From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v4 25/28] ARM: decompressor: Remove __hyp_get_vectors usage Date: Fri, 24 Mar 2017 15:34:40 +0100 Message-ID: <20170324143440.GE25903@cbox> References: <20170321192058.9300-1-marc.zyngier@arm.com> <20170321192058.9300-26-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Russell King , kvm@vger.kernel.org, Ard Biesheuvel , Catalin Marinas , linux-arm-kernel@lists.infradead.org, Keerthy , kvmarm@lists.cs.columbia.edu To: Marc Zyngier Return-path: Content-Disposition: inline In-Reply-To: <20170321192058.9300-26-marc.zyngier@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On Tue, Mar 21, 2017 at 07:20:55PM +0000, Marc Zyngier wrote: > When the compressed image needs to be relocated to avoid being > overwritten by the decompression process, we need to relocate > the hyp vectors as well so that we can find them once the > decompression has taken effect. > > For that, we perform the following calculation: > u32 v = __hyp_get_vectors(); > v += offset; > __hyp_set_vectors(v); > > But we're guaranteed that the initial value of v as returned by > __hyp_get_vectors is always __hyp_stub_vectors, because we have > just set it by calling __hyp_stub_install. > > So let's remove the use of __hyp_get_vectors, and directly use > __hyp_stub_vectors instead. > > Acked-by: Russell King > Signed-off-by: Marc Zyngier > --- > arch/arm/boot/compressed/head.S | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index 9150f9732785..d58bb104c6e8 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -422,7 +422,10 @@ dtb_check_done: > cmp r0, #HYP_MODE > bne 1f > > - bl __hyp_get_vectors > +0: adr r0, 0b > + movw r1, #:lower16:__hyp_stub_vectors - 0b > + movt r1, #:upper16:__hyp_stub_vectors - 0b > + add r0, r0, r1 nit: you could add a comment explaining what r0 ends up containing, because I'm pretty sure this will feel obscure when not read in the context of this series with your commit message above. > sub r0, r0, r5 > add r0, r0, r10 > bl __hyp_set_vectors > -- > 2.11.0 > Nevertheless: Acked-by: Christoffer Dall From mboxrd@z Thu Jan 1 00:00:00 1970 From: cdall@linaro.org (Christoffer Dall) Date: Fri, 24 Mar 2017 15:34:40 +0100 Subject: [PATCH v4 25/28] ARM: decompressor: Remove __hyp_get_vectors usage In-Reply-To: <20170321192058.9300-26-marc.zyngier@arm.com> References: <20170321192058.9300-1-marc.zyngier@arm.com> <20170321192058.9300-26-marc.zyngier@arm.com> Message-ID: <20170324143440.GE25903@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Mar 21, 2017 at 07:20:55PM +0000, Marc Zyngier wrote: > When the compressed image needs to be relocated to avoid being > overwritten by the decompression process, we need to relocate > the hyp vectors as well so that we can find them once the > decompression has taken effect. > > For that, we perform the following calculation: > u32 v = __hyp_get_vectors(); > v += offset; > __hyp_set_vectors(v); > > But we're guaranteed that the initial value of v as returned by > __hyp_get_vectors is always __hyp_stub_vectors, because we have > just set it by calling __hyp_stub_install. > > So let's remove the use of __hyp_get_vectors, and directly use > __hyp_stub_vectors instead. > > Acked-by: Russell King > Signed-off-by: Marc Zyngier > --- > arch/arm/boot/compressed/head.S | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index 9150f9732785..d58bb104c6e8 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -422,7 +422,10 @@ dtb_check_done: > cmp r0, #HYP_MODE > bne 1f > > - bl __hyp_get_vectors > +0: adr r0, 0b > + movw r1, #:lower16:__hyp_stub_vectors - 0b > + movt r1, #:upper16:__hyp_stub_vectors - 0b > + add r0, r0, r1 nit: you could add a comment explaining what r0 ends up containing, because I'm pretty sure this will feel obscure when not read in the context of this series with your commit message above. > sub r0, r0, r5 > add r0, r0, r10 > bl __hyp_set_vectors > -- > 2.11.0 > Nevertheless: Acked-by: Christoffer Dall