| Message ID | 20170321192058.9300-26-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <rmk+kernel@armlinux.org.uk> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > 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 <cdall@linaro.org>
On Fri, Mar 24 2017 at 2:34:40 pm GMT, Christoffer Dall <cdall@linaro.org> wrote: > 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 <rmk+kernel@armlinux.org.uk> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> 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. Sure. This is "Ard's magic stuff" - I'll document that. Thanks, M.
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 sub r0, r0, r5 add r0, r0, r10 bl __hyp_set_vectors