LXR linux/arch/sparc/kernel/ftrace.c

   1#include <linux/spinlock.h>
   2#include <linux/hardirq.h>
   3#include <linux/ftrace.h>
   4#include <linux/percpu.h>
   5#include <linux/init.h>
   6#include <linux/list.h>
   7
   8#include <asm/ftrace.h>
   9
  10#ifdef CONFIG_DYNAMIC_FTRACE
  11static const u32 ftrace_nop = 0x01000000;
  12
  13static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
  14{
  15        static u32 call;
  16        s32 off;
  17
  18        off = ((s32)addr - (s32)ip);
  19        call = 0x40000000 | ((u32)off >> 2);
  20
  21        return call;
  22}
  23
  24static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
  25{
  26        u32 replaced;
  27        int faulted;
  28
  29        __asm__ __volatile__(
  30        "1:     cas     [%[ip]], %[old], %[new]\n"
  31        "       flush   %[ip]\n"
  32        "       mov     0, %[faulted]\n"
  33        "2:\n"
  34        "       .section .fixup,#alloc,#execinstr\n"
  35        "       .align  4\n"
  36        "3:     sethi   %%hi(2b), %[faulted]\n"
  37        "       jmpl    %[faulted] + %%lo(2b), %%g0\n"
  38        "        mov    1, %[faulted]\n"
  39        "       .previous\n"
  40        "       .section __ex_table,\"a\"\n"
  41        "       .align  4\n"
  42        "       .word   1b, 3b\n"
  43        "       .previous\n"
  44        : "=r" (replaced), [faulted] "=r" (faulted)
  45        : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
  46        : "memory");
  47
  48        if (replaced != old && replaced != new)
  49                faulted = 2;
  50
  51        return faulted;
  52}
  53
  54int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
  55{
  56        unsigned long ip = rec->ip;
  57        u32 old, new;
  58
  59        old = ftrace_call_replace(ip, addr);
  60        new = ftrace_nop;
  61        return ftrace_modify_code(ip, old, new);
  62}
  63
  64int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
  65{
  66        unsigned long ip = rec->ip;
  67        u32 old, new;
  68
  69        old = ftrace_nop;
  70        new = ftrace_call_replace(ip, addr);
  71        return ftrace_modify_code(ip, old, new);
  72}
  73
  74int ftrace_update_ftrace_func(ftrace_func_t func)
  75{
  76        unsigned long ip = (unsigned long)(&ftrace_call);
  77        u32 old, new;
  78
  79        old = *(u32 *) &ftrace_call;
  80        new = ftrace_call_replace(ip, (unsigned long)func);
  81        return ftrace_modify_code(ip, old, new);
  82}
  83
  84int __init ftrace_dyn_arch_init(void *data)
  85{
  86        unsigned long *p = data;
  87
  88        *p = 0;
  89
  90        return 0;
  91}
  92#endif
  93
  94