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Commit d9f5ab7b authored by Jason Baron's avatar Jason Baron Committed by Steven Rostedt
Browse files

jump label: x86 support 



add x86 support for jump label. I'm keeping this patch separate so its clear
to arch maintainers what was required for x86 support this new feature.
Hopefully, it wouldn't be too painful for other archs.

Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
LKML-Reference: <f838f49f40fbea0254036194be66dc48b598dcea.1284733808.git.jbaron@redhat.com>

[ cleaned up some formatting ]

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 52159d98

arch/x86/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -59,6 +59,7 @@ config X86 
	select ANON_INODES

	select ANON_INODES

	select HAVE_ARCH_KMEMCHECK

	select HAVE_ARCH_KMEMCHECK

	select HAVE_USER_RETURN_NOTIFIER

	select HAVE_USER_RETURN_NOTIFIER

	select HAVE_ARCH_JUMP_LABEL if !CC_OPTIMIZE_FOR_SIZE





config INSTRUCTION_DECODER

config INSTRUCTION_DECODER

	def_bool (KPROBES || PERF_EVENTS)

	def_bool (KPROBES || PERF_EVENTS)

arch/x86/include/asm/jump_label.h

0 → 100644
+47 −0
Original line number Original line Diff line number Diff line 
#ifndef _ASM_X86_JUMP_LABEL_H

#define _ASM_X86_JUMP_LABEL_H



#ifdef __KERNEL__



#include <linux/types.h>

#include <asm/nops.h>



#define JUMP_LABEL_NOP_SIZE 5



# define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"



# define JUMP_LABEL(key, label)					\

	do {							\

		asm goto("1:"					\

			JUMP_LABEL_INITIAL_NOP			\

			".pushsection __jump_table,  \"a\" \n\t"\

			_ASM_PTR "1b, %l[" #label "], %c0 \n\t" \

			".popsection \n\t"			\

			: :  "i" (key) :  : label);		\

	} while (0)



#endif /* __KERNEL__ */



#ifdef CONFIG_X86_64



typedef u64 jump_label_t;



struct jump_entry {

	jump_label_t code;

	jump_label_t target;

	jump_label_t key;

};



#else



typedef u32 jump_label_t;



struct jump_entry {

	jump_label_t code;

	jump_label_t target;

	jump_label_t key;

};



#endif



#endif

arch/x86/kernel/Makefile

+1 −1
Original line number Original line Diff line number Diff line
@@ -32,7 +32,7 @@ GCOV_PROFILE_paravirt.o := n 
obj-y			:= process_$(BITS).o signal.o entry_$(BITS).o

obj-y			:= process_$(BITS).o signal.o entry_$(BITS).o

obj-y			+= traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o

obj-y			+= traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o

obj-y			+= time.o ioport.o ldt.o dumpstack.o

obj-y			+= time.o ioport.o ldt.o dumpstack.o

obj-y			+= setup.o x86_init.o i8259.o irqinit.o

obj-y			+= setup.o x86_init.o i8259.o irqinit.o jump_label.o

obj-$(CONFIG_X86_VISWS)	+= visws_quirks.o

obj-$(CONFIG_X86_VISWS)	+= visws_quirks.o

obj-$(CONFIG_X86_32)	+= probe_roms_32.o

obj-$(CONFIG_X86_32)	+= probe_roms_32.o

obj-$(CONFIG_X86_32)	+= sys_i386_32.o i386_ksyms_32.o

obj-$(CONFIG_X86_32)	+= sys_i386_32.o i386_ksyms_32.o

arch/x86/kernel/jump_label.c

0 → 100644
+50 −0
Original line number Original line Diff line number Diff line 
/*

 * jump label x86 support

 *

 * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>

 *

 */

#include <linux/jump_label.h>

#include <linux/memory.h>

#include <linux/uaccess.h>

#include <linux/module.h>

#include <linux/list.h>

#include <linux/jhash.h>

#include <linux/cpu.h>

#include <asm/kprobes.h>

#include <asm/alternative.h>



#ifdef HAVE_JUMP_LABEL



union jump_code_union {

	char code[JUMP_LABEL_NOP_SIZE];

	struct {

		char jump;

		int offset;

	} __attribute__((packed));

};



void arch_jump_label_transform(struct jump_entry *entry,

			       enum jump_label_type type)

{

	union jump_code_union code;



	if (type == JUMP_LABEL_ENABLE) {

		code.jump = 0xe9;

		code.offset = entry->target -

				(entry->code + JUMP_LABEL_NOP_SIZE);

	} else

		memcpy(&code, ideal_nop5, JUMP_LABEL_NOP_SIZE);

	get_online_cpus();

	mutex_lock(&text_mutex);

	text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);

	mutex_unlock(&text_mutex);

	put_online_cpus();

}



void arch_jump_label_text_poke_early(jump_label_t addr)

{

	text_poke_early((void *)addr, ideal_nop5, JUMP_LABEL_NOP_SIZE);

}



#endif

arch/x86/kernel/module.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -239,6 +239,9 @@ int module_finalize(const Elf_Ehdr *hdr, 
		apply_paravirt(pseg, pseg + para->sh_size);

		apply_paravirt(pseg, pseg + para->sh_size);

	}

	}





	/* make jump label nops */

	jump_label_apply_nops(me);



	return module_bug_finalize(hdr, sechdrs, me);

	return module_bug_finalize(hdr, sechdrs, me);

}

}