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Re: [needs doc review] Re: [RFA 3/3] Implement support for PowerPC BookE masked watchpoints
- From: Thiago Jung Bauermann <bauerman at br dot ibm dot com>
- To: Eli Zaretskii <eliz at gnu dot org>
- Cc: uweigand at de dot ibm dot com, gdb-patches ml <gdb-patches at sourceware dot org>
- Date: Thu, 05 May 2011 18:56:58 -0300
- Subject: Re: [needs doc review] Re: [RFA 3/3] Implement support for PowerPC BookE masked watchpoints
- References: <201104291745.p3THjh0k030472@d06av02.portsmouth.uk.ibm.com> <1304398554.2245.81.camel@hactar> <E1QH91Q-00028x-77@fencepost.gnu.org>
Hi Eli,
Thanks for your review.
On Tue, 2011-05-03 at 02:23 -0400, Eli Zaretskii wrote:
> > From: Thiago Jung Bauermann <bauerman@br.ibm.com>
> > Cc: gdb-patches ml <gdb-patches@sourceware.org>
> > Date: Tue, 03 May 2011 01:55:54 -0300
> >
> > The @code{@r{[}mask @var{maskvalue}@r{]}} argument allows creation
> > of masked watchpoints, if the current architecture supports this
> > feature. (Currently, this is only available on PowerPC Embedded
> > architecture, see @ref{PowerPC Embedded}.) Specifying a mask argument
> > implies the @code{-location} argument.
>
> I would prefer to avoid text in the manual that could easily become
> obsolete tomorrow: we don't have any efficient mechanism in place to
> tell us to revise such text. So instead of
>
> (Currently, this is only available on PowerPC Embedded architecture,
> see @ref{PowerPC Embedded}.)
>
> I would prefer either to say nothing, or use a more vague phrase,
> without the too-decisive "currently, available only on...". Like
> this, for example:
>
> The @code{@r{[}mask @var{maskvalue}@r{]}} argument allows creation
> of masked watchpoints, if the current architecture supports this
> feature (e.g., PowerPC Embedded architecture, see @ref{PowerPC
> Embedded}.)
Right. I adopted your text.
> > A @dfn{masked watchpoint} specifies a mask in addition to an address
> > to watch. The mask specifies that some bits of an address (the bits
> > which are reset in the mask) should be ignored when matching the
> > address accessed by the inferior against the watchpoint address.
> > Thus, a masked watchpoint watches many addresses
> > simultaneously---those addresses whose unmasked bits are identical
> > to the unmasked bits in the watchpoint address.
> >
> > became
> >
> > A @dfn{masked watchpoint} specifies a mask in addition to an address
> > to watch. The @code{mask} argument implies the @code{-location}
> > argument, which means that the expression will be resolved to a memory
> > address at watchpoint creation time (@pxref{Set Watchpoints}.)
>
> What do you mean by "implies"? Do you mean that -location must be
> specified if "mask" is specified? If so, "implies" is not a good
> word.
I mean that if you specify mask, then it's as if you specified -location
as well. Do you think it's not clear enough?
> I also don't really understand the part about "resolving to a memory
> address at watchpoint creation time". What were you trying to say?
I tried to explain what -location does in a very short sentence. :-)
In this version I moved the explanation about masked watchpoints from
the PowerPC section to the Set Watchpoints section. I think it makes
more sense there. This also made unnecessary any separate explanation
about -location since it comes right after the masked watchpoint
explanation.
What do you think of this version?
--
[]'s
Thiago Jung Bauermann
IBM Linux Technology Center
2011-05-05 Sergio Durigan Junior <sergiodj@linux.vnet.ibm.com>
Thiago Jung Bauermann <bauerman@br.ibm.com>
Implement support for PowerPC BookE masked watchpoints.
gdb/
* NEWS: Mention masked watchpoint support. Create "Changed commands"
section.
* breakpoint.h (struct breakpoint_ops) <works_in_software_mode>: New
method. Initialize to NULL in all existing breakpoint_ops instances.
(struct breakpoint) <hw_wp_mask>: New field.
* breakpoint.c (is_masked_watchpoint): Add prototype.
(update_watchpoint): Don't set b->val for masked watchpoints. Call
breakpoint's breakpoint_ops.works_in_software_mode if available.
(watchpoints_triggered): Handle the case of a hardware masked
watchpoint trigger.
(watchpoint_check): Likewise.
(works_in_software_mode_watchpoint): New function.
(insert_masked_watchpoint, remove_masked_watchpoint)
(resources_needed_masked_watchpoint)
(works_in_software_mode_masked_watchpoint, print_it_masked_watchpoint)
(print_one_detail_masked_watchpoint, print_mention_masked_watchpoint)
(print_recreate_masked_watchpoint, is_masked_watchpoint): New
functions.
(masked_watchpoint_breakpoint_ops): New structure.
(watch_command_1): Check for the existence of the `mask' parameter.
Set b->ops according to the type of hardware watchpoint being created.
* ppc-linux-nat.c (ppc_linux_insert_mask_watchpoint)
(ppc_linux_remove_mask_watchpoint)
(ppc_linux_masked_watch_num_registers): New functions.
(_initialize_ppc_linux_nat): Initialize to_insert_mask_watchpoint,
to_remove_mask_watchpoint and to_masked_watch_num_registers.
