| /* Native-dependent code for GNU/Linux x86 (i386 and x86-64). |
| |
| Copyright (C) 1999-2016 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 "elf/common.h" |
| #include "gdb_proc_service.h" |
| #include "nat/gdb_ptrace.h" |
| #include <sys/user.h> |
| #include <sys/procfs.h> |
| #include <sys/uio.h> |
| |
| #include "x86-nat.h" |
| #include "linux-nat.h" |
| #ifndef __x86_64__ |
| #include "i386-linux-nat.h" |
| #endif |
| #include "x86-linux-nat.h" |
| #include "i386-linux-tdep.h" |
| #ifdef __x86_64__ |
| #include "amd64-linux-tdep.h" |
| #endif |
| #include "x86-xstate.h" |
| #include "nat/linux-btrace.h" |
| #include "nat/linux-nat.h" |
| #include "nat/x86-linux.h" |
| #include "nat/x86-linux-dregs.h" |
| #include "nat/linux-ptrace.h" |
| |
| /* Per-thread arch-specific data we want to keep. */ |
| |
| struct arch_lwp_info |
| { |
| /* Non-zero if our copy differs from what's recorded in the thread. */ |
| int debug_registers_changed; |
| }; |
| |
| |
| |
| /* linux_nat_new_fork hook. */ |
| |
| static void |
| x86_linux_new_fork (struct lwp_info *parent, pid_t child_pid) |
| { |
| pid_t parent_pid; |
| struct x86_debug_reg_state *parent_state; |
| struct x86_debug_reg_state *child_state; |
| |
| /* NULL means no watchpoint has ever been set in the parent. In |
| that case, there's nothing to do. */ |
| if (parent->arch_private == NULL) |
| return; |
| |
| /* Linux kernel before 2.6.33 commit |
| 72f674d203cd230426437cdcf7dd6f681dad8b0d |
| will inherit hardware debug registers from parent |
| on fork/vfork/clone. Newer Linux kernels create such tasks with |
| zeroed debug registers. |
| |
| GDB core assumes the child inherits the watchpoints/hw |
| breakpoints of the parent, and will remove them all from the |
| forked off process. Copy the debug registers mirrors into the |
| new process so that all breakpoints and watchpoints can be |
| removed together. The debug registers mirror will become zeroed |
| in the end before detaching the forked off process, thus making |
| this compatible with older Linux kernels too. */ |
| |
| parent_pid = ptid_get_pid (parent->ptid); |
| parent_state = x86_debug_reg_state (parent_pid); |
| child_state = x86_debug_reg_state (child_pid); |
| *child_state = *parent_state; |
| } |
| |
| |
| static void (*super_post_startup_inferior) (struct target_ops *self, |
| ptid_t ptid); |
| |
| static void |
| x86_linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid) |
| { |
| x86_cleanup_dregs (); |
| super_post_startup_inferior (self, ptid); |
| } |
| |
| #ifdef __x86_64__ |
| /* Value of CS segment register: |
| 64bit process: 0x33 |
| 32bit process: 0x23 */ |
| #define AMD64_LINUX_USER64_CS 0x33 |
| |
| /* Value of DS segment register: |
| LP64 process: 0x0 |
| X32 process: 0x2b */ |
| #define AMD64_LINUX_X32_DS 0x2b |
| #endif |
| |
| /* Get Linux/x86 target description from running target. */ |
| |
| static const struct target_desc * |
| x86_linux_read_description (struct target_ops *ops) |
| { |
| int tid; |
| int is_64bit = 0; |
| #ifdef __x86_64__ |
| int is_x32; |
| #endif |
| static uint64_t xcr0; |
| uint64_t xcr0_features_bits; |
| |
| /* GNU/Linux LWP ID's are process ID's. */ |
| tid = ptid_get_lwp (inferior_ptid); |
| if (tid == 0) |
| tid = ptid_get_pid (inferior_ptid); /* Not a threaded program. */ |
| |
| #ifdef __x86_64__ |
| { |
| unsigned long cs; |
| unsigned long ds; |
| |
| /* Get CS register. */ |
| errno = 0; |
| cs = ptrace (PTRACE_PEEKUSER, tid, |
| offsetof (struct user_regs_struct, cs), 0); |
