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 <christophe.leroy@csgroup.eu>
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Petr Mladek <pmladek@suse.com>

Author: chleroy

MAINTAINERS

@@ -11338,8 +11338,6 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.g
 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

@@ -7,17 +7,9 @@
 #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

@@ -63,7 +63,6 @@
 #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

@@ -59,7 +59,7 @@
 #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

@@ -16,8 +16,6 @@
 
 #if IS_ENABLED(CONFIG_LIVEPATCH)
 
-#include <asm/livepatch.h>
-
 /* task patch states */
 #define KLP_UNDEFINED	-1
 #define KLP_UNPATCHED	 0

arch/x86/include/asm/livepatch.h

@@ -118,7 +118,7 @@ static void notrace klp_ftrace_handler(unsigned long ip,
 	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);