[PATCH] riscv: vector: only enable interrupts in the first-use trap

[Guo Ren]

Another one:
diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
index f9c8e19ab301..764b7c098165 100644
--- a/arch/riscv/kernel/vector.c
+++ b/arch/riscv/kernel/vector.c
@@ -84,7 +84,7 @@ static int riscv_v_thread_zalloc(void)
 {
        void *datap;

        datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
        if (!datap)
                return -ENOMEM;

@@ -162,10 +162,9 @@ bool riscv_v_first_use_handler(struct pt_regs *regs)
         * context where VS has been off. So, try to allocate the user's V
         * context and resume execution.
         */
-       if (riscv_v_thread_zalloc()) {
-               force_sig(SIGBUS);
-               return true;
-       }
+       if (riscv_v_thread_zalloc())
+               return false;
+
        riscv_v_vstate_on(regs);
        return true;
 }
--------

Your force_sig throws the debug info away, and the standard one is
enough for us.

On Thu, Jun 29, 2023 at 2:04 AM Guo Ren <guoren at kernel.org> wrote:
>
> On Sun, Jun 25, 2023 at 11:54 AM Andy Chiu <andy.chiu at sifive.com> wrote:
> >
> > The function irqentry_exit_to_user_mode() must be called with interrupt
> > disabled. The caller of do_trap_insn_illegal() also assumes running
> > without interrupts. So, we should turn off interrupts after
> > riscv_v_first_use_handler() returns.
> >
> > Fixes: cd054837243b ("riscv: Allocate user's vector context in the first-use trap")
> > Signed-off-by: Andy Chiu <andy.chiu at sifive.com>
> > ---
> >  arch/riscv/kernel/traps.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> > index 05ffdcd1424e..1595e246bda1 100644
> > --- a/arch/riscv/kernel/traps.c
> > +++ b/arch/riscv/kernel/traps.c
> > @@ -149,12 +149,18 @@ DO_ERROR_INFO(do_trap_insn_fault,
> >
> >  asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *regs)
> >  {
> > +       bool handled;
> > +
> >         if (user_mode(regs)) {
> >                 irqentry_enter_from_user_mode(regs);
> >
> >                 local_irq_enable();
> >
> > -               if (!riscv_v_first_use_handler(regs))
> > +               handled = riscv_v_first_use_handler(regs);
> How about making riscv_v_first_use_handler irq_disable safe?
> --------
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index 5158961ea977..545295045705 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -153,8 +153,6 @@ asmlinkage __visible __trap_section void
> do_trap_insn_illegal(struct pt_regs *re
>         if (user_mode(regs)) {
>                 irqentry_enter_from_user_mode(regs);
>
> -               local_irq_enable();
> -
>                 if (!riscv_v_first_use_handler(regs))
>                         do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->epc,
>                                       "Oops - illegal instruction");
> diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c
> index f9c8e19ab301..7616c027ee64 100644
> --- a/arch/riscv/kernel/vector.c
> +++ b/arch/riscv/kernel/vector.c
> @@ -84,7 +84,7 @@ static int riscv_v_thread_zalloc(void)
>  {
>         void *datap;
>
> -       datap = kzalloc(riscv_v_vsize, GFP_KERNEL);
> +       datap = kzalloc(riscv_v_vsize, GFP_KERNEL | GFP_ATOMIC);
>         if (!datap)
>                 return -ENOMEM;
> ---------
>
> > +
> > +               local_irq_disable();
> > +
> > +               if (!handled)
> >                         do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->epc,
> >                                       "Oops - illegal instruction");
> >
> > --
> > 2.17.1
> >
>
>
> --
> Best Regards
>  Guo Ren



-- 
Best Regards
 Guo Ren