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Re: [Qemu-arm] [PATCH 1/2] target/arm: Hyp mode R14 is shared with User
From: |
Peter Maydell |
Subject: |
Re: [Qemu-arm] [PATCH 1/2] target/arm: Hyp mode R14 is shared with User and System |
Date: |
Fri, 9 Nov 2018 18:15:20 +0000 |
On 9 November 2018 at 17:35, Peter Maydell <address@hidden> wrote:
> Hyp mode is an exception to the general rule that each AArch32
> mode has its own r13, r14 and SPSR -- it has a banked r13 and
> SPSR but shares its r14 with User and System mode. We were
> incorrectly implementing it as banked, which meant that on
> entry to Hyp mode r14 was 0 rather than the USR/SYS r14.
>
> We provide a new function r14_bank_number() which is like
> the existing bank_number() but provides the index into
> env->banked_r14[]; bank_number() provides the index to use
> for env->banked_r13[] and env->banked_cpsr[].
>
> All the points in the code that were using bank_number()
> to index into env->banked_r14[] are updated for consintency:
> * switch_mode() -- this is the only place where we fix
> an actual bug
> * aarch64_sync_32_to_64() and aarch64_sync_64_to_32():
> no behavioural change as we already special-cased Hyp R14
> * kvm32.c: no behavioural change since the guest can't ever
> be in Hyp mode, but conceptually the right thing to do
> * msr_banked()/mrs_banked(): we can never get to the case
> that accesses banked_r14[] with tgtmode == ARM_CPU_MODE_HYP,
> so no behavioural change
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> target/arm/internals.h | 16 ++++++++++++++++
> target/arm/helper.c | 29 +++++++++++++++--------------
> target/arm/kvm32.c | 4 ++--
> target/arm/op_helper.c | 2 +-
> 4 files changed, 34 insertions(+), 17 deletions(-)
Rats, this bit accidentally didn't make it into this patch:
diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c
index 2b62c53f5b5..eb6fb82fb81 100644
--- a/target/arm/op_helper.c
+++ b/target/arm/op_helper.c
@@ -725,7 +725,7 @@ uint32_t HELPER(mrs_banked)(CPUARMState *env,
uint32_t tgtmode, uint32_t regno)
case 13:
return env->banked_r13[bank_number(tgtmode)];
case 14:
- return env->banked_r14[bank_number(tgtmode)];
+ return env->banked_r14[r14_bank_number(tgtmode)];
case 8 ... 12:
switch (tgtmode) {
case ARM_CPU_MODE_USR:
(it's one of the "no behavioural change" bits).
thanks
-- PMM
- [Qemu-arm] [PATCH 0/2] Fix the last Hyp mode bug and turn it on for A7, A15, Peter Maydell, 2018/11/09
- [Qemu-arm] [PATCH 2/2] target/arm/cpu: Give Cortex-A15 and -A7 the EL2 feature, Peter Maydell, 2018/11/09
- [Qemu-arm] [PATCH 1/2] target/arm: Hyp mode R14 is shared with User and System, Peter Maydell, 2018/11/09
- Re: [Qemu-arm] [PATCH 0/2] Fix the last Hyp mode bug and turn it on for A7, A15, Philippe Mathieu-Daudé, 2018/11/11
- Re: [Qemu-arm] [Qemu-devel] [PATCH 0/2] Fix the last Hyp mode bug and turn it on for A7, A15, Richard Henderson, 2018/11/12