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 --- doc/README.trace | 361 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/common.h | 4 + include/trace.h | 125 ++++++++++++++++++ lib/Makefile | 1 + lib/trace.c | 378 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 869 insertions(+) create mode 100644 doc/README.trace create mode 100644 include/trace.h create mode 100644 lib/trace.c
diff --git a/doc/README.trace b/doc/README.trace new file mode 100644 index 0000000..b535c06 --- /dev/null +++ b/doc/README.trace @@ -0,0 +1,361 @@ +# +# Copyright (c) 2013 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 Foundatio; 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 +# + +Tracing in U-Boot +================= + +U-Boot supports a simple tracing feature which allows a record of excecution +to be collected and sent to a host machine for analysis. At present the +main use for this is to profile boot time. + + +Overview +-------- + +The trace feature uses GCC's instrument-functions feature to trace all +function entry/exit points. These are then recorded in a memory buffer. +The memory buffer can be saved to the host over a network link using +tftpput or by writing to an attached memory device such as MMC. + +On the host, the file is first converted with a tool called 'proftool', +which extracts useful information from it. The resulting trace output +resembles that emitted by Linux's ftrace feature, so can be visually +displayed by pytimechart. + + +Quick-start using Sandbox +------------------------- + +Sandbox is a build of U-Boot that can run under Linux so it is a convenient +way of trying out tracing before you use it on your actual board. To do +this, follow these steps: + +Add the following to include/configs/sandbox.h (if not already there) + +#define CONFIG_TRACE +#define CONFIG_CMD_TRACE +#define CONFIG_TRACE_BUFFER_SIZE (16 << 20) +#define CONFIG_TRACE_EARLY_SIZE (8 << 20) +#define CONFIG_TRACE_EARLY +#define CONFIG_TRACE_EARLY_ADDR 0x00100000 + +Build sandbox U-Boot with tracing enabled: + +$ make FTRACE=1 O=sandbox sandbox_config +$ make FTRACE=1 O=sandbox + +Run sandbox, wait for a bit of trace information to appear, and then capture +a trace: + +$ ./sandbox/u-boot + + +U-Boot 2013.04-rc2-00100-ga72fcef (Apr 17 2013 - 19:25:24) + +DRAM: 128 MiB +trace: enabled +Using default environment + +In: serial +Out: serial +Err: serial +=>trace stats + 671,406 function sites + 69,712 function calls + 0 untracked function calls + 73,373 traced function calls + 16 maximum observed call depth + 15 call depth limit + 66,491 calls not traced due to depth +=>trace stats + 671,406 function sites + 1,279,450 function calls + 0 untracked function calls + 950,490 traced function calls (333217 dropped due to overflow) + 16 maximum observed call depth + 15 call depth limit + 1,275,767 calls not traced due to depth +=>trace calls 0 e00000 +Call list dumped to 00000000, size 0xae0a40 +=>print +baudrate=115200 +profbase=0 +profoffset=ae0a40 +profsize=e00000 +stderr=serial +stdin=serial +stdout=serial + +Environment size: 117/8188 bytes +=>sb save host 0 trace 0 ${profoffset} +11405888 bytes written in 10 ms (1.1 GiB/s) +=>reset + + +Then run proftool to convert the trace information to ftrace format. + +$ ./sandbox/tools/proftool -m sandbox/System.map -p trace dump-ftrace >trace.txt + +Finally run pytimechart to display it: + +$ pytimechart trace.txt + +Using this tool you can zoom and pan across the trace, with the function +calls on the left and little marks representing the start and end of each +function. + + +CONFIG Options +-------------- + +- CONFIG_TRACE + Enables the trace feature in U-Boot. + +- CONFIG_CMD_TRACE + Enables the trace command. + +- CONFIG_TRACE_BUFFER_SIZE + Size of trace buffer to allocate for U-Boot. This buffer is + used after relocation, as a place to put function tracing + information. The address of the buffer is determined by + the relocation code. + +- CONFIG_TRACE_EARLY + Define this to start tracing early, before relocation. + +- CONFIG_TRACE_EARLY_SIZE + Size of 'early' trace buffer. Before U-Boot has relocated + it doesn't have a proper trace buffer. On many boards + you can define an area of memory to use for the trace + buffer until the 'real' trace buffer is available after + relocation. The contents of this buffer are then copied to + the real buffer. + +- CONFIG_TRACE_EARLY_ADDR + Address of early trace buffer + + +Building U-Boot with Tracing Enabled +------------------------------------ + +Pass 'FTRACE=1' to the U-Boot Makefile to actually instrument the code. +This is kept as a separate option so that it is easy to enable/disable +instrumenting from the command line instead of having to change board +config files. + + +Collecting Trace Data +--------------------- + +When you run U-Boot on your board it will collect trace data up to the +limit of the trace buffer size you have specified. Once that is exhausted +no more data will be collected. + +Collecting trace data has an affect on execution time/performance. You +will notice this particularly with trvial functions - the overhead of +recording their execution may even