| if (errno != 0) |
| perror_with_name (_("Couldn't get CS register")); |
| |
| is_64bit = cs == AMD64_LINUX_USER64_CS; |
| |
| /* Get DS register. */ |
| errno = 0; |
| ds = ptrace (PTRACE_PEEKUSER, tid, |
| offsetof (struct user_regs_struct, ds), 0); |
| if (errno != 0) |
| perror_with_name (_("Couldn't get DS register")); |
| |
| is_x32 = ds == AMD64_LINUX_X32_DS; |
| |
| if (sizeof (void *) == 4 && is_64bit && !is_x32) |
| error (_("Can't debug 64-bit process with 32-bit GDB")); |
| } |
| #elif HAVE_PTRACE_GETFPXREGS |
| if (have_ptrace_getfpxregs == -1) |
| { |
| elf_fpxregset_t fpxregs; |
| |
| if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) |
| { |
| have_ptrace_getfpxregs = 0; |
| have_ptrace_getregset = TRIBOOL_FALSE; |
| return tdesc_i386_mmx_linux; |
| } |
| } |
| #endif |
| |
| if (have_ptrace_getregset == TRIBOOL_UNKNOWN) |
| { |
| uint64_t xstateregs[(X86_XSTATE_SSE_SIZE / sizeof (uint64_t))]; |
| struct iovec iov; |
| |
| iov.iov_base = xstateregs; |
| iov.iov_len = sizeof (xstateregs); |
| |
| /* Check if PTRACE_GETREGSET works. */ |
| if (ptrace (PTRACE_GETREGSET, tid, |
| (unsigned int) NT_X86_XSTATE, &iov) < 0) |
| have_ptrace_getregset = TRIBOOL_FALSE; |
| else |
| { |
| have_ptrace_getregset = TRIBOOL_TRUE; |
| |
| /* Get XCR0 from XSAVE extended state. */ |
| xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET |
| / sizeof (uint64_t))]; |
| } |
| } |
| |
| /* Check the native XCR0 only if PTRACE_GETREGSET is available. If |
| PTRACE_GETREGSET is not available then set xcr0_features_bits to |
| zero so that the "no-features" descriptions are returned by the |
| switches below. */ |
| if (have_ptrace_getregset == TRIBOOL_TRUE) |
| xcr0_features_bits = xcr0 & X86_XSTATE_ALL_MASK; |
| else |
| xcr0_features_bits = 0; |
| |
| if (is_64bit) |
| { |
| #ifdef __x86_64__ |
| switch (xcr0_features_bits) |
| { |
| case X86_XSTATE_MPX_AVX512_MASK: |
| case X86_XSTATE_AVX512_MASK: |
| if (is_x32) |
| return tdesc_x32_avx512_linux; |
| else |
| return tdesc_amd64_avx512_linux; |
| case X86_XSTATE_MPX_MASK: |
| if (is_x32) |
| return tdesc_x32_avx_linux; /* No MPX on x32 using AVX. */ |
| else |
| return tdesc_amd64_mpx_linux; |
| case X86_XSTATE_AVX_MPX_MASK: |
| if (is_x32) |
| return tdesc_x32_avx_linux; /* No MPX on x32 using AVX. */ |
| else |
| return tdesc_amd64_avx_mpx_linux; |
| case X86_XSTATE_AVX_MASK: |
| if (is_x32) |
| return tdesc_x32_avx_linux; |
| else |
| return tdesc_amd64_avx_linux; |
| default: |
| if (is_x32) |
| return tdesc_x32_linux; |
| else |
| return tdesc_amd64_linux; |
| } |
| #endif |
| } |
| else |
| { |
| switch (xcr0_features_bits) |
| { |
| case X86_XSTATE_MPX_AVX512_MASK: |
| case X86_XSTATE_AVX512_MASK: |
| return tdesc_i386_avx512_linux; |
| case X86_XSTATE_MPX_MASK: |
| return tdesc_i386_mpx_linux; |
| case X86_XSTATE_AVX_MPX_MASK: |
| return tdesc_i386_avx_mpx_linux; |
| case X86_XSTATE_AVX_MASK: |
| return tdesc_i386_avx_linux; |
| default: |
| return tdesc_i386_linux; |
| } |
| } |
| |
| gdb_assert_not_reached ("failed to return tdesc"); |
| } |
| |
| |
| /* Enable branch tracing. */ |
| |
| static struct btrace_target_info * |
| x86_linux_enable_btrace (struct target_ops *self, ptid_t ptid, |
| const struct btrace_config *conf) |
| { |
| struct btrace_target_info *tinfo; |
| |
| errno = 0; |
| tinfo = linux_enable_btrace (ptid, conf); |
| |
| if (tinfo == NULL) |
| error (_("Could not enable branch tracing for %s: %s."), |
| target_pid_to_str (ptid), safe_strerror (errno)); |