* target.c (update_current_target): Mention to_insert_mask_watchpoint,
to_remove_mask_watchpoint, and to_masked_watch_num_registers.
(target_insert_mask_watchpoint, target_remove_mask_watchpoint)
(target_masked_watch_num_registers): New functions.
* target.h (struct target_ops) <to_insert_mask_watchpoint>,
<to_remove_mask_watchpoint>, <to_masked_watch_num_registers>: New
methods.
(target_insert_mask_watchpoint, target_remove_mask_watchpoint)
(target_masked_watch_num_registers): Add prototypes.
gdb/doc/
* gdb.texinfo (Set Watchpoints): Document mask parameter.
(PowerPC Embedded): Mention support of masked watchpoints.
diff --git a/gdb/NEWS b/gdb/NEWS
index 1a22c66..9b59419 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -3,10 +3,24 @@
*** Changes since GDB 7.3
+* When natively debugging programs on PowerPC BookE processors running
+ a Linux kernel version 2.6.34 or later, GDB supports masked hardware
+ watchpoints, which specify a mask in addition to an address to watch.
+ The mask specifies that some bits of an address (the bits which are
+ reset in the mask) should be ignored when matching the address accessed
+ by the inferior against the watchpoint address. See the "PowerPC Embedded"
+ section in the user manual for more details.
+
* The new option --once causes GDBserver to stop listening for connections once
the first connection is made. The listening port used by GDBserver will
become available after that.
+* Changed commands
+
+watch EXPRESSION mask MASK_VALUE
+ The watch command now supports the mask argument which allows creation
+ of masked watchpoints, if the current architecture supports this feature.
+
*** Changes in GDB 7.3
* GDB has a new command: "thread find [REGEXP]".
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index d434521..ebd5fd2 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -10950,6 +10950,7 @@ static struct breakpoint_ops catch_exception_breakpoint_ops =
NULL, /* remove */
NULL, /* breakpoint_hit */
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_exception,
print_one_catch_exception,
NULL, /* print_one_detail */
@@ -10990,6 +10991,7 @@ static struct breakpoint_ops catch_exception_unhandled_breakpoint_ops = {
NULL, /* remove */
NULL, /* breakpoint_hit */
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_exception_unhandled,
print_one_catch_exception_unhandled,
NULL, /* print_one_detail */
@@ -11028,6 +11030,7 @@ static struct breakpoint_ops catch_assert_breakpoint_ops = {
NULL, /* remove */
NULL, /* breakpoint_hit */
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_assert,
print_one_catch_assert,
NULL, /* print_one_detail */
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 8358dac..b864700 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -224,6 +224,8 @@ static void disable_trace_command (char *, int);
static void trace_pass_command (char *, int);
+static int is_masked_watchpoint (const struct breakpoint *b);
+
/* Assuming we're creating a static tracepoint, does S look like a
static tracepoint marker spec ("-m MARKER_ID")? */
#define is_marker_spec(s) \
@@ -1345,8 +1347,10 @@ update_watchpoint (struct breakpoint *b, int reparse)
/* Avoid setting b->val if it's already set. The meaning of
b->val is 'the last value' user saw, and we should update
it only if we reported that last value to user. As it
- happens, the code that reports it updates b->val directly. */
- if (!b->val_valid)
+ happens, the code that reports it updates b->val directly.
+ We don't keep track of the memory value for masked
+ watchpoints. */
+ if (!b->val_valid && !is_masked_watchpoint (b))
{
b->val = v;
b->val_valid = 1;
@@ -1435,19 +1439,23 @@ update_watchpoint (struct breakpoint *b, int reparse)
(b->type, i, other_type_used);
if (target_resources_ok <= 0)
{
- if (target_resources_ok == 0
- && b->type != bp_hardware_watchpoint)
+ /* If there's no works_in_software_mode method, we
+ assume that the watchpoint works in software mode. */
+ int sw_mode = (!b->ops || !b->ops->works_in_software_mode
+ || b->ops->works_in_software_mode (b));
+
+ if (target_resources_ok == 0 && !sw_mode)
error (_("Target does not support this type of "
"hardware watchpoint."));
- else if (target_resources_ok < 0
- && b->type != bp_hardware_watchpoint)
- error (_("Target can only support one kind "
- "of HW watchpoint at a time."));
+ else if (target_resources_ok < 0 && !sw_mode)
+ error (_("There are not enough available hardware "
+ "resources for this watchpoint."));
else
b->type = bp_watchpoint;
}
}
- else if (b->type != bp_hardware_watchpoint)
+ else if (b->ops && b->ops->works_in_software_mode
+ && !b->ops->works_in_software_mode (b))
error (_("Expression cannot be implemented with "
"read/access watchpoint."));
else
@@ -3694,15 +3702,27 @@ watchpoints_triggered (struct target_waitstatus *ws)
