From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5384 invoked by alias); 18 Apr 2011 21:24:04 -0000 Received: (qmail 4449 invoked by uid 22791); 18 Apr 2011 21:23:55 -0000 X-SWARE-Spam-Status: No, hits=0.0 required=5.0 tests=AWL,BAYES_50,SPF_SOFTFAIL,TW_EG,TW_XF,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from e9.ny.us.ibm.com (HELO e9.ny.us.ibm.com) (32.97.182.139) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 18 Apr 2011 21:23:33 +0000 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e9.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p3IKtNSA013855 for ; Mon, 18 Apr 2011 16:55:23 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p3ILMu48155162 for ; Mon, 18 Apr 2011 17:23:07 -0400 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p3ILMtEh030130 for ; Mon, 18 Apr 2011 15:22:55 -0600 Received: from [9.12.229.135] ([9.12.229.135]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p3ILMrpU029866; Mon, 18 Apr 2011 15:22:53 -0600 Subject: [RFA 3/3] Implement support for PowerPC BookE masked watchpoints From: Thiago Jung Bauermann To: Ulrich Weigand Cc: gdb-patches ml In-Reply-To: <201102171440.p1HEeIBJ012343@d06av02.portsmouth.uk.ibm.com> References: <201102171440.p1HEeIBJ012343@d06av02.portsmouth.uk.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Mon, 18 Apr 2011 21:24:00 -0000 Message-ID: <1303161770.1969.221.camel@hactar> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-04/txt/msg00293.txt.bz2 Hi Uli, Thanks for your review and suggestions! [ This patch depends on two patches that I'm posting as replies to your message too so that they'll be grouped together. ] On Thu, 2011-02-17 at 15:40 +0100, Ulrich Weigand wrote: > Thiago Jung Bauermann wrote: > The effect is that GDB will parse the expression, create the list of > memory regions it needs to watch to implement its high-level semantics. > Then, it will just add the mask to each of the addresses generated > in that manner. It seems to me that in general, the effects of what > will actually happen now are hard to predict, and will generally not > be what the user expects. > > Of course, the feature *can* be used in ways the user understands, > like in the example you show in the documentation: > watch *0xdeadbeef mask 0xffffff00 > > But if used in a more complex way, like > watch p->x mask 0xffffff00 > for some local variable p, this doesn't seem to have very useful > (or even well-defined) semantics ... This isn't a problem for PowerPC because there are only two hardware watchpoint registers, and both will be needed to set up a masked watchpoint (one for the address, the other for the mask). So the command you mention above would fail since it would need more registers than that. But I agree that in general it's a problem. > Now, I'm not sure how exactly the GDB command line syntax ought to > be modified to implement this. But most fundamentally, we should > go away from specifying "the value of an expression", and rather > go to specifying a memory region via address and mask. > > We've recently added the -location feature that already prevents > GDB from fully tracking the expression, but rather just evaluate > it one time for its address. Maybe one simple fix could be to > restrict the "mask" feature to watch -location (or have the > presence of "mask" automatically imply -location, or maybe have > instead a new keyword -masked-location or so). -location is indeed a good fit for this patch. I don't think we need a separate -masked-location keyword, so in this patch I made the mask parameter imply -location. Do you think this addresses your concerns regarding the semantics of masked watchpoints? > However, even so there are still differences: even with -location, > GDB watchpoint code will still treat a watchpoint as refering to > one value, and track it (e.g. remember the value we saw last time; > re-evaluate it each time execution stops etc.). This is really > not appropriate for the masked watchpoint case, because we do not > *have* any contiguous region that would define any single value. > Therefore, it seems to me that all this code ought to be disabled > for masked watchpoints. Indeed. With this new patch, the only place that evaluates the watchpoint expression is update_watchpoint. This is necessary because the resulting value chain is then used to create the bp_locations and also by can_use_hardware_watchpoint when deciding whether to set a software or hardware watchpoint. I could manually create a bp_location for masked watchpoints and implement a version of can_use_hardware_watchpoint just for masked watchpoints, but is it worth the extra special casing and complexity in update_watchpoint? > A couple of more specific comments on the patch: > > > @@ -1518,10 +1522,26 @@ update_watchpoint (struct breakpoint *b, int reparse) > > target_resources_ok = target_can_use_hardware_watchpoint > > (bp_hardware_watchpoint, i, other_type_used); > > if (target_resources_ok <= 0) > > - b->type = bp_watchpoint; > > + { > > + if (orig_type == bp_hardware_watchpoint > > + && b->ops && b->ops->works_in_software_mode > > + && !b->ops->works_in_software_mode (b)) > > + error (_("This watchpoint cannot