Unified support for hardware breakpoints and watchpoints on
x86 targets: * config/i386/nm-i386.h: New file. * config/i386/nm-i386.h: (i386_cleanup_dregs) (i386_insert_watchpoint, i386_remove_watchpoint) (i386_region_ok_for_watchpoint, i386_stopped_by_hwbp) (i386_stopped_data_address, i386_insert_hw_breakpoint) (i386_remove_hw_breakpoint): Declare prototypes. [I386_USE_GENERIC_WATCHPOINTS] (TARGET_CAN_USE_HARDWARE_WATCHPOINT): Define if not already defined. (TARGET_REGION_OK_FOR_HW_WATCHPOINT, HAVE_CONTINUABLE_WATCHPOINT) (STOPPED_BY_WATCHPOINT, target_stopped_data_address) (target_insert_watchpoint, target_remove_watchpoint) (target_insert_hw_breakpoint, target_remove_hw_breakpoint): Define to call the appropriate i386_* functions. * i386-nat.c: New file. * i386-nat.c (I386_DR_CONTROL_MASK, I386_DR_LOCAL_ENABLE) (I386_DR_GLOBAL_ENABLE, I386_DR_DISABLE, I386_DR_SET_RW_LEN) (I386_DR_GET_RW_LEN, I386_DR_WATCH_HIT): New macros. (dr_mirror, dr_status_mirror, dr_control_mirror, dr_ref_count) (maint_show_dr): New variables. (i386_cleanup_dregs, i386_show_dr, i386_length_and_rw_bits) (i386_insert_aligned_watchpoint, i386_remove_aligned_watchpoint) (i386_handle_nonaligned_watchpoint, i386_insert_watchpoint) (i386_remove_watchpoint, i386_region_ok_for_watchpoint) (i386_stopped_data_address, i386_stopped_by_hwbp) (i386_insert_hw_breakpoint, i386_remove_hw_breakpoint): New functions. (_initialize_i386_nat): New function. [I386_USE_GENERIC_WATCHPOINTS]: Add new maint command `show-debug-regs', sets maint_show_dr to non-zero value and activates debugging print-outs in functions which insert, remove, and test watchpoints and hardware breakpoints. * Makefile.in (i386-nat.o): New target. (ALLDEPFILES): Add i386-nat.o.
This commit is contained in:
Eli Zaretskii
parent
28e9e0f00d
commit
52b9821179
@ -1,3 +1,46 @@
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2001-03-21 Eli Zaretskii <eliz@is.elta.co.il>
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Unified support for hardware breakpoints and watchpoints on
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x86 targets:
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* config/i386/nm-i386.h: New file.
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* config/i386/nm-i386.h: (i386_cleanup_dregs)
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(i386_insert_watchpoint, i386_remove_watchpoint)
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(i386_region_ok_for_watchpoint, i386_stopped_by_hwbp)
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(i386_stopped_data_address, i386_insert_hw_breakpoint)
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(i386_remove_hw_breakpoint): Declare prototypes.
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[I386_USE_GENERIC_WATCHPOINTS] (TARGET_CAN_USE_HARDWARE_WATCHPOINT):
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Define if not already defined.
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(TARGET_REGION_OK_FOR_HW_WATCHPOINT, HAVE_CONTINUABLE_WATCHPOINT)
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(STOPPED_BY_WATCHPOINT, target_stopped_data_address)
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(target_insert_watchpoint, target_remove_watchpoint)
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(target_insert_hw_breakpoint, target_remove_hw_breakpoint): Define
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to call the appropriate i386_* functions.
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* i386-nat.c: New file.
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* i386-nat.c (I386_DR_CONTROL_MASK, I386_DR_LOCAL_ENABLE)
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(I386_DR_GLOBAL_ENABLE, I386_DR_DISABLE, I386_DR_SET_RW_LEN)
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(I386_DR_GET_RW_LEN, I386_DR_WATCH_HIT): New macros.
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(dr_mirror, dr_status_mirror, dr_control_mirror, dr_ref_count)
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(maint_show_dr): New variables.
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(i386_cleanup_dregs, i386_show_dr, i386_length_and_rw_bits)
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(i386_insert_aligned_watchpoint, i386_remove_aligned_watchpoint)
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(i386_handle_nonaligned_watchpoint, i386_insert_watchpoint)
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(i386_remove_watchpoint, i386_region_ok_for_watchpoint)
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(i386_stopped_data_address, i386_stopped_by_hwbp)
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(i386_insert_hw_breakpoint, i386_remove_hw_breakpoint): New
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functions.
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(_initialize_i386_nat): New function.
