Commit 9aabd8db authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Sasha Levin

powerpc/xmon: Fix data-breakpoint

[ Upstream commit c21a493a ]

Currently xmon data-breakpoint feature is broken.

Whenever there is a watchpoint match occurs, hw_breakpoint_handler will
be called by do_break via notifier chains mechanism. If watchpoint is
registered by xmon, hw_breakpoint_handler won't find any associated
perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break
also returns without notifying to xmon.

Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not
find any perf_event associated with matched watchpoint, rather than
NOTIFY_STOP, which tells the core code to continue calling the other
breakpoint handlers including the xmon one.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent c2fd678e
...@@ -227,8 +227,10 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) ...@@ -227,8 +227,10 @@ int __kprobes hw_breakpoint_handler(struct die_args *args)
rcu_read_lock(); rcu_read_lock();
bp = __this_cpu_read(bp_per_reg); bp = __this_cpu_read(bp_per_reg);
if (!bp) if (!bp) {
rc = NOTIFY_DONE;
goto out; goto out;
}
info = counter_arch_bp(bp); info = counter_arch_bp(bp);
/* /*
......
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