be used " > > + "in software mode.")); > > + else > > + b->type = bp_watchpoint; > > + } > > } > > else > > - b->type = bp_watchpoint; > > + { > > + if (b->type == bp_hardware_watchpoint > > + && b->ops && b->ops->works_in_software_mode > > + && !b->ops->works_in_software_mode (b)) > > + error (_("This watchpoint cannot be used " > > + "in software mode.")); > > + else > > + b->type = bp_watchpoint; > > + } > > What is the point of checking the original type? If works_in_software_mode > returns false, the original type couldn't have been a software watchpoint > anyway, could it? Right, removed. > > print_it_typical. */ > > /* FIXME: how breakpoint can ever be NULL here? */ > > if (b != NULL && b->ops != NULL && b->ops->print_it != NULL) > > - return b->ops->print_it (b); > > + return b->ops->print_it (b, bs->old_val); > > else > > return print_it_typical (bs); > > } > > I don't understand this change. You add the "old_val" argument to the > print_it routine, and the new instance of print_it for masked watchpoints > then uses it (for what purpose?) ... But for masked watchpoints, the > whole concept of its "value", new or old, doesn't make sense to start > with ... I added it for two reasons. First, because I thought it made sense to make available to print_it implementations the same information that print_it_typical uses itself. Also, I wasn't sure how important is this code in print_it_masked_watchpoint which I borrowed from print_it_typical: + case bp_access_watchpoint: + if (old_val != NULL) + annotate_watchpoint (b->number); So I decided to keep it. In this version I removed the old_val argument and the call to annotate_watchpoint. > > @@ -3761,6 +3796,11 @@ watchpoint_check (void *p) > > b->val_valid = 1; > > return WP_VALUE_CHANGED; > > } > > + else 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; > > This goes back to the issue discussed above: this should not even > attempt to "compute the old value" which doesn't make sense for a > masked watchpoint. Instead, it should simply report a stop to the > user whenever the hardware reports a hit. Right. This was solved simply by doing the is_masked_watchpoint check before fetching the watchpoint value. > > +static void > > +print_one_detail_masked_watchpoint (const struct breakpoint *b, > > + struct ui_out *uiout) > > +{ > > + ui_out_text (uiout, "\tmask "); > > + > > + /* I don't know whether it's possible to get here without a b->loc, > > + but we can handle the situation. */ > > + if (b->loc) > > + ui_out_field_core_addr (uiout, "mask", b->loc->gdbarch, b->hw_wp_mask); > > + else > > + ui_out_field_string (uiout, "mask", core_addr_to_string (b->hw_wp_mask)); > > I think we should enforce that there is always exactly one location on > masked watchpoints, just like we do e.g. for catchpoints. Ok, with -location now we are guaranteed to have only one location. Fixed. > > +/* 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); > > Depending on the discussion on command syntax this may need to change anyway, > but even with the current syntax, it ignores any -location flag that may have > been given initially ... Since mask now implies -location, no change is needed here anymore. > > @@ -8540,7 +8832,14 @@ watch_command_1 (char *arg, int accessflag, int from_tty, > > 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 = hw_wp_mask; > > + b->ops = &masked_watchpoint_breakpoint_ops; > > + } > > + else > > + b->ops = &watchpoint_breakpoint_ops; > > We shouldn't compute an intial value or set val_valid for masked watchpoints. Fixed. > > +/* 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 ()); > > + > > + if ((mask & 0xC0000000) != 0xC0000000) > > + error (_("\ > > +The given mask covers kernel address space and cannot be used.\n\ > > +You have to delete the masked watchpoint to continue the debugging session.")); > > Huh, this interface seems a bit odd. Shouldn't such watchpoints be rejected > right from the start, using something like the region_ok_for_watchpoint > callback? > > > +/* Return the number of registers needed for a masked hardware watchpoint. */ > > + > > +static int > > +ppc_linux_masked_watch_num_registers (struct target_ops *target) > > +{ > > + return ((have_ptrace_booke_interface () > > + && booke_debug_info.features & PPC_DEBUG_FEATURE_DATA_BP_MASK)? > > + 2 : -1); > > +} > > So maybe this interface ought to get parameters to be able to check > whether specific watchpoints are valid? Ok, it now gets an addr and mask parameter, and returns -2 if the region is rejected. > > INHERIT (to_insert_watchpoint, t); > > INHERIT (to_remove_watchpoint, t); > > + /* Do not inherit to_insert_mask_watchpoint. */ > > + /* Do not inherit to_remove_mask_watchpoint. */ > > Why should this differ between regular and masked watchpoints? Shouldn't > they either both use inheritance or none? This was discussed and settled in the ranged watchpoints patch, so I didn't change it here. Tested without regressions on ppc-linux, ppc64-linux and i386-linux. Ok? -- []'s Thiago Jung Bauermann IBM Linux Technology Center 2011-04-18 Sergio Durigan Junior Thiago Jung Bauermann Implement support for PowerPC BookE masked watchpoints. gdb/ *NEWS: