x86/itmt: Add debugfs file to show core priorities

Multiple drivers can report priorities to ITMT. To aid in debugging
any issues with the values reported by drivers introduce a debugfs
file to read out the values.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/20250609200518.3616080-14-superm1@kernel.org

diff --git a/arch/x86/kernel/itmt.c b/arch/x86/kernel/itmt.c
index 9cea1fc36c18faee0ca814f365584aeb8ce7d032..243a769fdd97b940cc5345cb4fd11aa438694cda 100644 (file)
--- a/arch/x86/kernel/itmt.c
+++ b/arch/x86/kernel/itmt.c
@@ -59,6 +59,18 @@ static ssize_t sched_itmt_enabled_write(struct file *filp,
        return result;
 }
 
+static int sched_core_priority_show(struct seq_file *s, void *unused)
+{
+       int cpu;
+
+       seq_puts(s, "CPU #\tPriority\n");
+       for_each_possible_cpu(cpu)
+               seq_printf(s, "%d\t%d\n", cpu, arch_asym_cpu_priority(cpu));
+
+       return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(sched_core_priority);
+
 static const struct file_operations dfs_sched_itmt_fops = {
        .read =         debugfs_read_file_bool,
        .write =        sched_itmt_enabled_write,
@@ -67,6 +79,7 @@ static const struct file_operations dfs_sched_itmt_fops = {
 };
 
 static struct dentry *dfs_sched_itmt;
+static struct dentry *dfs_sched_core_prio;
 
 /**
  * sched_set_itmt_support() - Indicate platform supports ITMT
@@ -102,6 +115,14 @@ int sched_set_itmt_support(void)
                return -ENOMEM;
        }
 
+       dfs_sched_core_prio = debugfs_create_file("sched_core_priority", 0644,
+                                                 arch_debugfs_dir, NULL,
+                                                 &sched_core_priority_fops);
+       if (IS_ERR_OR_NULL(dfs_sched_core_prio)) {
+               dfs_sched_core_prio = NULL;
+               return -ENOMEM;
+       }
+
        sched_itmt_capable = true;
 
        sysctl_sched_itmt_enabled = 1;
@@ -133,6 +154,8 @@ void sched_clear_itmt_support(void)
 
        debugfs_remove(dfs_sched_itmt);
        dfs_sched_itmt = NULL;
+       debugfs_remove(dfs_sched_core_prio);
+       dfs_sched_core_prio = NULL;
 
        if (sysctl_sched_itmt_enabled) {
                /* disable sched_itmt if we are no longer ITMT capable */