| /* Native-dependent code for GNU/Linux i386. |
| |
| Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 |
| 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 "gdbcore.h" |
| #include "regcache.h" |
| #include "target.h" |
| #include "linux-nat.h" |
| |
| #include "gdb_assert.h" |
| #include "gdb_string.h" |
| #include <sys/ptrace.h> |
| #include <sys/user.h> |
| #include <sys/procfs.h> |
| |
| #ifdef HAVE_SYS_REG_H |
| #include <sys/reg.h> |
| #endif |
| |
| #ifndef ORIG_EAX |
| #define ORIG_EAX -1 |
| #endif |
| |
| #ifdef HAVE_SYS_DEBUGREG_H |
| #include <sys/debugreg.h> |
| #endif |
| |
| #ifndef DR_FIRSTADDR |
| #define DR_FIRSTADDR 0 |
| #endif |
| |
| #ifndef DR_LASTADDR |
| #define DR_LASTADDR 3 |
| #endif |
| |
| #ifndef DR_STATUS |
| #define DR_STATUS 6 |
| #endif |
| |
| #ifndef DR_CONTROL |
| #define DR_CONTROL 7 |
| #endif |
| |
| /* Prototypes for supply_gregset etc. */ |
| #include "gregset.h" |
| |
| #include "i387-tdep.h" |
| #include "i386-tdep.h" |
| #include "i386-linux-tdep.h" |
| |
| /* Defines ps_err_e, struct ps_prochandle. */ |
| #include "gdb_proc_service.h" |
| |
| |
| /* The register sets used in GNU/Linux ELF core-dumps are identical to |
| the register sets in `struct user' that is used for a.out |
| core-dumps, and is also used by `ptrace'. The corresponding types |
| are `elf_gregset_t' for the general-purpose registers (with |
| `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' |
| for the floating-point registers. |
| |
| Those types used to be available under the names `gregset_t' and |
| `fpregset_t' too, and this file used those names in the past. But |
| those names are now used for the register sets used in the |
| `mcontext_t' type, and have a different size and layout. */ |
| |
| /* Mapping between the general-purpose registers in `struct user' |
| format and GDB's register array layout. */ |
| static int regmap[] = |
| { |
| EAX, ECX, EDX, EBX, |
| UESP, EBP, ESI, EDI, |
| EIP, EFL, CS, SS, |
| DS, ES, FS, GS, |
| -1, -1, -1, -1, /* st0, st1, st2, st3 */ |
| -1, -1, -1, -1, /* st4, st5, st6, st7 */ |
| -1, -1, -1, -1, /* fctrl, fstat, ftag, fiseg */ |
| -1, -1, -1, -1, /* fioff, foseg, fooff, fop */ |
| -1, -1, -1, -1, /* xmm0, xmm1, xmm2, xmm3 */ |
| -1, -1, -1, -1, /* xmm4, xmm5, xmm6, xmm6 */ |
| -1, /* mxcsr */ |
| ORIG_EAX |
| }; |
| |
| /* Which ptrace request retrieves which registers? |
| These apply to the corresponding SET requests as well. */ |
| |
| #define GETREGS_SUPPLIES(regno) \ |
| ((0 <= (regno) && (regno) <= 15) || (regno) == I386_LINUX_ORIG_EAX_REGNUM) |
| |
| #define GETFPXREGS_SUPPLIES(regno) \ |
| (I386_ST0_REGNUM <= (regno) && (regno) < I386_SSE_NUM_REGS) |
| |
| /* Does the current host support the GETREGS request? */ |
| int have_ptrace_getregs = |
| #ifdef HAVE_PTRACE_GETREGS |
| 1 |
| #else |
| 0 |
| #endif |
| ; |
| |
| /* Does the current host support the GETFPXREGS 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. |
| |
| 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_getfpxregs = |
| #ifdef HAVE_PTRACE_GETFPXREGS |
| 1 |
| #else |
| 0 |
| #endif |
| ; |
| |
| |
| /* Accessing registers through the U area, one at a time. */ |
| |
| /* Fetch one register. */ |
| |
| static void |
| fetch_register (struct regcache *regcache, int regno) |
| { |
| int tid; |
| int val; |
| |
| gdb_assert (!have_ptrace_getregs); |
| if (regmap[regno] == -1) |
| { |
| regcache_raw_supply (regcache, regno, NULL); |
| return; |
| } |
| |
| /* GNU/Linux LWP ID's are process ID's. */ |
| tid = TIDGET (inferior_ptid); |
| if (tid == 0) |
| tid = PIDGET (inferior_ptid); /* Not a threaded program. */ |
| |
| errno = 0; |
| val = ptrace (PTRACE_PEEKUSER, tid, 4 * regmap[regno], 0); |
| if (errno != 0) |
| error (_("Couldn't read register %s (#%d): %s."), |
