012b3a217a
With Intel Memory Protection Extensions it was introduced the concept of
boundary violation. A boundary violations is presented to the inferior as
a segmentation fault having SIGCODE 3. This patch adds a
handler for a boundary violation extending the information displayed
when a bound violation is presented to the inferior. In the stop mode
case the debugger will also display the kind of violation: "upper" or
"lower", bounds and the address accessed.
On no stop mode the information will still remain unchanged. Additional
information about bound violations are not meaningful in that case user
does not know the line in which violation occurred as well.
When the segmentation fault handler is stop mode the out puts will be
changed as exemplified below.
The usual output of a segfault is:
Program received signal SIGSEGV, Segmentation fault
0x0000000000400d7c in upper (p=0x603010, a=0x603030, b=0x603050,
c=0x603070, d=0x603090, len=7) at i386-mpx-sigsegv.c:68
68 value = *(p + len);
In case it is a bound violation it will be presented as:
Program received signal SIGSEGV, Segmentation fault
Upper bound violation while accessing address 0x7fffffffc3b3
Bounds: [lower = 0x7fffffffc390, upper = 0x7fffffffc3a3]
0x0000000000400d7c in upper (p=0x603010, a=0x603030, b=0x603050,
c=0x603070, d=0x603090, len=7) at i386-mpx-sigsegv.c:68
68 value = *(p + len);
In mi mode the output of a segfault is:
*stopped,reason="signal-received",signal-name="SIGSEGV",
signal-meaning="Segmentation fault", frame={addr="0x0000000000400d7c",
func="upper",args=[{name="p", value="0x603010"},{name="a",value="0x603030"}
,{name="b",value="0x603050"}, {name="c",value="0x603070"},
{name="d",value="0x603090"},{name="len",value="7"}],
file="i386-mpx-sigsegv.c",fullname="i386-mpx-sigsegv.c",line="68"},
thread-id="1",stopped-threads="all",core="6"
in the case of a bound violation:
*stopped,reason="signal-received",signal-name="SIGSEGV",
signal-meaning="Segmentation fault",
sigcode-meaning="Upper bound violation",
lower-bound="0x603010",upper-bound="0x603023",bound-access="0x60302f",
frame={addr="0x0000000000400d7c",func="upper",args=[{name="p",
value="0x603010"},{name="a",value="0x603030"},{name="b",value="0x603050"},
{name="c",value="0x603070"},{name="d",value="0x603090"},
{name="len",value="7"}],file="i386-mpx-sigsegv.c",
fullname="i386-mpx-sigsegv.c",line="68"},thread-id="1",
stopped-threads="all",core="6"
2016-02-18 Walfred Tedeschi <walfred.tedeschi@intel.com>
gdb/ChangeLog:
* NEWS: Add entry for bound violation.
* amd64-linux-tdep.c (amd64_linux_init_abi_common):
Add handler for segmentation fault.
* gdbarch.sh (handle_segmentation_fault): New.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* i386-linux-tdep.c (i386_linux_handle_segmentation_fault): New.
(SIG_CODE_BONDARY_FAULT): New define.
(i386_linux_init_abi): Use i386_mpx_bound_violation_handler.
* i386-linux-tdep.h (i386_linux_handle_segmentation_fault) New.
* i386-tdep.c (i386_mpx_enabled): Add as external.
* i386-tdep.c (i386_mpx_enabled): Add as external.
* infrun.c (handle_segmentation_fault): New function.
(print_signal_received_reason): Use handle_segmentation_fault.
gdb/testsuite/ChangeLog:
* gdb.arch/i386-mpx-sigsegv.c: New file.
* gdb.arch/i386-mpx-sigsegv.exp: New file.
* gdb.arch/i386-mpx-simple_segv.c: New file.
* gdb.arch/i386-mpx-simple_segv.exp: New file.
gdb/doc/ChangeLog:
* gdb.texinfo (Signals): Add bound violation display hints for
a SIGSEGV.
83 lines
3.1 KiB
C
83 lines
3.1 KiB
C
/* Target-dependent code for GNU/Linux x86.
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Copyright (C) 2002-2016 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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#ifndef I386_LINUX_TDEP_H
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#define I386_LINUX_TDEP_H
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/* The Linux kernel pretends there is an additional "orig_eax"
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register. Since GDB needs access to that register to be able to
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properly restart system calls when necessary (see
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i386-linux-tdep.c) we need our own versions of a number of
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functions that deal with GDB's register cache. */
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/* Register number for the "orig_eax" pseudo-register. If this
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pseudo-register contains a value >= 0 it is interpreted as the
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system call number that the kernel is supposed to restart. */
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#define I386_LINUX_ORIG_EAX_REGNUM (I386_ZMM7H_REGNUM + 1)
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/* Total number of registers for GNU/Linux. */
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#define I386_LINUX_NUM_REGS (I386_LINUX_ORIG_EAX_REGNUM + 1)
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/* Get XSAVE extended state xcr0 from core dump. */
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extern uint64_t i386_linux_core_read_xcr0 (bfd *abfd);
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/* Handle and display information related to the MPX bound violation
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to the user. */
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extern void i386_linux_handle_segmentation_fault (struct gdbarch *gdbarch,
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struct ui_out *uiout);
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/* Linux target description. */
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extern struct target_desc *tdesc_i386_linux;
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extern struct target_desc *tdesc_i386_mmx_linux;
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extern struct target_desc *tdesc_i386_avx_linux;
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extern struct target_desc *tdesc_i386_mpx_linux;
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extern struct target_desc *tdesc_i386_avx512_linux;
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/* Format of XSAVE extended state is:
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struct
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{
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fxsave_bytes[0..463]
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sw_usable_bytes[464..511]
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xstate_hdr_bytes[512..575]
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avx_bytes[576..831]
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mpx_bytes [960..1032]
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avx512_k_regs[1088..1152]
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avx512_zmmh_regs0-7[1153..1407]
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avx512_zmmh_regs8-15[1408..1663]
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avx512_zmm_regs16-31[1664..2687]
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future_state etc
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};
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Same memory layout will be used for the coredump NT_X86_XSTATE
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representing the XSAVE extended state registers.
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The first 8 bytes of the sw_usable_bytes[464..467] is the OS enabled
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extended state mask, which is the same as the extended control register
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0 (the XFEATURE_ENABLED_MASK register), XCR0. We can use this mask
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together with the mask saved in the xstate_hdr_bytes to determine what
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states the processor/OS supports and what state, used or initialized,
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the process/thread is in. */
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#define I386_LINUX_XSAVE_XCR0_OFFSET 464
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extern int i386_linux_gregset_reg_offset[];
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/* Return x86 siginfo type. */
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extern struct type *x86_linux_get_siginfo_type (struct gdbarch *gdbarch);
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#endif /* i386-linux-tdep.h */
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