i#4495: Preserve translated stolen register #4526
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Currently, a stolen register value that is translated by a client is discarded both in a synchall and a synchronous signal. We fix both paths here. Adds a new test client.stolen-reg which tests both a synchronous fault signal translation path as well as a synchall translation path via a synchall flush. The test was confirmed to fail without either of the fixes in place. Ensures the new test passes on 32-bit ARM. This exercised the translate_from_synchall_to_dispatch() path and found some ARM bugs: the reset exit stub is A32 mode, so we need to change the mode for the suspended sigcontext; yet thread_set_mcontext() did not support that. That is all fixed now and verified. Fixes #4495
derekbruening
commented
Nov 11, 2020
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Maybe the ARM mode fixes could be separated: but I'm not willing to make a separate test so they'd share this one. |
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(Note that the appveyor failure is alloc-noreset == #4436) |
abhinav92003
approved these changes
Nov 11, 2020
gregcawthorne
pushed a commit
that referenced
this pull request
Nov 28, 2020
Currently, a stolen register value that is translated by a client is discarded both in a synchall and a synchronous signal. We fix both paths here. Adds a new test client.stolen-reg which tests both a synchronous fault signal translation path as well as a synchall translation path via a synchall flush. The test was confirmed to fail without either of the fixes in place. Ensures the new test passes on 32-bit ARM. This exercised the translate_from_synchall_to_dispatch() path and found some ARM bugs: the reset exit stub is A32 mode, so we need to change the mode for the suspended sigcontext; yet thread_set_mcontext() did not support that. That is all fixed now and verified. Fixes #4495
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Currently, a stolen register value that is translated by a client is
discarded both in a synchall and a synchronous signal. We fix both
paths here.
Adds a new test client.stolen-reg which tests both a synchronous fault
signal translation path as well as a synchall translation path via a
synchall flush. The test was confirmed to fail without either of the
fixes in place.
Ensures the new test passes on 32-bit ARM. This exercised the
translate_from_synchall_to_dispatch() path and found some ARM bugs:
the reset exit stub is A32 mode, so we need to change the mode for the
suspended sigcontext; yet thread_set_mcontext() did not support that.
That is all fixed now and verified.
Fixes #4495