b->watchpoint_triggered = watch_triggered_no;
for (loc = b->loc; loc; loc = loc->next)
- /* Exact match not required. Within range is
- sufficient. */
- if (target_watchpoint_addr_within_range (¤t_target,
- addr, loc->address,
- loc->length))
- {
- b->watchpoint_triggered = watch_triggered_yes;
- break;
- }
+ {
+ if (is_masked_watchpoint (loc->owner))
+ {
+ CORE_ADDR newaddr = addr & loc->owner->hw_wp_mask;
+ CORE_ADDR start = loc->address & loc->owner->hw_wp_mask;
+
+ if (newaddr == start)
+ {
+ b->watchpoint_triggered = watch_triggered_yes;
+ break;
+ }
+ }
+ /* Exact match not required. Within range is sufficient. */
+ else if (target_watchpoint_addr_within_range (¤t_target,
+ addr, loc->address,
+ loc->length))
+ {
+ b->watchpoint_triggered = watch_triggered_yes;
+ break;
+ }
+ }
}
return 1;
@@ -3799,9 +3819,16 @@ watchpoint_check (void *p)
might be in the middle of evaluating a function call. */
int pc = 0;
- struct value *mark = value_mark ();
+ struct value *mark;
struct value *new_val;
+ if (is_masked_watchpoint (b))
+ /* Since we don't know the exact trigger address (from
+ stopped_data_address), just tell the user we've triggered
+ a mask watchpoint. */
+ return WP_VALUE_CHANGED;
+
+ mark = value_mark ();
fetch_subexp_value (b->exp, &pc, &new_val, NULL, NULL);
/* We use value_equal_contents instead of value_equal because
@@ -6303,6 +6330,7 @@ static struct breakpoint_ops catch_fork_breakpoint_ops =
remove_catch_fork,
breakpoint_hit_catch_fork,
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_fork,
print_one_catch_fork,
NULL, /* print_one_detail */
@@ -6401,6 +6429,7 @@ static struct breakpoint_ops catch_vfork_breakpoint_ops =
remove_catch_vfork,
breakpoint_hit_catch_vfork,
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_vfork,
print_one_catch_vfork,
NULL, /* print_one_detail */
@@ -6688,6 +6717,7 @@ static struct breakpoint_ops catch_syscall_breakpoint_ops =
remove_catch_syscall,
breakpoint_hit_catch_syscall,
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_syscall,
print_one_catch_syscall,
NULL, /* print_one_detail */
@@ -6845,6 +6875,7 @@ static struct breakpoint_ops catch_exec_breakpoint_ops =
remove_catch_exec,
breakpoint_hit_catch_exec,
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_catch_exec,
print_one_catch_exec,
NULL, /* print_one_detail */
@@ -8470,6 +8501,7 @@ static struct breakpoint_ops ranged_breakpoint_ops =
NULL, /* remove */
breakpoint_hit_ranged_breakpoint,
resources_needed_ranged_breakpoint,
+ NULL, /* works_in_software_mode */
print_it_ranged_breakpoint,
print_one_ranged_breakpoint,
print_one_detail_ranged_breakpoint,
@@ -8777,6 +8809,15 @@ resources_needed_watchpoint (const struct bp_location *bl)
return target_region_ok_for_hw_watchpoint (bl->address, length);
}
+/* Implement the "works_in_software_mode" breakpoint_ops method for
+ hardware watchpoints. */
+
+int
+works_in_software_mode_watchpoint (const struct breakpoint *b)
+{
+ return b->type == bp_hardware_watchpoint;
+}
+
/* The breakpoint_ops structure to be used in hardware watchpoints. */
static struct breakpoint_ops watchpoint_breakpoint_ops =
@@ -8785,6 +8826,7 @@ static struct breakpoint_ops watchpoint_breakpoint_ops =
remove_watchpoint,
NULL, /* breakpoint_hit */
resources_needed_watchpoint,
+ works_in_software_mode_watchpoint,
NULL, /* print_it */
NULL, /* print_one */
NULL, /* print_one_detail */
@@ -8792,6 +8834,192 @@ static struct breakpoint_ops watchpoint_breakpoint_ops =
NULL /* print_recreate */
};
+/* Implement the "insert" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static int
+insert_masked_watchpoint (struct bp_location *bl)
+{
+ return target_insert_mask_watchpoint (bl->address, bl->owner->hw_wp_mask,
+ bl->watchpoint_type);
+}
+
+/* Implement the "remove" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static int
+remove_masked_watchpoint (struct bp_location *bl)
+{
+ return target_remove_mask_watchpoint (bl->address, bl->owner->hw_wp_mask,
+ bl->watchpoint_type);
+}
+
+/* Implement the "resources_needed" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static int
+resources_needed_masked_watchpoint (const struct bp_location *bl)
+{
+ return target_masked_watch_num_registers (bl->address,
+ bl->owner->hw_wp_mask);
+}
+
+/* Implement the "works_in_software_mode" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static int
+works_in_software_mode_masked_watchpoint (const struct breakpoint *b)
+{
+ return 0;
+}
+
+/* Implement the "print_it" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static enum print_stop_action
+print_it_masked_watchpoint (struct breakpoint *b)
+{
+ /* Masked watchpoints have only one location. */
+ gdb_assert (b->loc && b->loc->next == NULL);
+
+ switch (b->type)
+ {
+ case bp_hardware_watchpoint:
+ annotate_watchpoint (b->number);
