Commit 04e43ec9 authored by Borislav Petkov's avatar Borislav Petkov Committed by Borislav Petkov (AMD)
Browse files

x86/split_lock: Restructure the unwieldy switch-case in sld_state_show() 



Split the handling in two parts:

1. handle the sld_state option first

2. handle X86_FEATURE flag-based printing afterwards

This splits the function nicely into two, separate logical things which
are easier to parse and understand.

Also, zap the printing in the disabled case.

Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Link: https://patch.msgid.link/20260226145033.GAaaBduQ0rWXydOkAm@fat_crate.local
parent ceea7868

arch/x86/kernel/cpu/bus_lock.c

+25 −24
Original line number Diff line number Diff line
@@ -391,34 +391,35 @@ static void __init split_lock_setup(struct cpuinfo_x86 *c) 


static void sld_state_show(void)

{

	if (!boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT) &&

	    !boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))

	const char *action = "warning";



	if ((!boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT) &&

	     !boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) ||

	    (sld_state == sld_off))

		return;



	switch (sld_state) {

	case sld_off:

		pr_info("disabled\n");

		break;

	case sld_warn:

	if (sld_state == sld_ratelimit) {

		if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))

			pr_info("#DB: setting system wide bus lock rate limit to %u/sec\n", bld_ratelimit.burst);

		return;

	} else if (sld_state == sld_fatal) {

		action = "sending SIGBUS";

	}



	if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) {

			pr_info("#AC: crashing the kernel on kernel split_locks and warning on user-space split_locks\n");

			if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,

					      "x86/splitlock", NULL, splitlock_cpu_offline) < 0)

		pr_info("#AC: crashing the kernel on kernel split_locks and %s on user-space split_locks\n", action);



		/*

		 * This is handling the case where a CPU goes offline at the

		 * moment where split lock detection is disabled in the warn

		 * setting, see split_lock_warn(). It doesn't have any effect

		 * in the fatal case.

		 */

		if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/splitlock", NULL, splitlock_cpu_offline) < 0)

			pr_warn("No splitlock CPU offline handler\n");



	} else if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT)) {

			pr_info("#DB: warning on user-space bus_locks\n");

		}

		break;

	case sld_fatal:

		if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))

			pr_info("#AC: crashing the kernel on kernel split_locks and sending SIGBUS on user-space split_locks\n");

		else if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))

			pr_info("#DB: sending SIGBUS on user-space bus_locks\n");

		break;

	case sld_ratelimit:

		if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))

			pr_info("#DB: setting system wide bus lock rate limit to %u/sec\n", bld_ratelimit.burst);

		break;

		pr_info("#DB: %s on user-space bus_locks\n", action);

	}

}