407 lines
11 KiB
C
407 lines
11 KiB
C
/* Native-dependent code for GNU/Linux x86 (i386 and x86-64).
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Copyright (C) 1999-2015 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "inferior.h"
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#include "elf/common.h"
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#include "gdb_proc_service.h"
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#include <sys/ptrace.h>
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#include <sys/user.h>
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#include <sys/procfs.h>
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#include <sys/uio.h>
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#include "x86-nat.h"
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#include "linux-nat.h"
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#ifndef __x86_64__
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#include "i386-linux-nat.h"
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#endif
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#include "x86-linux-nat.h"
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#include "i386-linux-tdep.h"
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#ifdef __x86_64__
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#include "amd64-linux-tdep.h"
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#endif
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#include "x86-xstate.h"
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#include "nat/linux-btrace.h"
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#include "nat/linux-nat.h"
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#include "nat/x86-linux.h"
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#include "nat/x86-linux-dregs.h"
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/* Per-thread arch-specific data we want to keep. */
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struct arch_lwp_info
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{
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/* Non-zero if our copy differs from what's recorded in the thread. */
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int debug_registers_changed;
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};
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/* Does the current host support PTRACE_GETREGSET? */
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int have_ptrace_getregset = -1;
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/* linux_nat_new_fork hook. */
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static void
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x86_linux_new_fork (struct lwp_info *parent, pid_t child_pid)
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{
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pid_t parent_pid;
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struct x86_debug_reg_state *parent_state;
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struct x86_debug_reg_state *child_state;
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/* NULL means no watchpoint has ever been set in the parent. In
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that case, there's nothing to do. */
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if (parent->arch_private == NULL)
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return;
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/* Linux kernel before 2.6.33 commit
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72f674d203cd230426437cdcf7dd6f681dad8b0d
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will inherit hardware debug registers from parent
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on fork/vfork/clone. Newer Linux kernels create such tasks with
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zeroed debug registers.
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GDB core assumes the child inherits the watchpoints/hw
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breakpoints of the parent, and will remove them all from the
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forked off process. Copy the debug registers mirrors into the
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new process so that all breakpoints and watchpoints can be
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removed together. The debug registers mirror will become zeroed
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in the end before detaching the forked off process, thus making
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this compatible with older Linux kernels too. */
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parent_pid = ptid_get_pid (parent->ptid);
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parent_state = x86_debug_reg_state (parent_pid);
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child_state = x86_debug_reg_state (child_pid);
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*child_state = *parent_state;
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}
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static void (*super_post_startup_inferior) (struct target_ops *self,
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ptid_t ptid);
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static void
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x86_linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
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{
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x86_cleanup_dregs ();
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super_post_startup_inferior (self, ptid);
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}
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#ifdef __x86_64__
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/* Value of CS segment register:
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64bit process: 0x33
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32bit process: 0x23 */
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#define AMD64_LINUX_USER64_CS 0x33
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/* Value of DS segment register:
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LP64 process: 0x0
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X32 process: 0x2b */
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#define AMD64_LINUX_X32_DS 0x2b
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#endif
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/* Get Linux/x86 target description from running target. */
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static const struct target_desc *
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x86_linux_read_description (struct target_ops *ops)
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{
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int tid;
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int is_64bit = 0;
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#ifdef __x86_64__
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int is_x32;
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#endif
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static uint64_t xcr0;
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uint64_t xcr0_features_bits;
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/* GNU/Linux LWP ID's are process ID's. */
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tid = ptid_get_lwp (inferior_ptid);
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if (tid == 0)
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tid = ptid_get_pid (inferior_ptid); /* Not a threaded program. */
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#ifdef __x86_64__
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{
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unsigned long cs;
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unsigned long ds;
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/* Get CS register. */
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errno = 0;
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cs = ptrace (PTRACE_PEEKUSER, tid,
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offsetof (struct user_regs_struct, cs), 0);
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if (errno != 0)
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perror_with_name (_("Couldn't get CS register"));
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is_64bit = cs == AMD64_LINUX_USER64_CS;
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/* Get DS register. */
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errno = 0;
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ds = ptrace (PTRACE_PEEKUSER, tid,
