new file mode 100644
@@ -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
@@ -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.
+ *
+ * Th 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"
/*
@@ -274,6 +443,677 @@ 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
*/