95 lines
2.0 KiB
C
95 lines
2.0 KiB
C
#include <linux/spinlock.h>
|
|
#include <linux/hardirq.h>
|
|
#include <linux/ftrace.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/init.h>
|
|
#include <linux/list.h>
|
|
|
|
#include <asm/ftrace.h>
|
|
|
|
static const u32 ftrace_nop = 0x01000000;
|
|
|
|
notrace unsigned char *ftrace_nop_replace(void)
|
|
{
|
|
return (char *)&ftrace_nop;
|
|
}
|
|
|
|
notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
|
|
{
|
|
static u32 call;
|
|
s32 off;
|
|
|
|
off = ((s32)addr - (s32)ip);
|
|
call = 0x40000000 | ((u32)off >> 2);
|
|
|
|
return (unsigned char *) &call;
|
|
}
|
|
|
|
notrace int
|
|
ftrace_modify_code(unsigned long ip, unsigned char *old_code,
|
|
unsigned char *new_code)
|
|
{
|
|
u32 old = *(u32 *)old_code;
|
|
u32 new = *(u32 *)new_code;
|
|
u32 replaced;
|
|
int faulted;
|
|
|
|
__asm__ __volatile__(
|
|
"1: cas [%[ip]], %[old], %[new]\n"
|
|
" flush %[ip]\n"
|
|
" mov 0, %[faulted]\n"
|
|
"2:\n"
|
|
" .section .fixup,#alloc,#execinstr\n"
|
|
" .align 4\n"
|
|
"3: sethi %%hi(2b), %[faulted]\n"
|
|
" jmpl %[faulted] + %%lo(2b), %%g0\n"
|
|
" mov 1, %[faulted]\n"
|
|
" .previous\n"
|
|
" .section __ex_table,\"a\"\n"
|
|
" .align 4\n"
|
|
" .word 1b, 3b\n"
|
|
" .previous\n"
|
|
: "=r" (replaced), [faulted] "=r" (faulted)
|
|
: [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
|
|
: "memory");
|
|
|
|
if (replaced != old && replaced != new)
|
|
faulted = 2;
|
|
|
|
return faulted;
|
|
}
|
|
|
|
notrace int ftrace_update_ftrace_func(ftrace_func_t func)
|
|
{
|
|
unsigned long ip = (unsigned long)(&ftrace_call);
|
|
unsigned char old[MCOUNT_INSN_SIZE], *new;
|
|
|
|
memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
|
|
new = ftrace_call_replace(ip, (unsigned long)func);
|
|
return ftrace_modify_code(ip, old, new);
|
|
}
|
|
|
|
notrace int ftrace_mcount_set(unsigned long *data)
|
|
{
|
|
unsigned long ip = (long)(&mcount_call);
|
|
unsigned long *addr = data;
|
|
unsigned char old[MCOUNT_INSN_SIZE], *new;
|
|
|
|
/*
|
|
* Replace the mcount stub with a pointer to the
|
|
* ip recorder function.
|
|
*/
|
|
memcpy(old, &mcount_call, MCOUNT_INSN_SIZE);
|
|
new = ftrace_call_replace(ip, *addr);
|
|
*addr = ftrace_modify_code(ip, old, new);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
int __init ftrace_dyn_arch_init(void *data)
|
|
{
|
|
ftrace_mcount_set(data);
|
|
return 0;
|
|
}
|