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Commit d82227cf authored by Rabin Vincent's avatar Rabin Vincent Committed by Russell King
Browse files

ARM: 7331/1: extract out insn generation code from ftrace 



Extract out the instruction generation code so that it can be used
for jump labels too.

Signed-off-by: default avatarRabin Vincent <rabin@rab.in>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 4394e282

arch/arm/kernel/Makefile

+3 −2
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ AFLAGS_head.o := -DTEXT_OFFSET=$(TEXT_OFFSET) 


ifdef CONFIG_FUNCTION_TRACER

CFLAGS_REMOVE_ftrace.o = -pg

CFLAGS_REMOVE_insn.o = -pg

endif



CFLAGS_REMOVE_return_address.o = -pg
@@ -34,8 +35,8 @@ obj-$(CONFIG_HAVE_SCHED_CLOCK) += sched_clock.o 
obj-$(CONFIG_SMP)		+= smp.o smp_tlb.o

obj-$(CONFIG_HAVE_ARM_SCU)	+= smp_scu.o

obj-$(CONFIG_HAVE_ARM_TWD)	+= smp_twd.o

obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o

obj-$(CONFIG_DYNAMIC_FTRACE)	+= ftrace.o insn.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o

obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o

obj-$(CONFIG_KPROBES)		+= kprobes.o kprobes-common.o

ifdef CONFIG_THUMB2_KERNEL

arch/arm/kernel/ftrace.c

+4 −57
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ 
#include <asm/opcodes.h>

#include <asm/ftrace.h>



#include "insn.h"



#ifdef CONFIG_THUMB2_KERNEL

#define	NOP		0xf85deb04	/* pop.w {lr} */

#else
@@ -61,64 +63,9 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr) 
}

#endif



#ifdef CONFIG_THUMB2_KERNEL

static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,

				       bool link)

{

	unsigned long s, j1, j2, i1, i2, imm10, imm11;

	unsigned long first, second;

	long offset;



	offset = (long)addr - (long)(pc + 4);

	if (offset < -16777216 || offset > 16777214) {

		WARN_ON_ONCE(1);

		return 0;

	}



	s	= (offset >> 24) & 0x1;

	i1	= (offset >> 23) & 0x1;

	i2	= (offset >> 22) & 0x1;

	imm10	= (offset >> 12) & 0x3ff;

	imm11	= (offset >>  1) & 0x7ff;



	j1 = (!i1) ^ s;

	j2 = (!i2) ^ s;



	first = 0xf000 | (s << 10) | imm10;

	second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;

	if (link)

		second |= 1 << 14;



	return __opcode_thumb32_compose(first, second);

}

#else

static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,

				       bool link)

{

	unsigned long opcode = 0xea000000;

	long offset;



	if (link)

		opcode |= 1 << 24;



	offset = (long)addr - (long)(pc + 8);

	if (unlikely(offset < -33554432 || offset > 33554428)) {

		/* Can't generate branches that far (from ARM ARM). Ftrace

		 * doesn't generate branches outside of kernel text.

		 */

		WARN_ON_ONCE(1);

		return 0;

	}



	offset = (offset >> 2) & 0x00ffffff;



	return opcode | offset;

}

#endif



static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)

{

	return ftrace_gen_branch(pc, addr, true);

	return arm_gen_branch_link(pc, addr);

}



static int ftrace_modify_code(unsigned long pc, unsigned long old,
@@ -258,7 +205,7 @@ static int __ftrace_modify_caller(unsigned long *callsite, 
{

	unsigned long caller_fn = (unsigned long) func;

	unsigned long pc = (unsigned long) callsite;

	unsigned long branch = ftrace_gen_branch(pc, caller_fn, false);

	unsigned long branch = arm_gen_branch(pc, caller_fn);

	unsigned long nop = 0xe1a00000;	/* mov r0, r0 */

	unsigned long old = enable ? nop : branch;

	unsigned long new = enable ? branch : nop;

arch/arm/kernel/insn.c

0 → 100644
+61 −0
Original line number Diff line number Diff line 
#include <linux/kernel.h>

#include <asm/opcodes.h>



static unsigned long

__arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)

{

	unsigned long s, j1, j2, i1, i2, imm10, imm11;

	unsigned long first, second;

	long offset;



	offset = (long)addr - (long)(pc + 4);

	if (offset < -16777216 || offset > 16777214) {

		WARN_ON_ONCE(1);

		return 0;

	}



	s	= (offset >> 24) & 0x1;

	i1	= (offset >> 23) & 0x1;

	i2	= (offset >> 22) & 0x1;

	imm10	= (offset >> 12) & 0x3ff;

	imm11	= (offset >>  1) & 0x7ff;



	j1 = (!i1) ^ s;

	j2 = (!i2) ^ s;



	first = 0xf000 | (s << 10) | imm10;

	second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;

	if (link)

		second |= 1 << 14;



	return __opcode_thumb32_compose(first, second);

}



static unsigned long

__arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)

{

	unsigned long opcode = 0xea000000;

	long offset;



	if (link)

		opcode |= 1 << 24;



	offset = (long)addr - (long)(pc + 8);

	if (unlikely(offset < -33554432 || offset > 33554428)) {

		WARN_ON_ONCE(1);

		return 0;

	}



	offset = (offset >> 2) & 0x00ffffff;



	return opcode | offset;

}



unsigned long

__arm_gen_branch(unsigned long pc, unsigned long addr, bool link)

{

	if (IS_ENABLED(CONFIG_THUMB2_KERNEL))

		return __arm_gen_branch_thumb2(pc, addr, link);

	else

		return __arm_gen_branch_arm(pc, addr, link);

}

arch/arm/kernel/insn.h

0 → 100644
+19 −0
Original line number Diff line number Diff line 
#ifndef __ASM_ARM_INSN_H

#define __ASM_ARM_INSN_H



unsigned long

__arm_gen_branch(unsigned long pc, unsigned long addr, bool link);



static inline unsigned long

arm_gen_branch(unsigned long pc, unsigned long addr)

{

	return __arm_gen_branch(pc, addr, false);

}



static inline unsigned long

arm_gen_branch_link(unsigned long pc, unsigned long addr)

{

	return __arm_gen_branch(pc, addr, true);

}



#endif