/* * Ftrace support for Microblaze. * * Copyright (C) 2009 Michal Simek <monstr@monstr.eu> * Copyright (C) 2009 PetaLogix * * Based on MIPS and PowerPC ftrace code * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. */ #include <asm/cacheflush.h>#include <linux/ftrace.h> #ifdef CONFIG_FUNCTION_GRAPH_TRACER/* * Hook the return address and push it in the stack of return addrs * in current thread info. */void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr){	unsigned long old;	int faulted;	unsigned long return_hooker = (unsigned long)				&return_to_handler; 	if (unlikely(ftrace_graph_is_dead()))		return; 	if (unlikely(atomic_read(&current->tracing_graph_pause)))		return; 	/*	 * Protect against fault, even if it shouldn't	 * happen. This tool is too much intrusive to	 * ignore such a protection.	 */	asm volatile("	1:	lwi	%0, %2, 0;"		\			"2:	swi	%3, %2, 0;"		\			"	addik	%1, r0, 0;"		\			"3:"					\			"	.section .fixup, \"ax\";"	\			"4:	brid	3b;"			\			"	addik	%1, r0, 1;"		\			"	.previous;"			\			"	.section __ex_table,\"a\";"	\			"	.word	1b,4b;"			\			"	.word	2b,4b;"			\			"	.previous;"			\			: "=&r" (old), "=r" (faulted)			: "r" (parent), "r" (return_hooker)	); 	flush_dcache_range((u32)parent, (u32)parent + 4);	flush_icache_range((u32)parent, (u32)parent + 4); 	if (unlikely(faulted)) {		ftrace_graph_stop();		WARN_ON(1);		return;	} 	if (function_graph_enter(old, self_addr, 0, NULL))		*parent = old;}#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ #ifdef CONFIG_DYNAMIC_FTRACE/* save value to addr - it is save to do it in asm */static int ftrace_modify_code(unsigned long addr, unsigned int value){	int faulted = 0; 	__asm__ __volatile__("	1:	swi	%2, %1, 0;"		\				"	addik	%0, r0, 0;"		\				"2:"					\				"	.section .fixup, \"ax\";"	\				"3:	brid	2b;"			\				"	addik	%0, r0, 1;"		\				"	.previous;"			\				"	.section __ex_table,\"a\";"	\				"	.word	1b,3b;"			\				"	.previous;"			\				: "=r" (faulted)				: "r" (addr), "r" (value)	); 	if (unlikely(faulted))		return -EFAULT; 	flush_dcache_range(addr, addr + 4);	flush_icache_range(addr, addr + 4); 	return 0;} #define MICROBLAZE_NOP 0x80000000#define MICROBLAZE_BRI 0xb800000C static unsigned int recorded; /* if save was or not */static unsigned int imm; /* saving whole imm instruction */ /* There are two approaches howto solve ftrace_make nop function - look below */#undef USE_FTRACE_NOP #ifdef USE_FTRACE_NOPstatic unsigned int bralid; /* saving whole bralid instruction */#endif int ftrace_make_nop(struct module *mod,			struct dyn_ftrace *rec, unsigned long addr){	/* we have this part of code which we are working with	 * b000c000        imm     -16384	 * b9fc8e30        bralid  r15, -29136     // c0008e30 <_mcount>	 * 80000000        or      r0, r0, r0	 *	 * The first solution (!USE_FTRACE_NOP-could be called branch solution)	 * b000c000        bri	12 (0xC - jump to any other instruction)	 * b9fc8e30        bralid  r15, -29136     // c0008e30 <_mcount>	 * 80000000        or      r0, r0, r0	 * any other instruction	 *	 * The second solution (USE_FTRACE_NOP) - no jump just nops	 * 80000000        or      r0, r0, r0	 * 80000000        or      r0, r0, r0	 * 80000000        or      r0, r0, r0	 */	int ret = 0; 	if (recorded == 0) {		recorded = 1;		imm = *(unsigned int *)rec->ip;		pr_debug("%s: imm:0x%x\n", __func__, imm);#ifdef USE_FTRACE_NOP		bralid = *(unsigned int *)(rec->ip + 4);		pr_debug("%s: bralid 0x%x\n", __func__, bralid);#endif /* USE_FTRACE_NOP */	} #ifdef USE_FTRACE_NOP	ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP);	ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP);#else /* USE_FTRACE_NOP */	ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI);#endif /* USE_FTRACE_NOP */	return ret;} /* I believe that first is called ftrace_make_nop before this function */int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr){	int ret;	pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n",		__func__, (unsigned int)addr, (unsigned int)rec->ip, imm);	ret = ftrace_modify_code(rec->ip, imm);#ifdef USE_FTRACE_NOP	pr_debug("%s: bralid:0x%x\n", __func__, bralid);	ret += ftrace_modify_code(rec->ip + 4, bralid);#endif /* USE_FTRACE_NOP */	return ret;} int ftrace_update_ftrace_func(ftrace_func_t func){	unsigned long ip = (unsigned long)(&ftrace_call);	unsigned int upper = (unsigned int)func;	unsigned int lower = (unsigned int)func;	int ret = 0; 	/* create proper saving to ftrace_call poll */	upper = 0xb0000000 + (upper >> 16); /* imm func_upper */	lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */ 	pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n",		__func__, (unsigned int)func, (unsigned int)ip, upper, lower); 	/* save upper and lower code */	ret = ftrace_modify_code(ip, upper);	ret += ftrace_modify_code(ip + 4, lower); 	/* We just need to replace the rtsd r15, 8 with NOP */	ret += ftrace_modify_code((unsigned long)&ftrace_caller,				  MICROBLAZE_NOP); 	return ret;} #ifdef CONFIG_FUNCTION_GRAPH_TRACERunsigned int old_jump; /* saving place for jump instruction */ int ftrace_enable_ftrace_graph_caller(void){	unsigned int ret;	unsigned long ip = (unsigned long)(&ftrace_call_graph); 	old_jump = *(unsigned int *)ip; /* save jump over instruction */	ret = ftrace_modify_code(ip, MICROBLAZE_NOP); 	pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);	return ret;} int ftrace_disable_ftrace_graph_caller(void){	unsigned int ret;	unsigned long ip = (unsigned long)(&ftrace_call_graph); 	ret = ftrace_modify_code(ip, old_jump); 	pr_debug("%s\n", __func__);	return ret;}#endif /* CONFIG_FUNCTION_GRAPH_TRACER */#endif /* CONFIG_DYNAMIC_FTRACE */