[RFC] Add watchpoint hit address function to procfs.c
Pedro Alves
pedro@codesourcery.com
Fri May 7 15:25:00 GMT 2010
On Monday 26 April 2010 15:17:33, Pierre Muller wrote:
> The following patch adds support for
> to_stopped_data_address field of target_ops,
> using
> prstatus.pr_lwp.pr_info.__data.__fault.__addr field.
> (or prstatus.pr_info.__data.__fault.__addr if NEW_PROC_API
> is not defined) I found that in the OpenSolaris sources.
>
> It works for my OpenSolaris 2.11.
>
> The main problem is that I have no ideas if this works for other
> targets using procfs.c source.
>
> How should this be modified to avoid problem if other targets
> do not have/set these fields?
>
> Comments welcome.
>
> Pierre Muller
> Pascal language support maintainer for GDB
>
> 2010-04-26 Pierre Muller <muller@ics.u-strasbg.fr>
>
> * procfs.c (proc_watchpoint_address): New function.
> (procfs_stopped_data_address): New function.
> (procfs_use_watchpoints): Register new watchpoint related
> function.
>
> Index: procfs.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/procfs.c,v
> retrieving revision 1.131
> diff -u -p -r1.131 procfs.c
> --- procfs.c 20 Apr 2010 22:36:35 -0000 1.131
> +++ procfs.c 26 Apr 2010 14:05:29 -0000
> @@ -1312,6 +1312,30 @@ proc_what (procinfo *pi)
> return pi->prstatus.pr_what;
> #endif
> }
> +/*
> + * Function: proc_watchpoint_address
> + *
> + * returns the prstatus.pr_lwp.pr_info.__data.__fault.__addr field.
> + */
> +
> +CORE_ADDR
> +proc_watchpoint_address (procinfo *pi)
> +{
> + if (!pi->status_valid)
> + if (!proc_get_status (pi))
> + return 0; /* FIXME: not a good failure value (but what is?) */
Add a new CORE_ADDR pointer parameter, and use that as
output. C hange the return type to int to indicate failure/success.
That is, model the interface of this function from to_stopped_data_address's
interface.
> +
> +#ifdef NEW_PROC_API
> + return unsigned_pointer_to_address (target_gdbarch,
> + builtin_type (target_gdbarch)->builtin_data_ptr,
> + (gdb_byte *) &pi->prstatus.pr_lwp.pr_info.__data.__fault.__addr);
> +#else
> + return unsigned_pointer_to_address (target_gdbarch,
> + builtin_type (target_gdbarch)->builtin_data_ptr,
> + (gdb_byte *) &pi->prstatus.pr_info.__data.__fault.__addr);
> +#endif
Isn't there a macro to access __data.__fault.__addr ? I'd have
guessed pi->prstatus.pr_info.sa_addr, similarly to
how we use pi->prstatus.pr_lwp.pr_info.si_signo already. That
is, pr_info is a siginfo_t. That would probably get rid of
the NEW_PROC_API usage and worries.
> +}
> +
>
> #ifndef PIOCSSPCACT /* The following is not supported on OSF. */
> /*
> @@ -5560,6 +5584,45 @@ procfs_stopped_by_watchpoint (void)
> }
> return 0;
> }
> +/*
> + * Function procfs_stopped_data_address
> + * Returns non-zero if we can find the position
> + * of the triggring watchpoint.
> + */
> +
> +static int
> +procfs_stopped_data_address (struct target_ops *targ, CORE_ADDR *addr)
> +{
> + CORE_ADDR waddr;
> + procinfo *pi;
> + int watchpoint_hit = 0;
> +
> + pi = find_procinfo_or_die (PIDGET (inferior_ptid), 0);
> +
> + if (!pi) /* If no process, then not stopped by watchpoint! */
> + return 0;
Find_procinfo_or_die throws if the procinfo isn't
found (it's the die part), so this check is dead code.
I wonder if this procinfo is the correct one. Shouldn't
this look for the the procinfo for the current thread (the tid
in inferior_ptid), not the one for the main thread?
> +
> + if (proc_flags (pi) & (PR_STOPPED | PR_ISTOP))
> + {
> + if (proc_why (pi) == PR_FAULTED)
> + {
> +#ifdef FLTWATCH
> + if (proc_what (pi) == FLTWATCH)
> + watchpoint_hit = 1;
> +#endif
> +#ifdef FLTKWATCH
> + if (proc_what (pi) == FLTKWATCH)
> + watchpoint_hit = 1;
> +#endif
> + }
> + }
> + if (!watchpoint_hit)
> + return 0;
You can assume that this target_ops method is only
ever called if a watchpoint is hit in the first
place (if target_stopped_by_watchpoint returned
true), so remove all this (duplicated) code.
> + waddr = proc_watchpoint_address (pi);
> + if (addr)
> + *addr = waddr;
> + return (waddr != 0);
> +}
>
> static int
> procfs_insert_watchpoint (CORE_ADDR addr, int len, int type)
> @@ -5607,6 +5670,7 @@ procfs_use_watchpoints (struct target_op
> t->to_remove_watchpoint = procfs_remove_watchpoint;
> t->to_region_ok_for_hw_watchpoint = procfs_region_ok_for_hw_watchpoint;
> t->to_can_use_hw_breakpoint = procfs_can_use_hw_breakpoint;
> + t->to_stopped_data_address = procfs_stopped_data_address;
> }
>
> /*
>
>
--
Pedro Alves
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