[PATCH v3 11/13] arm64: debug: split brk64 exception entry

[Mark Rutland]

This generally looks good; 

On Mon, Jun 09, 2025 at 06:34:11PM +0100, Ada Couprie Diaz wrote:
> +static int brk_handler(unsigned long esr, struct pt_regs *regs)
>  {
>  	if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
>  		return 0;
> @@ -279,6 +278,14 @@ static int brk_handler(unsigned long unused, unsigned long esr,
>  }
>  NOKPROBE_SYMBOL(brk_handler);
>  
> +void do_brk64(unsigned long esr, struct pt_regs *regs)
> +{
> +	if (brk_handler(esr, regs))
> +		arm64_notify_die("BRK handler", regs, SIGTRAP, TRAP_BRKPT, regs->pc,
> +			esr);
> +}
> +NOKPROBE_SYMBOL(do_brk64);

Could we please split this into separate do_el{0,1}_brk64() helpers?

e.g. rename call_break_hook() to call_el1_break_hook(), remove
brk_handler(), and have:

| void do_el0_brk64(struct pt_regs *regs, unsigned long esr)
| {
|         if (IS_ENABLED(CONFIG_UPROBES) &&
|             esr_brk_comment(esr) == UPROBES_BRK_IMM &&
|             uprobe_brk_handler(regs, esr) == DBG_HOOK_HANDLED)
|                 return;
| 
|         send_user_sigtrap(TRAP_BRKPT);
| }
|
| void do_el1_brk64(unsigned long esr, struct pt_regs *regs)
| {
|         if (call_el1_break_hook(regs, esr) == DBG_HOOK_HANDLED)
|                 return;
| 
|         pr_warn("Unexpected kernel BRK exception at EL1\n");
|         arm64_notify_die("BRK handler", regs, SIGTRAP, TRAP_BRKPT, regs->pc,
|                          esr);
| }
| NOKPROBE_SYMBOL(do_brk64);

... and we could probably simplify the latter to:

| void do_el1_brk64(unsigned long esr, struct pt_regs *regs)
| {
|         if (call_el1_break_hook(regs, esr) == DBG_HOOK_HANDLED)
|                 return;
| 
|	  die("Oops - BRK", regs, esr);
| }
| NOKPROBE_SYMBOL(do_brk64);

... matching do_el1_undef() and do_el1_bti().

Mark.