--- /dev/null
+# Copyright (c) 2008 The Regents of The University of Michigan
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Authors: Gabe Black
+
+microcode = '''
+def rom
+{
+ # This vectors the CPU into an interrupt handler in long mode.
+ # On entry, t1 is set to the vector of the interrupt and t7 is the current
+ # ip. We need that because rdip returns the next ip.
+ extern longModeInterrupt:
+
+ #
+ # Get the 64 bit interrupt or trap gate descriptor from the IDT
+ #
+
+ # Load the gate descriptor from the IDT
+ slli t4, t1, 4, dataSize=8
+ ld t2, idtr, [1, t0, t4], 8, dataSize=8, addressSize=8
+ ld t4, idtr, [1, t0, t4], dataSize=8, addressSize=8
+
+ # Check permissions
+ chks t1, t4, IntGateCheck
+
+ mov t1, t1, t4, dataSize=8
+
+ # Check that it's the right type
+ srli t4, t1, 40, dataSize=8
+ andi t4, t4, 0xe, dataSize=8
+ xori t4, t4, 0xe, flags=(EZF,), dataSize=8
+ fault "new GeneralProtection(0)", flags=(nCEZF,)
+
+
+ #
+ # Get the target CS descriptor using the selector in the gate
+ # descriptor.
+ #
+ srli t4, t1, 16, dataSize=8
+ andi t5, t4, 0xF8, dataSize=8
+ andi t0, t4, 0x4, flags=(EZF,), dataSize=2
+ br rom_local_label("globalDescriptor"), flags=(CEZF,)
+ ld t3, tsl, [1, t0, t5], dataSize=8, addressSize=8
+ br rom_local_label("processDescriptor")
+globalDescriptor:
+ ld t3, tsg, [1, t0, t5], dataSize=8, addressSize=8
+processDescriptor:
+ chks t4, t3, IntCSCheck, dataSize=8
+ wrdl hs, t3, t4, dataSize=8
+
+ # Check that the target offset is in canonical form
+ wrdh t4, t1, t2, dataSize=8
+ srli t4, t4, 47, dataSize=8
+ addi t4, t4, 1, dataSize=8
+ srli t4, t4, 1, dataSize=8
+ or t4, t4, t4, flags=(EZF,), dataSize=2
+ fault "new GeneralProtection(0)", flags=(nCEZF,)
+
+
+ #
+ # Figure out where the stack should be
+ #
+
+ # Record what we might set the stack selector to.
+ rdsel t6, ss
+ wrsel hs, t6
+
+ # Check if we're changing privelege level. At this point we can assume
+ # we're going to a DPL that's less than or equal to the CPL.
+ rdattr t4, hs, dataSize=8
+ srli t4, t4, 3, dataSize=8
+ andi t4, t4, 3, dataSize=8
+ rdattr t5, cs, dataSize=8
+ srli t5, t5, 3, dataSize=8
+ sub t5, t5, t4, dataSize=8
+ andi t0, t5, 0x3, flags=(EZF,), dataSize=8
+ # We're going to change priviledge, so zero out the stack selector. We
+ # need to let the IST have priority so we don't branch yet.
+ limm t4, 0
+ wrsel hs, t4, flags=(nCEZF,)
+
+ # Check the IST field of the gate descriptor
+ srli t4, t1, 32, dataSize=8
+ andi t4, t4, 0x7, dataSize=8
+ subi t0, t4, 1, flags=(ECF,), dataSize=8
+ br rom_local_label("istStackSwitch"), flags=(nCECF,)
+ br rom_local_label("cplStackSwitch"), flags=(nCEZF,)
+
+ # If we're here, it's because the stack isn't being switched.
+ # Set t6 to the new rsp.
+ subi t6, rsp, 40, dataSize=8
+
+ # Align the stack
+ andi t6, t6, 0xF0, dataSize=1
+
+ # Check that we can access everything we need to on the stack
+ ldst t0, hs, [1, t0, t6], dataSize=8, addressSize=8
+ ldst t0, hs, [1, t0, t6], 32, dataSize=8, addressSize=8
+ br rom_local_label("stackSwitched")
+
+istStackSwitch:
+ panic "IST based stack switching isn't implemented"
+ br rom_local_label("stackSwitched")
+
+cplStackSwitch:
+ panic "CPL change initiated stack switching isn't implemented"
+
+stackSwitched:
+
+
+ ##
+ ## Point of no return.
+ ## We're now going to irrevocably modify visible state.
+ ## Anything bad that's going to happen should have happened by now.
+ ##
+
+
+ #
+ # Build up the interrupt stack frame
+ #
+
+ # Write out the contents of memory
+ st t7, hs, [1, t0, t6], dataSize=8
+ limm t5, 0, dataSize=8
+ rdsel t5, cs, dataSize=2
+ st t5, hs, [1, t0, t6], 8, dataSize=8
+ rflags t4, dataSize=8
+ st t4, hs, [1, t0, t6], 16, dataSize=8
+ st rsp, hs, [1, t0, t6], 24, dataSize=8
+ rdsel t5, ss, dataSize=2
+ st t5, hs, [1, t0, t6], 32, dataSize=8
+
+ # Set the stack segment
+ mov rsp, rsp, t6, dataSize=8
+ rdsel t7, hs, dataSize=2
+ wrsel ss, t7, dataSize=2
+
+ #
+ # Set up the target code segment
+ #
+ srli t5, t1, 16, dataSize=8
+ andi t5, t5, 0xFF, dataSize=8
+ wrdl cs, t3, t5, dataSize=8
+ wrsel cs, t5, dataSize=2
+ wrdh t7, t1, t2, dataSize=8
+ wrip t0, t7, dataSize=8
+
+ #
+ # Adjust rflags which is still in t4 from above
+ #
+
+ # Set IF to the lowest bit of the original gate type.
+ # The type field of the original gate starts at bit 40.
+
+ # Set the TF, NT, and RF bits. We'll flip them at the end.
+ limm t6, (1 << 8) | (1 << 14) | (1 << 16)
+ or t4, t4, t6
+ srli t5, t1, 40, dataSize=8
+ srli t7, t4, 9, dataSize=8
+ xor t5, t7, t5, dataSize=8
+ andi t5, t5, 1, dataSize=8
+ slli t5, t5, 9, dataSize=8
+ or t6, t5, t6, dataSize=8
+
+ # Put the results into rflags
+ wrflags t6, t4
+
+ eret
+};
+
+def rom
+{
+ # This vectors the CPU into an interrupt handler in legacy mode.
+ extern legacyModeInterrupt:
+ panic "Legacy mode interrupts not implemented (in microcode)"
+ eret
+};
+'''
projects / gem5.git / commitdiff