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Diffstat (limited to 'libc/sysdeps/linux/i386/sys/debugreg.h')
| -rw-r--r-- | libc/sysdeps/linux/i386/sys/debugreg.h | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/i386/sys/debugreg.h b/libc/sysdeps/linux/i386/sys/debugreg.h new file mode 100644 index 000000000..c99c94359 --- /dev/null +++ b/libc/sysdeps/linux/i386/sys/debugreg.h @@ -0,0 +1,91 @@ +/* Copyright (C) 1998, 2000 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#ifndef _SYS_DEBUGREG_H +#define _SYS_DEBUGREG_H 1 + +/* Indicate the register numbers for a number of the specific + debug registers. Registers 0-3 contain the addresses we wish to trap on */ +#define DR_FIRSTADDR 0 /* u_debugreg[DR_FIRSTADDR] */ +#define DR_LASTADDR 3 /* u_debugreg[DR_LASTADDR] */ + +#define DR_STATUS 6 /* u_debugreg[DR_STATUS] */ +#define DR_CONTROL 7 /* u_debugreg[DR_CONTROL] */ + +/* Define a few things for the status register. We can use this to determine + which debugging register was responsible for the trap. The other bits + are either reserved or not of interest to us. */ + +#define DR_TRAP0 (0x1) /* db0 */ +#define DR_TRAP1 (0x2) /* db1 */ +#define DR_TRAP2 (0x4) /* db2 */ +#define DR_TRAP3 (0x8) /* db3 */ + +#define DR_STEP (0x4000) /* single-step */ +#define DR_SWITCH (0x8000) /* task switch */ + +/* Now define a bunch of things for manipulating the control register. + The top two bytes of the control register consist of 4 fields of 4 + bits - each field corresponds to one of the four debug registers, + and indicates what types of access we trap on, and how large the data + field is that we are looking at */ + +#define DR_CONTROL_SHIFT 16 /* Skip this many bits in ctl register */ +#define DR_CONTROL_SIZE 4 /* 4 control bits per register */ + +#define DR_RW_EXECUTE (0x0) /* Settings for the access types to trap on */ +#define DR_RW_WRITE (0x1) +#define DR_RW_READ (0x3) + +#define DR_LEN_1 (0x0) /* Settings for data length to trap on */ +#define DR_LEN_2 (0x4) +#define DR_LEN_4 (0xC) + +/* The low byte to the control register determine which registers are + enabled. There are 4 fields of two bits. One bit is "local", meaning + that the processor will reset the bit after a task switch and the other + is global meaning that we have to explicitly reset the bit. With linux, + you can use either one, since we explicitly zero the register when we enter + kernel mode. */ + +#define DR_LOCAL_ENABLE_SHIFT 0 /* Extra shift to the local enable bit */ +#define DR_GLOBAL_ENABLE_SHIFT 1 /* Extra shift to the global enable bit */ +#define DR_ENABLE_SIZE 2 /* 2 enable bits per register */ + +#define DR_LOCAL_ENABLE_MASK (0x55) /* Set local bits for all 4 regs */ +#define DR_GLOBAL_ENABLE_MASK (0xAA) /* Set global bits for all 4 regs */ + +/* The second byte to the control register has a few special things. + + On the i386, you should set the DR_LOCAL_SLOWDOWN or + DR_GLOBAL_SLOWDOWN bits if you want to know exactly which + instruction triggered the watchpoint. Setting these bits causes + the processor to run more slowly, but leaving them clear makes it + treat watchpoint hits as imprecise exceptions, so you can't + reliably determine which instruction caused the hit. + + The i486 and all later IA-32 processors ignore DR_LOCAL_SLOWDOWN + and DR_GLOBAL_SLOWDOWN. They always report the exception + precisely, except in some rare cases, which the user can't do + anything about. */ + +#define DR_CONTROL_RESERVED (0xFC00) /* Reserved by Intel */ +#define DR_LOCAL_SLOWDOWN (0x100) /* Local slow the pipeline */ +#define DR_GLOBAL_SLOWDOWN (0x200) /* Global slow the pipeline */ + +#endif /* sys/debugreg.h */ |