71 lines
2.8 KiB
C
71 lines
2.8 KiB
C
#ifndef _ASM_X86_DEBUGREG_H
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#define _ASM_X86_DEBUGREG_H
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/* Indicate the register numbers for a number of the specific
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debug registers. Registers 0-3 contain the addresses we wish to trap on */
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#define DR_FIRSTADDR 0 /* u_debugreg[DR_FIRSTADDR] */
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#define DR_LASTADDR 3 /* u_debugreg[DR_LASTADDR] */
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#define DR_STATUS 6 /* u_debugreg[DR_STATUS] */
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#define DR_CONTROL 7 /* u_debugreg[DR_CONTROL] */
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/* Define a few things for the status register. We can use this to determine
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which debugging register was responsible for the trap. The other bits
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are either reserved or not of interest to us. */
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#define DR_TRAP0 (0x1) /* db0 */
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#define DR_TRAP1 (0x2) /* db1 */
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#define DR_TRAP2 (0x4) /* db2 */
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#define DR_TRAP3 (0x8) /* db3 */
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#define DR_STEP (0x4000) /* single-step */
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#define DR_SWITCH (0x8000) /* task switch */
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/* Now define a bunch of things for manipulating the control register.
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The top two bytes of the control register consist of 4 fields of 4
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bits - each field corresponds to one of the four debug registers,
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and indicates what types of access we trap on, and how large the data
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field is that we are looking at */
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#define DR_CONTROL_SHIFT 16 /* Skip this many bits in ctl register */
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#define DR_CONTROL_SIZE 4 /* 4 control bits per register */
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#define DR_RW_EXECUTE (0x0) /* Settings for the access types to trap on */
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#define DR_RW_WRITE (0x1)
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#define DR_RW_READ (0x3)
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#define DR_LEN_1 (0x0) /* Settings for data length to trap on */
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#define DR_LEN_2 (0x4)
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#define DR_LEN_4 (0xC)
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#define DR_LEN_8 (0x8)
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/* The low byte to the control register determine which registers are
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enabled. There are 4 fields of two bits. One bit is "local", meaning
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that the processor will reset the bit after a task switch and the other
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is global meaning that we have to explicitly reset the bit. With linux,
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you can use either one, since we explicitly zero the register when we enter
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kernel mode. */
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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 register */
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#define DR_LOCAL_ENABLE_MASK (0x55) /* Set local bits for all 4 regs */
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#define DR_GLOBAL_ENABLE_MASK (0xAA) /* Set global bits for all 4 regs */
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/* The second byte to the control register has a few special things.
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We can slow the instruction pipeline for instructions coming via the
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gdt or the ldt if we want to. I am not sure why this is an advantage */
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#ifdef __i386__
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#define DR_CONTROL_RESERVED (0xFC00) /* Reserved by Intel */
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#else
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#define DR_CONTROL_RESERVED (0xFFFFFFFF0000FC00UL) /* Reserved */
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#endif
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#define DR_LOCAL_SLOWDOWN (0x100) /* Local slow the pipeline */
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#define DR_GLOBAL_SLOWDOWN (0x200) /* Global slow the pipeline */
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#endif /* _ASM_X86_DEBUGREG_H */
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