On Wed, 14 Feb 2018, Ingo Molnar wrote: > * Dave Hansen <dave.han...@intel.com> wrote: > > > On 02/13/2018 06:27 PM, Josh Poimboeuf wrote: > > > --- a/arch/x86/entry/entry_64.S > > > +++ b/arch/x86/entry/entry_64.S > > > @@ -1167,10 +1167,10 @@ ENTRY(paranoid_exit) > > > UNWIND_HINT_REGS > > > DISABLE_INTERRUPTS(CLBR_ANY) > > > TRACE_IRQS_OFF_DEBUG > > > + RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 > > > testl %ebx, %ebx /* swapgs needed? */ > > > jnz .Lparanoid_exit_no_swapgs > > > TRACE_IRQS_IRETQ > > > - RESTORE_CR3 scratch_reg=%rbx save_reg=%r14 > > > SWAPGS_UNSAFE_STACK > > > jmp .Lparanoid_exit_restore > > > .Lparanoid_exit_no_swapgs: > > > > TRACE_IRQS_* call non-entry functions that are not mapped by the user > > CR3. How can this possibly work? What am I missing? > > How about something like the patch below? (Totally untested)
But correct .... > Thanks, > > Ingo > --- > arch/x86/entry/entry_64.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S > index cd216c9431e1..8971bd64d515 100644 > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -1175,6 +1175,7 @@ ENTRY(paranoid_exit) > jmp .Lparanoid_exit_restore > .Lparanoid_exit_no_swapgs: > TRACE_IRQS_IRETQ_DEBUG > + RESTORE_CR3 scratch_reg=%rbx save_reg=%r14 > .Lparanoid_exit_restore: > jmp restore_regs_and_return_to_kernel > END(paranoid_exit) >
