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From: Will Deacon <will.deacon@arm.com>
To: Geoff Levand <geoff@infradead.org>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>,
	Catalin Marinas <Catalin.Marinas@arm.com>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"christoffer.dall@linaro.org" <christoffer.dall@linaro.org>
Subject: Re: [PATCH 04/13] arm64: Add new hcall HVC_CALL_FUNC
Date: Wed, 10 Sep 2014 18:07:40 +0100	[thread overview]
Message-ID: <20140910170740.GE1710@arm.com> (raw)
In-Reply-To: <ea28cfef061d06e86704845a877802e057749b39.1410302383.git.geoff@infradead.org>

On Tue, Sep 09, 2014 at 11:49:04PM +0100, Geoff Levand wrote:
> Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2.
> During CPU reset the CPU must be brought to the exception level it had on
> entry to the kernel.  The HVC_CALL_FUNC hcall will provide the mechanism
> needed for this exception level switch.
> 
> Signed-off-by: Geoff Levand <geoff@infradead.org>
> ---
>  arch/arm64/include/asm/virt.h | 11 +++++++++++
>  arch/arm64/kernel/hyp-stub.S  | 10 ++++++++++
>  2 files changed, 21 insertions(+)

[...]

> diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> index 9ab5f70..a21cf51 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -75,7 +75,17 @@ el1_sync:
>  1:	cmp	x10, #HVC_SET_VECTORS
>  	b.ne	1f
>  	msr	vbar_el2, x0
> +	b	2f
>  
> +1:	cmp	x10, #HVC_CALL_FUNC
> +	b.ne    1f
> +	mov	x29, lr
> +	mov	lr, x0
> +	mov	x0, x1
> +	mov	x1, x2
> +	mov	x2, x3
> +	blr	lr
> +	mov	lr, x29

Why are you clobbering x29?

Will

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  reply	other threads:[~2014-09-10 17:07 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-09 22:51 [PATCH 00/13] arm64 kexec kernel patches V2 Geoff Levand
2014-09-09 22:49 ` [PATCH 07/13] arm64: Add new routine local_disable Geoff Levand
2014-09-15 18:56   ` Mark Rutland
2014-09-25  0:24     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 03/13] arm64: Convert hcalls to use ISS field Geoff Levand
2014-09-11 16:14   ` Arun Chandran
2014-09-15 17:57   ` Mark Rutland
2014-09-22 21:46     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 04/13] arm64: Add new hcall HVC_CALL_FUNC Geoff Levand
2014-09-10 17:07   ` Will Deacon [this message]
2014-09-10 17:23     ` Geoff Levand
2014-09-10 17:35       ` Will Deacon
2014-09-10 18:11   ` [PATCH V2 " Geoff Levand
2014-09-15 18:11   ` [PATCH " Mark Rutland
2014-09-25  0:24     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 06/13] arm64: Add new routine read_cpu_properties Geoff Levand
2014-09-15 18:42   ` Mark Rutland
2014-09-25  0:23     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 01/13] arm64: Add ESR_EL2_EC macros to hyp-stub Geoff Levand
2014-09-15 16:10   ` Mark Rutland
2014-09-22 21:45     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 05/13] arm64: Add EL2 switch to soft_restart Geoff Levand
2014-09-09 22:49 ` [PATCH 02/13] arm64/kvm: Fix assembler compatibility of macros Geoff Levand
2014-09-10  8:40   ` Ard Biesheuvel
2014-09-10 16:35     ` Geoff Levand
2014-09-10 17:09       ` Ard Biesheuvel
2014-09-15 16:14         ` Mark Rutland
2014-09-10 18:04   ` [PATCH V2 " Geoff Levand
2014-09-09 22:49 ` [PATCH 11/13] arm64/kexec: Add core kexec support Geoff Levand
2014-09-18  1:13   ` Mark Rutland
2014-09-25  0:25     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 10/13] arm64/kexec: Revert change to machine_shutdown() Geoff Levand
2014-09-15 19:20   ` Mark Rutland
2014-09-09 22:49 ` [PATCH 08/13] arm64: Use cpu_ops for smp_stop Geoff Levand
2014-09-15 19:06   ` Mark Rutland
2014-09-25  0:24     ` Geoff Levand
2014-09-09 22:49 ` [PATCH 09/13] arm64/kexec: Kexec expects cpu_die Geoff Levand
2014-09-15 19:10   ` Mark Rutland
2014-09-09 22:49 ` [PATCH 13/13] arm64/kexec: Add kexec_ignore_compat_check param Geoff Levand
2014-09-09 22:49 ` [PATCH 12/13] arm64/kexec: Enable kexec in the arm64 defconfig Geoff Levand

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