+ if (ui_out_is_mi_like_p (uiout))
+ ui_out_field_string
+ (uiout, "reason",
+ async_reason_lookup (EXEC_ASYNC_WATCHPOINT_TRIGGER));
+ break;
+
+ case bp_read_watchpoint:
+ if (ui_out_is_mi_like_p (uiout))
+ ui_out_field_string
+ (uiout, "reason",
+ async_reason_lookup (EXEC_ASYNC_READ_WATCHPOINT_TRIGGER));
+ break;
+
+ case bp_access_watchpoint:
+ if (ui_out_is_mi_like_p (uiout))
+ ui_out_field_string
+ (uiout, "reason",
+ async_reason_lookup (EXEC_ASYNC_ACCESS_WATCHPOINT_TRIGGER));
+ break;
+ default:
+ internal_error (__FILE__, __LINE__,
+ _("Invalid hardware watchpoint type."));
+ }
+
+ mention (b);
+ ui_out_text (uiout, _("\n\
+Check the underlying instruction at PC for the memory\n\
+address and value which triggered this watchpoint.\n"));
+ ui_out_text (uiout, "\n");
+
+ /* More than one watchpoint may have been triggered. */
+ return PRINT_UNKNOWN;
+}
+
+/* Implement the "print_one_detail" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static void
+print_one_detail_masked_watchpoint (const struct breakpoint *b,
+ struct ui_out *uiout)
+{
+ /* Masked watchpoints have only one location. */
+ gdb_assert (b->loc && b->loc->next == NULL);
+
+ ui_out_text (uiout, "\tmask ");
+ ui_out_field_core_addr (uiout, "mask", b->loc->gdbarch, b->hw_wp_mask);
+ ui_out_text (uiout, "\n");
+}
+
+/* Implement the "print_mention" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static void
+print_mention_masked_watchpoint (struct breakpoint *b)
+{
+ struct cleanup *ui_out_chain;
+
+ switch (b->type)
+ {
+ case bp_hardware_watchpoint:
+ ui_out_text (uiout, "Masked hardware watchpoint ");
+ ui_out_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "wpt");
+ break;
+ case bp_read_watchpoint:
+ ui_out_text (uiout, "Masked hardware read watchpoint ");
+ ui_out_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "hw-rwpt");
+ break;
+ case bp_access_watchpoint:
+ ui_out_text (uiout, "Masked hardware access (read/write) watchpoint ");
+ ui_out_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "hw-awpt");
+ break;
+ default:
+ internal_error (__FILE__, __LINE__,
+ _("Invalid hardware watchpoint type."));
+ }
+
+ ui_out_field_int (uiout, "number", b->number);
+ ui_out_text (uiout, ": ");
+ ui_out_field_string (uiout, "exp", b->exp_string);
+ do_cleanups (ui_out_chain);
+}
+
+/* Implement the "print_recreate" breakpoint_ops method for
+ masked hardware watchpoints. */
+
+static void
+print_recreate_masked_watchpoint (struct breakpoint *b, struct ui_file *fp)
+{
+ char tmp[40];
+
+ switch (b->type)
+ {
+ case bp_hardware_watchpoint:
+ fprintf_unfiltered (fp, "watch");
+ break;
+ case bp_read_watchpoint:
+ fprintf_unfiltered (fp, "rwatch");
+ break;
+ case bp_access_watchpoint:
+ fprintf_unfiltered (fp, "awatch");
+ break;
+ default:
+ internal_error (__FILE__, __LINE__,
+ _("Invalid hardware watchpoint type."));
+ }
+
+ sprintf_vma (tmp, b->hw_wp_mask);
+ fprintf_unfiltered (fp, " %s mask 0x%s", b->exp_string, tmp);
+}
+
+/* The breakpoint_ops structure to be used in masked hardware watchpoints. */
+
+static struct breakpoint_ops masked_watchpoint_breakpoint_ops =
+{
+ insert_masked_watchpoint,
+ remove_masked_watchpoint,
+ NULL, /* breakpoint_hit */
+ resources_needed_masked_watchpoint,
+ works_in_software_mode_masked_watchpoint,
+ print_it_masked_watchpoint,
+ NULL, /* print_one */
+ print_one_detail_masked_watchpoint,
+ print_mention_masked_watchpoint,
+ print_recreate_masked_watchpoint
+};
+
+/* Tell whether the given watchpoint is a masked hardware watchpoint. */
+
+static int
+is_masked_watchpoint (const struct breakpoint *b)
+{
+ return b->ops == &masked_watchpoint_breakpoint_ops;
+}
+
/* accessflag: hw_write: watch write,
hw_read: watch read,
hw_access: watch access (read or write) */
@@ -8807,73 +9035,97 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
struct frame_info *frame;
char *exp_start = NULL;
char *exp_end = NULL;
- char *tok, *id_tok_start, *end_tok;
- int toklen;
+ char *tok, *end_tok;
+ int toklen = -1;
char *cond_start = NULL;
char *cond_end = NULL;
enum bptype bp_type;
int thread = -1;
int pc = 0;
+ /* Flag to indicate whether we are going to use masks for
+ the hardware watchpoint. */
+ int use_mask = 0;
+ CORE_ADDR mask = 0;
/* Make sure that we actually have parameters to parse. */
if (arg != NULL && arg[0] != '\0')
{
- toklen = strlen (arg); /* Size of argument list. */
+ char *value_start;
- /* Points tok to the end of the argument list. */
- tok = arg + toklen - 1;
+ /* Look for "parameter value" pairs at the end
+ of the arguments string. */
+ for (tok = arg + strlen (arg) - 1; tok > arg; tok--)
+ {
+ /* Skip whitespace at the end of the argument list. */
+ while (tok > arg && (*tok == ' ' || *tok == '\t'))
+ tok--;
+
+ /* Find the beginning of the last token.
