201 lines
7.5 KiB
C
201 lines
7.5 KiB
C
/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef COMMON_LINUX_PTRACE_H
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#define COMMON_LINUX_PTRACE_H
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struct buffer;
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#include "nat/gdb_ptrace.h"
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#ifdef __UCLIBC__
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#if !(defined(__UCLIBC_HAS_MMU__) || defined(__ARCH_HAS_MMU__))
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/* PTRACE_TEXT_ADDR and friends. */
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#include <asm/ptrace.h>
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#define HAS_NOMMU
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#endif
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#endif
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#if !defined(PTRACE_TYPE_ARG3)
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#define PTRACE_TYPE_ARG3 void *
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#endif
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#if !defined(PTRACE_TYPE_ARG4)
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#define PTRACE_TYPE_ARG4 void *
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#endif
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#ifndef PTRACE_GETSIGINFO
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# define PTRACE_GETSIGINFO 0x4202
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# define PTRACE_SETSIGINFO 0x4203
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#endif /* PTRACE_GETSIGINF */
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#ifndef PTRACE_GETREGSET
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#define PTRACE_GETREGSET 0x4204
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#endif
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#ifndef PTRACE_SETREGSET
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#define PTRACE_SETREGSET 0x4205
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#endif
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/* If the system headers did not provide the constants, hard-code the normal
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values. */
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#ifndef PTRACE_EVENT_FORK
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#define PTRACE_SETOPTIONS 0x4200
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#define PTRACE_GETEVENTMSG 0x4201
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/* options set using PTRACE_SETOPTIONS */
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#define PTRACE_O_TRACESYSGOOD 0x00000001
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#define PTRACE_O_TRACEFORK 0x00000002
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#define PTRACE_O_TRACEVFORK 0x00000004
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#define PTRACE_O_TRACECLONE 0x00000008
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#define PTRACE_O_TRACEEXEC 0x00000010
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#define PTRACE_O_TRACEVFORKDONE 0x00000020
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#define PTRACE_O_TRACEEXIT 0x00000040
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/* Wait extended result codes for the above trace options. */
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#define PTRACE_EVENT_FORK 1
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#define PTRACE_EVENT_VFORK 2
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#define PTRACE_EVENT_CLONE 3
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#define PTRACE_EVENT_EXEC 4
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#define PTRACE_EVENT_VFORK_DONE 5
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#define PTRACE_EVENT_EXIT 6
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#endif /* PTRACE_EVENT_FORK */
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#ifndef PTRACE_O_EXITKILL
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/* Only defined in Linux Kernel 3.8 or later. */
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#define PTRACE_O_EXITKILL 0x00100000
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#endif
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#if (defined __bfin__ || defined __frv__ || defined __sh__) \
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&& !defined PTRACE_GETFDPIC
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#define PTRACE_GETFDPIC 31
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#define PTRACE_GETFDPIC_EXEC 0
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#define PTRACE_GETFDPIC_INTERP 1
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#endif
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/* We can't always assume that this flag is available, but all systems
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with the ptrace event handlers also have __WALL, so it's safe to use
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in some contexts. */
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#ifndef __WALL
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#define __WALL 0x40000000 /* Wait for any child. */
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#endif
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/* True if whether a breakpoint/watchpoint triggered can be determined
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from the si_code of SIGTRAP's siginfo_t (TRAP_BRKPT/TRAP_HWBKPT).
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That is, if the kernel can tell us whether the thread executed a
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software breakpoint, we trust it. The kernel will be determining
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that from the hardware (e.g., from which exception was raised in
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the CPU). Relying on whether a breakpoint is planted in memory at
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the time the SIGTRAP is processed to determine whether the thread
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stopped for a software breakpoint can be too late. E.g., the
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breakpoint could have been removed since. Or the thread could have
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stepped an instruction the size of a breakpoint instruction, and
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before the stop is processed a breakpoint is inserted at its
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address. Getting these wrong is disastrous on decr_pc_after_break
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architectures. The moribund location mechanism helps with that
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somewhat but it is an heuristic, and can well fail. Getting that
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information out of the kernel and ultimately out of the CPU is the
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way to go. That said, some architecture may get the si_code wrong,
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and as such we're leaving fallback code in place. We'll remove
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this after a while if no problem is reported. */
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#define USE_SIGTRAP_SIGINFO 1
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/* The x86 kernel gets some of the si_code values backwards, like
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this:
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| what | si_code |
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|------------------------------------------+-------------|
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| software breakpoints (int3) | SI_KERNEL |
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| single-steps | TRAP_TRACE |
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| single-stepping a syscall | TRAP_BRKPT |
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| user sent SIGTRAP | 0 |
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| exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0 |
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| hardware breakpoints/watchpoints | TRAP_HWBKPT |
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That is, it reports SI_KERNEL for software breakpoints (and only
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for those), and TRAP_BRKPT for single-stepping a syscall... If the
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kernel is ever fixed, we'll just have to detect it like we detect
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optional ptrace features: by forking and debugging ourselves,
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running to a breakpoint and checking what comes out of
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siginfo->si_code.
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The ppc kernel does use TRAP_BRKPT for software breakpoints
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in PowerPC code, but it uses SI_KERNEL for software breakpoints
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in SPU code on a Cell/B.E. However, SI_KERNEL is never seen
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on a SIGTRAP for any other reason.
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The MIPS kernel up until 4.5 used SI_KERNEL for all kernel
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generated traps. Since:
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- MIPS doesn't do hardware single-step.
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- We don't need to care about exec SIGTRAPs --- we assume
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PTRACE_EVENT_EXEC is available.
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- The MIPS kernel doesn't support hardware breakpoints.
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on MIPS, all we need to care about is distinguishing between
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software breakpoints and hardware watchpoints, which can be done by
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peeking the debug registers.
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Beginning with Linux 4.6, the MIPS port reports proper TRAP_BRKPT and
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TRAP_HWBKPT codes, so we also match them.
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The generic Linux target code should use GDB_ARCH_IS_TRAP_* instead
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of TRAP_* to abstract out these peculiarities. */
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#if defined __i386__ || defined __x86_64__
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# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL)
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# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
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#elif defined __powerpc__
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# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT)
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# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
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#elif defined __mips__
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# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT)
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# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == SI_KERNEL || (X) == TRAP_HWBKPT)
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#else
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# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT)
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# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)
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#endif
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#ifndef TRAP_HWBKPT
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# define TRAP_HWBKPT 4
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#endif
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extern void linux_ptrace_attach_fail_reason (pid_t pid, struct buffer *buffer);
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/* Find all possible reasons we could have failed to attach to PTID
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and return them as a string. ERR is the error PTRACE_ATTACH failed
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with (an errno). The result is stored in a static buffer. This
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string should be copied into a buffer by the client if the string
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will not be immediately used, or if it must persist. */
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extern char *linux_ptrace_attach_fail_reason_string (ptid_t ptid, int err);
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extern void linux_ptrace_init_warnings (void);
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extern void linux_check_ptrace_features (void);
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extern void linux_enable_event_reporting (pid_t pid, int attached);
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extern void linux_disable_event_reporting (pid_t pid);
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extern int linux_supports_tracefork (void);
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extern int linux_supports_traceexec (void);
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extern int linux_supports_traceclone (void);
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extern int linux_supports_tracevforkdone (void);
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extern int linux_supports_tracesysgood (void);
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extern int linux_ptrace_get_extended_event (int wstat);
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extern int linux_is_extended_waitstatus (int wstat);
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extern int linux_wstatus_maybe_breakpoint (int wstat);
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#endif /* COMMON_LINUX_PTRACE_H */
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