Re: [kvm-unit-tests v3 10/13] powerpc: Add support for more interrupts including HV interrupts

[Joel Stanley <joel@jms.id.au>]

Hi Nick,

On Mon, 27 Mar 2023 at 12:55, Nicholas Piggin <npiggin@gmail.com> wrote:
>
> Interrupt vectors were not being populated for all architected
> interrupt types, which could lead to crashes rather than a message for
> unhandled interrupts.
>
> 0x20 sized vectors require some reworking of the code to fit. This
> also adds support for HV / HSRR type interrupts which will be used in
> a later change.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  powerpc/cstart64.S | 79 ++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 65 insertions(+), 14 deletions(-)
>
> diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S

> +handler_trampoline:
> +       mfctr   r0
> +       std     r0,_CTR(r1)
> +
> +       ld      r0, P_HANDLER(0)
> +       mtctr   r0
> +
> +       /* nip and msr */
> +       mfsrr0  r0

I tried building the tests on a power8 box with binutils 2.34 and gas complains:

powerpc/cstart64.S: Assembler messages:
powerpc/cstart64.S:337: Error: unrecognized opcode: `mfhsrr0'
powerpc/cstart64.S:340: Error: unrecognized opcode: `mfhsrr1'

It appears this mnemonic is only supported for power10 (and were only
added in binutils 2.36):

$ git grep -i mfhsrr
opcodes/ppc-opc.c:{"mfhsrr0",   XSPR(31,339,314), XSPR_MASK, POWER10,
 EXT,            {RS}},
opcodes/ppc-opc.c:{"mfhsrr1",   XSPR(31,339,315), XSPR_MASK, POWER10,
 EXT,            {RS}},

I replaced it with mfspr and the tests ran fine:

@@ -334,10 +338,10 @@ handler_htrampoline:
        mtctr   r0

        /* nip and msr */
-       mfhsrr0 r0
+       mfspr   r0, SPRN_HSRR0
        std     r0, _NIP(r1)

-       mfhsrr1 r0
+       mfspr   r0, SPRN_HSRR1
        std     r0, _MSR(r1)

Cheers,

Joel