| gdbarch_register_name (get_regcache_arch (regcache), regno), |
| regno, safe_strerror (errno)); |
| |
| regcache_raw_supply (regcache, regno, &val); |
| } |
| |
| /* Store one register. */ |
| |
| static void |
| store_register (const struct regcache *regcache, int regno) |
| { |
| int tid; |
| int val; |
| |
| gdb_assert (!have_ptrace_getregs); |
| if (regmap[regno] == -1) |
| return; |
| |
| /* GNU/Linux LWP ID's are process ID's. */ |
| tid = TIDGET (inferior_ptid); |
| if (tid == 0) |
| tid = PIDGET (inferior_ptid); /* Not a threaded program. */ |
| |
| errno = 0; |
| regcache_raw_collect (regcache, regno, &val); |
| ptrace (PTRACE_POKEUSER, tid, 4 * regmap[regno], val); |
| if (errno != 0) |
| error (_("Couldn't write register %s (#%d): %s."), |
| gdbarch_register_name (get_regcache_arch (regcache), regno), |
| regno, safe_strerror (errno)); |
| } |
| |
| |
| /* Transfering the general-purpose registers between GDB, inferiors |
| and core files. */ |
| |
| /* Fill GDB's register array with the general-purpose register values |
| in *GREGSETP. */ |
| |
| void |
| supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp) |
| { |
| const elf_greg_t *regp = (const elf_greg_t *) gregsetp; |
| int i; |
| |
| for (i = 0; i < I386_NUM_GREGS; i++) |
| regcache_raw_supply (regcache, i, regp + regmap[i]); |
| |
| if (I386_LINUX_ORIG_EAX_REGNUM |
| < gdbarch_num_regs (get_regcache_arch (regcache))) |
| regcache_raw_supply (regcache, I386_LINUX_ORIG_EAX_REGNUM, |
| regp + ORIG_EAX); |
| } |
| |
| /* Fill register REGNO (if it is a general-purpose register) in |
| *GREGSETPS with the value in GDB's register array. If REGNO is -1, |
| do this for all registers. */ |
| |
| void |
| fill_gregset (const struct regcache *regcache, |
| elf_gregset_t *gregsetp, int regno) |
| { |
| elf_greg_t *regp = (elf_greg_t *) gregsetp; |
| int i; |
| |
| for (i = 0; i < I386_NUM_GREGS; i++) |
| if (regno == -1 || regno == i) |
| regcache_raw_collect (regcache, i, regp + regmap[i]); |
| |
| if ((regno == -1 || regno == I386_LINUX_ORIG_EAX_REGNUM) |
| && I386_LINUX_ORIG_EAX_REGNUM |
| < gdbarch_num_regs (get_regcache_arch (regcache))) |
| regcache_raw_collect (regcache, I386_LINUX_ORIG_EAX_REGNUM, |
| regp + ORIG_EAX); |
| } |
| |
| #ifdef HAVE_PTRACE_GETREGS |
| |
| /* Fetch all general-purpose registers from process/thread TID and |
| store their values in GDB's register array. */ |
| |
| static void |
| fetch_regs (struct regcache *regcache, int tid) |
| { |
| elf_gregset_t regs; |
| elf_gregset_t *regs_p = ®s; |
| |
| if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) |
| { |
| if (errno == EIO) |
| { |
| /* The kernel we're running on doesn't support the GETREGS |
| request. Reset `have_ptrace_getregs'. */ |
| have_ptrace_getregs = 0; |
| return; |
| } |
| |
| perror_with_name (_("Couldn't get registers")); |
| } |
| |
| supply_gregset (regcache, (const elf_gregset_t *) regs_p); |
| } |
| |
| /* Store all valid general-purpose registers in GDB's register array |
| into the process/thread specified by TID. */ |
| |
| static void |
| store_regs (const struct regcache *regcache, int tid, int regno) |
| { |
| elf_gregset_t regs; |
| |
| if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) |
| perror_with_name (_("Couldn't get registers")); |
| |
| fill_gregset (regcache, ®s, regno); |
| |
| if (ptrace (PTRACE_SETREGS, tid, 0, (int) ®s) < 0) |
| perror_with_name (_("Couldn't write registers")); |
| } |
| |
| #else |
| |
| static void fetch_regs (struct regcache *regcache, int tid) {} |
| static void store_regs (const struct regcache *regcache, int tid, int regno) {} |
| |
| #endif |
| |
| |
| /* Transfering floating-point registers between GDB, inferiors and cores. */ |
| |
| /* Fill GDB's register array with the floating-point register values in |
