| 1 | /* Copyright (C) 2011-2018 Free Software Foundation, Inc. |
| 2 | |
| 3 | This file is part of GDB. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation; either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #ifndef COMMON_LINUX_PTRACE_H |
| 19 | #define COMMON_LINUX_PTRACE_H |
| 20 | |
| 21 | struct buffer; |
| 22 | |
| 23 | #include "nat/gdb_ptrace.h" |
| 24 | #include "gdb_wait.h" |
| 25 | |
| 26 | #ifdef __UCLIBC__ |
| 27 | #if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__)) |
| 28 | /* PTRACE_TEXT_ADDR and friends. */ |
| 29 | #include <asm/ptrace.h> |
| 30 | #define HAS_NOMMU |
| 31 | #endif |
| 32 | #endif |
| 33 | |
| 34 | #if !defined(PTRACE_TYPE_ARG3) |
| 35 | #define PTRACE_TYPE_ARG3 void * |
| 36 | #endif |
| 37 | |
| 38 | #if !defined(PTRACE_TYPE_ARG4) |
| 39 | #define PTRACE_TYPE_ARG4 void * |
| 40 | #endif |
| 41 | |
| 42 | #ifndef PTRACE_GETSIGINFO |
| 43 | # define PTRACE_GETSIGINFO 0x4202 |
| 44 | # define PTRACE_SETSIGINFO 0x4203 |
| 45 | #endif /* PTRACE_GETSIGINF */ |
| 46 | |
| 47 | #ifndef PTRACE_GETREGSET |
| 48 | #define PTRACE_GETREGSET 0x4204 |
| 49 | #endif |
| 50 | |
| 51 | #ifndef PTRACE_SETREGSET |
| 52 | #define PTRACE_SETREGSET 0x4205 |
| 53 | #endif |
| 54 | |
| 55 | /* If the system headers did not provide the constants, hard-code the normal |
| 56 | values. */ |
| 57 | #ifndef PTRACE_EVENT_FORK |
| 58 | |
| 59 | #define PTRACE_SETOPTIONS 0x4200 |
| 60 | #define PTRACE_GETEVENTMSG 0x4201 |
| 61 | |
| 62 | /* options set using PTRACE_SETOPTIONS */ |
| 63 | #define PTRACE_O_TRACESYSGOOD 0x00000001 |
| 64 | #define PTRACE_O_TRACEFORK 0x00000002 |
| 65 | #define PTRACE_O_TRACEVFORK 0x00000004 |
| 66 | #define PTRACE_O_TRACECLONE 0x00000008 |
| 67 | #define PTRACE_O_TRACEEXEC 0x00000010 |
| 68 | #define PTRACE_O_TRACEVFORKDONE 0x00000020 |
| 69 | #define PTRACE_O_TRACEEXIT 0x00000040 |
| 70 | |
| 71 | /* Wait extended result codes for the above trace options. */ |
| 72 | #define PTRACE_EVENT_FORK 1 |
| 73 | #define PTRACE_EVENT_VFORK 2 |
| 74 | #define PTRACE_EVENT_CLONE 3 |
| 75 | #define PTRACE_EVENT_EXEC 4 |
| 76 | #define PTRACE_EVENT_VFORK_DONE 5 |
| 77 | #define PTRACE_EVENT_EXIT 6 |
| 78 | |
| 79 | #endif /* PTRACE_EVENT_FORK */ |
| 80 | |
| 81 | #ifndef PTRACE_O_EXITKILL |
| 82 | /* Only defined in Linux Kernel 3.8 or later. */ |
| 83 | #define PTRACE_O_EXITKILL 0x00100000 |
| 84 | #endif |
| 85 | |
| 86 | #if (defined __bfin__ || defined __frv__ || defined __sh__) \ |
| 87 | && !defined PTRACE_GETFDPIC |
| 88 | #define PTRACE_GETFDPIC 31 |
| 89 | #define PTRACE_GETFDPIC_EXEC 0 |
| 90 | #define PTRACE_GETFDPIC_INTERP 1 |
| 91 | #endif |
| 92 | |
| 93 | /* We can't always assume that this flag is available, but all systems |
| 94 | with the ptrace event handlers also have __WALL, so it's safe to use |
| 95 | in some contexts. */ |
| 96 | #ifndef __WALL |
| 97 | #define __WALL 0x40000000 /* Wait for any child. */ |
| 98 | #endif |
| 99 | |
| 100 | /* True if whether a breakpoint/watchpoint triggered can be determined |
| 101 | from the si_code of SIGTRAP's siginfo_t (TRAP_BRKPT/TRAP_HWBKPT). |
| 102 | That is, if the kernel can tell us whether the thread executed a |
| 103 | software breakpoint, we trust it. The kernel will be determining |
| 104 | that from the hardware (e.g., from which exception was raised in |
| 105 | the CPU). Relying on whether a breakpoint is planted in memory at |
| 106 | the time the SIGTRAP is processed to determine whether the thread |
| 107 | stopped for a software breakpoint can be too late. E.g., the |
| 108 | breakpoint could have been removed since. Or the thread could have |
| 109 | stepped an instruction the size of a breakpoint instruction, and |
| 110 | before the stop is processed a breakpoint is inserted at its |
| 111 | address. Getting these wrong is disastrous on decr_pc_after_break |
| 112 | architectures. The moribund location mechanism helps with that |
| 113 | somewhat but it is an heuristic, and can well fail. Getting that |
| 114 | information out of the kernel and ultimately out of the CPU is the |
| 115 | way to go. That said, some architecture may get the si_code wrong, |
| 116 | and as such we're leaving fallback code in place. We'll remove |
| 117 | this after a while if no problem is reported. */ |
