn't register probe for supported instruction");
goto fail;
}
if (register_test_probe(&test_before_probe) < 0) {
test_case_failed("register test_before_probe failed");
goto fail;
}
if (register_test_probe(&test_after_probe) < 0) {
test_case_failed("register test_after_probe failed");
goto fail;
}
if (current_branch_target) {
test_after2_probe.kprobe.addr =
(kprobe_opcode_t *)current_branch_target;
if (register_test_probe(&test_after2_probe) < 0) {
test_case_failed("register test_after2_probe failed");
goto fail;
}
}
/* Start first run of test case */
test_case_run_count = 0;
++test_instance;
return current_code_start;
pass:
test_case_run_count = TEST_CASE_PASSED;
return (uintptr_t)test_after_probe.kprobe.addr;
fail:
test_case_run_count = TEST_CASE_FAILED;
return (uintptr_t)test_after_probe.kprobe.addr;
}
static bool check_test_results(void)
{
size_t mem_size = 0;
u32 *mem = 0;
if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
test_case_failed("registers differ");
goto fail;
}
if (memory_needs_checking) {
mem = (u32 *)result_regs.ARM_sp;
mem_size = expected_memory_size(mem);
if (memcmp(expected_memory, mem, mem_size)) {
test_case_failed("test memory differs");
goto fail;
}
}
return true;
fail:
pr_err("initial_regs:\n");
print_registers(&initial_regs);
pr_err("expected_regs:\n");
print_registers(&expected_regs);
pr_err("result_regs:\n");
print_registers(&result_regs);
if (mem) {
pr_err("current_stack=%p\n", current_stack);
pr_err("expected_memory:\n");
print_memory(expected_memory, mem_size);
pr_err("result_memory:\n");
print_memory(mem, mem_size);
}
return false;
}
static uintptr_t __used kprobes_test_case_end(void)
{
if (test_case_run_count < 0) {
if (test_case_run_count == TEST_CASE_PASSED)
/* kprobes_test_case_start did all the needed testing */
goto pass;
else
/* kprobes_test_case_start failed */
goto fail;
}
if (test_before_probe.hit != test_instance) {
test_case_failed("test_before_handler not run");
goto fail;
}
if (test_after_probe.hit != test_instance &&
test_after2_probe.hit != test_instance) {
test_case_failed("test_after_handler not run");
goto fail;
}
/*
* Even numbered test runs ran without a probe on the test case so
* we can gather reference results. The subsequent odd numbered run
* will have the probe inserted.
*/
if ((test_case_run_count & 1) == 0) {
/* Save results from run without probe */
u32 *mem = (u32 *)result_regs.ARM_sp;
expected_regs = result_regs;
memcpy(expected_memory, mem, expected_memory_size(mem));
/* Insert probe onto test case instruction */
if (register_test_probe(&test_case_probe) < 0) {
test_case_failed("register test_case_probe failed");
goto fail;
}
} else {
/* Check probe ran as expected */
if (probe_should_run == 1) {
if (test_case_probe.hit != test_instance) {
test_case_failed("test_case_handler not run");
goto fail;
}
} else if (probe_should_run == 0) {
if (test_case_probe.hit == test_instance) {
test_case_failed("test_case_handler ran");
goto fail;
}
}
/* Remove probe for any subsequent reference run */
unregister_test_probe(&test_case_probe);
if (!check_test_results())
goto fail;
if (is_last_scenario)
goto pass;
}
/* Do next test run */
++test_case_run_count;
++test_instance;
return current_code_start;
fail:
++test_fail_count;
goto end;
pass:
++test_pass_count;
end:
test_case_cleanup();
return 0;
}
/*
* Top level test functions
*/

View File

@ -0,0 +1,384 @@
/*
* arch/arm/kernel/kprobes-test.h
*
* Copyright (C) 2011 Jon Medhurst <tixy@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.
