On Thu, Aug 20, 2015 at 12:37:29PM +0100, Jens Wiklander wrote: > On Wed, Aug 19, 2015 at 05:50:09PM +0100, Will Deacon wrote: > > On Wed, Aug 19, 2015 at 09:40:25AM +0100, Jens Wiklander wrote: > > > Adds helpers to do SMC based on ARM SMC Calling Convention. > > > CONFIG_HAVE_SMCCC is enabled for architectures that may support > > > the SMC instruction. It's the responsibility of the caller to > > > know if the SMC instruction is supported by the platform. [...] > > > + mov x28, x0 > > > + ldp w0, w1, [x28, #SMC_PARAM_W0_OFFS] > > > + ldp w2, w3, [x28, #SMC_PARAM_W2_OFFS] > > > + ldp w4, w5, [x28, #SMC_PARAM_W4_OFFS] > > > + ldp w6, w7, [x28, #SMC_PARAM_W6_OFFS] > > > + smc #0 > > > + stp w0, w1, [x28, #SMC_PARAM_W0_OFFS] > > > + stp w2, w3, [x28, #SMC_PARAM_W2_OFFS] > > > + ldp x28, x30, [sp], #16 > > > + ret > > > +ENDPROC(smccc_call32) > > > > Could we deal with this like we do for PSCI instead? (see > > __invoke_psci_fn_smc). We could also then rename psci-call.S to fw-call.S > > and stick this in there too. > > I assume you're referring to when to use "hvc" and "smc". I assume he's on about passing the values in registers rather than a struct. >From the looks of the SMC Calling Convention documentation, it's valid to have return values in registers r0-r3, which necessitates the use of a struct (at least for the return values). Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
