This adds new debug feature information so that the DAWR can be
identified by userspace tools like GDB.
Unfortunately the DAWR doesn't sit nicely into the current description
that ptrace provides to userspace via struct ppc_debug_info. It doesn't
allow for specifying that only some ranges are possible or even the end
alignment constraints (DAWR only allows 512 byte wide ranges which can't
cross a 512 byte boundary).
After talking to Edjunior Machado (GDB ppc developer), it was decided
this was the best approach. Just mark it as debug feature DAWR and
tools like GDB can internally decide the constraints.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
We have a mix of decimal and hex here, so lets make them consistently
hex. Also, strace will print them in hex if it can't decode them, so
having them in hex here makes it easier to match up.
No functional change.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The DSCR (aka Data Stream Control Register) is supported on some
server PowerPC chips and allow some control over the prefetch
of data streams.
The kernel already supports DSCR value per thread but there is also
a need in a ability to change it from an external process for
the specific pid.
The patch adds new register index PT_DSCR (index=44) which can be
set/get by:
ptrace(PTRACE_POKEUSER, traced_process, PT_DSCR << 3, dscr);
dscr = ptrace(PTRACE_PEEKUSER, traced_process, PT_DSCR << 3, NULL);
The patch does not increase PT_REGS_COUNT as the pt_regs struct has not
been changed.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
