[kvmarm] [PATCH 04/29] arm64: KVM: system register definitions for 64bit guests

[Alexander Graf]

On 05.03.2013, at 04:47, Marc Zyngier wrote:

> Define the saved/restored registers for 64bit guests.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> ---
> arch/arm64/include/asm/kvm_asm.h | 68 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 68 insertions(+)
> create mode 100644 arch/arm64/include/asm/kvm_asm.h
> 
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> new file mode 100644
> index 0000000..851fee5
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -0,0 +1,68 @@
> +/*
> + * Copyright (C) 2012 - ARM Ltd
> + * Author: Marc Zyngier <marc.zyngier at arm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef __ARM_KVM_ASM_H__
> +#define __ARM_KVM_ASM_H__
> +
> +/*
> + * 0 is reserved as an invalid value.
> + * Order *must* be kept in sync with the hyp switch code.
> + */
> +#define	MPIDR_EL1	1	/* MultiProcessor Affinity Register */
> +#define	CSSELR_EL1	2	/* Cache Size Selection Register */
> +#define	SCTLR_EL1	3	/* System Control Register */
> +#define	ACTLR_EL1	4	/* Auxilliary Control Register */
> +#define	CPACR_EL1	5	/* Coprocessor Access Control */
> +#define	TTBR0_EL1	6	/* Translation Table Base Register 0 */
> +#define	TTBR1_EL1	7	/* Translation Table Base Register 1 */
> +#define	TCR_EL1		8	/* Translation Control Register */
> +#define	ESR_EL1		9	/* Exception Syndrome Register */
> +#define	AFSR0_EL1	10	/* Auxilary Fault Status Register 0 */
> +#define	AFSR1_EL1	11	/* Auxilary Fault Status Register 1 */
> +#define	FAR_EL1		12	/* Fault Address Register */
> +#define	MAIR_EL1	13	/* Memory Attribute Indirection Register */
> +#define	VBAR_EL1	14	/* Vector Base Address Register */
> +#define	CONTEXTIDR_EL1	15	/* Context ID Register */
> +#define	TPIDR_EL0	16	/* Thread ID, User R/W */
> +#define	TPIDRRO_EL0	17	/* Thread ID, User R/O */
> +#define	TPIDR_EL1	18	/* Thread ID, Privileged */
> +#define	AMAIR_EL1	19	/* Aux Memory Attribute Indirection Register */
> +#define	CNTKCTL_EL1	20	/* Timer Control Register (EL1) */
> +#define	NR_SYS_REGS	21

These are internal representations of the system registers. Keeping everything strictly linear is quite cumbersome, why not let the compiler do this for you?

enum kvm_sysreg_id {
    MPIDR_EL1 = 1,
    ...
    NR_SYS_REGS
}

That way gcc automatically counts the IDs up for you. You eliminate a potential source of breakage (duplicate IDs) and the code is even easier to read ;).


Alex