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xscale: trace buffer remains enabled until explicitly disabled 

Hi everyone,

Since a call went out for patches... been sitting on this for months.  For some
reason, the xscale trace buffer is automatically disabled as soon as a break
occurs and the trace data is collected.  This patch was a result of the
frustration of always re-enabling it, or else hitting a breakpoint and checking
the trace data, only to discover that I forgot to re-enable it before resuming.
Don't see why it should work this way.  There is no run-time penalty, AFAIK.

Along the way, I also cleaned up a little by removing the ugly practice of
recording wrap mode by setting the fill count variable to "-1", replacing it
with an enum that records the trace mode.

I've been using this for months.  Comments, criticisms gratefully received.

Mike

Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
This commit is contained in:
Mike Dunn 2010-12-02 11:08:28 -08:00 committed by Øyvind Harboe
parent 81790fb56a
commit 2e7d51c96a
2 changed files with 97 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

138
src/target/xscale.c
View File

@ -1044,21 +1044,20 @@ static int xscale_debug_entry(struct target *target)
xscale->armv4_5_mmu.armv4_5_cache.i_cache_enabled = (xscale->cp15_control_reg & 0x1000U) ? 1 : 0;
/* tracing enabled, read collected trace data */
if (xscale->trace.buffer_enabled)
if (xscale->trace.mode != XSCALE_TRACE_DISABLED)
{
xscale_read_trace(target);
xscale->trace.buffer_fill--;
/* resume if we're still collecting trace data */
if ((xscale->arch_debug_reason == XSCALE_DBG_REASON_TB_FULL)
&& (xscale->trace.buffer_fill > 0))
/* Resume if entered debug due to buffer fill and we're still collecting
* trace data. Note that a debug exception due to trace buffer full
* can only happen in fill mode. */
if (xscale->arch_debug_reason == XSCALE_DBG_REASON_TB_FULL)
{
if (--xscale->trace.fill_counter > 0)
xscale_resume(target, 1, 0x0, 1, 0);
}
else
{
xscale->trace.buffer_enabled = 0;
}
else /* entered debug for other reason; reset counter */
xscale->trace.fill_counter = 0;
}
return ERROR_OK;
@ -1162,6 +1161,20 @@ static void xscale_enable_breakpoints(struct target *target)
}
}
static void xscale_free_trace_data(struct xscale_common *xscale)
{
struct xscale_trace_data *td = xscale->trace.data;
while (td)
{
struct xscale_trace_data *next_td = td->next;
if (td->entries)
free(td->entries);
free(td);
td = next_td;
}
xscale->trace.data = NULL;
}
static int xscale_resume(struct target *target, int current,
uint32_t address, int handle_breakpoints, int debug_execution)
{
@ -1210,7 +1223,7 @@ static int xscale_resume(struct target *target, int current,
if (breakpoint != NULL)
{
uint32_t next_pc;
int saved_trace_buffer_enabled;
enum trace_mode saved_trace_mode;
/* there's a breakpoint at the current PC, we have to step over it */
LOG_DEBUG("unset breakpoint at 0x%8.8" PRIx32 "", breakpoint->address);
@ -1253,14 +1266,14 @@ static int xscale_resume(struct target *target, int current,
buf_get_u32(armv4_5->pc->value, 0, 32));
/* disable trace data collection in xscale_debug_entry() */
saved_trace_buffer_enabled = xscale->trace.buffer_enabled;
xscale->trace.buffer_enabled = 0;
saved_trace_mode = xscale->trace.mode;
xscale->trace.mode = XSCALE_TRACE_DISABLED;
/* wait for and process debug entry */
xscale_debug_entry(target);
/* re-enable trace buffer, if enabled previously */
xscale->trace.buffer_enabled = saved_trace_buffer_enabled;
xscale->trace.mode = saved_trace_mode;
LOG_DEBUG("disable single-step");
xscale_disable_single_step(target);
@ -1279,8 +1292,21 @@ static int xscale_resume(struct target *target, int current,
/* send resume request (command 0x30 or 0x31)
* clean the trace buffer if it is to be enabled (0x62) */
if (xscale->trace.buffer_enabled)
if (xscale->trace.mode != XSCALE_TRACE_DISABLED)
{
if (xscale->trace.mode == XSCALE_TRACE_FILL)
{
/* If trace enabled in fill mode and starting collection of new set
* of buffers, initialize buffer counter and free previous buffers */
if (xscale->trace.fill_counter == 0)
{
xscale->trace.fill_counter = xscale->trace.buffer_fill;
xscale_free_trace_data(xscale);
}
}
else /* wrap mode; free previous buffer */
xscale_free_trace_data(xscale);
xscale_send_u32(target, 0x62);
xscale_send_u32(target, 0x31);
}
@ -1356,7 +1382,7 @@ static int xscale_step_inner(struct target *target, int current,
/* send resume request (command 0x30 or 0x31)