| |
| return tinfo; |
| } |
| |
| /* Disable branch tracing. */ |
| |
| static void |
| x86_linux_disable_btrace (struct target_ops *self, |
| struct btrace_target_info *tinfo) |
| { |
| enum btrace_error errcode = linux_disable_btrace (tinfo); |
| |
| if (errcode != BTRACE_ERR_NONE) |
| error (_("Could not disable branch tracing.")); |
| } |
| |
| /* Teardown branch tracing. */ |
| |
| static void |
| x86_linux_teardown_btrace (struct target_ops *self, |
| struct btrace_target_info *tinfo) |
| { |
| /* Ignore errors. */ |
| linux_disable_btrace (tinfo); |
| } |
| |
| static enum btrace_error |
| x86_linux_read_btrace (struct target_ops *self, |
| struct btrace_data *data, |
| struct btrace_target_info *btinfo, |
| enum btrace_read_type type) |
| { |
| return linux_read_btrace (data, btinfo, type); |
| } |
| |
| /* See to_btrace_conf in target.h. */ |
| |
| static const struct btrace_config * |
| x86_linux_btrace_conf (struct target_ops *self, |
| const struct btrace_target_info *btinfo) |
| { |
| return linux_btrace_conf (btinfo); |
| } |
| |
| |
| |
| /* Helper for ps_get_thread_area. Sets BASE_ADDR to a pointer to |
| the thread local storage (or its descriptor) and returns PS_OK |
| on success. Returns PS_ERR on failure. */ |
| |
| ps_err_e |
| x86_linux_get_thread_area (pid_t pid, void *addr, unsigned int *base_addr) |
| { |
| /* 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 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]; |
| |
| /* This code assumes that "int" is 32 bits and that |
| GET_THREAD_AREA returns no more than 4 int values. */ |
| gdb_assert (sizeof (int) == 4); |
| |
| #ifndef PTRACE_GET_THREAD_AREA |
| #define PTRACE_GET_THREAD_AREA 25 |
| #endif |
| |
| if (ptrace (PTRACE_GET_THREAD_AREA, pid, addr, &desc) < 0) |
| return PS_ERR; |
| |
| *base_addr = desc[1]; |
| return PS_OK; |
| } |
| |
| |
| /* Create an x86 GNU/Linux target. */ |
| |
| struct target_ops * |
| x86_linux_create_target (void) |
| { |
| /* Fill in the generic GNU/Linux methods. */ |
| struct target_ops *t = linux_target (); |
| |
| /* Initialize the debug register function vectors. */ |
| x86_use_watchpoints (t); |
| x86_dr_low.set_control = x86_linux_dr_set_control; |
| x86_dr_low.set_addr = x86_linux_dr_set_addr; |
| x86_dr_low.get_addr = x86_linux_dr_get_addr; |
| x86_dr_low.get_status = x86_linux_dr_get_status; |
| x86_dr_low.get_control = x86_linux_dr_get_control; |
| x86_set_debug_register_length (sizeof (void *)); |
| |
| /* Override the GNU/Linux inferior startup hook. */ |
| super_post_startup_inferior = t->to_post_startup_inferior; |
| t->to_post_startup_inferior = x86_linux_child_post_startup_inferior; |
| |
| /* Add the description reader. */ |
| t->to_read_description = x86_linux_read_description; |
| |
| /* Add btrace methods. */ |
| t->to_supports_btrace = linux_supports_btrace; |
| t->to_enable_btrace = x86_linux_enable_btrace; |
| t->to_disable_btrace = x86_linux_disable_btrace; |
| t->to_teardown_btrace = x86_linux_teardown_btrace; |
| t->to_read_btrace = x86_linux_read_btrace; |
| t->to_btrace_conf = x86_linux_btrace_conf; |
| |
| return t; |
| } |
| |
| /* Add an x86 GNU/Linux target. */ |
| |
| void |
| x86_linux_add_target (struct target_ops *t) |
| { |
| linux_nat_add_target (t); |
| linux_nat_set_new_thread (t, x86_linux_new_thread); |
| linux_nat_set_new_fork (t, x86_linux_new_fork); |
| linux_nat_set_forget_process (t, x86_forget_process); |
| linux_nat_set_prepare_to_resume (t, x86_linux_prepare_to_resume); |
| } |