Add utilities for setting and dumping log buffer

libsel4debug/CMakeLists.txt

@@ -72,4 +72,13 @@ target_include_directories(
     sel4debug
     PUBLIC include "arch_include/${KernelArch}" sel4_arch_include/${KernelSel4Arch}
 )
-target_link_libraries(sel4debug PUBLIC muslc sel4 utils PRIVATE sel4debug_Config sel4_autoconf)
+target_link_libraries(
+    sel4debug
+    PUBLIC
+        muslc
+        sel4
+        utils
+        sel4vka
+        sel4vspace
+    PRIVATE sel4debug_Config sel4_autoconf
+)

libsel4debug/include/sel4debug/logbuffer.h

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2020, Data61
+ * Commonwealth Scientific and Industrial Research Organisation (CSIRO)
+ * ABN 41 687 119 230.
+ *
+ * This software may be distributed and modified according to the terms of
+ * the BSD 2-Clause license. Note that NO WARRANTY is provided.
+ * See "LICENSE_BSD2.txt" for details.
+ *
+ * @TAG(DATA61_BSD)
+ */
+
+#pragma once
+
+/* Utilities for working with the debug log buffer */
+
+#include <autoconf.h>
+#include <sel4/sel4.h>
+#include <sel4/log.h>
+#include <sel4/syscalls.h>
+#include <utils/base64.h>
+#include <vka/object.h>
+#include <vspace/vspace.h>
+
+/*
+ * Allocates and maps a new kernel log buffer.
+ *
+ * The large frame used for the kernel log buffer is placed in the frame
+ * argument and can be mapped into other address spaces.
+ */
+static int debug_log_buffer_init(vka_t *vka, vspace_t *vspace, vka_object_t *frame, seL4_LogBuffer *buffer)
+{
+#ifdef CONFIG_KERNEL_DEBUG_LOG_BUFFER
+    int err;
+    void *volatile vaddr;
+
+    err = vka_alloc_frame(vka, seL4_LogBufferBits, frame);
+    if (err != 0) {
+        return err;
+    }
+
+    err = seL4_BenchmarkSetLogBuffer(frame->cptr);
+    if (err != 0) {
+        ZF_LOGE("Failed to set debug log buffer frame using cap %lu.\n", frame->cptr);
+        return err;
+    }
+
+    vaddr = vspace_map_pages(vspace, &frame->cptr, NULL, seL4_AllRights, 1, seL4_LogBufferBits, 1);
+    if (vaddr == NULL) {
+        ZF_LOGE("Failed to map log buffer into VMM addrspace.\n");
+        return -1;
+    }
+
+    *buffer = seL4_LogBuffer_new(vaddr);
+
+    ZF_LOGD("Log buffer (cptr %lu) mapped to vaddr %p.\n", frame->cptr, vaddr);
+
+    return seL4_NoError;
+#else
+    *buffer = seL4_LogBuffer_new(NULL);
+    return seL4_NoError;
+#endif
+}
+
+/*
+ * Reset the debug log buffer.
+ *
+ * All new events will be placed at the start of the buffer.
+ */
+static int debug_log_buffer_reset(seL4_LogBuffer *buffer)
+{
+    seL4_LogBuffer_reset(buffer);
+#ifdef CONFIG_KERNEL_DEBUG_LOG_BUFFER
+    return seL4_BenchmarkResetLog();
+#else
+    return seL4_NoError;
+#endif
+}
+
+/*
+ * Finalise the debug log buffer.
+ *
+ * All new events will be placed at the start of the buffer.
+ */
+static void debug_log_buffer_finalise(seL4_LogBuffer *buffer)
+{
+#ifdef CONFIG_KERNEL_DEBUG_LOG_BUFFER
+    seL4_LogBuffer_setSize(buffer, seL4_BenchmarkFinalizeLog());
+#else
+    seL4_LogBuffer_reset(buffer);
+#endif
+}
+
+/*
+ * Dump the debug log to the given output.
+ *
+ * This will also finalise the kernel log buffer, stopping subsequent
+ * output.
+ */
+int debug_log_buffer_dump_cbor64(seL4_LogBuffer *buffer, base64_t *streamer);

