Add trace library
Add a library which supports tracing of execution using built-in gcc
features and a microsecond timer. This can be used to record a list of
function which are executed, along with a timestamp for each. Later
this information can be sent to the host for processing.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/trace.c b/lib/trace.c
new file mode 100644
index 0000000..e7455bc
--- /dev/null
+++ b/lib/trace.c
@@ -0,0 +1,379 @@
+/*
+ * Copyright (c) 2012 The Chromium OS Authors.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <trace.h>
+#include <asm/io.h>
+#include <asm/sections.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static char trace_enabled __attribute__((section(".data")));
+static char trace_inited __attribute__((section(".data")));
+
+/* The header block at the start of the trace memory area */
+struct trace_hdr {
+ int func_count; /* Total number of function call sites */
+ u64 call_count; /* Total number of tracked function calls */
+ u64 untracked_count; /* Total number of untracked function calls */
+ int funcs_used; /* Total number of functions used */
+
+ /*
+ * Call count for each function. This is indexed by the word offset
+ * of the function from gd->relocaddr
+ */
+ uintptr_t *call_accum;
+
+ /* Function trace list */
+ struct trace_call *ftrace; /* The function call records */
+ ulong ftrace_size; /* Num. of ftrace records we have space for */
+ ulong ftrace_count; /* Num. of ftrace records written */
+ ulong ftrace_too_deep_count; /* Functions that were too deep */
+
+ int depth;
+ int depth_limit;
+ int max_depth;
+};
+
+static struct trace_hdr *hdr; /* Pointer to start of trace buffer */
+
+static inline uintptr_t __attribute__((no_instrument_function))
+ func_ptr_to_num(void *func_ptr)
+{
+ uintptr_t offset = (uintptr_t)func_ptr;
+
+#ifdef CONFIG_SANDBOX
+ offset -= (uintptr_t)&_init;
+#else
+ if (gd->flags & GD_FLG_RELOC)
+ offset -= gd->relocaddr;
+ else
+ offset -= CONFIG_SYS_TEXT_BASE;
+#endif
+ return offset / FUNC_SITE_SIZE;
+}
+
+static void __attribute__((no_instrument_function)) add_ftrace(void *func_ptr,
+ void *caller, ulong flags)
+{
+ if (hdr->depth > hdr->depth_limit) {
+ hdr->ftrace_too_deep_count++;
+ return;
+ }
+ if (hdr->ftrace_count < hdr->ftrace_size) {
+ struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];
+
+ rec->func = func_ptr_to_num(func_ptr);
+ rec->caller = func_ptr_to_num(caller);
+ rec->flags = flags | (timer_get_us() & FUNCF_TIMESTAMP_MASK);
+ }
+ hdr->ftrace_count++;
+}
+
+static void __attribute__((no_instrument_function)) add_textbase(void)
+{
+ if (hdr->ftrace_count < hdr->ftrace_size) {
+ struct trace_call *rec = &hdr->ftrace[hdr->ftrace_count];
+
+ rec->func = CONFIG_SYS_TEXT_BASE;
+ rec->caller = 0;
+ rec->flags = FUNCF_TEXTBASE;
+ }
+ hdr->ftrace_count++;
+}
+
+/**
+ * This is called on every function entry
+ *
+ * We add to our tally for this function and add to the list of called
+ * functions.
+ *
+ * @param func_ptr Pointer to function being entered
+ * @param caller Pointer to function which called this function
+ */
+void __attribute__((no_instrument_function)) __cyg_profile_func_enter(
+ void *func_ptr, void *caller)
+{
+ if (trace_enabled) {
+ int func;
+
+ add_ftrace(func_ptr, caller, FUNCF_ENTRY);
+ func = func_ptr_to_num(func_ptr);
+ if (func < hdr->func_count) {
+ hdr->call_accum[func]++;
+ hdr->call_count++;
+ } else {
+ hdr->untracked_count++;
+ }
+ hdr->depth++;
+ if (hdr->depth > hdr->depth_limit)
+ hdr->max_depth = hdr->depth;
+ }
+}
+
+/**
+ * This is called on every function exit
+ *
+ * We do nothing here.