exceed their normal execution time. +In practice this doesn't matter much so long as you are aware of the +effect. Once you have done your optimisations, turn off tracing before +doing end-to-end timing. + +The best time to start tracing is right at the beginning of U-Boot. The +best time to stop tracing is right at the end. In practice it is hard +to achieve these ideals. + +This implementation enables tracing early in board_init_f(). This means +that it captures most of the board init process, missing only the +early architecture-specific init. However, it also misses the entire +SPL stage if there is one. + +U-Boot typically ends with a 'bootm' command which loads and runs an +OS. There is useful trace data in the execution of that bootm +command. Therefore this implementation provides a way to collect trace +data after bootm has finished processing, but just before it jumps to +the OS. In practical terms, U-Boot runs the 'fakegocmd' environment +variable at this point. This variable should have a short script which +collects the trace data and writes it somewhere. + +Trace data collection relies on a microsecond timer, accesed through +timer_get_us(). So the first think you should do is make sure that +this produces sensible results for your board. Suitable sources for +this timer include high resolution timers, PWMs or profile timers if +available. Most modern SOCs have a suitable timer for this. Make sure +that you mark this timer (and anything it calls) with +__attribute__((no_instrument_function)) so that the trace library can +use it without causing an infinite loop. + + +Commands +-------- + +The trace command has variable sub-commands: + +- stats + Display tracing statistics + +- pause + Pause tracing + +- resume + Resume tracing + +- funclist [<addr> <size>] + Dump a list of functions into the buffer + +- calls [<addr> <size>] + Dump function call trace into buffer + +If the address and size are not given, these are obtained from environment +variables (see below). In any case the environment variables are updated +after the command runs. + + +Environment Variables +--------------------- + +The following are used: + +- profbase + Base address of trace output buffer + +- profoffset + Offset of first unwritten byte in trace output buffer + +- profsize + Size of trace output buffer + +All of these are set by the 'trace calls' command. + +These variables keep track of the amount of data written to the trace +output buffer by the 'trace' command. The trace commands which write data +to the output buffer can use these to specify the buffer to write to, and +update profoffset each time. This allows successive commands to append data +to the same buffer, for example: + + trace funclist 10000 e00000 + trace calls + +(the latter command appends more data to the buffer). + + +- fakegocmd + Specifies commands to run just before booting the OS. This + is a useful time to write the trace data to the host for + processing. + + +Writing Out Trace Data +---------------------- + +Once the trace data is in an output buffer in memory there are various ways +to transmit it to the host. Notably you can use tftput to send the data +over a network link: + +fakegocmd=trace pause; usb start; set autoload n; bootp; + trace calls 10000000 1000000; + tftpput ${profbase} ${profoffset} 192.168.1.4:/tftpboot/calls + +This starts up USB (to talk to an attached USB Ethernet dongle), writes +a trace log to address 10000000 and sends it to a host machine using +TFTP. After this, U-Boot will boot the OS normally, albeit a little +later. + + +Converting Trace Output Data +---------------------------- + +The trace output data is kept in a binary format which is not documented +here. To convert it into something useful, you can use proftool. + +This tool must be given the U-Boot map file and the trace data received +from running that U-Boot. It produces a text output file. + +Options + -m <map_file> + Specify U-Boot map file + + -p <trace_file> + Specifiy profile/trace file + +Commands: + +- dump-ftrace + Write a text dump of the file in Linux ftrace format to stdout + + +Viewing the Trace Data +---------------------- + +You can use pytimechart for this (sudo apt-get pytimechart might work on +your Debian-style machine, and use your favourite search engine to obtain +documentation). It expects the file to have a .txt extension. The program +has terse user interface but is very convenient for viewing U-Boot +profile information. + + +Workflow Suggestions +-------------------- + +The following suggestions may be helpful if you are trying to reduce boot +time: + +1. Enable CONFIG_BOOTSTAGE and CONFIG_BOOTSTAGE_REPORT. This should get +you are helpful overall snapshot of the boot time. + +2. Build U-Boot with tracing and run it. Note the difference in boot time +(it is common for tracing to add 10% to the time) + +3. Collect the trace information as descibed above. Use this to find where +all the time is being spent. + +4. Take a look at that code and see if you can optimise it. Perhaps it is +possible to speed up the initialisation of a device, or remove an unused +feature. + +5. Rebuild, run