* clean the trace buffer if it is to be enabled (0x62) */
if (xscale->trace.buffer_enabled)
if (xscale->trace.mode != XSCALE_TRACE_DISABLED)
{
if ((retval = xscale_send_u32(target, 0x62)) != ERROR_OK)
return retval;
@ -1533,6 +1559,9 @@ static int xscale_deassert_reset(struct target *target)
breakpoint = breakpoint->next;
}
xscale->trace.mode = XSCALE_TRACE_DISABLED;
xscale_free_trace_data(xscale);
register_cache_invalidate(xscale->armv4_5_common.core_cache);
/* FIXME mark hardware watchpoints got unset too. Also,
@ -3120,11 +3149,11 @@ static int xscale_init_arch_info(struct target *target,
xscale->vector_catch = 0x1;
xscale->trace.capture_status = TRACE_IDLE;
xscale->trace.data = NULL;
xscale->trace.image = NULL;
xscale->trace.buffer_enabled = 0;
xscale->trace.mode = XSCALE_TRACE_DISABLED;
xscale->trace.buffer_fill = 0;
xscale->trace.fill_counter = 0;
/* prepare ARMv4/5 specific information */
armv4_5->arch_info = xscale;
@ -3466,47 +3495,54 @@ COMMAND_HANDLER(xscale_handle_trace_buffer_command)
return ERROR_OK;
}
if ((CMD_ARGC >= 1) && (strcmp("enable", CMD_ARGV[0]) == 0))
if (CMD_ARGC >= 1)
{
struct xscale_trace_data *td, *next_td;
xscale->trace.buffer_enabled = 1;
/* free old trace data */
td = xscale->trace.data;
while (td)
{
next_td = td->next;
if (td->entries)
free(td->entries);
free(td);
td = next_td;
}
xscale->trace.data = NULL;
}
else if ((CMD_ARGC >= 1) && (strcmp("disable", CMD_ARGV[0]) == 0))
{
xscale->trace.buffer_enabled = 0;
if (strcmp("enable", CMD_ARGV[0]) == 0)
xscale->trace.mode = XSCALE_TRACE_WRAP; /* default */
else if (strcmp("disable", CMD_ARGV[0]) == 0)
xscale->trace.mode = XSCALE_TRACE_DISABLED;
else
return ERROR_INVALID_ARGUMENTS;
}
if ((CMD_ARGC >= 2) && (strcmp("fill", CMD_ARGV[1]) == 0))
if (CMD_ARGC >= 2 && xscale->trace.mode != XSCALE_TRACE_DISABLED)
{
uint32_t fill = 1;
if (CMD_ARGC >= 3)
COMMAND_PARSE_NUMBER(u32, CMD_ARGV[2], fill);
xscale->trace.buffer_fill = fill;
if (strcmp("fill", CMD_ARGV[1]) == 0)
{
int buffcount = 1; /* default */
if (CMD_ARGC >= 3)
COMMAND_PARSE_NUMBER(int, CMD_ARGV[2], buffcount);
if (buffcount < 1) /* invalid */
{
command_print(CMD_CTX, "fill buffer count must be > 0");
xscale->trace.mode = XSCALE_TRACE_DISABLED;
return ERROR_INVALID_ARGUMENTS;
}
xscale->trace.buffer_fill = buffcount;
xscale->trace.mode = XSCALE_TRACE_FILL;
}
else if (strcmp("wrap", CMD_ARGV[1]) == 0)
xscale->trace.mode = XSCALE_TRACE_WRAP;
else
{
xscale->trace.mode = XSCALE_TRACE_DISABLED;
return ERROR_INVALID_ARGUMENTS;
}
}
else if ((CMD_ARGC >= 2) && (strcmp("wrap", CMD_ARGV[1]) == 0))
if (xscale->trace.mode != XSCALE_TRACE_DISABLED)
{
xscale->trace.buffer_fill = -1;
char fill_string[12];
sprintf(fill_string, "fill %" PRId32, xscale->trace.buffer_fill);
command_print(CMD_CTX, "trace buffer enabled (%s)",
(xscale->trace.mode == XSCALE_TRACE_FILL)
? fill_string : "wrap");
}
command_print(CMD_CTX, "trace buffer %s (%s)",
(xscale->trace.buffer_enabled) ? "enabled" : "disabled",
(xscale->trace.buffer_fill > 0) ? "fill" : "wrap");
else
command_print(CMD_CTX, "trace buffer disabled");
dcsr_value = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 0, 32);
if (xscale->trace.buffer_fill >= 0)
if (xscale->trace.mode == XSCALE_TRACE_FILL)
xscale_write_dcsr_sw(target, (dcsr_value & 0xfffffffc) | 2);
else
xscale_write_dcsr_sw(target, dcsr_value & 0xfffffffc);
@ -3774,7 +3810,7 @@ static const struct command_registration xscale_exec_command_handlers[] = {
.mode = COMMAND_EXEC,
.help = "display trace buffer status, enable or disable "
"tracing, and optionally reconfigure trace mode",
.usage = "['enable'|'disable' ['fill' number|'wrap']]",
.usage = "['enable'|'disable' ['fill' [number]|'wrap']]",
},
{
.name = "dump_trace",

13
src/target/xscale.h
View File

@ -71,13 +71,20 @@ struct xscale_trace_data
struct xscale_trace_data *next;
};
enum trace_mode
{
XSCALE_TRACE_DISABLED,
XSCALE_TRACE_FILL,
XSCALE_TRACE_WRAP
};
struct xscale_trace
{
trace_status_t capture_status; /* current state of capture run */
struct image *image; /* source for target opcodes */
struct xscale_trace_data *data; /* linked list of collected trace data */
int buffer_enabled; /* whether trace buffer is enabled */
int buffer_fill; /* maximum number of trace runs to read (-1 for wrap-around) */
int buffer_fill; /* maximum number of trace runs to read */
int fill_counter; /* running count during trace collection */
enum trace_mode mode;
enum arm_state core_state; /* current core state (ARM, Thumb) */
};