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[I386_USE_GENERIC_WATCHPOINTS]: Add new maint command
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`show-debug-regs', sets maint_show_dr to non-zero value and
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activates debugging print-outs in functions which insert, remove,
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and test watchpoints and hardware breakpoints.
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* Makefile.in (i386-nat.o): New target.
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(ALLDEPFILES): Add i386-nat.o.
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2001-03-21 Mark Kettenis <kettenis@gnu.org>
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* i386-tdep.c: Add back _initialize_i386_tdep prototype with
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@ -1147,7 +1147,7 @@ ALLDEPFILES = 29k-share/udi/udip2soc.c 29k-share/udi/udr.c \
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i386-tdep.c i386b-nat.c i386mach-nat.c i386v-nat.c i386-linux-nat.c \
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i386aix-nat.c i386m3-nat.c i386v4-nat.c i386ly-tdep.c \
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i387-tdep.c \
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i386-linux-tdep.c \
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i386-linux-tdep.c i386-nat.c \
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i960-tdep.c \
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ia64-linux-nat.c ia64-linux-tdep.c ia64-tdep.c \
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infptrace.c inftarg.c irix4-nat.c irix5-nat.c isi-xdep.c \
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@ -1484,6 +1484,8 @@ i386-tdep.o: i386-tdep.c $(defs_h) gdb_string.h $(frame_h) \
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$(inferior_h) $(gdbcore_h) target.h $(floatformat_h) \
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$(symtab_h) $(gdbcmd_h) $(command_h) $(arch_utils_h) $(regcache_h)
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i386-nat.o: i386-nat.c $(defs_h) $(breakpoint_h) $(command_h) $(gdbcmd_h)
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i386aix-nat.o: i386aix-nat.c $(defs_h) $(frame_h) $(inferior_h) \
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language.h $(gdbcore_h) $(floatformat_h) target.h $(regcache_h)
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122
gdb/config/i386/nm-i386.h
Normal file
122
gdb/config/i386/nm-i386.h
Normal file
@ -0,0 +1,122 @@
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/* Native macro definitions for GDB on an Intel i[3456]86.
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Copyright (C) 2001 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 2 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, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef NM_I386_H
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#define NM_I386_H 1
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/* Hardware-assisted breakpoints and watchpoints. */
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/* Targets should define this to use the generic x86 watchpoint support. */
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#ifdef I386_USE_GENERIC_WATCHPOINTS
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#ifndef TARGET_HAS_HARDWARE_WATCHPOINTS
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#define TARGET_HAS_HARDWARE_WATCHPOINTS
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#endif
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/* Clear the reference counts and forget everything we knew about DRi. */
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extern void i386_cleanup_dregs (void);
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/* Insert a watchpoint to watch a memory region which starts at
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address ADDR and whose length is LEN bytes. Watch memory accesses
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of the type TYPE. Return 0 on success, -1 on failure. */
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extern int i386_insert_watchpoint (CORE_ADDR addr, int len, int type);
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/* Remove a watchpoint that watched the memory region which starts at
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address ADDR, whose length is LEN bytes, and for accesses of the
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type TYPE. Return 0 on success, -1 on failure. */
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extern int i386_remove_watchpoint (CORE_ADDR addr, int len, int type);
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/* Return non-zero if we can watch a memory region that starts at
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address ADDR and whose length is LEN bytes. */
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extern int i386_region_ok_for_watchpoint (CORE_ADDR addr, int len);
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/* Return non-zero if the inferior has some break/watchpoint that
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triggered. */
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extern int i386_stopped_by_hwbp (void);
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/* If the inferior has some break/watchpoint that triggered, return
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the address associated with that break/watchpoint. Otherwise,
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return zero. */
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extern CORE_ADDR i386_stopped_data_address (void);
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/* Insert a hardware-assisted breakpoint at address ADDR. SHADOW is
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unused. Return 0 on success, EBUSY on failure. */
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extern int i386_insert_hw_breakpoint (CORE_ADDR addr, void *shadow);
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/* Remove a hardware-assisted breakpoint at address ADDR. SHADOW is
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unused. Return 0 on success, -1 on failure. */
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extern int i386_remove_hw_breakpoint (CORE_ADDR addr, void *shadow);
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/* Returns the number of hardware watchpoints of type TYPE that we can
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set. Value is positive if we can set CNT watchpoints, zero if
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setting watchpoints of type TYPE is not supported, and negative if
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CNT is more than the maximum number of watchpoints of type TYPE
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that we can support. TYPE is one of bp_hardware_watchpoint,
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bp_read_watchpoint, bp_write_watchpoint, or bp_hardware_breakpoint.
