[PATCH] disable ptrace BookE interface for PowerPC server processors

[Edjunior Barbosa Machado <emachado@linux.vnet.ibm.com>]

Hi,

the ptrace BookE interface originally implemented only for embedded systems
should be available for Power servers processors as well shortly [1].
However, while this is not usable in upstream kernel, gdb should enforce
the usage of the old ptrace mechanism (using PTRACE_SET_DEBUGREG) on
servers, even if BookE debug registers are reported as available.

This patch fixes several tests related to watchpoints that were failing
when running upstream kernel (> 3.0), decreasing the number of
unexpected failures on gdb testsuite from 337 to 200 (Fedora 17 running
kernel 3.3.4-5.fc17.ppc64).

Ok to apply?

Thanks,
--
Edjunior Barbosa Machado
IBM Linux Technology Center

[1] http://lists.ozlabs.org/pipermail/linuxppc-dev/2012-May/097922.html

gdb/
2012-22-05  Edjunior Machado  <emachado@linux.vnet.ibm.com>

	* ppc-linux-nat.c (have_ptrace_booke_interface): disable ptrace booke
	interface for powerpc server processors while this is not available
	in kernel.

diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 34c40b4..5c95926 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -1418,8 +1418,11 @@ have_ptrace_booke_interface (void)
       if (tid == 0)
 	tid = PIDGET (inferior_ptid);
 
-      /* Check for kernel support for BOOKE debug registers.  */
-      if (ptrace (PPC_PTRACE_GETHWDBGINFO, tid, 0, &booke_debug_info) >= 0)
+      /* Check for kernel support for BOOKE debug registers.
+         This interface is currently available only for embedded
+         processors.  */
+      if (ptrace (PPC_PTRACE_GETHWDBGINFO, tid, 0, &booke_debug_info) >= 0
+	  && ppc_linux_get_hwcap () & PPC_FEATURE_BOOKE)
 	{
 	  have_ptrace_booke_interface = 1;
 	  max_slots_number = booke_debug_info.num_instruction_bps