On Mon, Mar 24, 2025 at 05:40:29PM -0700, Atish Patra wrote:
> Save stval during exception handling so that it can be decoded to
> figure out the details of exception type.
>
> Signed-off-by: Atish Patra <ati...@rivosinc.com>
> ---
> tools/testing/selftests/kvm/include/riscv/processor.h | 1 +
> tools/testing/selftests/kvm/lib/riscv/handlers.S | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h
> b/tools/testing/selftests/kvm/include/riscv/processor.h
> index 5f389166338c..f4a7d64fbe9a 100644
> --- a/tools/testing/selftests/kvm/include/riscv/processor.h
> +++ b/tools/testing/selftests/kvm/include/riscv/processor.h
> @@ -95,6 +95,7 @@ struct ex_regs {
> unsigned long epc;
> unsigned long status;
> unsigned long cause;
> + unsigned long stval;
> };
>
> #define NR_VECTORS 2
> diff --git a/tools/testing/selftests/kvm/lib/riscv/handlers.S
> b/tools/testing/selftests/kvm/lib/riscv/handlers.S
> index aa0abd3f35bb..2884c1e8939b 100644
> --- a/tools/testing/selftests/kvm/lib/riscv/handlers.S
> +++ b/tools/testing/selftests/kvm/lib/riscv/handlers.S
> @@ -45,9 +45,11 @@
> csrr s0, CSR_SEPC
> csrr s1, CSR_SSTATUS
> csrr s2, CSR_SCAUSE
> + csrr s3, CSR_STVAL
> sd s0, 248(sp)
> sd s1, 256(sp)
> sd s2, 264(sp)
> + sd s3, 272(sp)
We can't add stval without also changing how much stack we allocate at the
top of this macro, but since we need to keep sp 16-byte aligned in order
to call C code (route_exception()) we'll need to decrement -8*36, not
-8*35. Or, we could just switch struct ex_regs to be the kernel's struct
pt_regs which has 36 unsigned longs. The 'badaddr' member is for stval and
the additional long is orig_a0.
> .endm
>
> .macro restore_context
I guess we should restore stval too.
Thanks,
drew
>
> --
> 2.43.0
>
>
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