+ *
+ * @param func_ptr Pointer to function being entered
+ * @param caller Pointer to function which called this function
+ */
+void __attribute__((no_instrument_function)) __cyg_profile_func_exit(
+ void *func_ptr, void *caller)
+{
+ if (trace_enabled) {
+ add_ftrace(func_ptr, caller, FUNCF_EXIT);
+ hdr->depth--;
+ }
+}
+
+/**
+ * Produce a list of called functions
+ *
+ * The information is written into the supplied buffer - a header followed
+ * by a list of function records.
+ *
+ * @param buff Buffer to place list into
+ * @param buff_size Size of buffer
+ * @param needed Returns size of buffer needed, which may be
+ * greater than buff_size if we ran out of space.
+ * @return 0 if ok, -1 if space was exhausted
+ */
+int trace_list_functions(void *buff, int buff_size, unsigned int *needed)
+{
+ struct trace_output_hdr *output_hdr = NULL;
+ void *end, *ptr = buff;
+ int func;
+ int upto;
+
+ end = buff ? buff + buff_size : NULL;
+
+ /* Place some header information */
+ if (ptr + sizeof(struct trace_output_hdr) < end)
+ output_hdr = ptr;
+ ptr += sizeof(struct trace_output_hdr);
+
+ /* Add information about each function */
+ for (func = upto = 0; func < hdr->func_count; func++) {
+ int calls = hdr->call_accum[func];
+
+ if (!calls)
+ continue;
+
+ if (ptr + sizeof(struct trace_output_func) < end) {
+ struct trace_output_func *stats = ptr;
+
+ stats->offset = func * FUNC_SITE_SIZE;
+ stats->call_count = calls;
+ upto++;
+ }
+ ptr += sizeof(struct trace_output_func);
+ }
+
+ /* Update the header */
+ if (output_hdr) {
+ output_hdr->rec_count = upto;
+ output_hdr->type = TRACE_CHUNK_FUNCS;
+ }
+
+ /* Work out how must of the buffer we used */
+ *needed = ptr - buff;
+ if (ptr > end)
+ return -1;
+ return 0;
+}
+
+int trace_list_calls(void *buff, int buff_size, unsigned *needed)
+{
+ struct trace_output_hdr *output_hdr = NULL;
+ void *end, *ptr = buff;
+ int rec, upto;
+ int count;
+
+ end = buff ? buff + buff_size : NULL;
+
+ /* Place some header information */
+ if (ptr + sizeof(struct trace_output_hdr) < end)
+ output_hdr = ptr;
+ ptr += sizeof(struct trace_output_hdr);
+
+ /* Add information about each call */
+ count = hdr->ftrace_count;
+ if (count > hdr->ftrace_size)
+ count = hdr->ftrace_size;
+ for (rec = upto = 0; rec < count; rec++) {
+ if (ptr + sizeof(struct trace_call) < end) {
+ struct trace_call *call = &hdr->ftrace[rec];
+ struct trace_call *out = ptr;
+
+ out->func = call->func * FUNC_SITE_SIZE;
+ out->caller = call->caller * FUNC_SITE_SIZE;
+ out->flags = call->flags;
+ upto++;
+ }
+ ptr += sizeof(struct trace_call);
+ }
+
+ /* Update the header */
+ if (output_hdr) {
+ output_hdr->rec_count = upto;
+ output_hdr->type = TRACE_CHUNK_CALLS;
+ }
+
+ /* Work out how must of the buffer we used */
+ *needed = ptr - buff;
+ if (ptr > end)
+ return -1;
+ return 0;
+}
+
+/* Print basic information about tracing */
+void trace_print_stats(void)
+{
+ ulong count;
+
+#ifndef FTRACE
+ puts("Warning: make U-Boot with FTRACE to enable function instrumenting.\n");
+ puts("You will likely get zeroed data here\n");
+#endif
+ if (!trace_inited) {
+ printf("Trace is disabled\n");
+ return;
+ }
+ print_grouped_ull(hdr->func_count, 10);
+ puts(" function sites\n");
+ print_grouped_ull(hdr->call_count, 10);
+ puts(" function calls\n");