and collect again. Compare your results. + +6. Keep going until you run out of steam, or your boot is fast enough. + + +Configuring Trace +----------------- + +There are a few parameters in the code that you may want to consider. +There is a function call depth limit (set to 15 by default). When the +stack depth goes above this then no tracing information is recorded. +The maximum depth reached is recorded and displayed by the 'trace stats' +command. + + +Future Work +----------- + +Tracing could be a little tidier in some areas, for example providing +run-time configuration options for trace. + +Some other features that might be useful: + +- Trace filter to select which functions are recorded +- Sample-based profiling using a timer interrupt +- Better control over trace depth +- Compression of trace information + + +Simon Glass sjg@chromium.org +April 2013 diff --git a/include/common.h b/include/common.h index 8003b62..26b7f3a 100644 --- a/include/common.h +++ b/include/common.h @@ -745,6 +745,10 @@ void irq_install_handler(int, interrupt_handler_t *, void *); void irq_free_handler (int); void reset_timer (void); ulong get_timer (ulong base); + +/* Return value of monotonic microsecond timer */ +unsigned long timer_get_us(void); + void enable_interrupts (void); int disable_interrupts (void);
diff --git a/include/trace.h b/include/trace.h new file mode 100644 index 0000000..8082466 --- /dev/null +++ b/include/trace.h @@ -0,0 +1,125 @@ +/* + * 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 + */ + +#ifndef __TRACE_H +#define __TRACE_H + +enum { + /* + * This affects the granularity of our trace. We can bin function + * entry points into groups on the basis that functions typically + * have a minimum size, so entry points can't appear any closer + * than this to each other. + * + * The value here assumes a minimum instruction size of 4 bytes, + * or that instructions are 2 bytes but there are at least 2 of + * them in every function. + * + * Increasing this value reduces the number of functions we can + * resolve, but reduces the size of the uintptr_t array used for + * our function list, which is the length of the code divided by + * this value. + */ + FUNC_SITE_SIZE = 4, /* distance between function sites */ +}; + +enum trace_chunk_type { + TRACE_CHUNK_FUNCS, + TRACE_CHUNK_CALLS, +}; + +/* A trace record for a function, as written to the profile output file */ +struct trace_output_func { + uint32_t offset; /* Function offset into code */ + uint32_t call_count; /* Number of times called */ +}; + +/* A header at the start of the trace output buffer */ +struct trace_output_hdr { + enum trace_chunk_type type; /* Record type */ + uint32_t rec_count; /* Number of records */ +}; + +/* Print statistics about traced function calls */ +void trace_print_stats(void); + +/** + * Dump a list of functions and call counts into a buffer + * + * Each record in the buffer is a struct trace_func_stats. The 'needed' + * parameter returns the number of bytes needed to complete the operation, + * which may be more than buff_size if your buffer is too small. + * + * @param buff Buffer in which to place data, or NULL to count size + * @param buff_size Size of buffer + * @param needed Returns number of bytes used / needed + * @return 0 if ok, -1 on error (buffer exhausted) + */ +int trace_list_functions(void *buff, int buff_size, unsigned *needed); + +/* Flags for ftrace_record */ +enum ftrace_flags { + FUNCF_EXIT = 0UL << 30, + FUNCF_ENTRY = 1UL << 30, + FUNCF_TEXTBASE = 2UL << 30, + + FUNCF_TIMESTAMP_MASK = 0x3fffffff, +}; + +#define TRACE_CALL_TYPE(call) ((call)->flags & 0xc0000000UL) + +/* Information about a single function entry/exit */ +struct trace_call { + uint32_t func; /* Function offset */ + uint32_t caller; /* Caller function offset */ + uint32_t flags; /* Flags and timestamp */ +}; + +int trace_list_calls(void *buff, int buff_size, unsigned int *needed); + +/** + * Turn function tracing on and off + * + * Don't enable trace if it has not been initialised. + * + * @param enabled 1 to enable trace, 0 to disable + */ +void trace_set_enabled(int enabled); + +#ifdef CONFIG_TRACE_EARLY +int trace_early_init(void); +#else +static inline int trace_early_init(void) +{ + return 0; +} +#endif + +/** + * Init the trace system + * + * This should be called after relocation with a suitably large buffer + * (typically as large as the U-Boot text area) + * + * @param buff Pointer to trace buffer + * @param buff_size Size of trace buffer + */ +int trace_init(void *buff, size_t buff_size); + +#endif diff --git a/lib/Makefile b/lib/Makefile index e901cc7..b681113 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -74,6 +74,7 @@ COBJS-y += div64.o COBJS-y += linux_string.o COBJS-y += string.o COBJS-y += time.o +COBJS-$(CONFIG_TRACE) += trace.o COBJS-$(CONFIG_BOOTP_PXE) += uuid.o COBJS-y += vsprintf.o COBJS-$(CONFIG_RANDOM_MACADDR) += rand.o diff --git a/lib/trace.c b/lib/trace.c new file mode 100644 index 0000000..1c0a40e --- /dev/null +++ b/lib/trace.c @@ -0,0 +1,378 @@ +/* + * 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, 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