/* Native-dependent code for Linux running on i386's, for GDB. 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 "inferior.h" #include "gdbcore.h" /* For i386_linux_skip_solib_resolver */ #include "symtab.h" #include "frame.h" #include "symfile.h" #include "objfiles.h" #include #include #include #ifdef HAVE_SYS_REG_H #include #endif /* * Some systems (Linux) may have threads implemented as pseudo-processes, * in which case we may be tracing more than one process at a time. * In that case, inferior_pid will contain the main process ID and the * individual thread (process) id mashed together. These macros are * used to separate them out. The definitions may be overridden in tm.h */ #if !defined (PIDGET) /* Default definition for PIDGET/TIDGET. */ #define PIDGET(PID) PID #define TIDGET(PID) 0 #endif /* This is a duplicate of the table in i386-xdep.c. */ static int regmap[] = { EAX, ECX, EDX, EBX, UESP, EBP, ESI, EDI, EIP, EFL, CS, SS, DS, ES, FS, GS, }; /* Which ptrace request retrieves which registers? These apply to the corresponding SET requests as well. */ #define GETREGS_SUPPLIES(regno) \ (0 <= (regno) && (regno) <= 15) #define GETFPREGS_SUPPLIES(regno) \ (FP0_REGNUM <= (regno) && (regno) <= LAST_FPU_CTRL_REGNUM) #define GETXFPREGS_SUPPLIES(regno) \ (FP0_REGNUM <= (regno) && (regno) <= MXCSR_REGNUM) /* Does the current host support the GETXFPREGS request? The header file may or may not define it, and even if it is defined, the kernel will return EIO if it's running on a pre-SSE processor. PTRACE_GETXFPREGS is a Cygnus invention, since we wrote our own Linux kernel patch for SSE support. That patch may or may not actually make it into the official distribution. If you find that years have gone by since this stuff was added, and Linux isn't using PTRACE_GETXFPREGS, that means that our patch didn't make it, and you can delete this, and the related code. My instinct is to attach this to some architecture- or target-specific data structure, but really, a particular GDB process can only run on top of one kernel at a time. So it's okay for this to be a simple variable. */ int have_ptrace_getxfpregs = #ifdef HAVE_PTRACE_GETXFPREGS 1 #else 0 #endif ; /* Transfering the general registers between GDB, inferiors and core files. */ /* Given a pointer to a general register set in struct user format (gregset_t *), unpack the register contents and supply them as gdb's idea of the current register values. */ void supply_gregset (gregsetp) gregset_t *gregsetp; { register int regi; register greg_t *regp = (greg_t *) gregsetp; for (regi = 0; regi < NUM_GREGS; regi++) { supply_register (regi, (char *) (regp + regmap[regi])); } } /* Fill in a gregset_t object with selected data from a gdb-format register file. - GREGSETP points to the gregset_t object to be filled. - GDB_REGS points to the GDB-style register file providing the data. - VALID is an array indicating which registers in GDB_REGS are valid; the parts of *GREGSETP that would hold registers marked invalid in GDB_REGS are left unchanged. If VALID is zero, all registers are assumed to be valid. */ void convert_to_gregset (gregset_t *gregsetp, char *gdb_regs, signed char *valid) { int regi; register greg_t *regp = (greg_t *) gregsetp; for (regi = 0; regi < NUM_GREGS; regi++) if (! valid || valid[regi]) *(regp + regmap[regi]) = * (int *) ®isters[REGISTER_BYTE (regi)]; } /* Store GDB's value for REGNO in *GREGSETP. If REGNO is -1, do all of them. */ void fill_gregset (gregset_t *gregsetp, int regno) { if (regno == -1) convert_to_gregset (gregsetp, registers, 0); else if (regno >= 0 && regno < NUM_GREGS) { signed char valid[NUM_GREGS]; memset (valid, 0, sizeof (valid)); valid[regno] = 1; convert_to_gregset (gregsetp, valid, valid); } } /* Read the general registers from the process, and store them in registers[]. */ static void fetch_regs (int tid) { int ret, regno; gregset_t buf; ret = ptrace (PTRACE_GETREGS, tid, 