Re: [GIT pull] x86/pti for 5.3-rc1

[Linus Torvalds]

On Mon, Jul 8, 2019 at 2:22 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> @@ -643,9 +644,11 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
>  {
>         struct thread_struct *thread = &tsk->thread;
>         unsigned long val = 0;
> +       int index = n;
>
>         if (n < HBP_NUM) {
> -               struct perf_event *bp = thread->ptrace_bps[n];
> +               index = array_index_nospec(index, HBP_NUM);
> +               struct perf_event *bp = thread->ptrace_bps[index];

This causes a new warning:

   warning: ISO C90 forbids mixed declarations and code

and I'm fixing it up in the merge as follows:

@@@ -633,9 -644,11 +634,10 @@@ static unsigned long ptrace_get_debugre
  {
        struct thread_struct *thread = &tsk->thread;
        unsigned long val = 0;
 -      int index = n;

        if (n < HBP_NUM) {
-               struct perf_event *bp = thread->ptrace_bps[n];
 -              index = array_index_nospec(index, HBP_NUM);
++              int index = array_index_nospec(n, HBP_NUM);
+               struct perf_event *bp = thread->ptrace_bps[index];

                if (bp)
                        val = bp->hw.info.address;

Holler if I did something stupid.

                Linus