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authorAravinda Prasad <aravinda@linux.vnet.ibm.com>2012-11-04 22:15:28 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-11-15 13:01:13 +1100
commita53fd61ac2f411745471c1c877d5e072fbbf0e5c (patch)
treed797a07b1a1294e30ebe2fd2aadcbc190966850a /arch
parent79597be99ac96b1409eb7ae41c336696d7c4f4d9 (diff)
downloadlinaro-lsk-a53fd61ac2f411745471c1c877d5e072fbbf0e5c.tar.gz
powerpc/ptrace: Enable hardware breakpoint upon re-registering
On powerpc, ptrace will disable hardware breakpoint request once the breakpoint is hit. It is the responsibility of the caller to set it again. However, when the caller sets the hardware breakpoint again using ptrace(PTRACE_SET_DEBUGREG, child_pid, 0, addr), the hardware breakpoint is not enabled. While gdb's approach is to unregister and re-register the hardware breakpoint every time the breakpoint is hit - which is working fine, this could affect other programs trying to re-register hardware breakpoint without unregistering. This patch enables hardware breakpoint if the caller is re-registering. Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com> Acked-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/ptrace.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 817b4116e5b..c4970004d44 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -952,6 +952,10 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
arch_bp_generic_fields(data &
(DABR_DATA_WRITE | DABR_DATA_READ),
&attr.bp_type);
+
+ /* Enable breakpoint */
+ attr.disabled = false;
+
ret = modify_user_hw_breakpoint(bp, &attr);
if (ret) {
ptrace_put_breakpoints(task);