| /* HPPA PA-RISC machine native support for BSD, for GDB. |
| Copyright 1991, 1992, 1993, 1994, 1995, 2002 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 2 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, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "somsolib.h" |
| #include "regcache.h" |
| |
| #define U_REGS_OFFSET 0 |
| |
| #define KERNEL_U_ADDR 0 |
| |
| /* What a coincidence! */ |
| #define REGISTER_U_ADDR(addr, blockend, regno) \ |
| { addr = (int)(blockend) + REGISTER_BYTE (regno);} |
| |
| /* 3rd argument to ptrace is supposed to be a caddr_t. */ |
| |
| #define PTRACE_ARG3_TYPE caddr_t |
| |
| /* HPUX 8.0, in its infinite wisdom, has chosen to prototype ptrace |
| with five arguments, so programs written for normal ptrace lose. */ |
| #define FIVE_ARG_PTRACE |
| |
| |
| /* fetch_inferior_registers is in hppab-nat.c. */ |
| #define FETCH_INFERIOR_REGISTERS |
| |
| /* attach/detach works to some extent under BSD and HPUX. So long |
| as the process you're attaching to isn't blocked waiting on io, |
| blocked waiting on a signal, or in a system call things work |
| fine. (The problems in those cases are related to the fact that |
| the kernel can't provide complete register information for the |
| target process... Which really pisses off GDB.) */ |
| |
| #define ATTACH_DETACH |
| |
| /* The PA-BSD kernel has support for using the data memory break bit |
| to implement fast watchpoints. |
| |
| Watchpoints on the PA act much like traditional page protection |
| schemes, but with some notable differences. |
| |
| First, a special bit in the page table entry is used to cause |
| a trap when a specific page is written to. This avoids having |
| to overload watchpoints on the page protection bits. This makes |
| it possible for the kernel to easily decide if a trap was caused |
| by a watchpoint or by the user writing to protected memory and can |
| signal the user program differently in each case. |
| |
| Second, the PA has a bit in the processor status word which causes |
| data memory breakpoints (aka watchpoints) to be disabled for a single |
| instruction. This bit can be used to avoid the overhead of unprotecting |
| and reprotecting pages when it becomes necessary to step over a watchpoint. |
| |
| |
| When the kernel receives a trap indicating a write to a page which |
| is being watched, the kernel performs a couple of simple actions. First |
| is sets the magic "disable memory breakpoint" bit in the processor |
| status word, it then sends a SIGTRAP to the process which caused the |
| trap. |
| |
| GDB will take control and catch the signal for the inferior. GDB then |
| examines the PSW-X bit to determine if the SIGTRAP was caused by a |
| watchpoint firing. If so GDB single steps the inferior over the |
| instruction which caused the watchpoint to trigger (note because the |
| kernel disabled the data memory break bit for one instruction no trap |
| will be taken!). GDB will then determines the appropriate action to |
| take. (this may include restarting the inferior if the watchpoint |
| fired because of a write to an address on the same page as a watchpoint, |
| but no write to the watched address occured). */ |
| |
| #define TARGET_HAS_HARDWARE_WATCHPOINTS /* Enable the code in procfs.c */ |
| |
| /* The PA can watch any number of locations, there's no need for it to reject |
| anything (generic routines already check that all intermediates are |
| in memory). */ |
| #define TARGET_CAN_USE_HARDWARE_WATCHPOINT(type, cnt, ot) \ |
| ((type) == bp_hardware_watchpoint) |
| |
| /* When a hardware watchpoint fires off the PC will be left at the |
| instruction which caused the watchpoint. It will be necessary for |
| GDB to step over the watchpoint. |
| |
| On a PA running BSD, it is trivial to identify when it will be |
| necessary to step over a hardware watchpoint as we can examine |
| the PSW-X bit. If the bit is on, then we trapped because of a |
| watchpoint, else we trapped for some other reason. */ |
| #define STOPPED_BY_WATCHPOINT(W) \ |
| ((W).kind == TARGET_WAITKIND_STOPPED \ |
| && (W).value.sig == TARGET_SIGNAL_TRAP \ |
| && ((int) read_register (IPSW_REGNUM) & 0x00100000)) |
| |
| /* The PA can single step over a watchpoint if the kernel has set the |
| "X" bit in the processor status word (disable data memory breakpoint |
| for one instruction). |
| |
| The kernel will always set this bit before notifying the inferior |
| that it hit a watchpoint. Thus, the inferior can single step over |
| the instruction which caused the watchpoint to fire. This avoids |
| the traditional need to disable the watchpoint, step the inferior, |
| then enable the watchpoint again. */ |
| #define HAVE_STEPPABLE_WATCHPOINT |
| |
| /* Use these macros for watchpoint insertion/deletion. */ |
| /* type can be 0: write watch, 1: read watch, 2: access watch (read/write) */ |
| #define target_insert_watchpoint(addr, len, type) hppa_set_watchpoint (addr, len, 1) |
| #define target_remove_watchpoint(addr, len, type) hppa_set_watchpoint (addr, len, 0) |