*/
#define VERBOSE 0 /* Set to '1' for more logging of test cases */
#ifdef CONFIG_THUMB2_KERNEL
#define NORMAL_ISA "16"
#else
#define NORMAL_ISA "32"
#endif
/* Flags used in kprobe_test_flags */
#define TEST_FLAG_NO_ITBLOCK (1<<0)
#define TEST_FLAG_FULL_ITBLOCK (1<<1)
#define TEST_FLAG_NARROW_INSTR (1<<2)
extern int kprobe_test_flags;
extern int kprobe_test_cc_position;
#define TEST_MEMORY_SIZE 256
/*
* Test case structures.
*
* The arguments given to test cases can be one of three types.
*
* ARG_TYPE_REG
* Load a register with the given value.
*
* ARG_TYPE_PTR
* Load a register with a pointer into the stack buffer (SP + given value).
*
* ARG_TYPE_MEM
* Store the given value into the stack buffer at [SP+index].
*
*/
#define ARG_TYPE_END 0
#define ARG_TYPE_REG 1
#define ARG_TYPE_PTR 2
#define ARG_TYPE_MEM 3
#define ARG_FLAG_UNSUPPORTED 0x01
#define ARG_FLAG_SUPPORTED 0x02
#define ARG_FLAG_THUMB 0x10 /* Must be 16 so TEST_ISA can be used */
#define ARG_FLAG_ARM 0x20 /* Must be 32 so TEST_ISA can be used */
struct test_arg {
u8 type; /* ARG_TYPE_x */
u8 _padding[7];
};
struct test_arg_regptr {
u8 type; /* ARG_TYPE_REG or ARG_TYPE_PTR */
u8 reg;
u8 _padding[2];
u32 val;
};
struct test_arg_mem {
u8 type; /* ARG_TYPE_MEM */
u8 index;
u8 _padding[2];
u32 val;
};
struct test_arg_end {
u8 type; /* ARG_TYPE_END */
u8 flags; /* ARG_FLAG_x */
u16 code_offset;
u16 branch_offset;
u16 end_offset;
};
/*
* Building blocks for test cases.
*
* Each test case is wrapped between TESTCASE_START and TESTCASE_END.
*
* To specify arguments for a test case the TEST_ARG_{REG,PTR,MEM} macros are
* used followed by a terminating TEST_ARG_END.
*
* After this, the instruction to be tested is defined with TEST_INSTRUCTION.
* Or for branches, TEST_BRANCH_B and TEST_BRANCH_F (branch forwards/backwards).
*
* Some specific test cases may make use of other custom constructs.
*/
#if VERBOSE
#define verbose(fmt, ...) pr_info(fmt, ##__VA_ARGS__)
#else
#define verbose(fmt, ...)
#endif
#define TEST_GROUP(title) \
verbose("\n"); \
verbose(title"\n"); \
verbose("---------------------------------------------------------\n");
#define TESTCASE_START(title) \
__asm__ __volatile__ ( \
"bl __kprobes_test_case_start \n\t" \
/* don't use .asciz here as 'title' may be */ \
/* multiple strings to be concatenated. */ \
".ascii "#title" \n\t" \
".byte 0 \n\t" \
".align 2 \n\t"
#define TEST_ARG_REG(reg, val) \
".byte "__stringify(ARG_TYPE_REG)" \n\t" \
".byte "#reg" \n\t" \
".short 0 \n\t" \
".word "#val" \n\t"
#define TEST_ARG_PTR(reg, val) \
".byte "__stringify(ARG_TYPE_PTR)" \n\t" \
".byte "#reg" \n\t" \
".short 0 \n\t" \
".word "#val" \n\t"
#define TEST_ARG_MEM(index, val) \
".byte "__stringify(ARG_TYPE_MEM)" \n\t" \
".byte "#index" \n\t" \
".short 0 \n\t" \
".word "#val" \n\t"
#define TEST_ARG_END(flags) \
".byte "__stringify(ARG_TYPE_END)" \n\t" \
".byte "TEST_ISA flags" \n\t" \
".short 50f-0f \n\t" \
".short 2f-0f \n\t" \
".short 99f-0f \n\t" \
".code "TEST_ISA" \n\t" \
"0: \n\t"
#define TEST_INSTRUCTION(instruction) \
"50: nop \n\t" \
"1: "instruction" \n\t" \
" nop \n\t"
