AArch64 registers are 64bit whereas AArch32 registers
are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
we should get rid of helpers READ/WRITE_SYSREG32
in favour of using READ/WRITE_SYSREG.
We should also use register_t type when reading sysregs
which can correspond to uint64_t or uint32_t.
Even though many AArch64 registers have upper 32bit reserved
it does not mean that they can't be widen in the future.

Modify type of register cntkctl to register_t.

Modify accesses to thumbee registers to use READ/WRITE_SYSREG.
Thumbee registers are only usable by a 32bit domain and in fact
should be only accessed on ARMv7 as they were retrospectively dropped
on ARMv8.

Signed-off-by: Michal Orzel <michal.orzel@arm.com>
---
Changes since v2:
-Modify the commit message
Changes since v1:
-Move modification of ACTLR into seperate patch
---
 xen/arch/arm/domain.c        | 18 +++++++++---------
 xen/include/asm-arm/domain.h |  2 +-
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index bdd3d3e5b5..621f518b83 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -113,13 +113,13 @@ static void ctxt_switch_from(struct vcpu *p)
     p->arch.tpidr_el1 = READ_SYSREG(TPIDR_EL1);
 
     /* Arch timer */
-    p->arch.cntkctl = READ_SYSREG32(CNTKCTL_EL1);
+    p->arch.cntkctl = READ_SYSREG(CNTKCTL_EL1);
     virt_timer_save(p);
 
     if ( is_32bit_domain(p->domain) && cpu_has_thumbee )
     {
-        p->arch.teecr = READ_SYSREG32(TEECR32_EL1);
-        p->arch.teehbr = READ_SYSREG32(TEEHBR32_EL1);
+        p->arch.teecr = READ_SYSREG(TEECR32_EL1);
+        p->arch.teehbr = READ_SYSREG(TEEHBR32_EL1);
     }
 
 #ifdef CONFIG_ARM_32
@@ -175,7 +175,7 @@ static void ctxt_switch_from(struct vcpu *p)
 
 static void ctxt_switch_to(struct vcpu *n)
 {
-    uint32_t vpidr;
+    register_t vpidr;
 
     /* When the idle VCPU is running, Xen will always stay in hypervisor
      * mode. Therefore we don't need to restore the context of an idle VCPU.
@@ -183,8 +183,8 @@ static void ctxt_switch_to(struct vcpu *n)
     if ( is_idle_vcpu(n) )
         return;
 
-    vpidr = READ_SYSREG32(MIDR_EL1);
-    WRITE_SYSREG32(vpidr, VPIDR_EL2);
+    vpidr = READ_SYSREG(MIDR_EL1);
+    WRITE_SYSREG(vpidr, VPIDR_EL2);
     WRITE_SYSREG(n->arch.vmpidr, VMPIDR_EL2);
 
     /* VGIC */
@@ -257,8 +257,8 @@ static void ctxt_switch_to(struct vcpu *n)
 
     if ( is_32bit_domain(n->domain) && cpu_has_thumbee )
     {
-        WRITE_SYSREG32(n->arch.teecr, TEECR32_EL1);
-        WRITE_SYSREG32(n->arch.teehbr, TEEHBR32_EL1);
+        WRITE_SYSREG(n->arch.teecr, TEECR32_EL1);
+        WRITE_SYSREG(n->arch.teehbr, TEEHBR32_EL1);
     }
 
 #ifdef CONFIG_ARM_32
@@ -274,7 +274,7 @@ static void ctxt_switch_to(struct vcpu *n)
 
     /* This is could trigger an hardware interrupt from the virtual
      * timer. The interrupt needs to be injected into the guest. */
-    WRITE_SYSREG32(n->arch.cntkctl, CNTKCTL_EL1);
+    WRITE_SYSREG(n->arch.cntkctl, CNTKCTL_EL1);
     virt_timer_restore(n);
 }
 
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 0a74df9931..c6b59ee755 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -190,7 +190,7 @@ struct arch_vcpu
     struct vgic_cpu vgic;
 
