path: root/drivers/firmware/arm_sdei.c

// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2017 Arm Ltd.
#define pr_fmt(fmt) "sdei: " fmt

#include <acpi/ghes.h>
#include <linux/acpi.h>
#include <linux/arm_sdei.h>
#include <linux/arm-smccc.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/cpuhotplug.h>
#include <linux/cpu.h>
#include <linux/cpu_pm.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/kvm_host.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/percpu.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/ptrace.h>
#include <linux/preempt.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>

/*
 * The call to use to reach the firmware.
 */
static asmlinkage void (*sdei_firmware_call)(unsigned long function_id,
		      unsigned long arg0, unsigned long arg1,
		      unsigned long arg2, unsigned long arg3,
		      unsigned long arg4, struct arm_smccc_res *res);

/* entry point from firmware to arch asm code */
static unsigned long sdei_entry_point;

struct sdei_event {
	/* These three are protected by the sdei_list_lock */
	struct list_head	list;
	bool			reregister;
	bool			reenable;

	u32			event_num;
	u8			type;
	u8			priority;

	/* This pointer is handed to firmware as the event argument. */
	union {
		/* Shared events */
		struct sdei_registered_event *registered;

		/* CPU private events */
		struct sdei_registered_event __percpu *private_registered;
	};
};

/* Take the mutex for any API call or modification. Take the mutex first. */
static DEFINE_MUTEX(sdei_events_lock);

/* and then hold this when modifying the list */
static DEFINE_SPINLOCK(sdei_list_lock);
static LIST_HEAD(sdei_list);

/* Private events are registered/enabled via IPI passing one of these */
struct sdei_crosscall_args {
	struct sdei_event *event;
	atomic_t errors;
	int first_error;
};

#define CROSSCALL_INIT(arg, event)	(arg.event = event, \
					 arg.first_error = 0, \
					 atomic_set(&arg.errors, 0))

static inline int sdei_do_cross_call(void *fn, struct sdei_event * event)
{
	struct sdei_crosscall_args arg;

	CROSSCALL_INIT(arg, event);
	on_each_cpu(fn, &arg, true);

	return arg.first_error;
}

static inline void
sdei_cross_call_return(struct sdei_crosscall_args *arg, int err)
{
	if (err && (atomic_inc_return(&arg->errors) == 1))
		arg->first_error = err;
}

static int sdei_to_linux_errno(unsigned long sdei_err)
{
	switch (sdei_err) {
	case SDEI_NOT_SUPPORTED:
		return -EOPNOTSUPP;
	case SDEI_INVALID_PARAMETERS:
		return -EINVAL;
	case SDEI_DENIED:
		return -EPERM;
	case SDEI_PENDING:
		return -EINPROGRESS;
	case SDEI_OUT_OF_RESOURCE:
		return -ENOMEM;
	}

	/* Not an error value ... */
	return sdei_err;
}

/*
 * If x0 is any of these values, then the call failed, use sdei_to_linux_errno()
 * to translate.
 */
static int sdei_is_err(struct arm_smccc_res *res)
{
	switch (res->a0) {
	case SDEI_NOT_SUPPORTED:
	case SDEI_INVALID_PARAMETERS:
	case SDEI_DENIED:
	case SDEI_PENDING:
	case SDEI_OUT_OF_RESOURCE:
		return true;
	}

	return false;
}

static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
			  unsigned long arg1, unsigned long arg2,
			  unsigned long arg3, unsigned long arg4,
			  u64 *result)
{
	int err = 0;
	struct arm_smccc_res res;

	if (sdei_firmware_call) {
		sdei_firmware_call(function_id, arg0, arg1, arg2, arg3, arg4,
				   &res);
		if (sdei_is_err(&res))
			err = sdei_to_linux_errno(res.a0);
	} else {
		/*
		 * !sdei_firmware_call means we failed to probe or called
		 * sdei_mark_interface_broken(). -EIO is not an error returned
		 * by sdei_to_linux_errno() and is used to suppress messages
		 * from this driver.
		 */
		err = -EIO;
		res.a0 = SDEI_NOT_SUPPORTED;
	}

	if (result)
		*result = res.a0;

	return err;
}
NOKPROBE_SYMBOL(invoke_sdei_fn);

static struct sdei_event *sdei_event_find(u32 event_num)
{
	struct sdei_event *e, *found = NULL;

	lockdep_assert_held(&sdei_events_lock);

	spin_lock(&