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

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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: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://patch.msgid.link/20260226145033.GAaaBduQ0rWXydOkAm@fat_crate.local
This commit is contained in:
Borislav Petkov
2026-02-26 15:50:33 +01:00
committed by Borislav Petkov (AMD)
parent ceea7868b5
commit 04e43ec9f0
1 changed files with 25 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

49
arch/x86/kernel/cpu/bus_lock.c
View File

@@ -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 (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_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 (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);
break;
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 %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: %s on user-space bus_locks\n", action);
}
}