/* Native-dependent code for OpenBSD/amd64. Copyright 2003, 2004 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 2 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, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "defs.h" #include "gdbcore.h" #include "regcache.h" #include "target.h" #include "gdb_assert.h" #include "amd64-tdep.h" #include "amd64-nat.h" /* Mapping between the general-purpose registers in OpenBSD/amd64 `struct reg' format and GDB's register cache layout for OpenBSD/i386. Note that most (if not all) OpenBSD/amd64 registers are 64-bit, while the OpenBSD/i386 registers are all 32-bit, but since we're little-endian we get away with that. */ /* From <machine/reg.h>. */ static int amd64obsd32_r_reg_offset[] = { 14 * 8, /* %eax */ 3 * 8, /* %ecx */ 2 * 8, /* %edx */ 13 * 8, /* %ebx */ 15 * 8, /* %esp */ 12 * 8, /* %ebp */ 1 * 8, /* %esi */ 0 * 8, /* %edi */ 16 * 8, /* %eip */ 17 * 8, /* %eflags */ 18 * 8, /* %cs */ 19 * 8, /* %ss */ 20 * 8, /* %ds */ 21 * 8, /* %es */ 22 * 8, /* %fs */ 23 * 8 /* %gs */ }; /* Support for debugging kernel virtual memory images. */ #include <sys/types.h> #include <machine/frame.h> #include <machine/pcb.h> #include "bsd-kvm.h" static int amd64obsd_supply_pcb (struct regcache *regcache, struct pcb *pcb) { struct switchframe sf; int regnum; /* The following is true for OpenBSD 3.5: The pcb contains the stack pointer at the point of the context switch in cpu_switch(). At that point we have a stack frame as described by `struct switchframe', which for OpenBSD 3.5 has the following layout: interrupt level %r15 %r14 %r13 %r12 %rbp %rbx return address Together with %rsp in the pcb, this accounts for all callee-saved registers specified by the psABI. From this information we reconstruct the register state as it would look when we just returned from cpu_switch(). For core dumps the pcb is saved by savectx(). In that case the stack frame only contains the return address, and there is no way to recover the other registers. */ /* The stack pointer shouldn't be zero. */ if (pcb->pcb_rsp == 0) return 0; /* Read the stack frame, and check its validity. */ read_memory (pcb->pcb_rsp, (char *) &sf, sizeof sf); if (sf.sf_rbp == pcb->pcb_rbp) { /* Yes, we have a frame that matches cpu_switch(). */ pcb->pcb_rsp += sizeof (struct switchframe); regcache_raw_supply (regcache, 12, &sf.sf_r12); regcache_raw_supply (regcache, 13, &sf.sf_r13); regcache_raw_supply (regcache, 14, &sf.sf_r14); regcache_raw_supply (regcache, 15, &sf.sf_r15); regcache_raw_supply (regcache, AMD64_RBX_REGNUM, &sf.sf_rbx); regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf.sf_rip); } else { /* No, the pcb must have been last updated by savectx(). */ pcb->pcb_rsp += 8; regcache_raw_supply (regcache, AMD64_RIP_REGNUM, &sf); } regcache_raw_supply (regcache, AMD64_RSP_REGNUM, &pcb->pcb_rsp); regcache_raw_supply (regcache, AMD64_RBP_REGNUM, &pcb->pcb_rbp); return 1; } /* Provide a prototype to silence -Wmissing-prototypes. */ void _initialize_amd64obsd_nat (void); void _initialize_amd64obsd_nat (void) { amd64_native_gregset32_reg_offset = amd64obsd32_r_reg_offset; amd64_native_gregset32_num_regs = ARRAY_SIZE (amd64obsd32_r_reg_offset); amd64_native_gregset64_reg_offset = amd64obsd_r_reg_offset; /* We've got nothing to add to the common *BSD/amd64 target. */ add_target (amd64bsd_target ()); /* Support debugging kernel virtual memory images. */ bsd_kvm_add_target (amd64obsd_supply_pcb); }