+ This is the value of the parameter. */
+ while (tok > arg && (*tok != ' ' && *tok != '\t'))
+ tok--;
+ value_start = tok + 1;
+
+ /* Skip whitespace. */
+ while (tok > arg && (*tok == ' ' || *tok == '\t'))
+ tok--;
+
+ end_tok = tok;
+
+ /* Find the beginning of the second to last token.
+ This is the parameter itself. */
+ while (tok > arg && (*tok != ' ' && *tok != '\t'))
+ tok--;
+ tok++;
+ toklen = end_tok - tok + 1;
+
+ if (toklen == 6 && !strncmp (tok, "thread", 6))
+ {
+ /* At this point we've found a "thread" token, which means
+ the user is trying to set a watchpoint that triggers
+ only in a specific thread. */
+ char *endp;
- /* Go backwards in the parameters list. Skip the last
- parameter. If we're expecting a 'thread <thread_num>'
- parameter, this should be the thread identifier. */
- while (tok > arg && (*tok == ' ' || *tok == '\t'))
- tok--;
- while (tok > arg && (*tok != ' ' && *tok != '\t'))
- tok--;
+ if (thread != -1)
+ error(_("You can specify only one thread."));
- /* Points end_tok to the beginning of the last token. */
- id_tok_start = tok + 1;
+ /* Extract the thread ID from the next token. */
+ thread = strtol (value_start, &endp, 0);
- /* Go backwards in the parameters list. Skip one more
- parameter. If we're expecting a 'thread <thread_num>'
- parameter, we should reach a "thread" token. */
- while (tok > arg && (*tok == ' ' || *tok == '\t'))
- tok--;
+ /* Check if the user provided a valid numeric value for the
+ thread ID. */
+ if (*endp != ' ' && *endp != '\t' && *endp != '\0')
+ error (_("Invalid thread ID specification %s."), value_start);
- end_tok = tok;
+ /* Check if the thread actually exists. */
+ if (!valid_thread_id (thread))
+ error (_("Unknown thread %d."), thread);
+ }
+ else if (toklen == 4 && !strncmp (tok, "mask", 4))
+ {
+ /* We've found a "mask" token, which means the user wants to
+ create a hardware watchpoint that is going to have the mask
+ facility. */
+ struct value *mask_value, *mark;
- while (tok > arg && (*tok != ' ' && *tok != '\t'))
- tok--;
+ if (use_mask)
+ error(_("You can specify only one mask."));
- /* Move the pointer forward to skip the whitespace and
- calculate the length of the token. */
- tok++;
- toklen = end_tok - tok;
+ use_mask = just_location = 1;
- if (toklen >= 1 && strncmp (tok, "thread", toklen) == 0)
- {
- /* At this point we've found a "thread" token, which means
- the user is trying to set a watchpoint that triggers
- only in a specific thread. */
- char *endp;
-
- /* Extract the thread ID from the next token. */
- thread = strtol (id_tok_start, &endp, 0);
-
- /* Check if the user provided a valid numeric value for the
- thread ID. */
- if (*endp != ' ' && *endp != '\t' && *endp != '\0')
- error (_("Invalid thread ID specification %s."), id_tok_start);
-
- /* Check if the thread actually exists. */
- if (!valid_thread_id (thread))
- error (_("Unknown thread %d."), thread);
-
- /* Truncate the string and get rid of the thread <thread_num>
- parameter before the parameter list is parsed by the
- evaluate_expression() function. */
- *tok = '\0';
- }
+ mark = value_mark ();
+ mask_value = parse_to_comma_and_eval (&value_start);
+ mask = value_as_address (mask_value);
+ value_free_to_mark (mark);
+ }
+ else
+ /* We didn't recognize what we found. We should stop here. */
+ break;
+
+ /* Truncate the string and get rid of the "parameter value" pair before
+ the arguments string is parsed by the parse_exp_1 function. */
+ *tok = '\0';
+ }
}
/* Parse the rest of the arguments. */
@@ -8904,10 +9156,22 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
if (just_location)
{
+ int ret;
+
exp_valid_block = NULL;
val = value_addr (result);
release_value (val);
value_free_to_mark (mark);
+
+ if (use_mask)
+ {
+ ret = target_masked_watch_num_registers (value_as_address (val),
+ mask);
+ if (ret == -1)
+ error (_("This target does not support masked watchpoints."));
+ else if (ret == -2)
+ error (_("Invalid mask or memory region."));
+ }
}
else if (val != NULL)
release_value (val);
@@ -9004,9 +9268,18 @@ watch_command_1 (char *arg, int accessflag, int from_tty,
}
else
b->exp_string = savestring (exp_start, exp_end - exp_start);
- b->val = val;
- b->val_valid = 1;
- b->ops = &watchpoint_breakpoint_ops;
+
+ if (use_mask)
+ {
+ b->hw_wp_mask = mask;
+ b->ops = &masked_watchpoint_breakpoint_ops;
+ }
+ else
+ {
+ b->val = val;
+ b->val_valid = 1;
+ b->ops = &watchpoint_breakpoint_ops;
+ }
if (cond_start)
b->cond_string = savestring (cond_start, cond_end - cond_start);
@@ -9543,6 +9816,7 @@ static struct breakpoint_ops gnu_v3_exception_catchpoint_ops = {
NULL, /* remove */
NULL, /* breakpoint_hit */
