On Wed, Jul 08, 2015 at 05:19:10PM +0100, Marc Zyngier wrote:
> --- /dev/null
> +++ b/arch/arm64/kvm/vhe-macros.h
> @@ -0,0 +1,36 @@
> +/*
> + * Copyright (C) 2015 - ARM Ltd
> + * Author: Marc Zyngier <marc.zyng...@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 __ARM64_VHE_MACROS_H__
> +#define __ARM64_VHE_MACROS_H__
> +
> +#include <asm/alternative.h>
> +#include <asm/cpufeature.h>
> +
> +#ifdef __ASSEMBLY__
> +
> +/* Hack to allow stringification of macros... */
> +#define __S__(a,args...) __stringify(a, ##args)
> +#define _S_(a,args...) __S__(a, args)
> +
> +.macro ifnvhe nonvhe vhe
> + alternative_insn "\nonvhe", "\vhe", ARM64_HAS_VIRT_HOST_EXTN
> +.endm
I always found the alternative_insn tricks hard to read but with
Daniel's patch queued in -next it gets slightly better. If you are not
targeting 4.3, could you do something like (untested):
.macro vhe_if_not
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
.endm
.macro vhe_else
alternative_else CONFIG_ARM64_VHE
.endm
.macro vhe_endif
alternative_endif CONFIG_ARM64_VHE
.endm
The kvm_call_hyp, for example, would become:
ENTRY(kvm_call_hyp)
vhe_if_not
hvc #0
ret
vhe_else
nop
push lr, xzr
vhe_endif
Or you can even ignore defining new vhe_* macros altogether and just use
"alternative_if_not ARM64_HAS_VIRT_HOST_EXTN" directly (more to type)
but you may be able to avoid a vhe-macros.h file.
--
Catalin
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