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Diffstat (limited to 'gdb/i386-fbsd-nat.c')
-rw-r--r-- | gdb/i386-fbsd-nat.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/gdb/i386-fbsd-nat.c b/gdb/i386-fbsd-nat.c new file mode 100644 index 0000000..a9bf2b1 --- /dev/null +++ b/gdb/i386-fbsd-nat.c @@ -0,0 +1,197 @@ +/* Native-dependent code for FreeBSD/i386. + + Copyright (C) 2001-2016 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include "defs.h" +#include "inferior.h" +#include "regcache.h" +#include "target.h" + +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/sysctl.h> +#include <sys/user.h> + +#include "fbsd-nat.h" +#include "i386-tdep.h" +#include "x86-nat.h" +#include "x86-bsd-nat.h" +#include "i386-bsd-nat.h" + +/* Resume execution of the inferior process. If STEP is nonzero, + single-step it. If SIGNAL is nonzero, give it that signal. */ + +static void +i386fbsd_resume (struct target_ops *ops, + ptid_t ptid, int step, enum gdb_signal signal) +{ + pid_t pid = ptid_get_pid (ptid); + int request = PT_STEP; + + if (pid == -1) + /* Resume all threads. This only gets used in the non-threaded + case, where "resume all threads" and "resume inferior_ptid" are + the same. */ + pid = ptid_get_pid (inferior_ptid); + + if (!step) + { + struct regcache *regcache = get_current_regcache (); + ULONGEST eflags; + + /* Workaround for a bug in FreeBSD. Make sure that the trace + flag is off when doing a continue. There is a code path + through the kernel which leaves the flag set when it should + have been cleared. If a process has a signal pending (such + as SIGALRM) and we do a PT_STEP, the process never really has + a chance to run because the kernel needs to notify the + debugger that a signal is being sent. Therefore, the process + never goes through the kernel's trap() function which would + normally clear it. */ + + regcache_cooked_read_unsigned (regcache, I386_EFLAGS_REGNUM, + &eflags); + if (eflags & 0x0100) + regcache_cooked_write_unsigned (regcache, I386_EFLAGS_REGNUM, + eflags & ~0x0100); + + request = PT_CONTINUE; + } + + /* An addres of (caddr_t) 1 tells ptrace to continue from where it + was. (If GDB wanted it to start some other way, we have already + written a new PC value to the child.) */ + if (ptrace (request, pid, (caddr_t) 1, + gdb_signal_to_host (signal)) == -1) + perror_with_name (("ptrace")); +} + + +/* Support for debugging kernel virtual memory images. */ + +#include <machine/pcb.h> + +#include "bsd-kvm.h" + +static int +i386fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) +{ + /* The following is true for FreeBSD 4.7: + + The pcb contains %eip, %ebx, %esp, %ebp, %esi, %edi and %gs. + This accounts for all callee-saved registers specified by the + psABI and then some. Here %esp contains the stack pointer at the + point just after the call to cpu_switch(). From this information + we reconstruct the register state as it would look when we just + returned from cpu_switch(). */ + + /* The stack pointer shouldn't be zero. */ + if (pcb->pcb_esp == 0) + return 0; + + pcb->pcb_esp += 4; + regcache_raw_supply (regcache, I386_EDI_REGNUM, &pcb->pcb_edi); + regcache_raw_supply (regcache, I386_ESI_REGNUM, &pcb->pcb_esi); + regcache_raw_supply (regcache, I386_EBP_REGNUM, &pcb->pcb_ebp); + regcache_raw_supply (regcache, I386_ESP_REGNUM, &pcb->pcb_esp); + regcache_raw_supply (regcache, I386_EBX_REGNUM, &pcb->pcb_ebx); + regcache_raw_supply (regcache, I386_EIP_REGNUM, &pcb->pcb_eip); + regcache_raw_supply (regcache, I386_GS_REGNUM, &pcb->pcb_gs); + + return 1; +} + + +#ifdef PT_GETXSTATE_INFO +/* Implement the to_read_description method. */ + +static const struct target_desc * +i386fbsd_read_description (struct target_ops *ops) +{ + static int xsave_probed; + static uint64_t xcr0; + + if (!xsave_probed) + { + struct ptrace_xstate_info info; + + if (ptrace (PT_GETXSTATE_INFO, ptid_get_pid (inferior_ptid), + (PTRACE_TYPE_ARG3) &info, sizeof (info)) == 0) + { + x86bsd_xsave_len = info.xsave_len; + xcr0 = info.xsave_mask; + } + xsave_probed = 1; + } + + if (x86bsd_xsave_len != 0) + { + return i386_target_description (xcr0); + } + else + return tdesc_i386; +} +#endif + +/* Prevent warning from -Wmissing-prototypes. */ +void _initialize_i386fbsd_nat (void); + +void +_initialize_i386fbsd_nat (void) +{ + struct target_ops *t; + + /* Add some extra features to the common *BSD/i386 target. */ + t = i386bsd_target (); + +#ifdef PT_GETXSTATE_INFO + t->to_read_description = i386fbsd_read_description; +#endif + + t->to_resume = i386fbsd_resume; + fbsd_nat_add_target (t); + + /* Support debugging kernel virtual memory images. */ + bsd_kvm_add_target (i386fbsd_supply_pcb); + +#ifdef KERN_PROC_SIGTRAMP + /* Normally signal frames are detected via i386fbsd_sigtramp_p. + However, FreeBSD 9.2 through 10.1 do not include the page holding + the signal code in core dumps. These releases do provide a + kern.proc.sigtramp.<pid> sysctl that returns the location of the + signal trampoline for a running process. We fetch the location + of the current (gdb) process and use this to identify signal + frames in core dumps from these releases. */ + { + int mib[4]; + struct kinfo_sigtramp kst; + size_t len; + + mib[0] = CTL_KERN; + mib[1] = KERN_PROC; + mib[2] = KERN_PROC_SIGTRAMP; + mib[3] = getpid (); + len = sizeof (kst); + if (sysctl (mib, 4, &kst, &len, NULL, 0) == 0) + { + i386fbsd_sigtramp_start_addr = (uintptr_t) kst.ksigtramp_start; + i386fbsd_sigtramp_end_addr = (uintptr_t) kst.ksigtramp_end; + } + } +#endif +} |