NULL, /* resources_needed */
+ NULL, /* works_in_software_mode */
print_it_exception_catchpoint,
print_one_exception_catchpoint,
NULL, /* print_one_detail */
diff --git a/gdb/breakpoint.h b/gdb/breakpoint.h
index 7a9c2d4..7fa705f 100644
--- a/gdb/breakpoint.h
+++ b/gdb/breakpoint.h
@@ -410,6 +410,11 @@ struct breakpoint_ops
the breakpoint or watchpoint needs one debug register. */
int (*resources_needed) (const struct bp_location *);
+ /* Tell whether we can downgrade from a hardware watchpoint to a software
+ one. If not, the user will not be able to enable the watchpoint when
+ there are not enough hardware resources available. */
+ int (*works_in_software_mode) (const struct breakpoint *);
+
/* The normal print routine for this breakpoint, called when we
hit it. */
enum print_stop_action (*print_it) (struct breakpoint *);
@@ -651,6 +656,9 @@ struct breakpoint
/* Whether this watchpoint is exact (see target_exact_watchpoints). */
int exact;
+
+ /* The mask address for a masked hardware watchpoint. */
+ CORE_ADDR hw_wp_mask;
};
typedef struct breakpoint *breakpoint_p;
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index ff5b7cb..54da5ab 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -3728,7 +3728,7 @@ watchpoints, which do not slow down the running of your program.
@table @code
@kindex watch
-@item watch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]}
+@item watch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]} @r{[}mask @var{maskvalue}@r{]}
Set a watchpoint for an expression. @value{GDBN} will break when the
expression @var{expr} is written into by the program and its value
changes. The simplest (and the most popular) use of this command is
@@ -3739,12 +3739,29 @@ to watch the value of a single variable:
@end smallexample
If the command includes a @code{@r{[}thread @var{threadnum}@r{]}}
-clause, @value{GDBN} breaks only when the thread identified by
+argument, @value{GDBN} breaks only when the thread identified by
@var{threadnum} changes the value of @var{expr}. If any other threads
change the value of @var{expr}, @value{GDBN} will not break. Note
that watchpoints restricted to a single thread in this way only work
with Hardware Watchpoints.
+The @code{@r{[}mask @var{maskvalue}@r{]}} argument allows creation
+of masked watchpoints, if the current architecture supports this
+feature (e.g., PowerPC Embedded architecture, see @ref{PowerPC
+Embedded}.) A @dfn{masked watchpoint} specifies a mask in addition
+to an address to watch. The mask specifies that some bits of an address
+(the bits which are reset in the mask) should be ignored when matching
+the address accessed by the inferior against the watchpoint address.
+Thus, a masked watchpoint watches many addresses simultaneously---those
+addresses whose unmasked bits are identical to the unmasked bits in the
+watchpoint address. The @code{mask} argument implies the @code{-location}
+argument. Examples:
+
+@smallexample
+(@value{GDBP}) watch foo mask 0xffff00ff
+(@value{GDBP}) watch *0xdeadbeef mask 0xffffff00
+@end smallexample
+
Ordinarily a watchpoint respects the scope of variables in @var{expr}
(see below). The @code{-location} argument tells @value{GDBN} to
instead watch the memory referred to by @var{expr}. In this case,
@@ -3755,12 +3772,12 @@ result does not have an address, then @value{GDBN} will print an
error.
@kindex rwatch
-@item rwatch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]}
+@item rwatch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]} @r{[}mask @var{maskvalue}@r{]}
Set a watchpoint that will break when the value of @var{expr} is read
by the program.
@kindex awatch
-@item awatch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]}
+@item awatch @r{[}-l@r{|}-location@r{]} @var{expr} @r{[}thread @var{threadnum}@r{]} @r{[}mask @var{maskvalue}@r{]}
Set a watchpoint that will break when @var{expr} is either read from
or written into by the program.
@@ -18783,6 +18800,9 @@ region using one of the following commands (@pxref{Expressions}):
(@value{GDBP}) watch @{char[@var{length}]@} @var{address}
@end smallexample
+PowerPC embedded processors support masked watchpoints. See the discussion
+about the @code{mask} argument in @ref{Set Watchpoints}.
+
@cindex ranged breakpoint
PowerPC embedded processors support hardware accelerated
@dfn{ranged breakpoints}. A ranged breakpoint stops execution of
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 6f11715..275de78 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -1739,6 +1739,64 @@ get_trigger_type (int rw)
return t;
}
+/* Insert a new masked watchpoint at ADDR using the mask MASK.
