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Re: [ppc-linux-nat]: set access flag for h/w watchpoint even if it is only read or write
- From: Daniel Jacobowitz <drow at false dot org>
- To: Eli Zaretskii <eliz at gnu dot org>
- Cc: Wu Zhou <woodzltc at cn dot ibm dot com>, gdb-patches at sourceware dot org
- Date: Thu, 6 Jul 2006 17:36:59 -0400
- Subject: Re: [ppc-linux-nat]: set access flag for h/w watchpoint even if it is only read or write
- References: <Pine.LNX.4.64.0606092320510.5286@localhost.localdomain> <20060706132020.GB18827@nevyn.them.org> <ulkr6qwkt.fsf@gnu.org>
On Thu, Jul 06, 2006 at 11:58:58PM +0300, Eli Zaretskii wrote:
> Yes, this problem is known on x86 and elsewhere. The problem is
> extremely rare, as reading and writing to the same address in the same
> instruction is a hard-to-accomplish treat. Wu, could you show a
> real-life example of where this matters?
I thought, though I may be misremembering, that it was actually a
different problem. Something like this:
- We set a read watchpoint. It does not trigger on writes.
- An instruction writes to the location.
- GDB stops, sees that it stopped at a watchpoint at the given address,
tries to determine what sort of watchpoint it was, determines that
the value had changed, and ignores the read watchpoint - the value
has changed since we last checked so this "must" have been a write
watchpoint.
Is that plausible or nonsensical?
--
Daniel Jacobowitz
CodeSourcery