#define TEST_BRANCH_F(instruction, xtra_dist) \
TEST_INSTRUCTION(instruction) \
".if "#xtra_dist" \n\t" \
" b 99f \n\t" \
".space "#xtra_dist" \n\t" \
".endif \n\t" \
" b 99f \n\t" \
"2: nop \n\t"
#define TEST_BRANCH_B(instruction, xtra_dist) \
" b 50f \n\t" \
" b 99f \n\t" \
"2: nop \n\t" \
" b 99f \n\t" \
".if "#xtra_dist" \n\t" \
".space "#xtra_dist" \n\t" \
".endif \n\t" \
TEST_INSTRUCTION(instruction)
#define TESTCASE_END \
"2: \n\t" \
"99: \n\t" \
" bl __kprobes_test_case_end_"TEST_ISA" \n\t" \
".code "NORMAL_ISA" \n\t" \
: : \
: "r0", "r1", "r2", "r3", "ip", "lr", "memory", "cc" \
);
/*
* Macros to define test cases.
*
* Those of the form TEST_{R,P,M}* can be used to define test cases
* which take combinations of the three basic types of arguments. E.g.
*
* TEST_R One register argument
* TEST_RR Two register arguments
* TEST_RPR A register, a pointer, then a register argument
*
* For testing instructions which may branch, there are macros TEST_BF_*
* and TEST_BB_* for branching forwards and backwards.
*
* TEST_SUPPORTED and TEST_UNSUPPORTED don't cause the code to be executed,
* the just verify that a kprobe is or is not allowed on the given instruction.
*/
#define TEST(code) \
TESTCASE_START(code) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code) \
TESTCASE_END
#define TEST_UNSUPPORTED(code) \
TESTCASE_START(code) \
TEST_ARG_END("|"__stringify(ARG_FLAG_UNSUPPORTED)) \
TEST_INSTRUCTION(code) \
TESTCASE_END
#define TEST_SUPPORTED(code) \
TESTCASE_START(code) \
TEST_ARG_END("|"__stringify(ARG_FLAG_SUPPORTED)) \
TEST_INSTRUCTION(code) \
TESTCASE_END
#define TEST_R(code1, reg, val, code2) \
TESTCASE_START(code1 #reg code2) \
TEST_ARG_REG(reg, val) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg code2) \
TESTCASE_END
#define TEST_RR(code1, reg1, val1, code2, reg2, val2, code3) \
TESTCASE_START(code1 #reg1 code2 #reg2 code3) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3) \
TESTCASE_END
#define TEST_RRR(code1, reg1, val1, code2, reg2, val2, code3, reg3, val3, code4)\
TESTCASE_START(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_REG(reg3, val3) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TESTCASE_END
#define TEST_RRRR(code1, reg1, val1, code2, reg2, val2, code3, reg3, val3, code4, reg4, val4) \
TESTCASE_START(code1 #reg1 code2 #reg2 code3 #reg3 code4 #reg4) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_REG(reg3, val3) \
TEST_ARG_REG(reg4, val4) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3 #reg3 code4 #reg4) \
TESTCASE_END
#define TEST_P(code1, reg1, val1, code2) \
TESTCASE_START(code1 #reg1 code2) \
TEST_ARG_PTR(reg1, val1) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2) \
TESTCASE_END
#define TEST_PR(code1, reg1, val1, code2, reg2, val2, code3) \
TESTCASE_START(code1 #reg1 code2 #reg2 code3) \
TEST_ARG_PTR(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3) \
TESTCASE_END
#define TEST_RP(code1, reg1, val1, code2, reg2, val2, code3) \
TESTCASE_START(code1 #reg1 code2 #reg2 code3) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_PTR(reg2, val2) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3) \