+ RW may be hw_read for a read watchpoint, hw_write for a write watchpoint
+ or hw_access for an access watchpoint. Returns 0 on success and throws
+ an error on failure. */
+
+static int
+ppc_linux_insert_mask_watchpoint (struct target_ops *ops, CORE_ADDR addr,
+ CORE_ADDR mask, int rw)
+{
+ ptid_t ptid;
+ struct lwp_info *lp;
+ struct ppc_hw_breakpoint p;
+
+ gdb_assert (have_ptrace_booke_interface ());
+
+ p.version = PPC_DEBUG_CURRENT_VERSION;
+ p.trigger_type = get_trigger_type (rw);
+ p.addr_mode = PPC_BREAKPOINT_MODE_MASK;
+ p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE;
+ p.addr = addr;
+ p.addr2 = mask;
+ p.condition_value = 0;
+
+ ALL_LWPS (lp, ptid)
+ booke_insert_point (&p, TIDGET (ptid));
+
+ return 0;
+}
+
+/* Remove a masked watchpoint at ADDR with the mask MASK.
+ RW may be hw_read for a read watchpoint, hw_write for a write watchpoint
+ or hw_access for an access watchpoint. Returns 0 on success and throws
+ an error on failure. */
+
+static int
+ppc_linux_remove_mask_watchpoint (struct target_ops *ops, CORE_ADDR addr,
+ CORE_ADDR mask, int rw)
+{
+ ptid_t ptid;
+ struct lwp_info *lp;
+ struct ppc_hw_breakpoint p;
+
+ gdb_assert (have_ptrace_booke_interface ());
+
+ p.version = PPC_DEBUG_CURRENT_VERSION;
+ p.trigger_type = get_trigger_type (rw);
+ p.addr_mode = PPC_BREAKPOINT_MODE_MASK;
+ p.condition_mode = PPC_BREAKPOINT_CONDITION_NONE;
+ p.addr = addr;
+ p.addr2 = mask;
+ p.condition_value = 0;
+
+ ALL_LWPS (lp, ptid)
+ booke_remove_point (&p, TIDGET (ptid));
+
+ return 0;
+}
+
/* Check whether we have at least one free DVC register. */
static int
can_use_watchpoint_cond_accel (void)
@@ -2224,6 +2282,26 @@ ppc_linux_watchpoint_addr_within_range (struct target_ops *target,
return start <= addr + mask && start + length - 1 >= addr;
}
+/* Return the number of registers needed for a masked hardware watchpoint. */
+
+static int
+ppc_linux_masked_watch_num_registers (struct target_ops *target,
+ CORE_ADDR addr, CORE_ADDR mask)
+{
+ if (!have_ptrace_booke_interface ()
+ || (booke_debug_info.features & PPC_DEBUG_FEATURE_DATA_BP_MASK) == 0)
+ return -1;
+ else if ((mask & 0xC0000000) != 0xC0000000)
+ {
+ warning (_("The given mask covers kernel address space "
+ "and cannot be used.\n"));
+
+ return -2;
+ }
+ else
+ return 2;
+}
+
static void
ppc_linux_store_inferior_registers (struct target_ops *ops,
struct regcache *regcache, int regno)
@@ -2438,11 +2516,14 @@ _initialize_ppc_linux_nat (void)
t->to_region_ok_for_hw_watchpoint = ppc_linux_region_ok_for_hw_watchpoint;
t->to_insert_watchpoint = ppc_linux_insert_watchpoint;
t->to_remove_watchpoint = ppc_linux_remove_watchpoint;
+ t->to_insert_mask_watchpoint = ppc_linux_insert_mask_watchpoint;
+ t->to_remove_mask_watchpoint = ppc_linux_remove_mask_watchpoint;
t->to_stopped_by_watchpoint = ppc_linux_stopped_by_watchpoint;
t->to_stopped_data_address = ppc_linux_stopped_data_address;
t->to_watchpoint_addr_within_range = ppc_linux_watchpoint_addr_within_range;
t->to_can_accel_watchpoint_condition
= ppc_linux_can_accel_watchpoint_condition;
+ t->to_masked_watch_num_registers = ppc_linux_masked_watch_num_registers;
t->to_ranged_break_num_registers = ppc_linux_ranged_break_num_registers;
t->to_read_description = ppc_linux_read_description;
diff --git a/gdb/target.c b/gdb/target.c
index 1e1c38e..9c522cb 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -595,6 +595,8 @@ update_current_target (void)
/* Do not inherit to_ranged_break_num_registers. */
INHERIT (to_insert_watchpoint, t);
INHERIT (to_remove_watchpoint, t);
+ /* Do not inherit to_insert_mask_watchpoint. */
+ /* Do not inherit to_remove_mask_watchpoint. */
INHERIT (to_stopped_data_address, t);
INHERIT (to_have_steppable_watchpoint, t);
INHERIT (to_have_continuable_watchpoint, t);
@@ -602,6 +604,7 @@ update_current_target (void)
INHERIT (to_watchpoint_addr_within_range, t);
INHERIT (to_region_ok_for_hw_watchpoint, t);
INHERIT (to_can_accel_watchpoint_condition, t);
+ /* Do not inherit to_masked_watch_num_registers. */
INHERIT (to_terminal_init, t);
INHERIT (to_terminal_inferior, t);
INHERIT (to_terminal_ours_for_output, t);
@@ -3518,6 +3521,75 @@ target_verify_memory (const gdb_byte *data, CORE_ADDR memaddr, ULONGEST size)