| 118 | #define USE_SIGTRAP_SIGINFO 1 |
| 119 | |
| 120 | /* The x86 kernel gets some of the si_code values backwards, like |
| 121 | this: |
| 122 | |
| 123 | | what | si_code | |
| 124 | |------------------------------------------+-------------| |
| 125 | | software breakpoints (int3) | SI_KERNEL | |
| 126 | | single-steps | TRAP_TRACE | |
| 127 | | single-stepping a syscall | TRAP_BRKPT | |
| 128 | | user sent SIGTRAP | 0 | |
| 129 | | exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0 | |
| 130 | | hardware breakpoints/watchpoints | TRAP_HWBKPT | |
| 131 | |
| 132 | That is, it reports SI_KERNEL for software breakpoints (and only |
| 133 | for those), and TRAP_BRKPT for single-stepping a syscall... If the |
| 134 | kernel is ever fixed, we'll just have to detect it like we detect |
| 135 | optional ptrace features: by forking and debugging ourselves, |
| 136 | running to a breakpoint and checking what comes out of |
| 137 | siginfo->si_code. |
| 138 | |
| 139 | The ppc kernel does use TRAP_BRKPT for software breakpoints |
| 140 | in PowerPC code, but it uses SI_KERNEL for software breakpoints |
| 141 | in SPU code on a Cell/B.E. However, SI_KERNEL is never seen |
| 142 | on a SIGTRAP for any other reason. |
| 143 | |
| 144 | The MIPS kernel up until 4.5 used SI_KERNEL for all kernel |
| 145 | generated traps. Since: |
| 146 | |
| 147 | - MIPS doesn't do hardware single-step. |
| 148 | - We don't need to care about exec SIGTRAPs --- we assume |
| 149 | PTRACE_EVENT_EXEC is available. |
| 150 | - The MIPS kernel doesn't support hardware breakpoints. |
| 151 | |
| 152 | on MIPS, all we need to care about is distinguishing between |
| 153 | software breakpoints and hardware watchpoints, which can be done by |
| 154 | peeking the debug registers. |
| 155 | |
| 156 | Beginning with Linux 4.6, the MIPS port reports proper TRAP_BRKPT and |
| 157 | TRAP_HWBKPT codes, so we also match them. |
| 158 | |
| 159 | The Alpha kernel uses TRAP_BRKPT for all traps. |
| 160 | |
| 161 | The generic Linux target code should use GDB_ARCH_IS_TRAP_* instead |
| 162 | of TRAP_* to abstract out these peculiarities. */ |
| 163 | #if defined __i386__ || defined __x86_64__ |
| 164 | # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL) |
| 165 | # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT) |
| 166 | #elif defined __powerpc__ |
| 167 | # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT) |
| 168 | # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT) |
| 169 | #elif defined __mips__ |
| 170 | # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT) |
| 171 | # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == SI_KERNEL || (X) == TRAP_HWBKPT) |
| 172 | #elif defined __alpha__ |
| 173 | # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT) |
| 174 | # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_BRKPT) |
| 175 | #else |
| 176 | # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT) |
| 177 | # define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT) |
| 178 | #endif |
| 179 | |
| 180 | #ifndef TRAP_HWBKPT |
| 181 | # define TRAP_HWBKPT 4 |
| 182 | #endif |
| 183 | |
| 184 | extern std::string linux_ptrace_attach_fail_reason (pid_t pid); |
| 185 | |
| 186 | /* Find all possible reasons we could have failed to attach to PTID |
| 187 | and return them as a string. ERR is the error PTRACE_ATTACH failed |
| 188 | with (an errno). */ |
| 189 | extern std::string linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err); |
| 190 | |
| 191 | extern void linux_ptrace_init_warnings (void); |
| 192 | extern void linux_check_ptrace_features (void); |
| 193 | extern void linux_enable_event_reporting (pid_t pid, int attached); |
| 194 | extern void linux_disable_event_reporting (pid_t pid); |
| 195 | extern int linux_supports_tracefork (void); |
| 196 | extern int linux_supports_traceexec (void); |
| 197 | extern int linux_supports_traceclone (void); |
| 198 | extern int linux_supports_tracevforkdone (void); |
| 199 | extern int linux_supports_tracesysgood (void); |
| 200 | extern int linux_ptrace_get_extended_event (int wstat); |
| 201 | extern int linux_is_extended_waitstatus (int wstat); |
| 202 | extern int linux_wstatus_maybe_breakpoint (int wstat); |
| 203 | |
| 204 | #endif /* COMMON_LINUX_PTRACE_H */ |