2860cd8a23
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>
42 lines
1.1 KiB
C
42 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* livepatch.h - powerpc-specific Kernel Live Patching Core
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*
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* Copyright (C) 2015-2016, SUSE, IBM Corp.
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*/
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#ifndef _ASM_POWERPC_LIVEPATCH_H
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#define _ASM_POWERPC_LIVEPATCH_H
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#include <linux/module.h>
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#include <linux/ftrace.h>
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#include <linux/sched/task_stack.h>
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#ifdef CONFIG_LIVEPATCH
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static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
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{
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struct pt_regs *regs = ftrace_get_regs(fregs);
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regs->nip = ip;
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}
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#define klp_get_ftrace_location klp_get_ftrace_location
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static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
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{
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/*
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* Live patch works only with -mprofile-kernel on PPC. In this case,
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* the ftrace location is always within the first 16 bytes.
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*/
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return ftrace_location_range(faddr, faddr + 16);
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}
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static inline void klp_init_thread_info(struct task_struct *p)
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{
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/* + 1 to account for STACK_END_MAGIC */
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task_thread_info(p)->livepatch_sp = end_of_stack(p) + 1;
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}
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#else
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static inline void klp_init_thread_info(struct task_struct *p) { }
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#endif /* CONFIG_LIVEPATCH */
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#endif /* _ASM_POWERPC_LIVEPATCH_H */
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