Re: [PATCH v2 09/10] x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup

2016-03-07 Thread Borislav Petkov
On Sat, Mar 05, 2016 at 09:52:22PM -0800, Andy Lutomirski wrote: > Right after SYSENTER, we can get a #DB or NMI. On x86_32, there's no IST, > so the exception handler is invoked on the temporary SYSENTER stack. > > Because the SYSENTER stack is very small, we have a fixup to switch > off the

Re: [PATCH v2 09/10] x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup

2016-03-07 Thread Borislav Petkov
On Sat, Mar 05, 2016 at 09:52:22PM -0800, Andy Lutomirski wrote: > Right after SYSENTER, we can get a #DB or NMI. On x86_32, there's no IST, > so the exception handler is invoked on the temporary SYSENTER stack. > > Because the SYSENTER stack is very small, we have a fixup to switch > off the

[PATCH v2 09/10] x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup

2016-03-05 Thread Andy Lutomirski
Right after SYSENTER, we can get a #DB or NMI. On x86_32, there's no IST, so the exception handler is invoked on the temporary SYSENTER stack. Because the SYSENTER stack is very small, we have a fixup to switch off the stack quickly when this happens. The old fixup had several issues: 1. It

[PATCH v2 09/10] x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup

2016-03-05 Thread Andy Lutomirski
Right after SYSENTER, we can get a #DB or NMI. On x86_32, there's no IST, so the exception handler is invoked on the temporary SYSENTER stack. Because the SYSENTER stack is very small, we have a fixup to switch off the stack quickly when this happens. The old fixup had several issues: 1. It