0, (int) &buf); if (ret < 0) { warning ("Couldn't get registers"); return; } supply_gregset (&buf); } /* Set the inferior's general registers to the values in registers[] --- but only those registers marked as valid. */ static void store_regs (int tid) { int ret, regno; gregset_t buf; ret = ptrace (PTRACE_GETREGS, tid, 0, (int) &buf); if (ret < 0) { warning ("Couldn't get registers"); return; } convert_to_gregset (&buf, registers, register_valid); ret = ptrace (PTRACE_SETREGS, tid, 0, (int)buf); if (ret < 0) { warning ("Couldn't write registers"); return; } } /* Transfering floating-point registers between GDB, inferiors and cores. */ /* What is the address of st(N) within the fpregset_t structure F? */ #define FPREGSET_T_FPREG_ADDR(f, n) \ ((char *) &(f)->st_space + (n) * 10) /* Fill GDB's register file with the floating-point register values in *FPREGSETP. */ void supply_fpregset (fpregset_t *fpregsetp) { int i; /* Supply the floating-point registers. */ for (i = 0; i < 8; i++) supply_register (FP0_REGNUM + i, FPREGSET_T_FPREG_ADDR (fpregsetp, i)); supply_register (FCTRL_REGNUM, (char *) &fpregsetp->cwd); supply_register (FSTAT_REGNUM, (char *) &fpregsetp->swd); supply_register (FTAG_REGNUM, (char *) &fpregsetp->twd); supply_register (FCOFF_REGNUM, (char *) &fpregsetp->fip); supply_register (FDS_REGNUM, (char *) &fpregsetp->fos); supply_register (FDOFF_REGNUM, (char *) &fpregsetp->foo); /* Extract the code segment and opcode from the "fcs" member. */ { long l; l = fpregsetp->fcs & 0xffff; supply_register (FCS_REGNUM, (char *) &l); l = (fpregsetp->fcs >> 16) & ((1 << 11) - 1); supply_register (FOP_REGNUM, (char *) &l); } } /* Fill in an fpregset_t structure with selected data from a gdb-format register file. - FPREGSETP points to the structure to be filled. - GDB_REGS points to the GDB-style register file providing the data. - VALID is an array indicating which registers in GDB_REGS are valid; the parts of *FPREGSETP that would hold registers marked invalid in GDB_REGS are left unchanged. If VALID is zero, all registers are assumed to be valid. */ void convert_to_fpregset (fpregset_t *fpregsetp, char *gdb_regs, signed char *valid) { int i; /* Fill in the floating-point registers. */ for (i = 0; i < 8; i++) if (!valid || valid[i]) memcpy (FPREGSET_T_FPREG_ADDR (fpregsetp, i), ®isters[REGISTER_BYTE (FP0_REGNUM + i)], REGISTER_RAW_SIZE(FP0_REGNUM + i)); #define fill(MEMBER, REGNO) \ if (! valid || valid[(REGNO)]) \ memcpy (&fpregsetp->MEMBER, ®isters[REGISTER_BYTE (REGNO)], \ sizeof (fpregsetp->MEMBER)) fill (cwd, FCTRL_REGNUM); fill (swd, FSTAT_REGNUM); fill (twd, FTAG_REGNUM); fill (fip, FCOFF_REGNUM); fill (foo, FDOFF_REGNUM); fill (fos, FDS_REGNUM); #undef fill if (! valid || valid[FCS_REGNUM]) fpregsetp->fcs = ((fpregsetp->fcs & ~0xffff) | (* (int *) ®isters[REGISTER_BYTE (FCS_REGNUM)] & 0xffff)); if (! valid || valid[FOP_REGNUM]) fpregsetp->fcs = ((fpregsetp->fcs & 0xffff) | ((*(int *) ®isters[REGISTER_BYTE (FOP_REGNUM)] & ((1 << 11) - 1)) << 16)); } /* Given a pointer to a floating point register set in (fpregset_t *) format, update all of the registers from gdb's idea of the current floating point register set. */ void fill_fpregset (fpregset_t *fpregsetp, int regno) { convert_to_fpregset (fpregsetp, registers, 0); } /* Get the whole floating point state of the process and store the floating point stack into registers[]. */ static void fetch_fpregs (int tid) { int ret, regno; fpregset_t buf; ret = ptrace (PTRACE_GETFPREGS, tid, 0, (int) &buf); if (ret < 0) { warning ("Couldn't get floating point status"); return; } /* ptrace fills an fpregset_t, so we can use the same function we do for core files. */ supply_fpregset (&buf); } /* Set the inferior's floating-point registers to the values in registers[] --- but only those registers marked valid. */ static void store_fpregs (int tid) { int ret; fpregset_t buf; ret = ptrace (PTRACE_GETFPREGS, tid, 