On 09/06/2016 12:11 PM, Catalin Marinas wrote:
On Tue, Aug 02, 2016 at 11:00:07AM +0530, Pratyush Anand wrote:--- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -246,6 +246,8 @@ static void send_user_sigtrap(int si_code) static int single_step_handler(unsigned long addr, unsigned int esr, struct pt_regs *regs) { + bool handler_found = false; + /* * If we are stepping a pending breakpoint, call the hw_breakpoint * handler first. @@ -253,7 +255,14 @@ static int single_step_handler(unsigned long addr, unsigned int esr, if (!reinstall_suspended_bps(regs)) return 0;- if (user_mode(regs)) { +#ifdef CONFIG_KPROBES + if (kprobe_single_step_handler(regs, esr) == DBG_HOOK_HANDLED) + handler_found = true; +#endif + if (!handler_found && call_step_hook(regs, esr) == DBG_HOOK_HANDLED) + handler_found = true; + + if (!handler_found && user_mode(regs)) { send_user_sigtrap(TRAP_HWBKPT);Could we register kprobe_single_step_handler() via register_set_hook() and only invoke call_step_hook() above?
I seem to recall a criticism of doing that in a much earlier kprobes64 patch of mine. The concern was that it would cause unnecessarily more kernel functions to be kprobes-blacklisted. Hence the hardcoded check and call.
-dl
