Re: [Xen-ia64-devel] [PATCH 0/2] vdso fix

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

This explanation is wrong. Please ignore those patches.
Sorry for confution.

On Thu, Aug 24, 2006 at 06:42:16PM +0900, Isaku Yamahata wrote:
> 
> __kernel_syscall_via_epc masks interrupt assuming page fault on the vDSO page
> can't occur during executing.
> However Xen might preempt vcpu when interrupt is disabled so that
> page fault might occur with interrupt masked unlike baremetal case.
> Such page fault results in acquiring semaphore with interrupt disabled.
> see ia64_do_page_fault().
> It means that we can't disable interrupt in vDSO page on xen environment.
> So we jumps kernel text area which is pinned by ITR before disabling interrupt
> to avoid such page fault.
> 
> thanks.
> 
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-- 
yamahata

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