0, (int) &buf); if (ret < 0) { warning ("Couldn't get floating point status"); return; } convert_to_fpregset (&buf, registers, register_valid); ret = ptrace (PTRACE_SETFPREGS, tid, 0, (int) &buf); if (ret < 0) { warning ("Couldn't write floating point status"); return; } } /* Transfering floating-point and SSE registers to and from GDB. */ /* PTRACE_GETXFPREGS is a Cygnus invention, since we wrote our own Linux kernel patch for SSE support. That patch may or may not actually make it into the official distribution. If you find that years have gone by since this code was added, and Linux isn't using PTRACE_GETXFPREGS, that means that our patch didn't make it, and you can delete this code. */ #ifdef HAVE_PTRACE_GETXFPREGS static void supply_xfpregset (struct user_xfpregs_struct *xfpregs) { int reg; /* Supply the floating-point registers. */ for (reg = 0; reg < 8; reg++) supply_register (FP0_REGNUM + reg, (char *) &xfpregs->st_space[reg]); { supply_register (FCTRL_REGNUM, (char *) &xfpregs->cwd); supply_register (FSTAT_REGNUM, (char *) &xfpregs->swd); supply_register (FTAG_REGNUM, (char *) &xfpregs->twd); supply_register (FCOFF_REGNUM, (char *) &xfpregs->fip); supply_register (FDS_REGNUM, (char *) &xfpregs->fos); supply_register (FDOFF_REGNUM, (char *) &xfpregs->foo); /* Extract the code segment and opcode from the "fcs" member. */ { long l; l = xfpregs->fcs & 0xffff; supply_register (FCS_REGNUM, (char *) &l); l = (xfpregs->fcs >> 16) & ((1 << 11) - 1); supply_register (FOP_REGNUM, (char *) &l); } } /* Supply the SSE registers. */ for (reg = 0; reg < 8; reg++) supply_register (XMM0_REGNUM + reg, (char *) &xfpregs->xmm_space[reg]); supply_register (MXCSR_REGNUM, (char *) &xfpregs->mxcsr); } static void convert_to_xfpregset (struct user_xfpregs_struct *xfpregs, char *gdb_regs, signed char *valid) { int reg; /* Fill in the floating-point registers. */ for (reg = 0; reg < 8; reg++) if (!valid || valid[reg]) memcpy (&xfpregs->st_space[reg], ®isters[REGISTER_BYTE (FP0_REGNUM + reg)], REGISTER_RAW_SIZE(FP0_REGNUM + reg)); #define fill(MEMBER, REGNO) \ if (! valid || valid[(REGNO)]) \ memcpy (&xfpregs->MEMBER, ®isters[REGISTER_BYTE (REGNO)], \ sizeof (xfpregs->MEMBER)) fill (cwd, FCTRL_REGNUM); fill (swd, FSTAT_REGNUM); fill (twd, FTAG_REGNUM); fill (fip, FCOFF_REGNUM); fill (foo, FDOFF_REGNUM); fill (fos, FDS_REGNUM); #undef fill if (! valid || valid[FCS_REGNUM]) xfpregs->fcs = ((xfpregs->fcs & ~0xffff) | (* (int *) ®isters[REGISTER_BYTE (FCS_REGNUM)] & 0xffff)); if (! valid || valid[FOP_REGNUM]) xfpregs->fcs = ((xfpregs->fcs & 0xffff) | ((*(int *) ®isters[REGISTER_BYTE (FOP_REGNUM)] & ((1 << 11) - 1)) << 16)); /* Fill in the XMM registers. */ for (reg = 0; reg < 8; reg++) if (! valid || valid[reg]) memcpy (&xfpregs->xmm_space[reg], ®isters[REGISTER_BYTE (XMM0_REGNUM + reg)], REGISTER_RAW_SIZE (XMM0_REGNUM + reg)); } /* Make a PTRACE_GETXFPREGS request, and supply all the register values that yields to GDB. */ static int fetch_xfpregs (int tid) { int ret; struct user_xfpregs_struct xfpregs; if (! have_ptrace_getxfpregs) return 0; ret = ptrace (PTRACE_GETXFPREGS, tid, 0, &xfpregs); if (ret == -1) { if (errno == EIO) { have_ptrace_getxfpregs = 0; return 0; } warning ("couldn't read floating-point and SSE registers."); return 0; } supply_xfpregset (&xfpregs); return 1; } /* Send all the valid register values in GDB's register file covered by the PTRACE_SETXFPREGS request to the inferior. */ static int store_xfpregs (int tid) { int ret; struct user_xfpregs_struct xfpregs; if (! have_ptrace_getxfpregs) return 0; ret = ptrace (PTRACE_GETXFPREGS, tid, 0, &xfpregs); if (ret == -1) { if (errno == EIO) { have_ptrace_getxfpregs = 0; return 0; } warning ("couldn't read floating-point and SSE registers."); return 0; } convert_to_xfpregset (&xfpregs, registers, register_valid); if (ptrace (PTRACE_SETXFPREGS, tid, 0, &xfpregs) < 0) { warning ("Couldn't write