TESTCASE_END
#define TEST_PRR(code1, reg1, val1, code2, reg2, val2, code3, reg3, val3, code4)\
TESTCASE_START(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TEST_ARG_PTR(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_REG(reg3, val3) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TESTCASE_END
#define TEST_RPR(code1, reg1, val1, code2, reg2, val2, code3, reg3, val3, code4)\
TESTCASE_START(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_PTR(reg2, val2) \
TEST_ARG_REG(reg3, val3) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TESTCASE_END
#define TEST_RRP(code1, reg1, val1, code2, reg2, val2, code3, reg3, val3, code4)\
TESTCASE_START(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_PTR(reg3, val3) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 #reg1 code2 #reg2 code3 #reg3 code4) \
TESTCASE_END
#define TEST_BF_P(code1, reg1, val1, code2) \
TESTCASE_START(code1 #reg1 code2) \
TEST_ARG_PTR(reg1, val1) \
TEST_ARG_END("") \
TEST_BRANCH_F(code1 #reg1 code2, 0) \
TESTCASE_END
#define TEST_BF_X(code, xtra_dist) \
TESTCASE_START(code) \
TEST_ARG_END("") \
TEST_BRANCH_F(code, xtra_dist) \
TESTCASE_END
#define TEST_BB_X(code, xtra_dist) \
TESTCASE_START(code) \
TEST_ARG_END("") \
TEST_BRANCH_B(code, xtra_dist) \
TESTCASE_END
#define TEST_BF_RX(code1, reg, val, code2, xtra_dist) \
TESTCASE_START(code1 #reg code2) \
TEST_ARG_REG(reg, val) \
TEST_ARG_END("") \
TEST_BRANCH_F(code1 #reg code2, xtra_dist) \
TESTCASE_END
#define TEST_BB_RX(code1, reg, val, code2, xtra_dist) \
TESTCASE_START(code1 #reg code2) \
TEST_ARG_REG(reg, val) \
TEST_ARG_END("") \
TEST_BRANCH_B(code1 #reg code2, xtra_dist) \
TESTCASE_END
#define TEST_BF(code) TEST_BF_X(code, 0)
#define TEST_BB(code) TEST_BB_X(code, 0)
#define TEST_BF_R(code1, reg, val, code2) TEST_BF_RX(code1, reg, val, code2, 0)
#define TEST_BB_R(code1, reg, val, code2) TEST_BB_RX(code1, reg, val, code2, 0)
#define TEST_BF_RR(code1, reg1, val1, code2, reg2, val2, code3) \
TESTCASE_START(code1 #reg1 code2 #reg2 code3) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_END("") \
TEST_BRANCH_F(code1 #reg1 code2 #reg2 code3, 0) \
TESTCASE_END
#define TEST_X(code, codex) \
TESTCASE_START(code) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code) \
" b 99f \n\t" \
" "codex" \n\t" \
TESTCASE_END
#define TEST_RX(code1, reg, val, code2, codex) \
TESTCASE_START(code1 #reg code2) \
TEST_ARG_REG(reg, val) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 __stringify(reg) code2) \
" b 99f \n\t" \
" "codex" \n\t" \
TESTCASE_END
#define TEST_RRX(code1, reg1, val1, code2, reg2, val2, code3, codex) \
TESTCASE_START(code1 #reg1 code2 #reg2 code3) \
TEST_ARG_REG(reg1, val1) \
TEST_ARG_REG(reg2, val2) \
TEST_ARG_END("") \
TEST_INSTRUCTION(code1 __stringify(reg1) code2 __stringify(reg2) code3) \
" b 99f \n\t" \
" "codex" \n\t" \
TESTCASE_END
/* Various values used in test cases... */
#define N(val) (val ^ 0xffffffff)
#define VAL1 0x12345678
#define VAL2 N(VAL1)
#define VAL3 0xa5f801
#define VAL4 N(VAL3)
#define VALM 0x456789ab
#define VALR 0xdeaddead
#define HH1 0x0123fecb
#define HH2 0xa9874567