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Message-ID: <480272f8fb3e46d24a0ee1418fb85809@kernel.org>
Date: Thu, 08 Apr 2021 11:24:05 +0100
From: Marc Zyngier <maz@...nel.org>
To: Pavel Tatashin <pasha.tatashin@...een.com>
Cc: jmorris@...ei.org, sashal@...nel.org, ebiederm@...ssion.com,
kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
corbet@....net, catalin.marinas@....com, will@...nel.org,
linux-arm-kernel@...ts.infradead.org, james.morse@....com,
vladimir.murzin@....com, matthias.bgg@...il.com,
linux-mm@...ck.org, mark.rutland@....com, steve.capper@....com,
rfontana@...hat.com, tglx@...utronix.de, selindag@...il.com,
tyhicks@...ux.microsoft.com, kernelfans@...il.com
Subject: Re: [PATCH v13 03/18] arm64: hyp-stub: Move el1_sync into the vectors
On 2021-04-08 05:05, Pavel Tatashin wrote:
> From: James Morse <james.morse@....com>
>
> The hyp-stub's el1_sync code doesn't do very much, this can easily fit
> in the vectors.
>
> With this, all of the hyp-stubs behaviour is contained in its vectors.
> This lets kexec and hibernate copy the hyp-stub when they need its
> behaviour, instead of re-implementing it.
>
> Signed-off-by: James Morse <james.morse@....com>
>
> [Fixed merging issues]
That's a pretty odd fix IMO.
>
> Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
> ---
> arch/arm64/kernel/hyp-stub.S | 59 ++++++++++++++++++------------------
> 1 file changed, 29 insertions(+), 30 deletions(-)
>
> diff --git a/arch/arm64/kernel/hyp-stub.S
> b/arch/arm64/kernel/hyp-stub.S
> index ff329c5c074d..d1a73d0f74e0 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -21,6 +21,34 @@ SYM_CODE_START_LOCAL(\label)
> .align 7
> b \label
> SYM_CODE_END(\label)
> +.endm
> +
> +.macro hyp_stub_el1_sync
> +SYM_CODE_START_LOCAL(hyp_stub_el1_sync)
> + .align 7
> + cmp x0, #HVC_SET_VECTORS
> + b.ne 2f
> + msr vbar_el2, x1
> + b 9f
> +
> +2: cmp x0, #HVC_SOFT_RESTART
> + b.ne 3f
> + mov x0, x2
> + mov x2, x4
> + mov x4, x1
> + mov x1, x3
> + br x4 // no return
> +
> +3: cmp x0, #HVC_RESET_VECTORS
> + beq 9f // Nothing to reset!
> +
> + /* Someone called kvm_call_hyp() against the hyp-stub... */
> + mov_q x0, HVC_STUB_ERR
> + eret
> +
> +9: mov x0, xzr
> + eret
> +SYM_CODE_END(hyp_stub_el1_sync)
You said you tested this on a TX2. I guess you don't care whether
it runs VHE or not...
M.
> .endm
>
> .text
> @@ -39,7 +67,7 @@ SYM_CODE_START(__hyp_stub_vectors)
> invalid_vector hyp_stub_el2h_fiq_invalid // FIQ EL2h
> invalid_vector hyp_stub_el2h_error_invalid // Error EL2h
>
> - ventry el1_sync // Synchronous 64-bit EL1
> + hyp_stub_el1_sync // Synchronous 64-bit EL1
> invalid_vector hyp_stub_el1_irq_invalid // IRQ 64-bit EL1
> invalid_vector hyp_stub_el1_fiq_invalid // FIQ 64-bit EL1
> invalid_vector hyp_stub_el1_error_invalid // Error 64-bit EL1
> @@ -55,35 +83,6 @@ SYM_CODE_END(__hyp_stub_vectors)
> # Check the __hyp_stub_vectors didn't overflow
> .org . - (__hyp_stub_vectors_end - __hyp_stub_vectors) + SZ_2K
>
> -
> -SYM_CODE_START_LOCAL(el1_sync)
> - cmp x0, #HVC_SET_VECTORS
> - b.ne 1f
> - msr vbar_el2, x1
> - b 9f
> -
> -1: cmp x0, #HVC_VHE_RESTART
> - b.eq mutate_to_vhe
> -
> -2: cmp x0, #HVC_SOFT_RESTART
> - b.ne 3f
> - mov x0, x2
> - mov x2, x4
> - mov x4, x1
> - mov x1, x3
> - br x4 // no return
> -
> -3: cmp x0, #HVC_RESET_VECTORS
> - beq 9f // Nothing to reset!
> -
> - /* Someone called kvm_call_hyp() against the hyp-stub... */
> - mov_q x0, HVC_STUB_ERR
> - eret
> -
> -9: mov x0, xzr
> - eret
> -SYM_CODE_END(el1_sync)
> -
> // nVHE? No way! Give me the real thing!
> SYM_CODE_START_LOCAL(mutate_to_vhe)
> // Sanity check: MMU *must* be off
--
Jazz is not dead. It just smells funny...
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