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

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/spinlock.h>
   3#include <linux/hardirq.h>
   4#include <linux/ftrace.h>
   5#include <linux/percpu.h>
   6#include <linux/init.h>
   7#include <linux/list.h>
   8#include <trace/syscall.h>
   9
  10#include <asm/ftrace.h>
  11
  12#ifdef CONFIG_DYNAMIC_FTRACE
  13static const u32 ftrace_nop = 0x01000000;
  14
  15static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
  16{
  17        u32 call;
  18        s32 off;
  19
  20        off = ((s32)addr - (s32)ip);
  21        call = 0x40000000 | ((u32)off >> 2);
  22
  23        return call;
  24}
  25
  26static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
  27{
  28        u32 replaced;
  29        int faulted;
  30
  31        __asm__ __volatile__(
  32        "1:     cas     [%[ip]], %[old], %[new]\n"
  33        "       flush   %[ip]\n"
  34        "       mov     0, %[faulted]\n"
  35        "2:\n"
  36        "       .section .fixup,#alloc,#execinstr\n"
  37        "       .align  4\n"
  38        "3:     sethi   %%hi(2b), %[faulted]\n"
  39        "       jmpl    %[faulted] + %%lo(2b), %%g0\n"
  40        "        mov    1, %[faulted]\n"
  41        "       .previous\n"
  42        "       .section __ex_table,\"a\"\n"
  43        "       .align  4\n"
  44        "       .word   1b, 3b\n"
  45        "       .previous\n"
  46        : "=r" (replaced), [faulted] "=r" (faulted)
  47        : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
  48        : "memory");
  49
  50        if (replaced != old && replaced != new)
  51                faulted = 2;
  52
  53        return faulted;
  54}
  55
  56int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
  57{
  58        unsigned long ip = rec->ip;
  59        u32 old, new;
  60
  61        old = ftrace_call_replace(ip, addr);
  62        new = ftrace_nop;
  63        return ftrace_modify_code(ip, old, new);
  64}
  65
  66int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
  67{
  68        unsigned long ip = rec->ip;
  69        u32 old, new;
  70
  71        old = ftrace_nop;
  72        new = ftrace_call_replace(ip, addr);
  73        return ftrace_modify_code(ip, old, new);
  74}
  75
  76int ftrace_update_ftrace_func(ftrace_func_t func)
  77{
  78        unsigned long ip = (unsigned long)(&ftrace_call);
  79        u32 old, new;
  80
  81        old = *(u32 *) &ftrace_call;
  82        new = ftrace_call_replace(ip, (unsigned long)func);
  83        return ftrace_modify_code(ip, old, new);
  84}
  85
  86int __init ftrace_dyn_arch_init(void)
  87{
  88        return 0;
  89}
  90#endif
  91
  92#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  93
  94#ifdef CONFIG_DYNAMIC_FTRACE
  95extern void ftrace_graph_call(void);
  96
  97int ftrace_enable_ftrace_graph_caller(void)
  98{
  99        unsigned long ip = (unsigned long)(&ftrace_graph_call);
 100        u32 old, new;
 101
 102        old = *(u32 *) &ftrace_graph_call;
 103        new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
 104        return ftrace_modify_code(ip, old, new);
 105}
 106
 107int ftrace_disable_ftrace_graph_caller(void)
 108{
 109        unsigned long ip = (unsigned long)(&ftrace_graph_call);
 110        u32 old, new;
 111
 112        old = *(u32 *) &ftrace_graph_call;
 113        new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
 114
 115        return ftrace_modify_code(ip, old, new);
 116}
 117
 118#endif /* !CONFIG_DYNAMIC_FTRACE */
 119
 120/*
 121 * Hook the return address and push it in the stack of return addrs
 122 * in current thread info.
 123 */
 124unsigned long prepare_ftrace_return(unsigned long parent,
 125                                    unsigned long self_addr,
 126                                    unsigned long frame_pointer)
 127{
 128        unsigned long return_hooker = (unsigned long) &return_to_handler;
 129        struct ftrace_graph_ent trace;
 130
 131        if (unlikely(atomic_read(&current->tracing_graph_pause)))
 132                return parent + 8UL;
 133
 134        trace.func = self_addr;
 135        trace.depth = current->curr_ret_stack + 1;
 136
 137        /* Only trace if the calling function expects to */
 138        if (!ftrace_graph_entry(&trace))
 139                return parent + 8UL;
 140
 141        if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
 142                                     frame_pointer, NULL) == -EBUSY)
 143                return parent + 8UL;
 144
 145        return return_hooker;
 146}
 147#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 148