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CNT is the number of such watchpoints used so far (including this
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one). OTHERTYPE is non-zero if other types of watchpoints are
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currently enabled.
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We always return 1 here because we don't have enough information
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about possible overlap of addresses that they want to watch. As
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an extreme example, consider the case where all the watchpoints
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watch the same address and the same region length: then we can
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handle a virtually unlimited number of watchpoints, due to debug
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register sharing implemented via reference counts in i386-tdep.c. */
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#define TARGET_CAN_USE_HARDWARE_WATCHPOINT(type, cnt, ot) 1
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/* Returns non-zero if we can use hardware watchpoints to watch a region
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whose address is ADDR and whose length is LEN. */
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#define TARGET_REGION_OK_FOR_HW_WATCHPOINT(addr,len) \
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i386_region_ok_for_watchpoint(addr,len)
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/* After a watchpoint trap, the PC points to the instruction after the
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one that caused the trap. Therefore we don't need to step over it.
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But we do need to reset the status register to avoid another trap. */
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#define HAVE_CONTINUABLE_WATCHPOINT
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#define STOPPED_BY_WATCHPOINT(W) (i386_stopped_data_address () != 0)
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#define target_stopped_data_address() i386_stopped_data_address ()
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/* Use these macros for watchpoint insertion/removal. */
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#define target_insert_watchpoint(addr, len, type) \
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i386_insert_watchpoint (addr, len, type)
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#define target_remove_watchpoint(addr, len, type) \
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i386_remove_watchpoint (addr, len, type)
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#define target_insert_hw_breakpoint(addr, shadow) \
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i386_insert_hw_breakpoint(addr, shadow)
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#define target_remove_hw_breakpoint(addr, shadow) \
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i386_remove_hw_breakpoint(addr, shadow)
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#define DECR_PC_AFTER_HW_BREAK 0
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#endif /* I386_USE_GENERIC_WATCHPOINTS */
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#endif /* NM_I386_H */
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618
gdb/i386-nat.c
Normal file
618
gdb/i386-nat.c
Normal file
@ -0,0 +1,618 @@
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/* Intel x86 (a.k.a. ia32) native-dependent code.
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Copyright (C) 2001 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 2 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, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "breakpoint.h"
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#include "command.h"
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#include "gdbcmd.h"
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/* Support for hardware watchpoints and breakpoints using the x86
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debug registers.
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This provides several functions for inserting and removing
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hardware-assisted breakpoints and watchpoints, testing if
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one or more of the watchpoints triggerd and at what address,
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checking whether a given region can be watched, etc.
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A target which wants to use these functions should define
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several macros, such as `target_insert_watchpoint' and
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`target_stopped_data_address', listed in target.h, to call
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the appropriate functions below. It should also define
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I386_USE_GENERIC_WATCHPOINTS in its tm.h file.
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In addition, each target should provide several low-level
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macros that will be called to insert watchpoints and hardware
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breakpoints into the inferior, remove them, and check their
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status. These macros are:
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I386_DR_LOW_SET_CONTROL -- set the debug control (DR7)
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register to a given value
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I386_DR_LOW_SET_ADDR -- put an address into one debug
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register
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I386_DR_LOW_RESET_ADDR -- reset the address stored in
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one debug register
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I386_DR_LOW_GET_STATUS -- return the value of the debug
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status (DR6) register.
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The functions below implement debug registers sharing by
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reference counts, and allow to watch regions up to 16 bytes
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long. */
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#ifdef I386_USE_GENERIC_WATCHPOINTS
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/* Debug registers' indices. */
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#define DR_NADDR 4 /* the number of debug address registers */
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#define DR_STATUS 6 /* index of debug status register (DR6) */
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#define DR_CONTROL 7 /* index of debug control register (DR7) */
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/* DR7 Debug Control register fields. */
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/* How many bits to skip in DR7 to get to R/W and LEN fields. */
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#define DR_CONTROL_SHIFT 16
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/* How many bits in DR7 per R/W and LEN field for each watchpoint. */
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#define DR_CONTROL_SIZE 4
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/* Watchpoint/breakpoint read/write fields in DR7. */
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#define DR_RW_EXECUTE (0x0) /* break on instruction execution */
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#define DR_RW_WRITE (0x1) /* break on data writes */
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#define DR_RW_READ (0x3) /* break on data reads or writes */
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/* This is here for completeness. No platform supports this
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functionality yet (as of Mar-2001). Note that the DE flag in the
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CR4 register needs to be set to support this. */
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#ifndef DR_RW_IORW
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#define DR_RW_IORW (0x2) /* break on I/O reads or writes */
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#endif
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/* Watchpoint/breakpoint length fields in DR7. The 2-bit left shift
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is so we could OR this with the read/write field defined above. */
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#define DR_LEN_1 (0x0 << 2) /* 1-byte region watch or breakpt */
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#define DR_LEN_2 (0x1 << 2) /* 2-byte region watch */
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#define DR_LEN_4 (0x3 << 2) /* 4-byte region watch */
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/* Local and Global Enable flags in DR7.
