Messages in this thread | | | Date | Mon, 15 Jun 2009 13:14:45 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [tip:perfcounters/core] perf_counter: x86: Fix call-chain support to use NMI-safe methods |
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On 06/15/09 12:04, Linus Torvalds wrote: > That's an odd way of writing it. > > Don't we have a per-cpu segment here? I'd much rather just see it do > something like this (_before_ restoring the regular registers) > > movq EIP(%esp),%rax > movq ESP(%esp),%rdx > movq %rax,gs:saved_esp > movq %rdx,gs:saved_eip > > # restore regular regs > RESTORE_ALL > > # skip eip/esp to get at eflags > addl $16,%esp > popfq > > # restore rsp/rip > movq gs:saved_esp,%rsp > jmpq *(gs:saved_eip) > > but I haven't thought deeply about it. Maybe there's something wrong with > the above. >
We have to restore the usermode %gs somewhere...
J
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