| *FPREGSETP. */ |
| |
| void |
| supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp) |
| { |
| i387_supply_fsave (regcache, -1, fpregsetp); |
| } |
| |
| /* Fill register REGNO (if it is a floating-point register) in |
| *FPREGSETP with the value in GDB's register array. If REGNO is -1, |
| do this for all registers. */ |
| |
| void |
| fill_fpregset (const struct regcache *regcache, |
| elf_fpregset_t *fpregsetp, int regno) |
| { |
| i387_collect_fsave (regcache, regno, fpregsetp); |
| } |
| |
| #ifdef HAVE_PTRACE_GETREGS |
| |
| /* Fetch all floating-point registers from process/thread TID and store |
| thier values in GDB's register array. */ |
| |
| static void |
| fetch_fpregs (struct regcache *regcache, int tid) |
| { |
| elf_fpregset_t fpregs; |
| |
| if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) |
| perror_with_name (_("Couldn't get floating point status")); |
| |
| supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs); |
| } |
| |
| /* Store all valid floating-point registers in GDB's register array |
| into the process/thread specified by TID. */ |
| |
| static void |
| store_fpregs (const struct regcache *regcache, int tid, int regno) |
| { |
| elf_fpregset_t fpregs; |
| |
| if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) |
| perror_with_name (_("Couldn't get floating point status")); |
| |
| fill_fpregset (regcache, &fpregs, regno); |
| |
| if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0) |
| perror_with_name (_("Couldn't write floating point status")); |
| } |
| |
| #else |
| |
| static void fetch_fpregs (struct regcache *regcache, int tid) {} |
| static void store_fpregs (const struct regcache *regcache, int tid, int regno) {} |
| |
| #endif |
| |
| |
| /* Transfering floating-point and SSE registers to and from GDB. */ |
| |
| #ifdef HAVE_PTRACE_GETFPXREGS |
| |
| /* Fill GDB's register array with the floating-point and SSE register |
| values in *FPXREGSETP. */ |
| |
| void |
| supply_fpxregset (struct regcache *regcache, |
| const elf_fpxregset_t *fpxregsetp) |
| { |
| i387_supply_fxsave (regcache, -1, fpxregsetp); |
| } |
| |
| /* Fill register REGNO (if it is a floating-point or SSE register) in |
| *FPXREGSETP with the value in GDB's register array. If REGNO is |
| -1, do this for all registers. */ |
| |
| void |
| fill_fpxregset (const struct regcache *regcache, |
| elf_fpxregset_t *fpxregsetp, int regno) |
| { |
| i387_collect_fxsave (regcache, regno, fpxregsetp); |
| } |
| |
| /* Fetch all registers covered by the PTRACE_GETFPXREGS request from |
| process/thread TID and store their values in GDB's register array. |
| Return non-zero if successful, zero otherwise. */ |
| |
| static int |
| fetch_fpxregs (struct regcache *regcache, int tid) |
| { |
| elf_fpxregset_t fpxregs; |
| |
| if (! have_ptrace_getfpxregs) |
| return 0; |
| |
| if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) |
| { |
| if (errno == EIO) |
| { |
| have_ptrace_getfpxregs = 0; |
| return 0; |
| } |
| |
| perror_with_name (_("Couldn't read floating-point and SSE registers")); |
| } |
| |
| supply_fpxregset (regcache, (const elf_fpxregset_t *) &fpxregs); |
| return 1; |
| } |
| |
| /* Store all valid registers in GDB's register array covered by the |
| PTRACE_SETFPXREGS request into the process/thread specified by TID. |
| Return non-zero if successful, zero otherwise. */ |
| |
| static int |
| store_fpxregs (const struct regcache *regcache, int tid, int regno) |
| { |
| elf_fpxregset_t fpxregs; |
| |
| if (! have_ptrace_getfpxregs) |
| return 0; |
| |
| if (ptrace (PTRACE_GETFPXREGS, tid, 0, &fpxregs) == -1) |
| { |
| if (errno == EIO) |
| { |
| have_ptrace_getfpxregs = 0; |
| return 0; |
| } |
| |
| perror_with_name (_("Couldn't read floating-point and SSE registers")); |
