linux-stable/arch/x86/include/asm/livepatch.h
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-or-later */
/*
* livepatch.h - x86-specific Kernel Live Patching Core
*
* Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
* Copyright (C) 2014 SUSE
*/
#ifndef _ASM_X86_LIVEPATCH_H
#define _ASM_X86_LIVEPATCH_H
#include <asm/setup.h>
#include <linux/ftrace.h>
static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
{
ftrace_instruction_pointer_set(fregs, ip);
}
#endif /* _ASM_X86_LIVEPATCH_H */