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
  12 static const u32 ftrace_nop = 0x01000000;
  13
  14 static 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
  25 static 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
  55 int 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
  65 int 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
  75 int 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
  85 int __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
  94 extern void ftrace_graph_call(void);
  95
  96 int 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
 106 int 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  */
 123 unsigned 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) == -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 */