Messages in this thread | | | Date | Wed, 29 Jul 2015 10:47:17 -0700 | Subject | Re: [PATCH 4/8] x86/vm86: Use the normal pt_regs area for vm86 | From | Linus Torvalds <> |
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On Wed, Jul 29, 2015 at 10:36 AM, Brian Gerst <brgerst@gmail.com> wrote: > > I think I remember now what the issue was. Since entering vm86 mode > uses force_iret(), the work_pending code path was being taken. I had > to move the call to save_v86_state out of here to handle_signal(), > otherwise it would just restore the 32-bit regs and exit the syscall > without ever entering vm86 mode. But that meant that the test for > kernel CS was seeing the vm86 regs instead of 32-bit regs, and was > failing because it didn't account for the VM bit (if the real-mode CS > looked like RPL 0). A fault would get stuck in a loop because it > couldn't exit to the signal handling code.
Hmm. I think we'd want a big comment about that code then, and how it is only used for user-space (including vm86 mode).
Linus
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