On Wed, May 05, 2021 at 02:49:14PM +0100, Mark Rutland wrote: > Hi Sudeep, > > On Wed, May 05, 2021 at 10:38:38AM +0100, Sudeep Holla wrote: > > SMCCC v1.2 allows x8-x17 to be used as parameter registers and x4—x17 > > to be used as result registers in SMC64/HVC64. Arm Firmware Framework > > for Armv8-A specification makes use of x0-x7 as parameter and result > > registers. There are other users like Hyper-V who intend to use beyond > > x0-x7 as well. > > > > Current SMCCC interface in the kernel just use x0-x7 as parameter and > > x0-x3 as result registers as required by SMCCCv1.0. Let us add new > > interface to support this extended set of input/output registers namely > > x0-x17 as both parameter and result registers. > > > > Cc: Michael Kelley <mikelley@xxxxxxxxxxxxx> > > Cc: Will Deacon <will@xxxxxxxxxx> > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > Cc:Catalin Marinas <catalin.marinas@xxxxxxx> > > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> > > I have one minor comment below, otherwise this looks good to me, and > regardless: > > Acked-by: Mark Rutland <mark.rutland@xxxxxxx> > > [...] > > > +/** > > + * arm_smccc_1_2_hvc() - make HVC calls > > + * @args: arguments passed via struct arm_smccc_1_2_regs > > + * @res: result values via struct arm_smccc_1_2_regs > > + * > > + * This function is used to make HVC calls following SMC Calling Convention > > + * v1.2 or above. The content of the supplied param are copied from the > > + * structure to registers prior to the HVC instruction. The return values > > + * are updated with the content from registers on return from the HVC > > + * instruction. > > + */ > > +asmlinkage void arm_smccc_1_2_hvc(struct arm_smccc_1_2_regs *args, > > + struct arm_smccc_1_2_regs *res); > > + > > +/** > > + * arm_smccc_1_2_smc() - make SMC calls > > + * @args: arguments passed via struct arm_smccc_1_2_regs > > + * @res: result values via struct arm_smccc_1_2_regs > > + * > > + * This function is used to make SMC calls following SMC Calling Convention > > + * v1.2 or above. The content of the supplied param are copied from the > > + * structure to registers prior to the SMC instruction. The return values > > + * are updated with the content from registers on return from the SMC > > + * instruction. > > + */ > > +asmlinkage void arm_smccc_1_2_smc(struct arm_smccc_1_2_regs *args, > > + struct arm_smccc_1_2_regs *res); > > +#endif > > It might be worth making the args parameter to these const, since we > never write to it in the asm. > Makes sense, will fix it. Thanks for the review. -- Regards, Sudeep
