Commit 9a0e3b92 authored by Liao Chang's avatar Liao Chang Committed by Catalin Marinas
Browse files

arm64: Return early when break handler is found on linked-list 



The search for breakpoint handlers iterate through the entire
linked list. Given that all registered hook has a valid fn field, and no
registered hooks share the same mask and imm. This commit optimize the
efficiency slightly by returning early as a matching handler is found.

Signed-off-by: default avatarLiao Chang <liaochang1@huawei.com>
Acked-by: default avatarWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241024034120.3814224-1-liaochang1@huawei.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent f8192813

arch/arm64/kernel/debug-monitors.c

+2 −3
Original line number Diff line number Diff line
@@ -303,7 +303,6 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) 
{

	struct break_hook *hook;

	struct list_head *list;

	int (*fn)(struct pt_regs *regs, unsigned long esr) = NULL;



	list = user_mode(regs) ? &user_break_hook : &kernel_break_hook;
@@ -313,10 +312,10 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr) 
	 */

	list_for_each_entry_rcu(hook, list, node) {

		if ((esr_brk_comment(esr) & ~hook->mask) == hook->imm)

			fn = hook->fn;

			return hook->fn(regs, esr);

	}



	return fn ? fn(regs, esr) : DBG_HOOK_ERROR;

	return DBG_HOOK_ERROR;

}

NOKPROBE_SYMBOL(call_break_hook);