floating-point and SSE registers."); return 0; } return 1; } /* Fill the XMM registers in the register file with dummy values. For cases where we don't have access to the XMM registers. I think this is cleaner than printing a warning. For a cleaner solution, we should gdbarchify the i386 family. */ static void dummy_sse_values () { /* C doesn't have a syntax for NaN's, so write it out as an array of longs. */ static long dummy[4] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff }; static long mxcsr = 0x1f80; int reg; for (reg = 0; reg < 8; reg++) supply_register (XMM0_REGNUM + reg, (char *) dummy); supply_register (MXCSR_REGNUM, (char *) &mxcsr); } #else /* Stub versions of the above routines, for systems that don't have PTRACE_GETXFPREGS. */ static int store_xfpregs (int tid) { return 0; } static int fetch_xfpregs (int tid) { return 0; } static void dummy_sse_values () {} #endif /* Transferring arbitrary registers between GDB and inferior. */ /* Fetch registers from the child process. Fetch all if regno == -1, otherwise fetch all ordinary registers or all floating point registers depending upon the value of regno. */ void fetch_inferior_registers (int regno) { /* linux lwp id's are process id's */ int tid; if ((tid = TIDGET (inferior_pid)) == 0) tid = inferior_pid; /* not a threaded program */ /* Use the xfpregs requests whenever possible, since they transfer more registers in one system call, and we'll cache the results. But remember that fetch_xfpregs can fail, and return zero. */ if (regno == -1) { fetch_regs (tid); if (fetch_xfpregs (tid)) return; fetch_fpregs (tid); return; } if (GETREGS_SUPPLIES (regno)) { fetch_regs (tid); return; } if (GETXFPREGS_SUPPLIES (regno)) { if (fetch_xfpregs (tid)) return; /* Either our processor or our kernel doesn't support the SSE registers, so read the FP registers in the traditional way, and fill the SSE registers with dummy values. It would be more graceful to handle differences in the register set using gdbarch. Until then, this will at least make things work plausibly. */ fetch_fpregs (tid); dummy_sse_values (); return; } internal_error ("i386-linux-nat.c (fetch_inferior_registers): " "got request for bad register number %d", regno); } /* Store our register values back into the inferior. If REGNO is -1, do this for all registers. Otherwise, REGNO specifies which register, which then determines whether we store all ordinary registers or all of the floating point registers. */ void store_inferior_registers (regno) int regno; { /* linux lwp id's are process id's */ int tid; if ((tid = TIDGET (inferior_pid)) == 0) tid = inferior_pid; /* not a threaded program */ /* Use the xfpregs requests whenever possible, since they transfer more registers in one system call. But remember that store_xfpregs can fail, and return zero. */ if (regno == -1) { store_regs (tid); if (store_xfpregs (tid)) return; store_fpregs (tid); return; } if (GETREGS_SUPPLIES (regno)) { store_regs (tid); return; } if (GETXFPREGS_SUPPLIES (regno)) { if (store_xfpregs (tid)) return; /* Either our processor or our kernel doesn't support the SSE registers, so just write the FP registers in the traditional way. */ store_fpregs (tid); return; } internal_error ("i386-linux-nat.c (store_inferior_registers): " "got request to store bad register number %d", regno); } /* Interpreting register set info found in core files. */ /* Provide registers to GDB from a core file. (We can't use the generic version of this function in core-regset.c, because Linux has *three* different kinds of register set notes. core-regset.c would have to call supply_xfpregset, which most platforms don't have.) CORE_REG_SECT points to an array of bytes, which are the contents of a `note' from a core file which BFD thinks might contain register contents. CORE_REG_SIZE is its size. WHICH says which register set corelow suspects this is: 0 --- the general register set, in gregset