ndis: patch for review

[Bernhard Schmidt]

9, 2010 at 23:53, Paul B Mahol <onemda at gmail.com> wrote:
> Hi,
>
> First: we should pin curthread on CPU before we check on which CPU is curthread.
>
> Second: instead of sti & cli use critical sections when saving %fs register.
>
> Third: I do not know what happens if we get preempted while windows
> code were running,
> so leave critical section only _after_ executing windows code.


Do you have a test case for that? If so, can you post it?


> diff --git a/sys/compat/ndis/kern_windrv.c b/sys/compat/ndis/kern_windrv.c
> index f231863..ba29fd2 100644
> --- a/sys/compat/ndis/kern_windrv.c
> +++ b/sys/compat/ndis/kern_windrv.c
> @@ -613,8 +613,6 @@ struct gdt {
>  extern uint16_t        x86_getfs(void);
>  extern void x86_setfs(uint16_t);
>  extern void *x86_gettid(void);
> -extern void x86_critical_enter(void);
> -extern void x86_critical_exit(void);
>  extern void x86_getldt(struct gdt *, uint16_t *);
>  extern void x86_setldt(struct gdt *, uint16_t);
>
> @@ -668,8 +666,10 @@ extern void x86_setldt(struct gdt *, uint16_t);
>  void
>  ctxsw_utow(void)
>  {
> -       struct tid              *t;
> +       struct tid *t;
>
> +       sched_pin();
> +       critical_enter();
>        t = &my_tids[curthread->td_oncpu];
>
>        /*
> @@ -685,12 +685,9 @@ ctxsw_utow(void)
>        if (t->tid_self != t)
>                x86_newldt(NULL);
>
> -       x86_critical_enter();
>        t->tid_oldfs = x86_getfs();
>        t->tid_cpu = curthread->td_oncpu;
> -       sched_pin();
>        x86_setfs(SEL_TO_FS(t->tid_selector));
> -       x86_critical_exit();
>
>        /* Now entering Windows land, population: you. */
>  }
> @@ -706,11 +703,10 @@ ctxsw_wtou(void)
>  {
>        struct tid              *t;
>
> -       x86_critical_enter();
>        t = x86_gettid();
>        x86_setfs(t->tid_oldfs);
> +       critical_exit();
>        sched_unpin();
> -       x86_critical_exit();
>
>        /* Welcome back to UNIX land, we missed you. */
>
> diff --git a/sys/compat/ndis/winx32_wrap.S b/sys/compat/ndis/winx32_wrap.S
> index c051504..fa4aa87 100644
> --- a/sys/compat/ndis/winx32_wrap.S
> +++ b/sys/compat/ndis/winx32_wrap.S
> @@ -375,11 +375,3 @@ ENTRY(x86_setfs)
>  ENTRY(x86_gettid)
>        mov     %fs:12,%eax
>        ret
> -
> -ENTRY(x86_critical_enter)
> -       cli
> -       ret
> -
> -ENTRY(x86_critical_exit)
> -       sti
> -       ret
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-- 
Bernhard