Re: [PATCH 3/6] fix register corruption in irq on qemu

[Samuel Thibault]

Luca Dariz, le sam. 05 févr. 2022 18:51:26 +0100, a ecrit:
> rbx was used to compute the irq index in iunit and ivect arrays,
> however it should be preserved by pushing it in to the stack.  As a
> solution, we use rax instead, that is preserved across function calls
> and is not used as a function argument.
> 
> Signed-off-by: Luca Dariz <luca@orpolo.org>

Applied, thanks!

> ---
>  x86_64/interrupt.S | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/x86_64/interrupt.S b/x86_64/interrupt.S
> index fccf6e28..73151b06 100644
> --- a/x86_64/interrupt.S
> +++ b/x86_64/interrupt.S
> @@ -38,15 +38,15 @@ ENTRY(interrupt)
>       pushq   %rax                    /* save irq number */
>       call    spl7                    /* set ipl */
>       pushq   %rax                    /* save previous ipl */
> -     movl    8(%esp),%edx            /* set irq number as 3rd arg */
> -     movl    %edx,%ebx               /* copy irq number */
> -     shll    $2,%ebx                 /* irq * 4 */
> -     movl    EXT(iunit)(%ebx),%edi   /* get device unit number as 1st arg */
>       movl    %eax, %esi              /* previous ipl as 2nd arg */
> +     movl    8(%esp),%edx            /* set irq number as 3rd arg */
> +     movl    %edx,%eax               /* copy irq number */
> +     shll    $2,%eax                 /* irq * 4 */
> +     movl    EXT(iunit)(%eax),%edi   /* get device unit number as 1st arg */
>       movq    16(%esp), %rcx          /* return address as 4th arg */
>       movq    24(%esp), %r8           /* address of interrupted registers as 
> 5th arg */
> -     shll    $1,%ebx                 /* irq * 8 */
> -     call    *EXT(ivect)(%ebx)       /* call interrupt handler */
> +     shll    $1,%eax                 /* irq * 8 */
> +     call    *EXT(ivect)(%eax)       /* call interrupt handler */
>       popq    %rdi                    /* restore previous ipl */
>       call    splx_cli                /* restore previous ipl */
>  
> -- 
> 2.30.2
> 
> 

-- 
Samuel
---
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