livepatch: Use the default ftrace_ops instead of REGS when ARGS is available
When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS is available, the ftrace call will be able to set the ip of the calling function. This will improve the performance of live kernel patching where it does not need all the regs to be stored just to change the instruction pointer. If all archs that support live kernel patching also support HAVE_DYNAMIC_FTRACE_WITH_ARGS, then the architecture specific function klp_arch_set_pc() could be made generic. It is possible that an arch can support HAVE_DYNAMIC_FTRACE_WITH_ARGS but not HAVE_DYNAMIC_FTRACE_WITH_REGS and then have access to live patching. Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: live-patching@vger.kernel.org Acked-by:Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Miroslav Benes <mbenes@suse.cz> Signed-off-by:
Steven Rostedt (VMware) <rostedt@goodmis.org>
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