x86/hw-breakpoints: Optimize return code from notifier chain in hw_breakpoint_handler
authorK.Prasad <prasad@linux.vnet.ibm.com>
Thu, 28 Jan 2010 11:14:15 +0000 (16:14 +0530)
committerFrederic Weisbecker <fweisbec@gmail.com>
Fri, 29 Jan 2010 01:44:30 +0000 (02:44 +0100)
commite0e53db6133c32964fd17f20b17073a402f07ed3
tree72daeb1abb53901a0c8c10cbff234b5c4f9521c0
parent40f9249a73f6c251adea492b1c3d19d39e2a9bda
x86/hw-breakpoints: Optimize return code from notifier chain in hw_breakpoint_handler

Processing of debug exceptions in do_debug() can stop if it
originated from a hw-breakpoint exception by returning NOTIFY_STOP
in most cases.

But for certain cases such as:

a) user-space breakpoints with pending SIGTRAP signal delivery (as
in the case of ptrace induced breakpoints).

b) exceptions due to other causes than breakpoints

We will continue to process the exception by returning NOTIFY_DONE.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
LKML-Reference: <20100128111415.GC13935@in.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
arch/x86/kernel/hw_breakpoint.c