Messages in this thread | | | Subject | Re: sysenter cause a segmentation fault. | From | Andi Kleen <> | Date | 18 Mar 2007 16:51:21 +0100 |
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"Ying Chu" <xjtuychu@gmail.com> writes:
> A simple code running on PIII 800,kernel 2.6.20 with SEP enabled > causes a segmentation fault.
SYSENTER has a hardcoded return address, that is why you cannot be used anywhere but in the vsyscall trampoline. In addition it doesn't work on x86-64 for 32bit processes for AMD. The only system call method supported without the vDSO is int 0x80. Better you just use the vDSO.
> More, when i enabled Kdb and set "bp sysenter_entry",it went with a > catastrophic error errupted.
The stack and some other kernel state are not set up yet at this point.
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