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When the Local Enable flag is set, the breakpoint/watchpoint is
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enabled only for the current task; the processor automatically
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clears this flag on every task switch. When the Global Enable
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flag is set, the breakpoint/watchpoint is enabled for all tasks;
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the processor never clears this flag.
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Currently, all watchpoint are locally enabled. If you need to
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enable them globally, read the comment which pertains to this in
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i386_insert_aligned_watchpoint below. */
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#define DR_LOCAL_ENABLE_SHIFT 0 /* extra shift to the local enable bit */
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#define DR_GLOBAL_ENABLE_SHIFT 1 /* extra shift to the global enable bit */
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#define DR_ENABLE_SIZE 2 /* 2 enable bits per debug register */
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/* Local and global exact breakpoint enable flags (a.k.a. slowdown
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flags). These are only required on i386, to allow detection of the
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exact instruction which caused a watchpoint to break; i486 and
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later processors do that automatically. We set these flags for
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back compatibility. */
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#define DR_LOCAL_SLOWDOWN (0x100)
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#define DR_GLOBAL_SLOWDOWN (0x200)
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/* Fields reserved by Intel. This includes the GD (General Detect
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Enable) flag, which causes a debug exception to be generated when a
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MOV instruction accesses one of the debug registers.
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FIXME: My Intel manual says we should use 0xF800, not 0xFC00. */
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#define DR_CONTROL_RESERVED (0xFC00)
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/* Auxiliary helper macros. */
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/* A value that masks all fields in DR7 that are reserved by Intel. */
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#define I386_DR_CONTROL_MASK (~DR_CONTROL_RESERVED)
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/* The I'th debug register is vacant if its Local and Global Enable
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bits are reset in the Debug Control register. */
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#define I386_DR_VACANT(i) \
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((dr_control_mirror & (3 << (DR_ENABLE_SIZE * (i)))) == 0)
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/* Locally enable the break/watchpoint in the I'th debug register. */
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#define I386_DR_LOCAL_ENABLE(i) \
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dr_control_mirror |= (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i)))
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/* Globally enable the break/watchpoint in the I'th debug register. */
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#define I386_DR_GLOBAL_ENABLE(i) \
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dr_control_mirror |= (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i)))
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/* Disable the break/watchpoint in the I'th debug register. */
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#define I386_DR_DISABLE(i) \
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dr_control_mirror &= ~(3 << (DR_ENABLE_SIZE * (i)))
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/* Set in DR7 the RW and LEN fields for the I'th debug register. */
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#define I386_DR_SET_RW_LEN(i,rwlen) \
