xreturn.py revision 9671
1# Copyright (c) 2007-2008 The Hewlett-Packard Development Company 2# All rights reserved. 3# 4# The license below extends only to copyright in the software and shall 5# not be construed as granting a license to any other intellectual 6# property including but not limited to intellectual property relating 7# to a hardware implementation of the functionality of the software 8# licensed hereunder. You may use the software subject to the license 9# terms below provided that you ensure that this notice is replicated 10# unmodified and in its entirety in all distributions of the software, 11# modified or unmodified, in source code or in binary form. 12# 13# Redistribution and use in source and binary forms, with or without 14# modification, are permitted provided that the following conditions are 15# met: redistributions of source code must retain the above copyright 16# notice, this list of conditions and the following disclaimer; 17# redistributions in binary form must reproduce the above copyright 18# notice, this list of conditions and the following disclaimer in the 19# documentation and/or other materials provided with the distribution; 20# neither the name of the copyright holders nor the names of its 21# contributors may be used to endorse or promote products derived from 22# this software without specific prior written permission. 23# 24# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 27# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 28# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 29# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 30# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 34# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35# 36# Authors: Gabe Black 37 38microcode = ''' 39def macroop RET_NEAR 40{ 41 # Make the default data size of rets 64 bits in 64 bit mode 42 .adjust_env oszIn64Override 43 44 ld t1, ss, [1, t0, rsp] 45 # Check address of return 46 addi rsp, rsp, dsz 47 wripi t1, 0 48}; 49 50def macroop RET_NEAR_I 51{ 52 # Make the default data size of rets 64 bits in 64 bit mode 53 .adjust_env oszIn64Override 54 55 limm t2, imm 56 ld t1, ss, [1, t0, rsp] 57 # Check address of return 58 addi rsp, rsp, dsz 59 add rsp, rsp, t2 60 wripi t1, 0 61}; 62 63def macroop RET_FAR { 64 .adjust_env oszIn64Override 65 66 # Get the return RIP 67 ld t1, ss, [1, t0, rsp] 68 69 # Get the return CS 70 ld t2, ss, [1, t0, rsp], ssz 71 72 # increment the stack pointer to pop the instruction pointer 73 # and the code segment from the stack. 74 addi rsp, rsp, dsz 75 addi rsp, rsp, dsz 76 77 # Get the rpl 78 andi t3, t2, 0x3 79 80 # Get the cpl 81 82 # Here we'd check if we're changing priviledge levels. We'll just hope 83 # that doesn't happen yet. 84 85 # Do stuff if they're equal 86 andi t0, t2, 0xFC, flags=(EZF,), dataSize=2 87 br label("processDescriptor"), flags=(CEZF,) 88 andi t3, t2, 0xF8, dataSize=8 89 andi t0, t2, 0x4, flags=(EZF,), dataSize=2 90 br label("globalDescriptor"), flags=(CEZF,) 91 ld t3, tsl, [1, t0, t3], dataSize=8 92 br label("processDescriptor") 93globalDescriptor: 94 ld t3, tsg, [1, t0, t3], dataSize=8 95processDescriptor: 96 chks t2, t3, IretCheck, dataSize=8 97 # There should be validity checks on the RIP checks here, but I'll do 98 # that later. 99 wrdl cs, t3, t2 100 wrsel cs, t2 101 wrip t0, t1 102 br label("end") 103 104 # Do other stuff if they're not. 105end: 106 fault "NoFault" 107}; 108''' 109