211 lines
6.1 KiB
C
211 lines
6.1 KiB
C
/* Native-dependent code for FreeBSD/i386.
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Copyright (C) 2001-2018 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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#include "defs.h"
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#include "inferior.h"
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#include "regcache.h"
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#include "target.h"
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#include <sys/types.h>
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#include <sys/ptrace.h>
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#include <sys/sysctl.h>
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#include <sys/user.h>
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#include "fbsd-nat.h"
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#include "i386-tdep.h"
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#include "x86-nat.h"
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#include "x86-xstate.h"
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#include "x86-bsd-nat.h"
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#include "i386-bsd-nat.h"
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class i386_fbsd_nat_target final
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: public i386_bsd_nat_target<fbsd_nat_target>
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{
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public:
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/* Add some extra features to the common *BSD/i386 target. */
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#ifdef PT_GETXSTATE_INFO
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const struct target_desc *read_description () override;
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#endif
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void resume (ptid_t, int, enum gdb_signal) override;
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#if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
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bool supports_stopped_by_hw_breakpoint () override;
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#endif
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};
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static i386_fbsd_nat_target the_i386_fbsd_nat_target;
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/* Resume execution of the inferior process. If STEP is nonzero,
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single-step it. If SIGNAL is nonzero, give it that signal. */
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void
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i386_fbsd_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signal)
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{
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pid_t pid = ptid.pid ();
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int request = PT_STEP;
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if (pid == -1)
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/* Resume all threads. This only gets used in the non-threaded
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case, where "resume all threads" and "resume inferior_ptid" are
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the same. */
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pid = inferior_ptid.pid ();
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if (!step)
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{
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struct regcache *regcache = get_current_regcache ();
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ULONGEST eflags;
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/* Workaround for a bug in FreeBSD. Make sure that the trace
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flag is off when doing a continue. There is a code path
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through the kernel which leaves the flag set when it should
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have been cleared. If a process has a signal pending (such
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as SIGALRM) and we do a PT_STEP, the process never really has
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a chance to run because the kernel needs to notify the
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debugger that a signal is being sent. Therefore, the process
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never goes through the kernel's trap() function which would
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normally clear it. */
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regcache_cooked_read_unsigned (regcache, I386_EFLAGS_REGNUM,
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&eflags);
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if (eflags & 0x0100)
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regcache_cooked_write_unsigned (regcache, I386_EFLAGS_REGNUM,
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eflags & ~0x0100);
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request = PT_CONTINUE;
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}
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/* An addres of (caddr_t) 1 tells ptrace to continue from where it
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was. (If GDB wanted it to start some other way, we have already
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written a new PC value to the child.) */
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if (ptrace (request, pid, (caddr_t) 1,
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gdb_signal_to_host (signal)) == -1)
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perror_with_name (("ptrace"));
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}
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/* Support for debugging kernel virtual memory images. */
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#include <machine/pcb.h>
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#include "bsd-kvm.h"
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static int
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i386fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
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{
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/* The following is true for FreeBSD 4.7:
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The pcb contains %eip, %ebx, %esp, %ebp, %esi, %edi and %gs.
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This accounts for all callee-saved registers specified by the
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psABI and then some. Here %esp contains the stack pointer at the
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point just after the call to cpu_switch(). From this information
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we reconstruct the register state as it would look when we just
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returned from cpu_switch(). */
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/* The stack pointer shouldn't be zero. */
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if (pcb->pcb_esp == 0)
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return 0;
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pcb->pcb_esp += 4;
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regcache->raw_supply (I386_EDI_REGNUM, &pcb->pcb_edi);
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regcache->raw_supply (I386_ESI_REGNUM, &pcb->pcb_esi);
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regcache->raw_supply (I386_EBP_REGNUM, &pcb->pcb_ebp);
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regcache->raw_supply (I386_ESP_REGNUM, &pcb->pcb_esp);
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regcache->raw_supply (I386_EBX_REGNUM, &pcb->pcb_ebx);
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regcache->raw_supply (I386_EIP_REGNUM, &pcb->pcb_eip);
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regcache->raw_supply (I386_GS_REGNUM, &pcb->pcb_gs);
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return 1;
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}
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#ifdef PT_GETXSTATE_INFO
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/* Implement the read_description method. */
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const struct target_desc *
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i386_fbsd_nat_target::read_description ()
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{
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static int xsave_probed;
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static uint64_t xcr0;
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if (!xsave_probed)
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{
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struct ptrace_xstate_info info;
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if (ptrace (PT_GETXSTATE_INFO, inferior_ptid.pid (),
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(PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0)
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{
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x86bsd_xsave_len = info.xsave_len;
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xcr0 = info.xsave_mask;
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}
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xsave_probed = 1;
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}
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if (x86bsd_xsave_len == 0)
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xcr0 = X86_XSTATE_SSE_MASK;
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return i386_target_description (xcr0);
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}
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#endif
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#if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
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/* Implement the supports_stopped_by_hw_breakpoints method. */
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bool
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i386_fbsd_nat_target::supports_stopped_by_hw_breakpoint ()
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{
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return true;
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}
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#endif
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void
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_initialize_i386fbsd_nat (void)
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{
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add_inf_child_target (&the_i386_fbsd_nat_target);
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/* Support debugging kernel virtual memory images. */
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bsd_kvm_add_target (i386fbsd_supply_pcb);
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#ifdef KERN_PROC_SIGTRAMP
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/* Normally signal frames are detected via i386fbsd_sigtramp_p.
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However, FreeBSD 9.2 through 10.1 do not include the page holding
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the signal code in core dumps. These releases do provide a
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kern.proc.sigtramp.<pid> sysctl that returns the location of the
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signal trampoline for a running process. We fetch the location
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of the current (gdb) process and use this to identify signal
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frames in core dumps from these releases. */
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{
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int mib[4];
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struct kinfo_sigtramp kst;
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size_t len;
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mib[0] = CTL_KERN;
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mib[1] = KERN_PROC;
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mib[2] = KERN_PROC_SIGTRAMP;
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mib[3] = getpid ();
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len = sizeof (kst);
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if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0)
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{
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i386fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start;
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i386fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end;
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}
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}
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#endif
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}
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