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do { \
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dr_control_mirror &= ~(0x0f << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \
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dr_control_mirror |= ((rwlen) << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \
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} while (0)
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/* Get from DR7 the RW and LEN fields for the I'th debug register. */
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#define I386_DR_GET_RW_LEN(i) \
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((dr_control_mirror >> (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))) & 0x0f)
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/* Did the watchpoint whose address is in the I'th register break? */
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#define I386_DR_WATCH_HIT(i) (dr_status_mirror & (1 << (i)))
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/* A macro to loop over all debug registers. */
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#define ALL_DEBUG_REGISTERS(i) for (i = 0; i < DR_NADDR; i++)
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/* Mirror the inferior's DRi registers. We keep the status and
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control registers separated because they don't hold addresses. */
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static CORE_ADDR dr_mirror[DR_NADDR];
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static unsigned dr_status_mirror, dr_control_mirror;
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/* Reference counts for each debug register. */
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static int dr_ref_count[DR_NADDR];
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/* Whether or not to print the mirrored debug registers. */
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static int maint_show_dr;
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/* Types of operations supported by i386_handle_nonaligned_watchpoint. */
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typedef enum { WP_INSERT, WP_REMOVE, WP_COUNT } i386_wp_op_t;
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/* Internal functions. */
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/* Return the value of a 4-bit field for DR7 suitable for watching a
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region of LEN bytes for accesses of type TYPE. LEN is assumed
|
||||
to have the value of 1, 2, or 4. */
|
||||
static unsigned i386_length_and_rw_bits (int len, enum target_hw_bp_type type);
|
||||
|
||||
/* Insert a watchpoint at address ADDR, which is assumed to be aligned
|
||||
according to the length of the region to watch. LEN_RW_BITS is the
|
||||
value of the bit-field from DR7 which describes the length and
|
||||
access type of the region to be watched by this watchpoint. Return
|
||||
0 on success, -1 on failure. */
|
||||
static int i386_insert_aligned_watchpoint (CORE_ADDR addr,
|
||||
unsigned len_rw_bits);
|
||||
|
||||
/* Remove a watchpoint at address ADDR, which is assumed to be aligned
|
||||
according to the length of the region to watch. LEN_RW_BITS is the
|
||||
value of the bits from DR7 which describes the length and access
|
||||
type of the region watched by this watchpoint. Return 0 on
|
||||
success, -1 on failure. */
|
||||
static int i386_remove_aligned_watchpoint (CORE_ADDR addr,
|
||||
unsigned len_rw_bits);
|
||||
|
||||
/* Insert or remove a (possibly non-aligned) watchpoint, or count the
|
||||
number of debug registers required to watch a region at address
|
||||
ADDR whose length is LEN for accesses of type TYPE. Return 0 on
|
||||
successful insertion or removal, a positive number when queried
|
||||
about the number of registers, or -1 on failure. If WHAT is not
|
||||
a valid value, bombs through internal_error. */
|
||||
static int i386_handle_nonaligned_watchpoint (i386_wp_op_t what,
|
||||
CORE_ADDR addr, int len,
|
||||
enum target_hw_bp_type type);
|
||||
|
||||
/* Implementation. */
|
||||
|
||||
/* Clear the reference counts and forget everything we knew about
|
||||
the debug registers. */
|
||||
void
|
||||
i386_cleanup_dregs (void)
|
||||
{
|
||||
int i;
|
||||
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
dr_mirror[i] = 0;
|
||||
dr_ref_count[i] = 0;
|
||||
}
|
||||
dr_control_mirror = 0;
