path: root/arch/x86/platform/uv/uv_nmi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SGI NMI support routines
 *
 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
 * Copyright (C) 2007-2017 Silicon Graphics, Inc. All rights reserved.
 * Copyright (c) Mike Travis
 */

#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/kdb.h>
#include <linux/kexec.h>
#include <linux/kgdb.h>
#include <linux/moduleparam.h>
#include <linux/nmi.h>
#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>
#include <asm/current.h>
#include <asm/kdebug.h>
#include <asm/local64.h>
#include <asm/nmi.h>
#include <asm/reboot.h>
#include <asm/traps.h>
#include <asm/uv/uv.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/uv_mmrs.h>

/*
 * UV handler for NMI
 *
 * Handle system-wide NMI events generated by the global 'power nmi' command.
 *
 * Basic operation is to field the NMI interrupt on each CPU and wait
 * until all CPU's have arrived into the nmi handler.  If some CPU's do not
 * make it into the handler, try and force them in with the IPI(NMI) signal.
 *
 * We also have to lessen UV Hub MMR accesses as much as possible as this
 * disrupts the UV Hub's primary mission of directing NumaLink traffic and
 * can cause system problems to occur.
 *
 * To do this we register our primary NMI notifier on the NMI_UNKNOWN
 * chain.  This reduces the number of false NMI calls when the perf
 * tools are running which generate an enormous number of NMIs per
 * second (~4M/s for 1024 CPU threads).  Our secondary NMI handler is
 * very short as it only checks that if it has been "pinged" with the
 * IPI(NMI) signal as mentioned above, and does not read the UV Hub's MMR.
 *
 */

static struct uv_hub_nmi_s **uv_hub_nmi_list;

DEFINE_PER_CPU(struct uv_cpu_nmi_s, uv_cpu_nmi);

/* Newer SMM NMI handler, not present in all systems */
static unsigned long uvh_nmi_mmrx;		/* UVH_EVENT_OCCURRED0/1 */
static unsigned long uvh_nmi_mmrx_clear;	/* UVH_EVENT_OCCURRED0/1_ALIAS */
static int uvh_nmi_mmrx_shift;			/* UVH_EVENT_OCCURRED0/1_EXTIO_INT0_SHFT */
static char *uvh_nmi_mmrx_type;			/* "EXTIO_INT0" */

/* Non-zero indicates newer SMM NMI handler present */
static unsigned long uvh_nmi_mmrx_supported;	/* UVH_EXTIO_INT0_BROADCAST */

/* Indicates to BIOS that we want to use the newer SMM NMI handler */
static unsigned long uvh_nmi_mmrx_req;		/* UVH_BIOS_KERNEL_MMR_ALIAS_2 */
static int uvh_nmi_mmrx_req_shift;		/* 62 */

/* UV hubless values */
#define NMI_CONTROL_PORT	0x70
#define NMI_DUMMY_PORT		0x71
#define PAD_OWN_GPP_D_0		0x2c
#define GPI_NMI_STS_GPP_D_0	0x164
#define GPI_NMI_ENA_GPP_D_0	0x174
#define STS_GPP_D_0_MASK	0x1
#define PAD_CFG_DW0_GPP_D_0	0x4c0
#define GPIROUTNMI		(1ul << 17)
#define PCH_PCR_GPIO_1_BASE	0xfdae0000ul
#define PCH_PCR_GPIO_ADDRESS(offset) (int *)((u64)(pch_base) | (u64)(offset))

static u64 *pch_base;
static unsigned long nmi_mmr;
static unsigned long nmi_mmr_clear;
static unsigned long nmi_mmr_pending;

static atomic_t	uv_in_nmi;
static atomic_t uv_nmi_cpu = ATOMIC_INIT(-1);
static atomic_t uv_nmi_cpus_in_nmi = ATOMIC_INIT(-1);
static atomic_t uv_nmi_slave_continue;
static cpumask_var_t uv_nmi_cpu_mask;

static atomic_t uv_nmi_kexec_failed;

/* Values for uv_nmi_slave_continue */
#define SLAVE_CLEAR	0
#define SLAVE_CONTINUE	1
#define SLAVE_EXIT	2

/*
 * Default is all stack dumps go to the console and buffer.
 * Lower level to send to log buffer only.
 */
static int uv_nmi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
module_param_named(dump_loglevel, uv_nmi_loglevel, int, 0644);

/*
 * The following values show statistics on how perf events are affecting
 * this system.
 */
static int param_get_local64(char *buffer, const struct kernel_param *kp)
{
	return sprintf(buffer, "%lu\n", local64_read((local64_t *)kp->arg));
}

static int param_set_local64(const char *val, const struct kernel_param *kp)
{
	/* Clear on any write */
	local64_set((local64_t *)kp->arg, 0);
	return 0;
}

static const struct kernel_param_ops param_ops_local64 = {
	.get = param_get_local64,
	.set = param_set_local64,
};
#define param_check_local64(name, p) __param_check(name, p, local64_t)

static local64_t uv_nmi_count;
module_param_named(nmi_count, uv_nmi_count, local64, 0644);

static local64_t uv_nmi_misses;
module_param_named(nmi_misses, uv_nmi_misses, local64, 0644);

static local64_t uv_nmi_ping_count;
module_param_named(ping_count, uv_nmi_ping_count, local64, 0644);

static local64_t uv_nmi_ping_misses;
module_param_named(ping_misses, uv_nmi_ping_misses, local64, 0644);

/*
 * Following values allow tuning for large systems under heavy loading
 */
static int uv_nmi_initial_delay = 100;
module_param_named(initial_delay, uv_nmi_initial_delay, int, 0644);

static int uv_nmi_slave_delay = 100;
module_param_named(slave_delay, uv_nmi_slave_delay, int, 0644);

static int uv_nmi_loop_delay = 100;
module_param_named(loop_delay, uv_nmi_loop_delay, int, 0644);

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