     /* Timer registers  */
-    uint32_t cntkctl;
+    register_t cntkctl;
 
     struct vtimer phys_timer;
     struct vtimer virt_timer;
-- 
2.29.0

Hi Michal,

On 05/05/2021 08:43, Michal Orzel wrote:
> AArch64 registers are 64bit whereas AArch32 registers
> are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
> we should get rid of helpers READ/WRITE_SYSREG32
> in favour of using READ/WRITE_SYSREG.
> We should also use register_t type when reading sysregs
> which can correspond to uint64_t or uint32_t.
> Even though many AArch64 registers have upper 32bit reserved
> it does not mean that they can't be widen in the future.
> 
> Modify type of register cntkctl to register_t.
> 
> Modify accesses to thumbee registers to use READ/WRITE_SYSREG.
> Thumbee registers are only usable by a 32bit domain and in fact
> should be only accessed on ARMv7 as they were retrospectively dropped
> on ARMv8.

Sorry for not replying on v2. How about:

"
Thumbee registers are only usable by a 32-bit domain and therefore we 
can just store the bottom 32-bit (IOW there is no type change). In fact, 
this could technically be restricted to Armv7 HW (the support was 
dropped retrospectively in Armv8) but leave it as-is for now.
"

If you are happy with it, I will do it on commit.

Cheers,

-- 
Julien Grall

Hi Julien,

On 05.05.2021 20:03, Julien Grall wrote:
> Hi Michal,
> 
> On 05/05/2021 08:43, Michal Orzel wrote:
>> AArch64 registers are 64bit whereas AArch32 registers
>> are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
>> we should get rid of helpers READ/WRITE_SYSREG32
>> in favour of using READ/WRITE_SYSREG.
>> We should also use register_t type when reading sysregs
>> which can correspond to uint64_t or uint32_t.
>> Even though many AArch64 registers have upper 32bit reserved
>> it does not mean that they can't be widen in the future.
>>
>> Modify type of register cntkctl to register_t.
>>
>> Modify accesses to thumbee registers to use READ/WRITE_SYSREG.
>> Thumbee registers are only usable by a 32bit domain and in fact
>> should be only accessed on ARMv7 as they were retrospectively dropped
>> on ARMv8.
> 
> Sorry for not replying on v2. How about:
> 
> "
> Thumbee registers are only usable by a 32-bit domain and therefore we can just store the bottom 32-bit (IOW there is no type change). In fact, this could technically be restricted to Armv7 HW (the support was dropped retrospectively in Armv8) but leave it as-is for now.
> "
> 
> If you are happy with it, I will do it on commit.
> 
I am happy with it. Please ack and change it on commit.
Thanks.
> Cheers,
> 

Cheers,
Michal

On 06/05/2021 07:13, Michal Orzel wrote:
> Hi Julien,

Hi Michal,

> On 05.05.2021 20:03, Julien Grall wrote:
>> Hi Michal,
>>
>> On 05/05/2021 08:43, Michal Orzel wrote:
>>> AArch64 registers are 64bit whereas AArch32 registers
>>> are 32bit or 64bit. MSR/MRS are expecting 64bit values thus
>>> we should get rid of helpers READ/WRITE_SYSREG32
>>> in favour of using READ/WRITE_SYSREG.
>>> We should also use register_t type when reading sysregs
>>> which can correspond to uint64_t or uint32_t.
>>> Even though many AArch64 registers have upper 32bit reserved
>>> it does not mean that they can't be widen in the future.
>>>
>>> Modify type of register cntkctl to register_t.
>>>
>>> Modify accesses to thumbee registers to use READ/WRITE_SYSREG.
>>> Thumbee registers are only usable by a 32bit domain and in fact
>>> should be only accessed on ARMv7 as they were retrospectively dropped
>>> on ARMv8.
>>
>> Sorry for not replying on v2. How about:
>>
>> "
>> Thumbee registers are only usable by a 32-bit domain and therefore we can just store the bottom 32-bit (IOW there is no type change). In fact, this could technically be restricted to Armv7 HW (the support was dropped retrospectively in Armv8) but leave it as-is for now.
>> "
>>
>> If you are happy with it, I will do it on commit.
>>
> I am happy with it. Please ack and change it on commit.

Thanks.

Reviewed-by: Julien Grall <jgrall@amazon.com>

Cheers,

-- 
Julien Grall