Re: [PATCH 0/2] Fix mtfsf, mtfsfi and mtfsb1 bug

[Matheus K. Ferst]

CC'ing the reporter

On 20/10/2021 09:57, Lucas Mateus Castro (alqotel) wrote:
> From: "Lucas Mateus Castro (alqotel)" <lucas.castro@eldorado.org.br>
>
> The instructions mtfsf, mtfsfi and mtfsb, when called, fail to set the FI
> bit (bit 46 in the FPSCR) and can set to 1 the reserved bit 52 of the
> FPSCR, as reported in https://gitlab.com/qemu-project/qemu/-/issues/266
> (although the bug report is only for mtfsf, the bug applies to mtfsfi and
> mtfsb1 as well).
>
> These instructions also fail to throw an exception when the exception
> and enabling bits are set, this can be tested by adding
> 'prctl(PR_SET_FPEXC, PR_FP_EXC_PRECISE);' before the __builtin_mtfsf
> call in the test case of the bug report.
>
> These patches aim to fix these issues.
>
> Lucas Mateus Castro (alqotel) (2):
>    target/ppc: Fixed call to deferred exception
>    target/ppc: ppc_store_fpscr doesn't update bit 52
>
>   target/ppc/cpu.c                   |  2 +-
>   target/ppc/cpu.h                   |  3 +++
>   target/ppc/fpu_helper.c            | 41 ++++++++++++++++++++++++++++++
>   target/ppc/helper.h                |  1 +
>   target/ppc/translate/fp-impl.c.inc |  6 ++---
>   5 files changed, 49 insertions(+), 4 deletions(-)
>
> --
> 2.31.1
--
Matheus K. Ferst
Instituto de Pesquisas ELDORADO <http://www.eldorado.org.br/>
Analista de Software
Aviso Legal - Disclaimer <https://www.eldorado.org.br/disclaimer.html>