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)
  86{
  87        return 0;
  88}
  89#endif
  90
  91#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  92
  93#ifdef CONFIG_DYNAMIC_FTRACE
  94extern void ftrace_graph_call(void);
  95
  96int ftrace_enable_ftrace_graph_caller(void)
  97{
  98        unsigned long ip = (unsigned long)(&ftrace_graph_call);
  99        u32 old, new;
 100
 101        old = *(u32 *) &ftrace_graph_call;
 102        new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
 103        return ftrace_modify_code(ip, old, new);
 104}
 105
 106int ftrace_disable_ftrace_graph_caller(void)
 107{
 108        unsigned long ip = (unsigned long)(&ftrace_graph_call);
 109        u32 old, new;
 110
 111        old = *(u32 *) &ftrace_graph_call;
 112        new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
 113
 114        return ftrace_modify_code(ip, old, new);
 115}
 116
 117#endif /* !CONFIG_DYNAMIC_FTRACE */
 118
 119/*
 120 * Hook the return address and push it in the stack of return addrs
 121 * in current thread info.
 122 */
 123unsigned long prepare_ftrace_return(unsigned long parent,
 124                                    unsigned long self_addr,
 125                                    unsigned long frame_pointer)
 126{
 127        unsigned long return_hooker = (unsigned long) &return_to_handler;
 128        struct ftrace_graph_ent trace;
 129
 130        if (unlikely(atomic_read(&current->tracing_graph_pause)))
 131                return parent + 8UL;
 132
 133        if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
 134                                     frame_pointer, NULL) == -EBUSY)
 135                return parent + 8UL;
 136
 137        trace.func = self_addr;
 138
 139        /* Only trace if the calling function expects to */
 140        if (!ftrace_graph_entry(&trace)) {
 141                current->curr_ret_stack--;
 142                return parent + 8UL;
 143        }
 144
 145        return return_hooker;
 146}
 147#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 148