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

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Code for tracing calls in Linux kernel.
   4 * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
   5 *
   6 * based on code for x86 which is:
   7 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   8 *
   9 * future possible enhancements:
  10 *      - add CONFIG_STACK_TRACER
  11 */
  12
  13#include <linux/init.h>
  14#include <linux/ftrace.h>
  15#include <linux/uaccess.h>
  16
  17#include <asm/assembly.h>
  18#include <asm/sections.h>
  19#include <asm/ftrace.h>
  20#include <asm/patch.h>
  21
  22#define __hot __attribute__ ((__section__ (".text.hot")))
  23
  24#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  25/*
  26 * Hook the return address and push it in the stack of return addrs
  27 * in current thread info.
  28 */
  29static void __hot prepare_ftrace_return(unsigned long *parent,
  30                                        unsigned long self_addr)
  31{
  32        unsigned long old;
  33        extern int parisc_return_to_handler;
  34
  35        if (unlikely(ftrace_graph_is_dead()))
  36                return;
  37
  38        if (unlikely(atomic_read(&current->tracing_graph_pause)))
  39                return;
  40
  41        old = *parent;
  42
  43        if (!function_graph_enter(old, self_addr, 0, NULL))
  44                /* activate parisc_return_to_handler() as return point */
  45                *parent = (unsigned long) &parisc_return_to_handler;
  46}
  47#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  48
  49void notrace __hot ftrace_function_trampoline(unsigned long parent,
  50                                unsigned long self_addr,
  51                                unsigned long org_sp_gr3)
  52{
  53#ifndef CONFIG_DYNAMIC_FTRACE
  54        extern ftrace_func_t ftrace_trace_function;
  55#endif
  56        if (ftrace_trace_function != ftrace_stub)
  57                ftrace_trace_function(self_addr, parent, NULL, NULL);
  58
  59#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  60        if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
  61                ftrace_graph_entry != ftrace_graph_entry_stub) {
  62                unsigned long *parent_rp;
  63
  64                /* calculate pointer to %rp in stack */
  65                parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
  66                /* sanity check: parent_rp should hold parent */
  67                if (*parent_rp != parent)
  68                        return;
  69
  70                prepare_ftrace_return(parent_rp, self_addr);
  71                return;
  72        }
  73#endif
  74}
  75
  76#ifdef CONFIG_FUNCTION_GRAPH_TRACER
  77int ftrace_enable_ftrace_graph_caller(void)
  78{
  79        return 0;
  80}
  81
  82int ftrace_disable_ftrace_graph_caller(void)
  83{
  84        return 0;
  85}
  86#endif
  87
  88#ifdef CONFIG_DYNAMIC_FTRACE
  89
  90int __init ftrace_dyn_arch_init(void)
  91{
  92        return 0;
  93}
  94int ftrace_update_ftrace_func(ftrace_func_t func)
  95{
  96        return 0;
  97}
  98
  99unsigned long ftrace_call_adjust(unsigned long addr)
 100{
 101        return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4;
 102}
 103
 104int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 105{
 106        u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
 107        u32 *tramp;
 108        int size, ret, i;
 109        void *ip;
 110
 111#ifdef CONFIG_64BIT
 112        unsigned long addr2 =
 113                (unsigned long)dereference_function_descriptor((void *)addr);
 114
 115        u32 ftrace_trampoline[] = {
 116                0x73c10208, /* std,ma r1,100(sp) */
 117                0x0c2110c1, /* ldd -10(r1),r1 */
 118                0xe820d002, /* bve,n (r1) */
 119                addr2 >> 32,
 120                addr2 & 0xffffffff,
 121                0xe83f1fd7, /* b,l,n .-14,r1 */
 122        };
 123
 124        u32 ftrace_trampoline_unaligned[] = {
 125                addr2 >> 32,
 126                addr2 & 0xffffffff,
 127                0x37de0200, /* ldo 100(sp),sp */
 128                0x73c13e01, /* std r1,-100(sp) */
 129                0x34213ff9, /* ldo -4(r1),r1 */
 130                0x50213fc1, /* ldd -20(r1),r1 */
 131                0xe820d002, /* bve,n (r1) */
 132                0xe83f1fcf, /* b,l,n .-20,r1 */
 133        };
 134
 135        BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) >
 136                                FTRACE_PATCHABLE_FUNCTION_SIZE);
 137#else
 138        u32 ftrace_trampoline[] = {
 139                (u32)addr,
 140                0x6fc10080, /* stw,ma r1,40(sp) */
 141                0x48213fd1, /* ldw -18(r1),r1 */
 142                0xe820c002, /* bv,n r0(r1) */
 143                0xe83f1fdf, /* b,l,n .-c,r1 */
 144        };
 145#endif
 146
 147        BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) >
 148                                FTRACE_PATCHABLE_FUNCTION_SIZE);
 149
 150        size = sizeof(ftrace_trampoline);
 151        tramp = ftrace_trampoline;
 152
 153#ifdef CONFIG_64BIT
 154        if (rec->ip & 0x4) {
 155                size = sizeof(ftrace_trampoline_unaligned);
 156                tramp = ftrace_trampoline_unaligned;
 157        }
 158#endif
 159
 160        ip = (void *)(rec->ip + 4 - size);
 161
 162        ret = probe_kernel_read(insn, ip, size);
 163        if (ret)
 164                return ret;
 165
 166        for (i = 0; i < size / 4; i++) {
 167                if (insn[i] != INSN_NOP)
 168                        return -EINVAL;
 169        }
 170
 171        __patch_text_multiple(ip, tramp, size);
 172        return 0;
 173}
 174
 175int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
 176                    unsigned long addr)
 177{
 178        u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
 179        int i;
 180
 181        for (i = 0; i < ARRAY_SIZE(insn); i++)
 182                insn[i] = INSN_NOP;
 183
 184        __patch_text((void *)rec->ip, INSN_NOP);
 185        __patch_text_multiple((void *)rec->ip + 4 - sizeof(insn),
 186                              insn, sizeof(insn)-4);
 187        return 0;
 188}
 189#endif
 190