159 lines
5.1 KiB
C
159 lines
5.1 KiB
C
/* Native-dependent code for FreeBSD/i386.
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Copyright (C) 2001, 2002, 2003, 2004, 2007, 2008, 2009
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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 "fbsd-nat.h"
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#include "i386-tdep.h"
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#include "i386bsd-nat.h"
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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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static void
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i386fbsd_resume (ptid_t ptid, int step, enum target_signal signal)
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{
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pid_t pid = ptid_get_pid (ptid);
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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 = ptid_get_pid (inferior_ptid);
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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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target_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 <sys/types.h>
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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 (regcache, I386_EDI_REGNUM, &pcb->pcb_edi);
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regcache_raw_supply (regcache, I386_ESI_REGNUM, &pcb->pcb_esi);
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regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp);
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regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp);
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regcache_raw_supply (regcache, I386_EBX_REGNUM, &pcb->pcb_ebx);
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regcache_raw_supply (regcache, I386_EIP_REGNUM, &pcb->pcb_eip);
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regcache_raw_supply (regcache, I386_GS_REGNUM, &pcb->pcb_gs);
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return 1;
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}
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/* Prevent warning from -Wmissing-prototypes. */
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void _initialize_i386fbsd_nat (void);
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void
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_initialize_i386fbsd_nat (void)
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{
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struct target_ops *t;
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/* Add some extra features to the common *BSD/i386 target. */
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t = i386bsd_target ();
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t->to_resume = i386fbsd_resume;
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t->to_pid_to_exec_file = fbsd_pid_to_exec_file;
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t->to_find_memory_regions = fbsd_find_memory_regions;
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t->to_make_corefile_notes = fbsd_make_corefile_notes;
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add_target (t);
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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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/* FreeBSD provides a kern.ps_strings sysctl that we can use to
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locate the sigtramp. That way we can still recognize a sigtramp
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if its location is changed in a new kernel. Of course this is
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still based on the assumption that the sigtramp is placed
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directly under the location where the program arguments and
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environment can be found. */
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#ifdef KERN_PS_STRINGS
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{
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int mib[2];
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u_long ps_strings;
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size_t len;
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mib[0] = CTL_KERN;
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mib[1] = KERN_PS_STRINGS;
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len = sizeof (ps_strings);
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if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
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{
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i386fbsd_sigtramp_start_addr = ps_strings - 128;
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i386fbsd_sigtramp_end_addr = ps_strings;
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}
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}
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#endif
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}
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