/* * Copyright (c) 2004 Marcel Moolenaar * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "defs.h" #include "frame-unwind.h" #include "gdbcore.h" #include "inferior.h" #include "osabi.h" #include "regcache.h" #include "progspace.h" #include "solib.h" #include "trad-frame.h" #include "i386-tdep.h" #ifdef __i386__ #include #include #include #include #include #endif #include "kgdb.h" struct i386fbsd_info { int ofs_fix; }; /* Per-program-space data key. */ static const registry::key i386fbsd_pspace_data; /* Get the current i386fbsd data. If none is found yet, add it now. This function always returns a valid object. */ static struct i386fbsd_info * get_i386fbsd_info (void) { struct i386fbsd_info *info; info = i386fbsd_pspace_data.get (current_program_space); if (info != nullptr) return info; info = i386fbsd_pspace_data.emplace (current_program_space); /* * In revision 1.117 of i386/i386/exception.S trap handlers * were changed to pass trapframes by reference rather than * by value. Detect this by seeing if the first instruction * at the 'calltrap' label is a "push %esp" which has the * opcode 0x54. */ if (parse_and_eval_long("((char *)calltrap)[0]") == 0x54) info->ofs_fix = 4; else info->ofs_fix = 0; return info; } /* * Even though the pcb contains fields for the segment selectors, only * %gs is updated on each context switch. The other selectors are * saved in stoppcbs[], but we just hardcode their known values rather * than handling that special case. */ static const int i386fbsd_pcb_offset[] = { -1, /* %eax */ -1, /* %ecx */ -1, /* %edx */ 4 * 4, /* %ebx */ 3 * 4, /* %esp */ 2 * 4, /* %ebp */ 1 * 4, /* %esi */ 0 * 4, /* %edi */ 5 * 4, /* %eip */ -1, /* %eflags */ -1, /* %cs */ -1, /* %ss */ -1, /* %ds */ -1, /* %es */ -1, /* %fs */ -1, /* %gs */ }; #define CODE_SEL (4 << 3) #define DATA_SEL (5 << 3) #define PRIV_SEL (1 << 3) static void i386fbsd_supply_pcb(struct regcache *regcache, CORE_ADDR pcb_addr) { gdb_byte buf[4]; int i; memset(buf, 0, sizeof(buf)); /* * XXX The PCB may have been swapped out. Supply a dummy %eip value * so as to avoid triggering an exception during stack unwinding. */ regcache->raw_supply(I386_EIP_REGNUM, buf); for (i = 0; i < ARRAY_SIZE (i386fbsd_pcb_offset); i++) if (i386fbsd_pcb_offset[i] != -1) { if (target_read_memory(pcb_addr + i386fbsd_pcb_offset[i], buf, sizeof buf) != 0) continue; regcache->raw_supply(i, buf); } regcache->raw_supply_unsigned(I386_CS_REGNUM, CODE_SEL); regcache->raw_supply_unsigned(I386_DS_REGNUM, DATA_SEL); regcache->raw_supply_unsigned(I386_ES_REGNUM, DATA_SEL); regcache->raw_supply_unsigned(I386_FS_REGNUM, PRIV_SEL); regcache->raw_supply_unsigned(I386_GS_REGNUM, DATA_SEL); regcache->raw_supply_unsigned(I386_SS_REGNUM, DATA_SEL); } #ifdef __i386__ /* TODO: Make this cross-debugger friendly. */ static const int i386fbsd_tss_offset[] = { 10 * 4, /* %eax */ 11 * 4, /* %ecx */ 12 * 4, /* %edx */ 13 * 4, /* %ebx */ 14 * 4, /* %esp */ 15 * 4, /* %ebp */ 16 * 4, /* %esi */ 17 * 4, /* %edi */ 8 * 4, /* %eip */ 9 * 4, /* %eflags */ 19 * 4, /* %cs */ 20 * 4, /* %ss */ 21 * 4, /* %ds */ 18 * 4, /* %es */ 22 * 4, /* %fs */ 23 * 4, /* %gs */ }; /* * If the current thread is executing on a CPU, fetch the common_tss * for that CPU. * * This is painful because 'struct pcpu' is variant sized, so we can't * use it. Instead, we lookup the GDT selector for this CPU and * extract the base of the TSS from there. */ static CORE_ADDR i386fbsd_fetch_tss(void) { struct kthr *kt; struct segment_descriptor sd; CORE_ADDR addr, cpu0prvpage, tss; kt = kgdb_thr_lookup_tid(inferior_ptid.tid()); if (kt == NULL || kt->cpu == NOCPU || kt->cpu < 0) return (0); addr = kgdb_lookup("gdt"); if (addr == 0) return (0); addr += (kt->cpu * NGDT + GPROC0_SEL) * sizeof(sd); if (target_read_memory(addr, (gdb_byte *)&sd, sizeof(sd)) != 0) return (0); if (sd.sd_type != SDT_SYS386BSY) { warning ("descriptor is not a busy TSS"); return (0); } tss = sd.sd_hibase << 24 | sd.sd_lobase; /* * In SMP kernels, the TSS is stored as part of the per-CPU * data. On older kernels, the CPU0's private page * is stored at an address that isn't mapped in minidumps. * However, the data is mapped at the alternate cpu0prvpage * address. Thus, if the TSS is at the invalid address, * change it to be relative to cpu0prvpage instead. */ if (trunc_page(tss) == 0xffc00000) { try { cpu0prvpage = parse_and_eval_address("cpu0prvpage"); } catch (const gdb_exception_error &e) { return (0); } tss = cpu0prvpage + (tss & PAGE_MASK); } return (tss); } static struct trad_frame_cache * i386fbsd_dblfault_cache (const frame_info_ptr &this_frame, void **this_cache) { struct gdbarch *gdbarch = get_frame_arch (this_frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); struct trad_frame_cache *cache; CORE_ADDR addr, func, tss; int i; if (*this_cache != NULL) return (struct trad_frame_cache *)(*this_cache); cache = trad_frame_cache_zalloc (this_frame); *this_cache = cache; func = get_frame_func (this_frame); tss = i386fbsd_fetch_tss (); for (i = 0; i < ARRAY_SIZE (i386fbsd_tss_offset); i++) if (i386fbsd_tss_offset[i] != -1) trad_frame_set_reg_addr (cache, i, tss + i386fbsd_tss_offset[i]); /* Construct the frame ID using the function start. */ /* XXX: Stack address should be dbfault_stack + PAGE_SIZE. */ trad_frame_set_id (cache, frame_id_build (tss + sizeof(struct i386tss), func)); return cache; } static void i386fbsd_dblfault_this_id (const frame_info_ptr &this_frame, void **this_cache, struct frame_id *this_id) { struct trad_frame_cache *cache = i386fbsd_dblfault_cache (this_frame, this_cache); trad_frame_get_id (cache, this_id); } static struct value * i386fbsd_dblfault_prev_register (const frame_info_ptr &this_frame, void **this_cache, int regnum) { struct trad_frame_cache *cache = i386fbsd_dblfault_cache (this_frame, this_cache); return trad_frame_get_register (cache, this_frame, regnum); } static int i386fbsd_dblfault_sniffer (const struct frame_unwind *self, const frame_info_ptr &this_frame, void **this_prologue_cache) { const char *name; find_pc_partial_function (get_frame_func (this_frame), &name, NULL, NULL); return (name && strcmp (name, "dblfault_handler") == 0); } static const struct frame_unwind i386fbsd_dblfault_unwind = { "i386 FreeBSD double fault", SIGTRAMP_FRAME, default_frame_unwind_stop_reason, i386fbsd_dblfault_this_id, i386fbsd_dblfault_prev_register, NULL, i386fbsd_dblfault_sniffer }; #endif static const int i386fbsd_trapframe_offset[] = { 10 * 4, /* %eax */ 9 * 4, /* %ecx */ 8 * 4, /* %edx */ 7 * 4, /* %ebx */ 16 * 4, /* %esp */ 5 * 4, /* %ebp */ 4 * 4, /* %esi */ 3 * 4, /* %edi */ 13 * 4, /* %eip */ 15 * 4, /* %eflags */ 14 * 4, /* %cs */ 17 * 4, /* %ss */ 2 * 4, /* %ds */ 1 * 4, /* %es */ 0 * 4, /* %fs */ -1 /* %gs */ }; #define TRAPFRAME_SIZE 72 static struct trad_frame_cache * i386fbsd_trapframe_cache (const frame_info_ptr &this_frame, void **this_cache) { struct gdbarch *gdbarch = get_frame_arch (this_frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); struct trad_frame_cache *cache; struct i386fbsd_info *info; CORE_ADDR addr, cs, func, pc, sp; const char *name; int i; if (*this_cache != NULL) return ((struct trad_frame_cache *)*this_cache); info = get_i386fbsd_info(); cache = trad_frame_cache_zalloc (this_frame); *this_cache = cache; func = get_frame_func (this_frame); sp = get_frame_register_unsigned (this_frame, I386_ESP_REGNUM); find_pc_partial_function (func, &name, NULL, NULL); if (strcmp(name, "calltrap") == 0 || strcmp(name, "Xlcall_syscall") == 0 || strcmp(name, "Xint0x80_syscall") == 0) /* Traps in later kernels pass the trap frame by reference. */ sp += info->ofs_fix; else if (strcmp(name, "Xtimerint") == 0) /* Timer interrupts also pass the trap frame by reference. */ sp += info->ofs_fix; else if (strcmp(name, "Xcpustop") == 0 || strcmp(name, "Xrendezvous") == 