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#include <trace/syscall.h>
   8
   9#include <asm/ftrace.h>
  10
  11#ifdef CONFIG_DYNAMIC_FTRACE
  12static const u32 ftrace_nop = 0x01000000;
  13
  14static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
  15{
  16        u32 call;
  17        s32 off;
  18
  19        off = ((s32)addr - (s32)ip);
  20        call = 0x40000000 | ((u32)off >> 2);
  21
  22        return call;
  23}
  24
  25static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
  26{
  27        u32 replaced;
  28        int faulted;
  29
  30        __asm__ __volatile__(
  31        "1:     cas     [%[ip]], %[old], %[new]\n"
  32        "       flush   %[ip]\n"
  33        "       mov     0, %[faulted]\n"
  34        "2:\n"
  35        "       .section .fixup,#alloc,#execinstr\n"
  36        "       .align  4\n"
  37        "3:     sethi   %%hi(2b), %[faulted]\n"
  38        "       jmpl    %[faulted] + %%lo(2b), %%g0\n"
  39        "        mov    1, %[faulted]\n"
  40        "       .previous\n"
  41        "       .section __ex_table,\"a\"\n"
  42        "       .align  4\n"
  43        "       .word   1b, 3b\n"
  44        "       .previous\n"
  45        : "=r" (replaced), [faulted] "=r" (faulted)
  46        : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
  47        : "memory");
  48
  49        if (replaced != old && replaced != new)
  50                faulted = 2;
  51
  52        return faulted;
  53}
  54
  55int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
  56{
  57        unsigned long ip = rec->ip;
  58        u32 old, new;
  59
  60        old = ftrace_call_replace(ip, addr);
  61        new = ftrace_nop;
  62        return ftrace_modify_code(ip, old, new);
  63}
  64
  65int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
  66{
  67        unsigned long ip = rec->ip;
  68        u32 old, new;
  69
  70        old = ftrace_nop;
  71        new = ftrace_call_replace(ip, addr);
  72        return ftrace_modify_code(ip, old, new);
  73}
  74
  75int ftrace_update_ftrace_func(ftrace_func_t func)
  76{
  77        unsigned long ip = (unsigned long)(&ftrace_call);
  78        u32 old, new;
  79
  80        old = *(u32 *) &ftrace_call;
  81        new = ftrace_call_replace(ip, (unsigned long)func);
  82        return ftrace_modify_code(ip, old, new);
  83}
  84
  85int __init ftrace_dyn_arch_init(void *data)
  86{
  87        unsigned long *p = data;
  88
  89        *p = 0;
  90
  91        return 0;
  92}
  93#endif
  94
  95#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  96
  97#ifdef CONFIG_DYNAMIC_FTRACE
  98extern void ftrace_graph_call(void);
  99
 100int ftrace_enable_ftrace_graph_caller(void)
 101{
 102        unsigned long ip = (unsigned long)(&ftrace_graph_call);
 103        u32 old, new;
 104
 105        old = *(u32 *) &ftrace_graph_call;
 106        new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
 107        return ftrace_modify_code(ip, old, new);
 108}
 109
 110int ftrace_disable_ftrace_graph_caller(void)
 111{
 112        unsigned long ip = (unsigned long)(&ftrace_graph_call);
 113        u32 old, new;
 114
 115        old = *(u32 *) &ftrace_graph_call;
 116        new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
 117
 118        return ftrace_modify_code(ip, old, new);
 119}
 120
 121#endif /* !CONFIG_DYNAMIC_FTRACE */
 122
 123/*
 124 * Hook the return address and push it in the stack of return addrs
 125 * in current thread info.
 126 */
 127unsigned long prepare_ftrace_return(unsigned long parent,
 128                                    unsigned long self_addr,
 129                                    unsigned long frame_pointer)
 130{
 131        unsigned long return_hooker = (unsigned long) &return_to_handler;
 132        struct ftrace_graph_ent trace;
 133
 134        if (unlikely(atomic_read(&current->tracing_graph_pause)))
 135                return parent + 8UL;
 136
 137        if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
 138                                     frame_pointer) == -EBUSY)
 139                return parent + 8UL;
 140
 141        trace.func = self_addr;
 142
 143        /* Only trace if the calling function expects to */
 144        if (!ftrace_graph_entry(&trace)) {
 145                current->curr_ret_stack--;
 146                return parent + 8UL;
 147        }
 148
 149        return return_hooker;
 150}
 151#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 152