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Stricter instruction restart checks, and some machine config cleanup

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This commit is contained in:
Jeff Parsons 2016-03-18 15:46:32 -07:00
commit 6c6decc7ae
29 changed files with 1802 additions and 1215 deletions
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40
modules/pcjs/lib/x86help.js
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@ -752,25 +752,43 @@ X86.helpFault = function(nFault, nError, nCycles, fHalt)
if (this.nFault < 0) {
/*
* Single-fault (error code is passed through, and the responsible instruction is restartable.
*
* TODO: The following opCS/opLIP/opSS/opLSP checks are primarily required for 80386-based machines
* with paging enabled, because page faults introduce a new set of complex faults that our current
* segment load "probes" are insufficient to catch. So as a stop-gap measure, we rely on these FOUR
* "snapshot" registers to temporarily resolve the general instruction restartability problem.
*
* If you want to closely examine the underlying causes of these more complex faults, set breakpoints
* where indicated below, and examine the stack trace.
*/
if (this.opCS != -1) {
/*
* HACK: We must slam 3 into this.segCS.cpl to ensure that loading the original CS segment doesn't
* fail. For example, if we faulted in the middle of a ring transition that loaded CS with a higher
* privilege (lower CPL) code segment, then our attempt here to reload the lower privilege (higher CPL)
* code segment could be viewed as a privilege violation (which it would be outside this context).
*/
this.segCS.cpl = 3;
this.setCS(this.opCS);
if (this.opCS !== this.segCS.sel) {
/*
* HACK: We slam the RPL into this.segCS.cpl to ensure that loading the original CS segment doesn't
* fail. For example, if we faulted in the middle of a ring transition that loaded CS with a higher
* privilege (lower CPL) code segment, then our attempt here to reload the lower privilege (higher CPL)
* code segment could be viewed as a privilege violation (which it would be outside this context).
*/
this.segCS.cpl = this.opCS & 0x3; // set breakpoint here to inspect complex faults
this.setCS(this.opCS);
}
this.opCS = -1;
}
this.setLIP(this.opLIP);
if (this.opLIP !== this.regLIP) {
this.setLIP(this.opLIP); // set breakpoint here to inspect complex faults
this.assert(this.opLIP === this.regLIP);
}
if (this.opSS != -1) {
this.setSS(this.opSS);
if (this.opSS !== this.segSS.sel) {
this.setSS(this.opSS); // set breakpoint here to inspect complex faults
}
this.opSS = -1;
}
if (this.opLSP !== X86.ADDR_INVALID) {
this.setSP((this.regESP & ~this.segSS.maskAddr) | (this.opLSP - this.segSS.base));
if (this.opLSP !== this.regLSP) { // set breakpoint below to inspect complex faults
this.setSP((this.regESP & ~this.segSS.maskAddr) | (this.opLSP - this.segSS.base));
this.assert(this.opLSP === this.regLSP);
}
this.opLSP = X86.ADDR_INVALID;
}
}