|
||||
dr_status_mirror = 0;
|
||||
}
|
||||
|
||||
/* Print the values of the mirrored debug registers.
|
||||
This is called when maint_show_dr is non-zero. To set that
|
||||
up, type "maint show-debug-regs" at GDB's prompt. */
|
||||
static void
|
||||
i386_show_dr (const char *func, CORE_ADDR addr,
|
||||
int len, enum target_hw_bp_type type)
|
||||
{
|
||||
int i;
|
||||
|
||||
puts_unfiltered (func);
|
||||
if (addr || len)
|
||||
printf_unfiltered (" (addr=%lx, len=%d, type=%s)",
|
||||
/* This code is for ia32, so casting CORE_ADDR
|
||||
to unsigned long should be okay. */
|
||||
(unsigned long)addr, len,
|
||||
type == hw_write ? "data-write"
|
||||
: (type == hw_read ? "data-read"
|
||||
: (type == hw_access ? "data-read/write"
|
||||
: (type == hw_execute ? "instruction-execute"
|
||||
/* FIXME: if/when I/O read/write
|
||||
watchpoints are supported, add them
|
||||
here. */
|
||||
: "??unknown??"))));
|
||||
puts_unfiltered (":\n");
|
||||
printf_unfiltered ("\tCONTROL (DR7): %08x STATUS (DR6): %08x\n",
|
||||
dr_control_mirror, dr_status_mirror);
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
printf_unfiltered ("\tDR%d: addr=%08lx, ref.count=%d DR%d: addr=%08lx, ref.count=%d\n",
|
||||
i, dr_mirror[i], dr_ref_count[i],
|
||||
i+1, dr_mirror[i+1], dr_ref_count[i+1]);
|
||||
i++;
|
||||
}
|
||||
}
|
||||
|
||||
/* Return the value of a 4-bit field for DR7 suitable for watching a
|
||||
region of LEN bytes for accesses of type TYPE. LEN is assumed
|
||||
to have the value of 1, 2, or 4. */
|
||||
static unsigned
|
||||
i386_length_and_rw_bits (int len, enum target_hw_bp_type type)
|
||||
{
|
||||
unsigned rw;
|
||||
|
||||
switch (type)
|
||||
{
|
||||
case hw_execute:
|
||||
rw = DR_RW_EXECUTE;
|
||||
break;
|
||||
case hw_write:
|
||||
rw = DR_RW_WRITE;
|
||||
break;
|
||||
case hw_read: /* x86 doesn't support data-read watchpoints */
|
||||
case hw_access:
|
||||
rw = DR_RW_READ;
|
||||
break;
|
||||
#if 0
|
||||
case hw_io_access: /* not yet supported */
|
||||
rw = DR_RW_IORW;
|
||||
break;
|
||||
#endif
|
||||
default:
|
||||
internal_error (__FILE__, __LINE__, "\
|
||||
Invalid hw breakpoint type %d in i386_length_and_rw_bits.\n", (int)type);
|
||||
}
|
||||
|
||||
switch (len)
|
||||
{
|
||||
case 4:
|
||||
return (DR_LEN_4 | rw);
|
||||
case 2:
|
||||
return (DR_LEN_2 | rw);
|
||||
case 1:
|
||||
return (DR_LEN_1 | rw);
|
||||
default:
|
||||
internal_error (__FILE__, __LINE__, "\
|
||||
Invalid hw breakpoint length %d in i386_length_and_rw_bits.\n", len);
|
||||
}
|
||||
}
|
||||
|
||||
/* Insert a watchpoint at address ADDR, which is assumed to be aligned
|
||||
according to the length of the region to watch. LEN_RW_BITS is the
|
||||
value of the bits from DR7 which describes the length and access
|
||||
type of the region to be watched by this watchpoint. Return 0 on
|
||||
success, -1 on failure. */
|
||||
static int
|
||||
i386_insert_aligned_watchpoint (CORE_ADDR addr, unsigned len_rw_bits)
|
||||
{
|
||||
int i;
|
||||
|
||||
/* First, look for an occupied debug register with the same address
|
||||
and the same RW and LEN definitions. If we find one, we can
|
||||
reuse it for this watchpoint as well (and save a register). */
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
if (!I386_DR_VACANT (i)
|
||||
&& dr_mirror[i] == addr
|
||||
&& I386_DR_GET_RW_LEN (i) == len_rw_bits)
|
||||
{
|
||||
dr_ref_count[i]++;
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
|
||||
/* Next, look for a vacant debug register. */
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
if (I386_DR_VACANT (i))
|
||||
break;
|
||||
}
|
||||
|
||||
/* No more debug registers! */
|
||||
if (i >= DR_NADDR)
|
||||
return -1;
|
||||
|
||||
/* Now set up the register I to watch our region. */
|
||||
|
||||
/* Record the info in our local mirrored array. */
|
||||
dr_mirror[i] = addr;
|
||||
dr_ref_count[i] = 1;
|
||||
I386_DR_SET_RW_LEN (i, len_rw_bits);
|
||||
/* Note: we only enable the watchpoint locally, i.e. in the current
|
||||
task. Currently, no x86 target allows or supports global
|
||||
watchpoints; however, if any target would want that in the
|
||||
future, GDB should probably provide a command to control whether
|
||||
to enable watchpoints globally or locally, and the code below
|
||||
should use global or local enable and slow-down flags as
|
||||
appropriate. */
|
||||
I386_DR_LOCAL_ENABLE (i);
|
||||
dr_control_mirror |= DR_LOCAL_SLOWDOWN;
|
||||
