linux-stable/kernel/livepatch/Kconfig
Steven Rostedt (VMware) 2860cd8a23 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>
2020-11-13 12:15:28 -05:00

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# SPDX-License-Identifier: GPL-2.0-only
config HAVE_LIVEPATCH
bool
help
Arch supports kernel live patching
config LIVEPATCH
bool "Kernel Live Patching"
depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
depends on MODULES
depends on SYSFS
depends on KALLSYMS_ALL
depends on HAVE_LIVEPATCH
depends on !TRIM_UNUSED_KSYMS
help
Say Y here if you want to support kernel live patching.
This option has no runtime impact until a kernel "patch"
module uses the interface provided by this option to register
a patch, causing calls to patched functions to be redirected
to new function code contained in the patch module.