| } |
| |
| fill_fpxregset (regcache, &fpxregs, regno); |
| |
| if (ptrace (PTRACE_SETFPXREGS, tid, 0, &fpxregs) == -1) |
| perror_with_name (_("Couldn't write floating-point and SSE registers")); |
| |
| return 1; |
| } |
| |
| #else |
| |
| static int fetch_fpxregs (struct regcache *regcache, int tid) { return 0; } |
| static int store_fpxregs (const struct regcache *regcache, int tid, int regno) { return 0; } |
| |
| #endif /* HAVE_PTRACE_GETFPXREGS */ |
| |
| |
| /* Transferring arbitrary registers between GDB and inferior. */ |
| |
| /* Fetch register REGNO from the child process. If REGNO is -1, do |
| this for all registers (including the floating point and SSE |
| registers). */ |
| |
| static void |
| i386_linux_fetch_inferior_registers (struct regcache *regcache, int regno) |
| { |
| int tid; |
| |
| /* Use the old method of peeking around in `struct user' if the |
| GETREGS request isn't available. */ |
| if (!have_ptrace_getregs) |
| { |
| int i; |
| |
| for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++) |
| if (regno == -1 || regno == i) |
| fetch_register (regcache, i); |
| |
| return; |
| } |
| |
| /* GNU/Linux LWP ID's are process ID's. */ |
| tid = TIDGET (inferior_ptid); |
| if (tid == 0) |
| tid = PIDGET (inferior_ptid); /* Not a threaded program. */ |
| |
| /* Use the PTRACE_GETFPXREGS request whenever possible, since it |
| transfers more registers in one system call, and we'll cache the |
| results. But remember that fetch_fpxregs can fail, and return |
| zero. */ |
| if (regno == -1) |
| { |
| fetch_regs (regcache, tid); |
| |
| /* The call above might reset `have_ptrace_getregs'. */ |
| if (!have_ptrace_getregs) |
| { |
| i386_linux_fetch_inferior_registers (regcache, regno); |
| return; |
| } |
| |
| if (fetch_fpxregs (regcache, tid)) |
| return; |
| fetch_fpregs (regcache, tid); |
| return; |
| } |
| |
| if (GETREGS_SUPPLIES (regno)) |
| { |
| fetch_regs (regcache, tid); |
| return; |
| } |
| |
| if (GETFPXREGS_SUPPLIES (regno)) |
| { |
| if (fetch_fpxregs (regcache, 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 (regcache, tid); |
| return; |
| } |
| |
| internal_error (__FILE__, __LINE__, |
| _("Got request for bad register number %d."), regno); |
| } |
| |
| /* Store register REGNO back into the child process. If REGNO is -1, |
| do this for all registers (including the floating point and SSE |
| registers). */ |
| static void |
| i386_linux_store_inferior_registers (struct regcache *regcache, int regno) |
| { |
| int tid; |
| |
| /* Use the old method of poking around in `struct user' if the |
| SETREGS request isn't available. */ |
| if (!have_ptrace_getregs) |
| { |
| int i; |
| |
| for (i = 0; i < gdbarch_num_regs (get_regcache_arch (regcache)); i++) |
| if (regno == -1 || regno == i) |
| store_register (regcache, i); |
| |
| return; |
| } |
| |
| /* GNU/Linux LWP ID's are process ID's. */ |
| tid = TIDGET (inferior_ptid); |
| if (tid == 0) |
| tid = PIDGET (inferior_ptid); /* Not a threaded program. */ |
| |
| /* Use the PTRACE_SETFPXREGS requests whenever possible, since it |
| transfers more registers in one system call. But remember that |
| store_fpxregs can fail, and return zero. */ |
| if (regno == -1) |
| { |
| store_regs (regcache, tid, regno); |
| if (store_fpxregs (regcache, tid, regno)) |
| return; |
| store_fpregs (regcache, tid, regno); |
| return; |
| } |
| |
| if (GETREGS_SUPPLIES (regno)) |
| { |
| store_regs (regcache, tid, regno); |
| return; |
| } |
| |
| if (GETFPXREGS_SUPPLIES (regno)) |
| { |
| if (store_fpxregs (regcache, tid, regno)) |
| 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 (regcache, tid, regno); |
| return; |
| } |
| |
| internal_error (__FILE__, __LINE__, |
| _("Got request to store bad register number %d."), regno); |