format 2 --- the floating-point register set, in fpregset format 3 --- the extended floating-point register set, in struct user_xfpregs_struct format DUMMY isn't used on Linux. */ static void i386_linux_fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which, CORE_ADDR dummy) { gregset_t gregset; fpregset_t fpregset; switch (which) { case 0: if (core_reg_size != sizeof (gregset)) warning ("wrong size gregset struct in core file"); else { memcpy (&gregset, core_reg_sect, sizeof (gregset)); supply_gregset (&gregset); } break; case 2: if (core_reg_size != sizeof (fpregset)) warning ("wrong size fpregset struct in core file"); else { memcpy (&fpregset, core_reg_sect, sizeof (fpregset)); supply_fpregset (&fpregset); } break; #ifdef HAVE_PTRACE_GETXFPREGS { struct user_xfpregs_struct xfpregset; case 3: if (core_reg_size != sizeof (struct user_xfpregs_struct)) warning ("wrong size user_xfpregs_struct in core file"); else { memcpy (&xfpregset, core_reg_sect, sizeof (xfpregset)); supply_xfpregset (&xfpregset); } break; } #endif default: /* We've covered all the kinds of registers we know about here, so this must be something we wouldn't know what to do with anyway. Just ignore it. */ break; } } static struct core_fns i386_linux_nat_core_fns = { bfd_target_elf_flavour, /* core_flavour */ default_check_format, /* check_format */ default_core_sniffer, /* core_sniffer */ i386_linux_fetch_core_registers, /* core_read_registers */ NULL /* next */ }; /* Calling functions in shared libraries. */ /* Find the minimal symbol named NAME, and return both the minsym struct and its objfile. This probably ought to be in minsym.c, but everything there is trying to deal with things like C++ and SOFUN_ADDRESS_MAYBE_TURQUOISE, ... Since this is so simple, it may be considered too special-purpose for general consumption. */ static struct minimal_symbol * find_minsym_and_objfile (char *name, struct objfile **objfile_p) { struct objfile *objfile; ALL_OBJFILES (objfile) { struct minimal_symbol *msym; ALL_OBJFILE_MSYMBOLS (objfile, msym) { if (SYMBOL_NAME (msym) && STREQ (SYMBOL_NAME (msym), name)) { *objfile_p = objfile; return msym; } } } return 0; } static CORE_ADDR skip_hurd_resolver (CORE_ADDR pc) { /* The HURD dynamic linker is part of the GNU C library, so many GNU/Linux distributions use it. (All ELF versions, as far as I know.) An unresolved PLT entry points to "_dl_runtime_resolve", which calls "fixup" to patch the PLT, and then passes control to the function. We look for the symbol `_dl_runtime_resolve', and find `fixup' in the same objfile. If we are at the entry point of `fixup', then we set a breakpoint at the return address (at the top of the stack), and continue. It's kind of gross to do all these checks every time we're called, since they don't change once the executable has gotten started. But this is only a temporary hack --- upcoming versions of Linux will provide a portable, efficient interface for debugging programs that use shared libraries. */ struct objfile *objfile; struct minimal_symbol *resolver = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile); if (resolver) { struct minimal_symbol *fixup = lookup_minimal_symbol ("fixup", 0, objfile); if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc) return (SAVED_PC_AFTER_CALL (get_current_frame ())); } return 0; } /* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c. This function: 1) decides whether a PLT has sent us into the linker to resolve a function reference, and 2) if so, tells us where to set a temporary breakpoint that will trigger when the dynamic linker is done. */ CORE_ADDR i386_linux_skip_solib_resolver (CORE_ADDR pc) { CORE_ADDR result; /* Plug in functions for other kinds of resolvers here. */ result = skip_hurd_resolver (pc); if (result) return result; return 0; } /* Module initialization. */ void _initialize_i386_linux_nat () { add_core_fns (&i386_linux_nat_core_fns); }