x86/platform/uv: Rework NMI "action" modparam handling (ec2f16f1) · Commits · github.com / kvm-riscv / linux

arch/x86/platform/uv/uv_nmi.c

+57 −47

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#include <linux/sched.h>
		#include <linux/sched/debug.h>
		#include <linux/slab.h>
		#include <linux/string.h>
		#include <linux/clocksource.h>

		#include <asm/apic.h>
		@@ -178,49 +179,56 @@ module_param_named(debug, uv_nmi_debug, int, 0644);
		} while (0)

		/* Valid NMI Actions */
		#define ACTION_LEN 16
		static struct nmi_action {
		char *action;
		char *desc;
		} valid_acts[] = {
		{ "kdump", "do kernel crash dump" },
		{ "dump", "dump process stack for each cpu" },
		{ "ips", "dump Inst Ptr info for each cpu" },
		{ "kdb", "enter KDB (needs kgdboc= assignment)" },
		{ "kgdb", "enter KGDB (needs gdb target remote)" },
		{ "health", "check if CPUs respond to NMI" },
		enum action_t {
		nmi_act_kdump,
		nmi_act_dump,
		nmi_act_ips,
		nmi_act_kdb,
		nmi_act_kgdb,
		nmi_act_health,
		nmi_act_max
		};
		typedef char action_t[ACTION_LEN];
		static action_t uv_nmi_action = { "dump" };

		static const char * const actions[nmi_act_max] = {
		[nmi_act_kdump] = "kdump",
		[nmi_act_dump] = "dump",
		[nmi_act_ips] = "ips",
		[nmi_act_kdb] = "kdb",
		[nmi_act_kgdb] = "kgdb",
		[nmi_act_health] = "health",
		};

		static const char * const actions_desc[nmi_act_max] = {
		[nmi_act_kdump] = "do kernel crash dump",
		[nmi_act_dump] = "dump process stack for each cpu",
		[nmi_act_ips] = "dump Inst Ptr info for each cpu",
		[nmi_act_kdb] = "enter KDB (needs kgdboc= assignment)",
		[nmi_act_kgdb] = "enter KGDB (needs gdb target remote)",
		[nmi_act_health] = "check if CPUs respond to NMI",
		};

		static enum action_t uv_nmi_action = nmi_act_dump;

		static int param_get_action(char buffer, const struct kernel_param kp)
		{
		return sprintf(buffer, "%s\n", uv_nmi_action);
		return sprintf(buffer, "%s\n", actions[uv_nmi_action]);
		}

		static int param_set_action(const char val, const struct kernel_param kp)
		{
		int i;
		int n = ARRAY_SIZE(valid_acts);
		char arg[ACTION_LEN];

		/* (remove possible '\n') */
		strscpy(arg, val, strnchrnul(val, sizeof(arg)-1, '\n') - val + 1);

		for (i = 0; i < n; i++)
		if (!strcmp(arg, valid_acts[i].action))
		break;
		int i, n = ARRAY_SIZE(actions);

		if (i < n) {
		strscpy(uv_nmi_action, arg, sizeof(uv_nmi_action));
		pr_info("UV: New NMI action:%s\n", uv_nmi_action);
		i = sysfs_match_string(actions, val);
		if (i >= 0) {
		uv_nmi_action = i;
		pr_info("UV: New NMI action:%s\n", actions[i]);
		return 0;
		}

		pr_err("UV: Invalid NMI action:%s, valid actions are:\n", arg);
		pr_err("UV: Invalid NMI action. Valid actions are:\n");
		for (i = 0; i < n; i++)
		pr_err("UV: %-8s - %s\n",
		valid_acts[i].action, valid_acts[i].desc);
		pr_err("UV: %-8s - %s\n", actions[i], actions_desc[i]);

		return -EINVAL;
		}

		@@ -228,15 +236,10 @@ static const struct kernel_param_ops param_ops_action = {
		.get = param_get_action,
		.set = param_set_action,
		};
		#define param_check_action(name, p) __param_check(name, p, action_t)
		#define param_check_action(name, p) __param_check(name, p, enum action_t)

		module_param_named(action, uv_nmi_action, action, 0644);

		static inline bool uv_nmi_action_is(const char *action)
		{
		return (strncmp(uv_nmi_action, action, strlen(action)) == 0);
		}

		/* Setup which NMI support is present in system */
		static void uv_nmi_setup_mmrs(void)
		{
		@@ -727,10 +730,10 @@ static void uv_nmi_dump_state_cpu(int cpu, struct pt_regs *regs)
		if (cpu == 0)
		uv_nmi_dump_cpu_ip_hdr();

		if (current->pid != 0 \|\| !uv_nmi_action_is("ips"))
		if (current->pid != 0 \|\| uv_nmi_action != nmi_act_ips)
		uv_nmi_dump_cpu_ip(cpu, regs);

		if (uv_nmi_action_is("dump")) {
		if (uv_nmi_action == nmi_act_dump) {
		pr_info("UV:%sNMI process trace for CPU %d\n", dots, cpu);
		show_regs(regs);
		}
		@@ -798,7 +801,7 @@ static void uv_nmi_dump_state(int cpu, struct pt_regs *regs, int master)
		int saved_console_loglevel = console_loglevel;

		pr_alert("UV: tracing %s for %d CPUs from CPU %d\n",
		uv_nmi_action_is("ips") ? "IPs" : "processes",
		uv_nmi_action == nmi_act_ips ? "IPs" : "processes",
		atomic_read(&uv_nmi_cpus_in_nmi), cpu);

		console_loglevel = uv_nmi_loglevel;
		@@ -874,7 +877,7 @@ static inline int uv_nmi_kdb_reason(void)
		static inline int uv_nmi_kdb_reason(void)
		{
		/* Ensure user is expecting to attach gdb remote */
		if (uv_nmi_action_is("kgdb"))
		if (uv_nmi_action == nmi_act_kgdb)
		return 0;

		pr_err("UV: NMI error: KDB is not enabled in this kernel\n");
		@@ -950,28 +953,35 @@ static int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
		master = (atomic_read(&uv_nmi_cpu) == cpu);

		/* If NMI action is "kdump", then attempt to do it */
		if (uv_nmi_action_is("kdump")) {
		if (uv_nmi_action == nmi_act_kdump) {
		uv_nmi_kdump(cpu, master, regs);

		/* Unexpected return, revert action to "dump" */
		if (master)
		strscpy(uv_nmi_action, "dump", sizeof(uv_nmi_action));
		uv_nmi_action = nmi_act_dump;
		}

		/* Pause as all CPU's enter the NMI handler */
		uv_nmi_wait(master);

		/* Process actions other than "kdump": */
		if (uv_nmi_action_is("health")) {
		switch (uv_nmi_action) {
		case nmi_act_health:
		uv_nmi_action_health(cpu, regs, master);
		} else if (uv_nmi_action_is("ips") \|\| uv_nmi_action_is("dump")) {
		break;
		case nmi_act_ips:
		case nmi_act_dump:
		uv_nmi_dump_state(cpu, regs, master);
		} else if (uv_nmi_action_is("kdb") \|\| uv_nmi_action_is("kgdb")) {
		break;
		case nmi_act_kdb:
		case nmi_act_kgdb:
		uv_call_kgdb_kdb(cpu, regs, master);
		} else {
		break;
		default:
		if (master)
		pr_alert("UV: unknown NMI action: %s\n", uv_nmi_action);
		pr_alert("UV: unknown NMI action: %d\n", uv_nmi_action);
		uv_nmi_sync_exit(master);
		break;
		}

		/* Clear per_cpu "in_nmi" flag */