| } |
| |
| |
| /* Support for debug registers. */ |
| |
| static unsigned long i386_linux_dr[DR_CONTROL + 1]; |
| |
| static unsigned long |
| i386_linux_dr_get (ptid_t ptid, int regnum) |
| { |
| int tid; |
| unsigned long value; |
| |
| tid = TIDGET (ptid); |
| if (tid == 0) |
| tid = PIDGET (ptid); |
| |
| /* FIXME: kettenis/2001-03-27: Calling perror_with_name if the |
| ptrace call fails breaks debugging remote targets. The correct |
| way to fix this is to add the hardware breakpoint and watchpoint |
| stuff to the target vector. For now, just return zero if the |
| ptrace call fails. */ |
| errno = 0; |
| value = ptrace (PTRACE_PEEKUSER, tid, |
| offsetof (struct user, u_debugreg[regnum]), 0); |
| if (errno != 0) |
| #if 0 |
| perror_with_name (_("Couldn't read debug register")); |
| #else |
| return 0; |
| #endif |
| |
| return value; |
| } |
| |
| static void |
| i386_linux_dr_set (ptid_t ptid, int regnum, unsigned long value) |
| { |
| int tid; |
| |
| tid = TIDGET (ptid); |
| if (tid == 0) |
| tid = PIDGET (ptid); |
| |
| errno = 0; |
| ptrace (PTRACE_POKEUSER, tid, |
| offsetof (struct user, u_debugreg[regnum]), value); |
| if (errno != 0) |
| perror_with_name (_("Couldn't write debug register")); |
| } |
| |
| void |
| i386_linux_dr_set_control (unsigned long control) |
| { |
| struct lwp_info *lp; |
| ptid_t ptid; |
| |
| i386_linux_dr[DR_CONTROL] = control; |
| ALL_LWPS (lp, ptid) |
| i386_linux_dr_set (ptid, DR_CONTROL, control); |
| } |
| |
| void |
| i386_linux_dr_set_addr (int regnum, CORE_ADDR addr) |
| { |
| struct lwp_info *lp; |
| ptid_t ptid; |
| |
| gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR); |
| |
| i386_linux_dr[DR_FIRSTADDR + regnum] = addr; |
| ALL_LWPS (lp, ptid) |
| i386_linux_dr_set (ptid, DR_FIRSTADDR + regnum, addr); |
| } |
| |
| void |
| i386_linux_dr_reset_addr (int regnum) |
| { |
| i386_linux_dr_set_addr (regnum, 0); |
| } |
| |
| unsigned long |
| i386_linux_dr_get_status (void) |
| { |
| return i386_linux_dr_get (inferior_ptid, DR_STATUS); |
| } |
| |
| static void |
| i386_linux_new_thread (ptid_t ptid) |
| { |
| int i; |
| |
| for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) |
| i386_linux_dr_set (ptid, i, i386_linux_dr[i]); |
| |
| i386_linux_dr_set (ptid, DR_CONTROL, i386_linux_dr[DR_CONTROL]); |
| } |
| |
| |
| /* Called by libthread_db. Returns a pointer to the thread local |
| storage (or its descriptor). */ |
| |
| ps_err_e |
| ps_get_thread_area (const struct ps_prochandle *ph, |
| lwpid_t lwpid, int idx, void **base) |
| { |
| /* NOTE: cagney/2003-08-26: The definition of this buffer is found |
| in the kernel header <asm-i386/ldt.h>. It, after padding, is 4 x |
| 4 byte integers in size: `entry_number', `base_addr', `limit', |
| and a bunch of status bits. |
| |
| The values returned by this ptrace call should be part of the |
| regcache buffer, and ps_get_thread_area should channel its |
| request through the regcache. That way remote targets could |
| provide the value using the remote protocol and not this direct |
| call. |
| |
| Is this function needed? I'm guessing that the `base' is the |
| address of a a descriptor that libthread_db uses to find the |
| thread local address base that GDB needs. Perhaps that |
| descriptor is defined by the ABI. Anyway, given that |
| libthread_db calls this function without prompting (gdb |
| requesting tls base) I guess it needs info in there anyway. */ |
| unsigned int desc[4]; |
| gdb_assert (sizeof (int) == 4); |
| |
| #ifndef PTRACE_GET_THREAD_AREA |
| #define PTRACE_GET_THREAD_AREA 25 |
| #endif |
| |
| if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, |
| (void *) idx, (unsigned long) &desc) < 0) |
| return PS_ERR; |
| |
| *(int *)base = desc[1]; |
| return PS_OK; |