dr_control_mirror &= I386_DR_CONTROL_MASK;
|
||||
|
||||
/* Finally, actually pass the info to the inferior. */
|
||||
I386_DR_LOW_SET_CONTROL (dr_control_mirror);
|
||||
I386_DR_LOW_SET_ADDR (i, addr);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Remove a watchpoint at address ADDR, which is assumed to be aligned
|
||||
according to the length of the region to watch. LEN_RW_BITS is the
|
||||
value of the bits from DR7 which describes the length and access
|
||||
type of the region watched by this watchpoint. Return 0 on
|
||||
success, -1 on failure. */
|
||||
static int
|
||||
i386_remove_aligned_watchpoint (CORE_ADDR addr, unsigned len_rw_bits)
|
||||
{
|
||||
int i, retval = -1;
|
||||
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
if (!I386_DR_VACANT (i)
|
||||
&& dr_mirror[i] == addr
|
||||
&& I386_DR_GET_RW_LEN (i) == len_rw_bits)
|
||||
{
|
||||
if (--dr_ref_count[i] == 0) /* no longer in use? */
|
||||
{
|
||||
/* Reset our mirror. */
|
||||
dr_mirror[i] = 0;
|
||||
I386_DR_DISABLE (i);
|
||||
/* Reset it in the inferior. */
|
||||
I386_DR_LOW_RESET_ADDR (i);
|
||||
I386_DR_LOW_SET_CONTROL (dr_control_mirror);
|
||||
}
|
||||
retval = 0;
|
||||
}
|
||||
}
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
/* Insert or remove a (possibly non-aligned) watchpoint, or count the
|
||||
number of debug registers required to watch a region at address
|
||||
ADDR whose length is LEN for accesses of type TYPE. Return 0 on
|
||||
successful insertion or removal, a positive number when queried
|
||||
about the number of registers, or -1 on failure. If WHAT is not
|
||||
a valid value, bombs through internal_error. */
|
||||
static int
|
||||
i386_handle_nonaligned_watchpoint (i386_wp_op_t what, CORE_ADDR addr, int len,
|
||||
enum target_hw_bp_type type)
|
||||
{
|
||||
int align;
|
||||
int size;
|
||||
int rv = 0, status = 0;
|
||||
|
||||
static int size_try_array[4][4] =
|
||||
{
|
||||
{ 1, 1, 1, 1 }, /* trying size one */
|
||||
{ 2, 1, 2, 1 }, /* trying size two */
|
||||
{ 2, 1, 2, 1 }, /* trying size three */
|
||||
{ 4, 1, 2, 1 } /* trying size four */
|
||||
};
|
||||
|
||||
while (len > 0)
|
||||
{
|
||||
align = addr % 4;
|
||||
/* Four is the maximum length an x86 debug register can watch. */
|
||||
size = size_try_array[len > 4 ? 3 : len - 1][align];
|
||||
if (what == WP_COUNT)
|
||||
/* size_try_array[] is defined so that each iteration through
|
||||
the loop is guaranteed to produce an address and a size
|
||||
that can be watched with a single debug register. Thus,
|
||||
for counting the registers required to watch a region, we
|
||||
simply need to increment the count on each iteration. */
|
||||
rv++;
|
||||
else
|
||||
{
|
||||
unsigned len_rw = i386_length_and_rw_bits (size, type);
|
||||
|
||||
if (what == WP_INSERT)
|
||||
status = i386_insert_aligned_watchpoint (addr, len_rw);
|
||||
else if (what == WP_REMOVE)
|
||||
status = i386_remove_aligned_watchpoint (addr, len_rw);
|
||||
else
|
||||
internal_error (__FILE__, __LINE__, "\
|
||||
Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n",
|
||||
(int)what);
|
||||
/* We keep the loop going even after a failure, because some
|
||||
of the other aligned watchpoints might still succeed
|
||||
(e.g. if they watch addresses that are already watched,
|
||||
in which case we just increment the reference counts of
|
||||
occupied debug registers). If we break out of the loop
|
||||
too early, we could cause those addresses watched by
|
||||
other watchpoints to be disabled when breakpoint.c reacts
|
||||
to our failure to insert this watchpoint and tries to
|
||||
remove it. */
|
||||
if (status)
|
||||
rv = status;
|
||||
}
|
||||
addr += size;
|
||||
len -= size;
|
||||
}
|
||||
return rv;
|
||||
}
|
||||
|
||||
/* Insert a watchpoint to watch a memory region which starts at
|
||||
address ADDR and whose length is LEN bytes. Watch memory accesses
|
||||
of the type TYPE. Return 0 on success, -1 on failure. */
|
||||
int
|
||||
i386_insert_watchpoint (CORE_ADDR addr, int len, int type)
|
||||
{
|
||||
int retval;
|
||||
|
||||
if (len == 3 || len > 4 || addr % len != 0)
|
||||
retval = i386_handle_nonaligned_watchpoint (WP_INSERT, addr, len, type);
|
||||
else
|
||||
{
|
||||
unsigned len_rw = i386_length_and_rw_bits (len, type);
|
||||
|
||||
retval = i386_insert_aligned_watchpoint (addr, len_rw);
|
||||
}
|
||||
|
||||
if (maint_show_dr)
|
||||
i386_show_dr ("insert_watchpoint", addr, len, type);