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offsetof (struct user_regs_struct, ds), 0);
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if (errno != 0)
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perror_with_name (_("Couldn't get DS register"));
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is_x32 = ds == AMD64_LINUX_X32_DS;
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if (sizeof (void *) == 4 && is_64bit && !is_x32)
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error (_("Can't debug 64-bit process with 32-bit GDB"));
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}
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#elif HAVE_PTRACE_GETFPXREGS
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if (have_ptrace_getfpxregs == -1)
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{
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elf_fpxregset_t fpxregs;
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if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0)
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{
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have_ptrace_getfpxregs = 0;
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have_ptrace_getregset = 0;
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return tdesc_i386_mmx_linux;
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}
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}
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#endif
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if (have_ptrace_getregset == -1)
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{
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uint64_t xstateregs[(X86_XSTATE_SSE_SIZE / sizeof (uint64_t))];
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struct iovec iov;
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iov.iov_base = xstateregs;
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iov.iov_len = sizeof (xstateregs);
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/* Check if PTRACE_GETREGSET works. */
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if (ptrace (PTRACE_GETREGSET, tid,
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(unsigned int) NT_X86_XSTATE, &iov) < 0)
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have_ptrace_getregset = 0;
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else
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{
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have_ptrace_getregset = 1;
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/* Get XCR0 from XSAVE extended state. */
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xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
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/ sizeof (uint64_t))];
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}
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}
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/* Check the native XCR0 only if PTRACE_GETREGSET is available. If
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PTRACE_GETREGSET is not available then set xcr0_features_bits to
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zero so that the "no-features" descriptions are returned by the
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switches below. */
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if (have_ptrace_getregset)
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xcr0_features_bits = xcr0 & X86_XSTATE_ALL_MASK;
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else
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xcr0_features_bits = 0;
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if (is_64bit)
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{
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#ifdef __x86_64__
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switch (xcr0_features_bits)
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{
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case X86_XSTATE_MPX_AVX512_MASK:
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case X86_XSTATE_AVX512_MASK:
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if (is_x32)
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return tdesc_x32_avx512_linux;
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else
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return tdesc_amd64_avx512_linux;
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case X86_XSTATE_MPX_MASK:
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if (is_x32)
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return tdesc_x32_avx_linux; /* No MPX on x32 using AVX. */
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else
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return tdesc_amd64_mpx_linux;
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case X86_XSTATE_AVX_MASK:
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if (is_x32)
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return tdesc_x32_avx_linux;
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else
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return tdesc_amd64_avx_linux;
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default:
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if (is_x32)
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return tdesc_x32_linux;
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else
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return tdesc_amd64_linux;
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}
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#endif
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}
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else
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{
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switch (xcr0_features_bits)
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{
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case X86_XSTATE_MPX_AVX512_MASK:
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case X86_XSTATE_AVX512_MASK:
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return tdesc_i386_avx512_linux;
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case X86_XSTATE_MPX_MASK:
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return tdesc_i386_mpx_linux;
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case X86_XSTATE_AVX_MASK:
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return tdesc_i386_avx_linux;
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default:
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return tdesc_i386_linux;
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}
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}
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gdb_assert_not_reached ("failed to return tdesc");
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}
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/* Enable branch tracing. */
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static struct btrace_target_info *
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x86_linux_enable_btrace (struct target_ops *self, ptid_t ptid,
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const struct btrace_config *conf)
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{
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struct btrace_target_info *tinfo;
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struct gdbarch *gdbarch;
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errno = 0;
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tinfo = linux_enable_btrace (ptid, conf);
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if (tinfo == NULL)
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error (_("Could not enable branch tracing for %s: %s."),
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target_pid_to_str (ptid), safe_strerror (errno));
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/* Fill in the size of a pointer in bits. */
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if (tinfo->ptr_bits == 0)
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{
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gdbarch = target_thread_architecture (ptid);
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tinfo->ptr_bits = gdbarch_ptr_bit (gdbarch);
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}
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return tinfo;
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}
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/* Disable branch tracing. */
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static void
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x86_linux_disable_btrace (struct target_ops *self,
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struct btrace_target_info *tinfo)