| } |
| |
| |
| /* The instruction for a GNU/Linux system call is: |
| int $0x80 |
| or 0xcd 0x80. */ |
| |
| static const unsigned char linux_syscall[] = { 0xcd, 0x80 }; |
| |
| #define LINUX_SYSCALL_LEN (sizeof linux_syscall) |
| |
| /* The system call number is stored in the %eax register. */ |
| #define LINUX_SYSCALL_REGNUM I386_EAX_REGNUM |
| |
| /* We are specifically interested in the sigreturn and rt_sigreturn |
| system calls. */ |
| |
| #ifndef SYS_sigreturn |
| #define SYS_sigreturn 0x77 |
| #endif |
| #ifndef SYS_rt_sigreturn |
| #define SYS_rt_sigreturn 0xad |
| #endif |
| |
| /* Offset to saved processor flags, from <asm/sigcontext.h>. */ |
| #define LINUX_SIGCONTEXT_EFLAGS_OFFSET (64) |
| |
| /* Resume execution of the inferior process. |
| If STEP is nonzero, single-step it. |
| If SIGNAL is nonzero, give it that signal. */ |
| |
| static void |
| i386_linux_resume (ptid_t ptid, int step, enum target_signal signal) |
| { |
| int pid = PIDGET (ptid); |
| |
| int request = PTRACE_CONT; |
| |
| if (step) |
| { |
| struct regcache *regcache = get_thread_regcache (pid_to_ptid (pid)); |
| ULONGEST pc; |
| gdb_byte buf[LINUX_SYSCALL_LEN]; |
| |
| request = PTRACE_SINGLESTEP; |
| |
| regcache_cooked_read_unsigned |
| (regcache, gdbarch_pc_regnum (get_regcache_arch (regcache)), &pc); |
| |
| /* Returning from a signal trampoline is done by calling a |
| special system call (sigreturn or rt_sigreturn, see |
| i386-linux-tdep.c for more information). This system call |
| restores the registers that were saved when the signal was |
| raised, including %eflags. That means that single-stepping |
| won't work. Instead, we'll have to modify the signal context |
| that's about to be restored, and set the trace flag there. */ |
| |
| /* First check if PC is at a system call. */ |
| if (read_memory_nobpt (pc, buf, LINUX_SYSCALL_LEN) == 0 |
| && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0) |
| { |
| ULONGEST syscall; |
| regcache_cooked_read_unsigned (regcache, |
| LINUX_SYSCALL_REGNUM, &syscall); |
| |
| /* Then check the system call number. */ |
| if (syscall == SYS_sigreturn || syscall == SYS_rt_sigreturn) |
| { |
| ULONGEST sp, addr; |
| unsigned long int eflags; |
| |
| regcache_cooked_read_unsigned (regcache, I386_ESP_REGNUM, &sp); |
| if (syscall == SYS_rt_sigreturn) |
| addr = read_memory_integer (sp + 8, 4) + 20; |
| else |
| addr = sp; |
| |
| /* Set the trace flag in the context that's about to be |
| restored. */ |
| addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET; |
| read_memory (addr, (gdb_byte *) &eflags, 4); |
| eflags |= 0x0100; |
| write_memory (addr, (gdb_byte *) &eflags, 4); |
| } |
| } |
| } |
| |
| if (ptrace (request, pid, 0, target_signal_to_host (signal)) == -1) |
| perror_with_name (("ptrace")); |
| } |
| |
| static void (*super_post_startup_inferior) (ptid_t ptid); |
| |
| static void |
| i386_linux_child_post_startup_inferior (ptid_t ptid) |
| { |
| i386_cleanup_dregs (); |
| super_post_startup_inferior (ptid); |
| } |
| |
| void |
| _initialize_i386_linux_nat (void) |
| { |
| struct target_ops *t; |
| |
| /* Fill in the generic GNU/Linux methods. */ |
| t = linux_target (); |
| |
| /* Override the default ptrace resume method. */ |
| t->to_resume = i386_linux_resume; |
| |
| /* Override the GNU/Linux inferior startup hook. */ |
| super_post_startup_inferior = t->to_post_startup_inferior; |
| t->to_post_startup_inferior = i386_linux_child_post_startup_inferior; |
| |
| /* Add our register access methods. */ |
| t->to_fetch_registers = i386_linux_fetch_inferior_registers; |
| t->to_store_registers = i386_linux_store_inferior_registers; |
| |
| /* Register the target. */ |
| linux_nat_add_target (t); |
| linux_nat_set_new_thread (t, i386_linux_new_thread); |
| } |