Messages in this thread | | | Date | Tue, 29 Apr 2008 00:44:05 -0400 | From | Rik van Riel <> | Subject | Re: PTRACE_{READ,WRITE}{TEXT,DATA} |
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On Mon, 28 Apr 2008 21:34:16 -0700 (PDT) David Miller <davem@davemloft.net> wrote:
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Date: Tue, 29 Apr 2008 13:54:08 +1000 > > > I noticed kernel/ptrace.c has ptrace_readdata/writedata functions that > > are only used by sparc and sparc64 which implements the ptrace requests > > PTRACE_READ_DATA, PTRACE_WRITE_DATA (and _TEXT variants). > > > > Any reason not to make everybody benefit from these and moving the sparc > > implementation to the generic ptrace_request (&compat) ? > > > > It's more efficient than read/writing one word at a time... I thought > > about it in the light of some work Rik is doing to make > > access_process_vm useable on video ram mappings done by the X server... > > It's kind of pointless because what gdb does these days on Linux is > use the procfs 'mem' file to directly read in parts of the inferior's > address space. > > See linux_proc_xfer_partial() in gdb/linux-nat.c
Strange, changing access_process_vm on Fedora 9 made gdb able to see video memory that the X server had mmapped.
Are you sure gdb behaves as you suggest?
On x86 my patch seems to work as I expected...
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