0 || strcmp(name, "Xipi_intr_bitmap_handler") == 0 || strcmp(name, "Xlazypmap") == 0) /* These handlers push a trap frame only. */ ; else if (strcmp(name, "fork_trampoline") == 0) if (get_frame_pc (this_frame) == func) { /* fork_exit hasn't been called (kthread has never run), so %esp in the pcb points to the word above the trapframe. */ sp += 4; } else { /* fork_exit has been called, so %esp in fork_exit's frame is &tf - 12. */ sp += 12; } else { /* Interrupt frames pass the IDT vector in addition to the trap frame. */ sp += info->ofs_fix + 4; } addr = sp + i386fbsd_trapframe_offset[I386_CS_REGNUM]; cs = read_memory_unsigned_integer (addr, 4, byte_order); for (i = 0; i < ARRAY_SIZE (i386fbsd_trapframe_offset); i++) { /* %ss/%esp are only present in the trapframe for a trap from userland. */ if ((cs & I386_SEL_RPL) == I386_SEL_KPL) { if (i == I386_SS_REGNUM) continue; if (i == I386_ESP_REGNUM) { trad_frame_set_reg_value (cache, i, sp + TRAPFRAME_SIZE - 8); continue; } } if (i386fbsd_trapframe_offset[i] != -1) trad_frame_set_reg_addr (cache, i, sp + i386fbsd_trapframe_offset[i]); } /* Read %eip from trap frame. */ addr = sp + i386fbsd_trapframe_offset[I386_EIP_REGNUM]; pc = read_memory_unsigned_integer (addr, 4, byte_order); if (pc == 0 && strcmp(name, "fork_trampoline") == 0) { /* Initial frame of a kthread; terminate backtrace. */ trad_frame_set_id (cache, outer_frame_id); } else { /* Construct the frame ID using the function start. */ sp += TRAPFRAME_SIZE; if ((cs & I386_SEL_RPL) == I386_SEL_KPL) sp -= 8; trad_frame_set_id (cache, frame_id_build (sp, func)); } return cache; } static void i386fbsd_trapframe_this_id (const frame_info_ptr &this_frame, void **this_cache, struct frame_id *this_id) { struct trad_frame_cache *cache = i386fbsd_trapframe_cache (this_frame, this_cache); trad_frame_get_id (cache, this_id); } static struct value * i386fbsd_trapframe_prev_register (const frame_info_ptr &this_frame, void **this_cache, int regnum) { struct trad_frame_cache *cache = i386fbsd_trapframe_cache (this_frame, this_cache); return trad_frame_get_register (cache, this_frame, regnum); } static int i386fbsd_trapframe_sniffer (const struct frame_unwind *self, const frame_info_ptr &this_frame, void **this_prologue_cache) { const char *name; find_pc_partial_function (get_frame_func (this_frame), &name, NULL, NULL); return (name && ((strcmp (name, "calltrap") == 0) || (strcmp (name, "fork_trampoline") == 0) || (name[0] == 'X' && name[1] != '_'))); } static const struct frame_unwind i386fbsd_trapframe_unwind = { "i386 FreeBSD kernel trap", SIGTRAMP_FRAME, default_frame_unwind_stop_reason, i386fbsd_trapframe_this_id, i386fbsd_trapframe_prev_register, NULL, i386fbsd_trapframe_sniffer }; static void i386fbsd_kernel_init_abi(struct gdbarch_info info, struct gdbarch *gdbarch) { i386_elf_init_abi(info, gdbarch); #ifdef __i386__ frame_unwind_prepend_unwinder(gdbarch, &i386fbsd_dblfault_unwind); #endif frame_unwind_prepend_unwinder(gdbarch, &i386fbsd_trapframe_unwind); set_gdbarch_so_ops(gdbarch, &kld_so_ops); fbsd_vmcore_set_supply_pcb(gdbarch, i386fbsd_supply_pcb); fbsd_vmcore_set_cpu_pcb_addr(gdbarch, kgdb_trgt_stop_pcb); } void _initialize_i386_kgdb_tdep (); void _initialize_i386_kgdb_tdep () { /* This is used for both i386 and amd64, but amd64 always includes this target, so just include it here. */ gdbarch_register_osabi_sniffer(bfd_arch_i386, bfd_target_elf_flavour, fbsd_kernel_osabi_sniffer); gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_KERNEL, i386fbsd_kernel_init_abi); #ifdef __i386__ /* * FreeBSD/i386 kernels prior to the introduction of AVX * support used a different layout for the PCB. If gdb is * compiled on these systems, these asserts will fail. The * package builders build packages on older systems which are * then run on newer systems. These binaries trip over these * assertions even when debugging user programs