tcomplain ();
}
+/* The documentation for this function is in its prototype declaration in
+ target.h. */
+
+int
+target_insert_mask_watchpoint (CORE_ADDR addr, CORE_ADDR mask, int rw)
+{
+ struct target_ops *t;
+
+ for (t = current_target.beneath; t != NULL; t = t->beneath)
+ if (t->to_insert_mask_watchpoint != NULL)
+ {
+ int ret;
+
+ ret = t->to_insert_mask_watchpoint (t, addr, mask, rw);
+
+ if (targetdebug)
+ fprintf_unfiltered (gdb_stdlog, "\
+target_insert_mask_watchpoint (%s, %s, %d) = %d\n",
+ core_addr_to_string (addr),
+ core_addr_to_string (mask), rw, ret);
+
+ return ret;
+ }
+
+ return 1;
+}
+
+/* The documentation for this function is in its prototype declaration in
+ target.h. */
+
+int
+target_remove_mask_watchpoint (CORE_ADDR addr, CORE_ADDR mask, int rw)
+{
+ struct target_ops *t;
+
+ for (t = current_target.beneath; t != NULL; t = t->beneath)
+ if (t->to_remove_mask_watchpoint != NULL)
+ {
+ int ret;
+
+ ret = t->to_remove_mask_watchpoint (t, addr, mask, rw);
+
+ if (targetdebug)
+ fprintf_unfiltered (gdb_stdlog, "\
+target_remove_mask_watchpoint (%s, %s, %d) = %d\n",
+ core_addr_to_string (addr),
+ core_addr_to_string (mask), rw, ret);
+
+ return ret;
+ }
+
+ return 1;
+}
+
+/* The documentation for this function is in its prototype declaration
+ in target.h. */
+
+int
+target_masked_watch_num_registers (CORE_ADDR addr, CORE_ADDR mask)
+{
+ struct target_ops *t;
+
+ for (t = current_target.beneath; t != NULL; t = t->beneath)
+ if (t->to_masked_watch_num_registers != NULL)
+ return t->to_masked_watch_num_registers (t, addr, mask);
+
+ return -1;
+}
+
/* The documentation for this function is in its prototype declaration
in target.h. */
diff --git a/gdb/target.h b/gdb/target.h
index 11380ed..52e0276 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -459,6 +459,10 @@ struct target_ops
int (*to_remove_watchpoint) (CORE_ADDR, int, int, struct expression *);
int (*to_insert_watchpoint) (CORE_ADDR, int, int, struct expression *);
+ int (*to_insert_mask_watchpoint) (struct target_ops *,
+ CORE_ADDR, CORE_ADDR, int);
+ int (*to_remove_mask_watchpoint) (struct target_ops *,
+ CORE_ADDR, CORE_ADDR, int);
int (*to_stopped_by_watchpoint) (void);
int to_have_steppable_watchpoint;
int to_have_continuable_watchpoint;
@@ -472,6 +476,8 @@ struct target_ops
int (*to_can_accel_watchpoint_condition) (CORE_ADDR, int, int,
struct expression *);
+ int (*to_masked_watch_num_registers) (struct target_ops *,
+ CORE_ADDR, CORE_ADDR);
void (*to_terminal_init) (void);
void (*to_terminal_inferior) (void);
void (*to_terminal_ours_for_output) (void);
@@ -1362,6 +1368,20 @@ extern char *target_thread_name (struct thread_info *);
#define target_remove_watchpoint(addr, len, type, cond) \
(*current_target.to_remove_watchpoint) (addr, len, type, cond)
+/* Insert a new masked watchpoint at ADDR using the mask MASK.
+ RW may be hw_read for a read watchpoint, hw_write for a write watchpoint
+ or hw_access for an access watchpoint. Returns 0 for success, 1 if
+ masked watchpoints are not supported, -1 for failure. */
+
+extern int target_insert_mask_watchpoint (CORE_ADDR, CORE_ADDR, int);
+
+/* Remove a masked watchpoint at ADDR with the mask MASK.
+ RW may be hw_read for a read watchpoint, hw_write for a write watchpoint
+ or hw_access for an access watchpoint. Returns 0 for success, non-zero
+ for failure. */
+
+extern int target_remove_mask_watchpoint (CORE_ADDR, CORE_ADDR, int);
+
#define target_insert_hw_breakpoint(gdbarch, bp_tgt) \
(*current_target.to_insert_hw_breakpoint) (gdbarch, bp_tgt)
@@ -1395,6 +1415,12 @@ extern int target_ranged_break_num_registers (void);
#define target_can_accel_watchpoint_condition(addr, len, type, cond) \
(*current_target.to_can_accel_watchpoint_condition) (addr, len, type, cond)
+/* Return number of debug registers needed for a masked watchpoint,
+ -1 if masked watchpoints are not supported or -2 if the given address
+ and mask combination cannot be used. */
+
+extern int target_masked_watch_num_registers (CORE_ADDR addr, CORE_ADDR mask);
+
/* Target can execute in reverse? */
#define target_can_execute_reverse \
(current_target.to_can_execute_reverse ? \