livepatch: Remove klp_arch_set_pc() and asm/livepatch.h

All three versions of klp_arch_set_pc() do exactly the same: they
call ftrace_instruction_pointer_set().

Call ftrace_instruction_pointer_set() directly and remove
klp_arch_set_pc().

As klp_arch_set_pc() was the only thing remaining in asm/livepatch.h
on x86 and s390, remove asm/livepatch.h

livepatch.h remains on powerpc but its content is exclusively used
by powerpc specific code.

Signed-off-by: Christophe Leroy <[e-mail]>
Acked-by: Petr Mladek <[e-mail]>
Acked-by: Peter Zijlstra (Intel) <[e-mail]>
Acked-by: Miroslav Benes <[e-mail]>
Signed-off-by: Petr Mladek <[e-mail]>

MAINTAINERS

···
 F:	Documentation/ABI/testing/sysfs-kernel-livepatch
 F:	Documentation/livepatch/
 F:	arch/powerpc/include/asm/livepatch.h
-F:	arch/s390/include/asm/livepatch.h
-F:	arch/x86/include/asm/livepatch.h
 F:	include/linux/livepatch.h
 F:	kernel/livepatch/
 F:	lib/livepatch/

arch/powerpc/include/asm/livepatch.h

···
 #ifndef _ASM_POWERPC_LIVEPATCH_H
 #define _ASM_POWERPC_LIVEPATCH_H
 
-#include <linux/module.h>
-#include <linux/ftrace.h>
+#include <linux/sched.h>
 #include <linux/sched/task_stack.h>
-
-#ifdef CONFIG_LIVEPATCH
-static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
-{
-	ftrace_instruction_pointer_set(fregs, ip);
-}
-#endif /* CONFIG_LIVEPATCH */
 
 #ifdef CONFIG_LIVEPATCH_64
 static inline void klp_init_thread_info(struct task_struct *p)

arch/powerpc/kernel/irq.c

···
 #include <asm/machdep.h>
 #include <asm/udbg.h>
 #include <asm/smp.h>
-#include <asm/livepatch.h>
 #include <asm/hw_irq.h>
 #include <asm/softirq_stack.h>
 

arch/powerpc/kernel/setup_64.c

···
 #include <asm/udbg.h>
 #include <asm/kexec.h>
 #include <asm/code-patching.h>
-#include <asm/livepatch.h>
+#include <asm/ftrace.h>
 #include <asm/opal.h>
 #include <asm/cputhreads.h>
 #include <asm/hw_irq.h>

arch/s390/include/asm/livepatch.h

···
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * livepatch.h - s390-specific Kernel Live Patching Core
- *
- *  Copyright (c) 2013-2015 SUSE
- *   Authors: Jiri Kosina
- *	      Vojtech Pavlik
- *	      Jiri Slaby
- */
-
-#ifndef ASM_LIVEPATCH_H
-#define ASM_LIVEPATCH_H
-
-#include <linux/ftrace.h>
-#include <asm/ptrace.h>
-
-static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
-{
-	ftrace_instruction_pointer_set(fregs, ip);
-}
-
-#endif

arch/x86/include/asm/livepatch.h

···
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * livepatch.h - x86-specific Kernel Live Patching Core
- *
- * Copyright (C) 2014 Seth Jennings <[e-mail]>
- * 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 */

include/linux/livepatch.h

···
 
 #if IS_ENABLED(CONFIG_LIVEPATCH)
 
-#include <asm/livepatch.h>
-
 /* task patch states */
 #define KLP_UNDEFINED	-1
 #define KLP_UNPATCHED	 0

kernel/livepatch/patch.c

···
 	if (func->nop)
 		goto unlock;
 
-	klp_arch_set_pc(fregs, (unsigned long)func->new_func);
+	ftrace_instruction_pointer_set(fregs, (unsigned long)func->new_func);
 
 unlock:
 	ftrace_test_recursion_unlock(bit);