and even * though the running kernel is new enough. To cope, disable * the assertion checks unless gdb is built against a new * enough world. Note that this means kgdb is not going to * parse PCBs correctly on FreeBSD/i386 kernels before AVX was * merged. */ #if __FreeBSD_version >= 1001505 gdb_assert(offsetof(struct pcb, pcb_ebx) == i386fbsd_pcb_offset[I386_EBX_REGNUM]); gdb_assert(offsetof(struct pcb, pcb_esp) == i386fbsd_pcb_offset[I386_ESP_REGNUM]); gdb_assert(offsetof(struct pcb, pcb_ebp) == i386fbsd_pcb_offset[I386_EBP_REGNUM]); gdb_assert(offsetof(struct pcb, pcb_esi) == i386fbsd_pcb_offset[I386_ESI_REGNUM]); gdb_assert(offsetof(struct pcb, pcb_edi) == i386fbsd_pcb_offset[I386_EDI_REGNUM]); gdb_assert(offsetof(struct pcb, pcb_eip) == i386fbsd_pcb_offset[I386_EIP_REGNUM]); #endif gdb_assert(CODE_SEL == GSEL(GCODE_SEL, SEL_KPL)); gdb_assert(DATA_SEL == GSEL(GDATA_SEL, SEL_KPL)); gdb_assert(PRIV_SEL == GSEL(GPRIV_SEL, SEL_KPL)); gdb_assert(sizeof(struct trapframe) == TRAPFRAME_SIZE); gdb_assert(offsetof(struct trapframe, tf_eax) == i386fbsd_trapframe_offset[I386_EAX_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_ecx) == i386fbsd_trapframe_offset[I386_ECX_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_edx) == i386fbsd_trapframe_offset[I386_EDX_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_ebx) == i386fbsd_trapframe_offset[I386_EBX_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_esp) == i386fbsd_trapframe_offset[I386_ESP_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_ebp) == i386fbsd_trapframe_offset[I386_EBP_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_esi) == i386fbsd_trapframe_offset[I386_ESI_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_edi) == i386fbsd_trapframe_offset[I386_EDI_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_eip) == i386fbsd_trapframe_offset[I386_EIP_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_eflags) == i386fbsd_trapframe_offset[I386_EFLAGS_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_cs) == i386fbsd_trapframe_offset[I386_CS_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_ss) == i386fbsd_trapframe_offset[I386_SS_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_ds) == i386fbsd_trapframe_offset[I386_DS_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_es) == i386fbsd_trapframe_offset[I386_ES_REGNUM]); gdb_assert(offsetof(struct trapframe, tf_fs) == i386fbsd_trapframe_offset[I386_FS_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_eax) == i386fbsd_tss_offset[I386_EAX_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_ecx) == i386fbsd_tss_offset[I386_ECX_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_edx) == i386fbsd_tss_offset[I386_EDX_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_ebx) == i386fbsd_tss_offset[I386_EBX_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_esp) == i386fbsd_tss_offset[I386_ESP_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_ebp) == i386fbsd_tss_offset[I386_EBP_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_esi) == i386fbsd_tss_offset[I386_ESI_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_edi) == i386fbsd_tss_offset[I386_EDI_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_eip) == i386fbsd_tss_offset[I386_EIP_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_eflags) == i386fbsd_tss_offset[I386_EFLAGS_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_cs) == i386fbsd_tss_offset[I386_CS_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_ss) == i386fbsd_tss_offset[I386_SS_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_ds) == i386fbsd_tss_offset[I386_DS_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_es) == i386fbsd_tss_offset[I386_ES_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_fs) == i386fbsd_tss_offset[I386_FS_REGNUM]); gdb_assert(offsetof(struct i386tss, tss_gs) == i386fbsd_tss_offset[I386_GS_REGNUM]); #endif }