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#include <linux/spinlock.h>
#include <linux/hardirq.h>
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/list.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[4], *new;
memcpy(old, &ftrace_call, 4);
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[4], *new;
/*
* Replace the mcount stub with a pointer to the
* ip recorder function.
*/
memcpy(old, &mcount_call, 4);
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;
}
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