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
/* Remove a watchpoint that watched the memory region which starts at
|
||||
address ADDR, whose length is LEN bytes, and for accesses of the
|
||||
type TYPE. Return 0 on success, -1 on failure. */
|
||||
int
|
||||
i386_remove_watchpoint (CORE_ADDR addr, int len, int type)
|
||||
{
|
||||
int retval;
|
||||
|
||||
if (len == 3 || len > 4 || addr % len != 0)
|
||||
retval = i386_handle_nonaligned_watchpoint (WP_REMOVE, addr, len, type);
|
||||
else
|
||||
{
|
||||
unsigned len_rw = i386_length_and_rw_bits (len, type);
|
||||
|
||||
retval = i386_remove_aligned_watchpoint (addr, len_rw);
|
||||
}
|
||||
|
||||
if (maint_show_dr)
|
||||
i386_show_dr ("remove_watchpoint", addr, len, type);
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
/* Return non-zero if we can watch a memory region that starts at
|
||||
address ADDR and whose length is LEN bytes. */
|
||||
int
|
||||
i386_region_ok_for_watchpoint (CORE_ADDR addr, int len)
|
||||
{
|
||||
/* Compute how many aligned watchpoints we would need to cover this
|
||||
region. */
|
||||
int nregs = i386_handle_nonaligned_watchpoint (WP_COUNT, addr, len,
|
||||
hw_write);
|
||||
|
||||
return nregs <= DR_NADDR ? 1 : 0;
|
||||
}
|
||||
|
||||
/* If the inferior has some watchpoint that triggered, return the
|
||||
address associated with that watchpoint. Otherwise, return
|
||||
zero. */
|
||||
CORE_ADDR
|
||||
i386_stopped_data_address (void)
|
||||
{
|
||||
int i;
|
||||
CORE_ADDR ret = 0;
|
||||
|
||||
dr_status_mirror = I386_DR_LOW_GET_STATUS ();
|
||||
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
if (I386_DR_WATCH_HIT (i)
|
||||
/* This second condition makes sure DRi is set up for a data
|
||||
watchpoint, not a hardware breakpoint. The reason is
|
||||
that GDB doesn't call the target_stopped_data_address
|
||||
method except for data watchpoints. In other words, I'm
|
||||
being paranoiac. */
|
||||
&& I386_DR_GET_RW_LEN (i) != 0)
|
||||
{
|
||||
ret = dr_mirror[i];
|
||||
if (maint_show_dr)
|
||||
i386_show_dr ("watchpoint_hit", ret, -1, hw_write);
|
||||
}
|
||||
}
|
||||
if (maint_show_dr && ret == 0)
|
||||
i386_show_dr ("stopped_data_addr", 0, 0, hw_write);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Return non-zero if the inferior has some break/watchpoint that
|
||||
triggered. */
|
||||
int
|
||||
i386_stopped_by_hwbp (void)
|
||||
{
|
||||
int i;
|
||||
|
||||
dr_status_mirror = I386_DR_LOW_GET_STATUS ();
|
||||
if (maint_show_dr)
|
||||
i386_show_dr ("stopped_by_hwbp", 0, 0, hw_execute);
|
||||
|
||||
ALL_DEBUG_REGISTERS(i)
|
||||
{
|
||||
if (I386_DR_WATCH_HIT (i))
|
||||
return 1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Insert a hardware-assisted breakpoint at address ADDR. SHADOW is
|
||||
unused. Return 0 on success, EBUSY on failure. */
|
||||
int
|
||||
i386_insert_hw_breakpoint (CORE_ADDR addr, void *shadow)
|
||||
{
|
||||
unsigned len_rw = i386_length_and_rw_bits (1, hw_execute);
|
||||
int retval = i386_insert_aligned_watchpoint (addr, len_rw) ? EBUSY : 0;
|
||||
|
||||
if (maint_show_dr)
|
||||
i386_show_dr ("insert_hwbp", addr, 1, hw_execute);
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
/* Remove a hardware-assisted breakpoint at address ADDR. SHADOW is
|
||||
unused. Return 0 on success, -1 on failure. */
|
||||
int
|
||||
i386_remove_hw_breakpoint (CORE_ADDR addr, void *shadow)
|
||||
{
|
||||
unsigned len_rw = i386_length_and_rw_bits (1, hw_execute);
|
||||
int retval = i386_remove_aligned_watchpoint (addr, len_rw);
|
||||
|
||||
if (maint_show_dr)
|
||||
i386_show_dr ("remove_hwbp", addr, 1, hw_execute);
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
#endif /* I386_USE_GENERIC_WATCHPOINTS */
|
||||
|
||||
|
||||
void
|
||||
_initialize_i386_nat (void)
|
||||
{
|
||||
#ifdef I386_USE_GENERIC_WATCHPOINTS
|
||||
/* A maintenance command to enable printing the internal DRi mirror
|
||||
variables. */
|
||||
add_set_cmd ("show-debug-regs", class_maintenance,
|
||||
var_boolean, (char *) &maint_show_dr,
|
||||
"\
|
||||
Set whether to show variables that mirror the x86 debug registers.\n\
|
||||
Use \"on\" to enable, \"off\" to disable.\n\
|
||||
If enabled, the debug registers values are shown when GDB inserts\n\
|
||||
or removes a hardware breakpoint or watchpoint, and when the inferior\n\
|
||||
triggers a breakpoint or watchpoint.", &maintenancelist);
|
||||
#endif
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user