mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 20:53:53 +08:00
7d241ff056
With dynamic function tracer, by default, _mcount is defined as an "empty" function, it returns directly without any more action. When enabling it in user-space, it will jump to a real tracing function(ftrace_caller), and do the real job for us. Differ from the static function tracer, dynamic function tracer provides two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the tracing of some indicated kernel functions(set_ftrace_filter). In the kernel version, there is only one "_mcount" string for every kernel function, so, we just need to match this one in mcount_regex of scripts/recordmcount.pl. For more information please look at code and Documentation/trace folder. Steven ACK that scripts/recordmcount.pl part. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Michal Simek <monstr@monstr.eu>
152 lines
4.2 KiB
C
152 lines
4.2 KiB
C
/*
|
|
* 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_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;
|
|
|
|
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_NOP
|
|
static 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;
|
|
}
|
|
|
|
static int ret_addr; /* initialized as 0 by default */
|
|
|
|
/* 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;
|
|
ret_addr = addr; /* saving where the barrier jump is */
|
|
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 __init ftrace_dyn_arch_init(void *data)
|
|
{
|
|
/* The return code is retured via data */
|
|
*(unsigned long *)data = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
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 remove the rtsd r15, 8 by NOP */
|
|
BUG_ON(!ret_addr);
|
|
if (ret_addr)
|
|
ret += ftrace_modify_code(ret_addr, MICROBLAZE_NOP);
|
|
else
|
|
ret = 1; /* fault */
|
|
|
|
/* All changes are done - lets do caches consistent */
|
|
flush_icache();
|
|
return ret;
|
|
}
|
|
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|