hardware debug API: aarch64 and single stepping

Signed-off-by: Alwin Joshy <[email protected]>

apps/sel4test-tests/arch/arm/arch/debug.h

@@ -5,16 +5,36 @@
  */
 #pragma once
 
+#ifdef CONFIG_ARCH_AARCH32
 #define TEST_SOFTWARE_BREAK_ASM() \
     asm volatile( \
         ".global sbreak, post_sbreak\n\t" \
         ".type post_sbreak, function\n\t" \
         "sbreak:\n\t" \
         "bkpt\n\t")
+#else
+#define TEST_SOFTWARE_BREAK_ASM() \
+    asm volatile( \
+        ".global sbreak, post_sbreak\n\t" \
+        ".type post_sbreak, function\n\t" \
+        "sbreak:\n\t" \
+        "brk #0\n\t")
+#endif
+
+#define TEST_SINGLE_STEP_ASM() \
+    asm volatile( \
+        ".global label_one, label_two\n\t" \
+        "label_one: \n\t" \
+        "nop \n\t" \
+        "label_two: \n\t" \
+        "nop \n\t" \
+        )
 
 /* Tell C about the symbols exported by the ASM above. */
-extern char sbreak;
+extern char sbreak, label_one, label_two;
 #define TEST_SOFTWARE_BREAK_EXPECTED_FAULT_LABEL sbreak
+#define TEST_SS_LABEL_ONE label_one
+#define TEST_SS_LABEL_TWO label_two
 #define SINGLESTEP_EXPECTED_BP_CONSUMPTION_VALUE (true)
 #define TEST_NUM_DATA_WPS seL4_NumExclusiveWatchpoints
 #define TEST_NUM_INSTR_BPS seL4_NumExclusiveBreakpoints

apps/sel4test-tests/src/arch/arm/tests/breakpoints.c

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2024, UNSW Sydney
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <autoconf.h>
+
+#ifdef CONFIG_HARDWARE_DEBUG_API
+
+#include <sel4/sel4.h>
+#include <utils/attribute.h>
+
+#include <arch/debug.h>
+#include "../../../helpers.h"
+#include "../../../test.h"
+#include "../../../tests/breakpoints.h"
+
+static int faulter_main(seL4_Word arg0, seL4_Word arg1, seL4_Word arg2, seL4_Word arg3) {
+    TEST_SINGLE_STEP_ASM();
+    /* NOTHING BELOW SHOULD EVER BE REACHED */
+    int *ptr = NULL;
+    *ptr = 0xBEEF;
+    return 0;
+}
+
+static int handler_main(seL4_Word faulter_tcb, seL4_Word a1, seL4_Word a2, seL4_Word a3) {
+    seL4_Word sender_badge;
+    seL4_MessageInfo_t tag;
+    seL4_Word label;
+
+    /* Wait for the faulter to trigger an event. */
+    tag = api_wait(fault_ep_cspath.capPtr, &sender_badge);
+    ZF_LOGV("Handler got a fault on the ep.\n");
+    label = seL4_MessageInfo_get_label(tag);
+
+    /* Check that it is a breakpoint exception */
+    if (label != seL4_Fault_DebugException || seL4_GetMR(seL4_DebugException_ExceptionReason) != seL4_InstructionBreakpoint) {
+        ZF_LOGV("Received exception other than instruction breakpoint exception.\n");
+        return -1;
+    }
+
+    /* Disable the breakpoint and enable single stepping */
+    int error = seL4_TCB_UnsetBreakpoint(faulter_tcb, 0);
+    test_eq(error, 0);
+
+    seL4_TCB_ConfigureSingleStepping_t res = seL4_TCB_ConfigureSingleStepping(faulter_tcb, 0,1);
+    test_eq(res.error, 0);
+
+    /* Reply to the thread to resume it */
+    tag = api_reply_recv(fault_ep_cspath.capPtr, seL4_MessageInfo_new(0, 0, 0, 0), &sender_badge, 0);
+    label = seL4_MessageInfo_get_label(tag);
+
+    /* Wait for the single step exception */
+    fault_data.vaddr = seL4_GetMR(seL4_DebugException_FaultIP);
+    fault_data.reason = seL4_GetMR(seL4_DebugException_ExceptionReason);
+    fault_data.vaddr2 = seL4_GetMR(seL4_DebugException_TriggerAddress);
+    fault_data.bp_num = seL4_GetMR(seL4_DebugException_BreakpointNumber);
+
+    if (label == seL4_Fault_DebugException &&
+        fault_data.reason == seL4_SingleStep &&
+        fault_data.vaddr == (seL4_Word) &TEST_SS_LABEL_TWO) {
+
+        return 0;
+    } else {
+            ZF_LOGE("Fault of type %zd received. Vaddr 0x%zx\n", label, fault_data.vaddr);
+            fault_data.bp_num = 0;
+            return -1;
+    }
+}
+
+static int test_single_step_one(struct env *env) {
+    int error, result;
+    helper_thread_t faulter_thread, handler_thread;
+    test_eq(setup_caps_for_test(env), 0);
+
+    create_helper_thread(env, &handler_thread);
+    set_helper_priority(env, &handler_thread, BREAKPOINT_TEST_HANDLER_PRIO);
+
+    error = setup_faulter_thread_for_test(env, &faulter_thread);
+    test_eq(error, seL4_NoError);
+
+    /* We want it to run until the first label */
+    error = seL4_TCB_SetBreakpoint(get_helper_tcb(&faulter_thread), 0, (seL4_Word) &TEST_SS_LABEL_ONE,
+                                   seL4_InstructionBreakpoint, 0, seL4_BreakOnRead);
+    test_eq(error, seL4_NoError);
+
+    start_helper(env, &handler_thread, &handler_main, get_helper_tcb(&faulter_thread), 0, 0, 0);
+    start_helper(env, &faulter_thread, &faulter_main, 0, 0, 0, 0);
+
+    result = wait_for_helper(&handler_thread);
+
+    cleanup_helper(env, &faulter_thread);
+    cleanup_helper(env, &handler_thread);
+
+    /* Ensure the test was a success */
+    test_eq(result, 0);
+
+    return sel4test_get_result();
+}
+
+DEFINE_TEST(SINGLESTEP_001, "Test that single stepping 1 instruction works",
+            test_single_step_one, config_set(CONFIG_HARDWARE_DEBUG_API))
+
+#endif /* CONFIG_HARDWARE_DEBUG_API */