+ print_grouped_ull(hdr->untracked_count, 10);
+ puts(" untracked function calls\n");
+ count = min(hdr->ftrace_count, hdr->ftrace_size);
+ print_grouped_ull(count, 10);
+ puts(" traced function calls");
+ if (hdr->ftrace_count > hdr->ftrace_size) {
+ printf(" (%lu dropped due to overflow)",
+ hdr->ftrace_count - hdr->ftrace_size);
+ }
+ puts("\n");
+ printf("%15d maximum observed call depth\n", hdr->max_depth);
+ printf("%15d call depth limit\n", hdr->depth_limit);
+ print_grouped_ull(hdr->ftrace_too_deep_count, 10);
+ puts(" calls not traced due to depth\n");
+}
+
+void __attribute__((no_instrument_function)) trace_set_enabled(int enabled)
+{
+ trace_enabled = enabled != 0;
+}
+
+/**
+ * Init the tracing system ready for used, and enable it
+ *
+ * @param buff Pointer to trace buffer
+ * @param buff_size Size of trace buffer
+ */
+int __attribute__((no_instrument_function)) trace_init(void *buff,
+ size_t buff_size)
+{
+ ulong func_count = gd->mon_len / FUNC_SITE_SIZE;
+ size_t needed;
+ int was_disabled = !trace_enabled;
+
+ if (!was_disabled) {
+#ifdef CONFIG_TRACE_EARLY
+ char *end;
+ ulong used;
+
+ /*
+ * Copy over the early trace data if we have it. Disable
+ * tracing while we are doing this.
+ */
+ trace_enabled = 0;
+ hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR,
+ CONFIG_TRACE_EARLY_SIZE);
+ end = (char *)&hdr->ftrace[hdr->ftrace_count];
+ used = end - (char *)hdr;
+ printf("trace: copying %08lx bytes of early data from %x to %08lx\n",
+ used, CONFIG_TRACE_EARLY_ADDR,
+ (ulong)map_to_sysmem(buff));
+ memcpy(buff, hdr, used);
+#else
+ puts("trace: already enabled\n");
+ return -1;
+#endif
+ }
+ hdr = (struct trace_hdr *)buff;
+ needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
+ if (needed > buff_size) {
+ printf("trace: buffer size %zd bytes: at least %zd needed\n",
+ buff_size, needed);
+ return -1;
+ }
+
+ if (was_disabled)
+ memset(hdr, '\0', needed);
+ hdr->func_count = func_count;
+ hdr->call_accum = (uintptr_t *)(hdr + 1);
+
+ /* Use any remaining space for the timed function trace */
+ hdr->ftrace = (struct trace_call *)(buff + needed);
+ hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
+ add_textbase();
+
+ puts("trace: enabled\n");
+ hdr->depth_limit = 15;
+ trace_enabled = 1;
+ trace_inited = 1;
+ return 0;
+}
+
+#ifdef CONFIG_TRACE_EARLY
+int __attribute__((no_instrument_function)) trace_early_init(void)
+{
+ ulong func_count = gd->mon_len / FUNC_SITE_SIZE;
+ size_t buff_size = CONFIG_TRACE_EARLY_SIZE;
+ size_t needed;
+
+ /* We can ignore additional calls to this function */
+ if (trace_enabled)
+ return 0;
+
+ hdr = map_sysmem(CONFIG_TRACE_EARLY_ADDR, CONFIG_TRACE_EARLY_SIZE);
+ needed = sizeof(*hdr) + func_count * sizeof(uintptr_t);
+ if (needed > buff_size) {
+ printf("trace: buffer size is %zd bytes, at least %zd needed\n",
+ buff_size, needed);
+ return -1;
+ }
+
+ memset(hdr, '\0', needed);
+ hdr->call_accum = (uintptr_t *)(hdr + 1);
+ hdr->func_count = func_count;
+
+ /* Use any remaining space for the timed function trace */
+ hdr->ftrace = (struct trace_call *)((char *)hdr + needed);
+ hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
+ add_textbase();
+ hdr->depth_limit = 200;
+ printf("trace: early enable at %08x\n", CONFIG_TRACE_EARLY_ADDR);
+
+ trace_enabled = 1;
+ return 0;
+}
+#endif