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x86/platform/uv: Rework NMI "action" modparam handling

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Rework NMI "action" modparam handling:

 - Replace the uv_nmi_action string with an enum; and
 - Use sysfs_match_string() for string parsing in param_set_action()

No change in functionality intended.

Suggested-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230916130653.243532-1-hdegoede@redhat.com
This commit is contained in:
Hans de Goede 2023-09-16 15:06:53 +02:00 committed by Ingo Molnar
parent f0b0d403ea
commit ec2f16f180
1 changed files with 57 additions and 47 deletions
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104
arch/x86/platform/uv/uv_nmi.c
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@ -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];
int i, n = ARRAY_SIZE(actions);
/* (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;
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 */