Mention masked watchpoint support. Create "Changed commands" section. * breakpoint.h (struct breakpoint_ops) : New method. Initialize to NULL in all existing breakpoint_ops instances. (struct breakpoint) : 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) , , : 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): Document masked watchpoints. diff --git a/gdb/NEWS b/gdb/NEWS index a673d7a..5a68154 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -3,6 +3,20 @@ *** 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. + +* 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 0a0b09f..c91df6f 100644 --- a/gdb/ada-lang.c +++ b/gdb/ada-lang.c @@ -10951,6 +10951,7 @@ 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 */ @@ -10991,6 +10992,7 @@ 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 */ @@ -11029,6 +11031,7 @@ 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 2bfdfb0..7d01737 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; @@ -1437,19 +1441,23 @@ update_watchpoint (struct breakpoint *b, int reparse) (bp_hardware_watchpoint, 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 @@ -3695,15 +3703,30 @@ 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; - } + { + CORE_ADDR newaddr, start; + + if (is_masked_watchpoint (loc->owner)) + { + newaddr = addr & loc->owner->hw_wp_mask; + start = loc->address & loc->owner->hw_wp_mask; + } + else + { + newaddr = addr; + start = loc->address; + } + + /* Exact match not required. Within range is + sufficient. */ + if (target_watchpoint_addr_within_range (¤t_target, + newaddr, start, + loc->length)) + { + b->watchpoint_triggered = watch_triggered_yes; + break; + } + } } return 1; @@ -3800,9 +3823,16 @@ 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 @@ -6306,6 +6336,7 @@ 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 */ @@ -6404,6 +6435,7 @@ 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 */ @@ -6691,6 +6723,7 @@ 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 */ @@ -6847,6 +6880,7 @@ 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 */ @@ -8479,6 +8513,7 @@ 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, @@ -8785,6 +8820,15 @@ 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 = @@ -8793,6 +8837,7 @@ 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 */ @@ -8800,6 +8845,200 @@ 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) +{ + struct ui_stream *stb; + struct cleanup *old_chain; + + /* Masked watchpoints have only one location. */ + gdb_assert (b->loc && b->loc->next == NULL); + + stb = ui_out_stream_new (uiout); + old_chain = make_cleanup_ui_out_stream_delete (stb); + + 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"); + + do_cleanups (old_chain); + + /* 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) */ @@ -8815,73 +9054,97 @@ 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 ' - 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 ' - 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 - 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. */ @@ -8912,10 +9175,22 @@ 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); @@ -9013,9 +9288,18 @@ 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); @@ -9550,6 +9834,7 @@ 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 bf827e5..ccd7c3c 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 c71d664..b1fb0ff 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -3727,7 +3727,7 @@ 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 @@ -3738,12 +3738,17 @@ 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. (Currently, this is only available on PowerPC Embedded +architecture, see @ref{PowerPC Embedded}.) + 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, @@ -3754,12 +3759,12 @@ 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. @@ -18742,6 +18747,23 @@ 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. + +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. + +To set a masked watchpoint in @value{GDBN}, use the @code{mask} argument in +the @code{watch} command (@pxref{Set Watchpoints}), as in: + +@smallexample +(@value{GDBP}) watch *0xdeadbeef mask 0xffffff00 +@end smallexample + @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..d20a288 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 +2282,27 @@ 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\ +You have to delete the masked watchpoint to continue the debugging session.")); + + return -2; + } + else + return 2; +} + static void ppc_linux_store_inferior_registers (struct target_ops *ops, struct regcache *regcache, int regno) @@ -2438,11 +2517,14 @@ _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 a032052..5028247 100644 --- a/gdb/target.c +++ b/gdb/target.c @@ -597,6 +597,8 @@ 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); @@ -604,6 +606,7 @@ 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); @@ -3492,6 +3495,75 @@ 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 f0b2e43..ef15022 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); @@ -1349,6 +1355,20 @@ 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) @@ -1382,6 +1402,12 @@ 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 ? \