[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH 02/24] xen/arm: hypercalls



Hi Stefano,

On 07/26/2012 11:33 AM, Stefano Stabellini wrote:
> Use r12 to pass the hypercall number to the hypervisor.
> 
> We need a register to pass the hypercall number because we might not
> know it at compile time and HVC only takes an immediate argument.

You're not going to JIT assemble the appropriate HVC instruction? Darn.

How many call numbers are there, though? 8? It seems like it'd be
reasonable to take the approach that seems to be favored for MRC/MCR
instructions, using a function containing switch statement that chooses
between several inline assembly instructions based off an enum passed to
the function. See for example arch_timer_reg_read in
arch/arm/kernel/arch_timer.c.

Regards,
Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.