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{
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enum btrace_error errcode = linux_disable_btrace (tinfo);
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if (errcode != BTRACE_ERR_NONE)
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error (_("Could not disable branch tracing."));
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}
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/* Teardown branch tracing. */
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static void
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x86_linux_teardown_btrace (struct target_ops *self,
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struct btrace_target_info *tinfo)
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{
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/* Ignore errors. */
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linux_disable_btrace (tinfo);
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}
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static enum btrace_error
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x86_linux_read_btrace (struct target_ops *self,
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struct btrace_data *data,
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struct btrace_target_info *btinfo,
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enum btrace_read_type type)
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{
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return linux_read_btrace (data, btinfo, type);
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}
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/* See to_btrace_conf in target.h. */
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static const struct btrace_config *
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x86_linux_btrace_conf (struct target_ops *self,
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const struct btrace_target_info *btinfo)
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{
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return linux_btrace_conf (btinfo);
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}
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/* Helper for ps_get_thread_area. Sets BASE_ADDR to a pointer to
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the thread local storage (or its descriptor) and returns PS_OK
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on success. Returns PS_ERR on failure. */
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ps_err_e
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x86_linux_get_thread_area (pid_t pid, void *addr, unsigned int *base_addr)
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{
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/* NOTE: cagney/2003-08-26: The definition of this buffer is found
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in the kernel header <asm-i386/ldt.h>. It, after padding, is 4 x
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4 byte integers in size: `entry_number', `base_addr', `limit',
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and a bunch of status bits.
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The values returned by this ptrace call should be part of the
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regcache buffer, and ps_get_thread_area should channel its
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request through the regcache. That way remote targets could
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provide the value using the remote protocol and not this direct
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call.
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Is this function needed? I'm guessing that the `base' is the
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address of a descriptor that libthread_db uses to find the
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thread local address base that GDB needs. Perhaps that
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descriptor is defined by the ABI. Anyway, given that
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libthread_db calls this function without prompting (gdb
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requesting tls base) I guess it needs info in there anyway. */
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unsigned int desc[4];
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/* This code assumes that "int" is 32 bits and that
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GET_THREAD_AREA returns no more than 4 int values. */
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gdb_assert (sizeof (int) == 4);
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#ifndef PTRACE_GET_THREAD_AREA
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#define PTRACE_GET_THREAD_AREA 25
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#endif
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if (ptrace (PTRACE_GET_THREAD_AREA, pid, addr, &desc) < 0)
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return PS_ERR;
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*base_addr = desc[1];
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return PS_OK;
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}
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/* Create an x86 GNU/Linux target. */
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struct target_ops *
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x86_linux_create_target (void)
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{
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/* Fill in the generic GNU/Linux methods. */
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struct target_ops *t = linux_target ();
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/* Initialize the debug register function vectors. */
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x86_use_watchpoints (t);
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x86_dr_low.set_control = x86_linux_dr_set_control;
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x86_dr_low.set_addr = x86_linux_dr_set_addr;
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x86_dr_low.get_addr = x86_linux_dr_get_addr;
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x86_dr_low.get_status = x86_linux_dr_get_status;
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x86_dr_low.get_control = x86_linux_dr_get_control;
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x86_set_debug_register_length (sizeof (void *));
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/* Override the GNU/Linux inferior startup hook. */
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super_post_startup_inferior = t->to_post_startup_inferior;
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t->to_post_startup_inferior = x86_linux_child_post_startup_inferior;
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/* Add the description reader. */
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t->to_read_description = x86_linux_read_description;
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/* Add btrace methods. */
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t->to_supports_btrace = linux_supports_btrace;
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t->to_enable_btrace = x86_linux_enable_btrace;
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t->to_disable_btrace = x86_linux_disable_btrace;
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t->to_teardown_btrace = x86_linux_teardown_btrace;
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t->to_read_btrace = x86_linux_read_btrace;
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t->to_btrace_conf = x86_linux_btrace_conf;
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return t;
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}
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/* Add an x86 GNU/Linux target. */
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void
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x86_linux_add_target (struct target_ops *t)
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{
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linux_nat_add_target (t);
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linux_nat_set_new_thread (t, x86_linux_new_thread);
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linux_nat_set_new_fork (t, x86_linux_new_fork);
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linux_nat_set_forget_process (t, x86_forget_process);
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linux_nat_set_prepare_to_resume (t, x86_linux_prepare_to_resume);
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}
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