libsel4debug/src/logbuffer.c

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2020, Data61
+ * Commonwealth Scientific and Industrial Research Organisation (CSIRO)
+ * ABN 41 687 119 230.
+ *
+ * This software may be distributed and modified according to the terms of
+ * the BSD 2-Clause license. Note that NO WARRANTY is provided.
+ * See "LICENSE_BSD2.txt" for details.
+ *
+ * @TAG(DATA61_BSD)
+ */
+
+/* Utilities for working with the debug log buffer */
+
+#include <sel4debug/logbuffer.h>
+#include <utils/base64.h>
+#include <utils/cbor64.h>
+
+/* Strings tracked and compressed in the string domain */
+char *identifiers[] = {
+    /* Event type */
+    "type",
+    "Unknown",
+
+    /* None event */
+    "None",
+
+    /* Entry and exit events */
+    "Entry",
+    "Exit",
+    "cpu-id",
+    "timestamp",
+
+    /* NULL array terminator */
+    NULL,
+};
+
+/* Number of fields in event other than the type fields */
+size_t field_count[seL4_NumLogTypeIds] = {
+    [seL4_Log_TypeId(None)] = 0,
+    [seL4_Log_TypeId(Entry)] = 2,
+    [seL4_Log_TypeId(Exit)] = 2,
+};
+
+/*
+ * Dump a single event as JSON
+ */
+static int event_cbor64(seL4_LogEvent *event, cbor64_domain_t *domain, base64_t *streamer)
+{
+    int event_type = seL4_LogEvent_type(event);
+
+    /* Display the type */
+    cbor64_map_length(streamer, field_count[event_type] + 1);
+    cbor64_utf8_ref(streamer, domain, "type");
+
+    switch (event_type) {
+    case seL4_Log_TypeId(None): {
+        cbor64_utf8_ref(streamer, domain, "None");
+        break;
+    }
+
+    case seL4_Log_TypeId(Entry): {
+        seL4_Log_Type(Entry) *entry = seL4_Log_Cast(Entry)event;
+        cbor64_utf8_ref(streamer, domain, "Entry");
+
+        cbor64_utf8_ref(streamer, domain, "cpu-id");
+        cbor64_uint(streamer, event->data);
+
+        cbor64_utf8_ref(streamer, domain, "timestamp");
+        cbor64_uint(streamer, entry->timestamp);
+        break;
+    }
+
+    case seL4_Log_TypeId(Exit): {
+        seL4_Log_Type(Exit) *exit = seL4_Log_Cast(Exit)event;
+        cbor64_utf8_ref(streamer, domain, "Exit");
+
+        cbor64_utf8_ref(streamer, domain, "cpu-id");
+        cbor64_uint(streamer, event->data);
+
+        cbor64_utf8_ref(streamer, domain, "timestamp");
+        cbor64_uint(streamer, exit->timestamp);
+        break;
+    }
+
+    default: {
+        cbor64_utf8_ref(streamer, domain, "Unknown");
+        break;
+    }
+    }
+
+    return 0;
+}
+
+/*
+ * Dump the debug log to the given output
+ */
+int debug_log_buffer_dump_cbor64(seL4_LogBuffer *buffer, base64_t *streamer)
+{
+    /* Start a new string domain */
+    cbor64_domain_t domain;
+    cbor64_string_ref_domain(streamer, identifiers, &domain);
+
+    /* Stop logging events */
+    debug_log_buffer_finalise(buffer);
+
+    /* Create a copy of the log buffer to traverse the events */
+    seL4_LogBuffer cursor = *buffer;
+
+    cbor64_array_start(streamer);
+    seL4_LogEvent *event = seL4_LogBuffer_next(&cursor);
+    while (event != NULL) {
+        int err = event_cbor64(event, &domain, streamer);
+        if (err != 0) {
+            return err;
+        }
+
+        event = seL4_LogBuffer_next(&cursor);
+    }
+    return cbor64_array_end(streamer);
+}