cregit-Linux how code gets into the kernel

Release 4.10 drivers/acpi/acpi_ipmi.c

Directory: drivers/acpi
/*
 *  acpi_ipmi.c - ACPI IPMI opregion
 *
 *  Copyright (C) 2010, 2013 Intel Corporation
 *    Author: Zhao Yakui <yakui.zhao@intel.com>
 *            Lv Zheng <lv.zheng@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/ipmi.h>
#include <linux/spinlock.h>

MODULE_AUTHOR("Zhao Yakui");
MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
MODULE_LICENSE("GPL");


#define ACPI_IPMI_OK			0

#define ACPI_IPMI_TIMEOUT		0x10

#define ACPI_IPMI_UNKNOWN		0x07
/* the IPMI timeout is 5s */

#define IPMI_TIMEOUT			(5000)

#define ACPI_IPMI_MAX_MSG_LENGTH	64


struct acpi_ipmi_device {
	/* the device list attached to driver_data.ipmi_devices */
	
struct list_head head;

	/* the IPMI request message list */
	
struct list_head tx_msg_list;

	
spinlock_t tx_msg_lock;
	
acpi_handle handle;
	
struct device *dev;
	
ipmi_user_t user_interface;
	
int ipmi_ifnum; /* IPMI interface number */
	
long curr_msgid;
	
bool dead;
	
struct kref kref;
};


struct ipmi_driver_data {
	
struct list_head ipmi_devices;
	
struct ipmi_smi_watcher bmc_events;
	
struct ipmi_user_hndl ipmi_hndlrs;
	
struct mutex ipmi_lock;

	/*
         * NOTE: IPMI System Interface Selection
         * There is no system interface specified by the IPMI operation
         * region access.  We try to select one system interface with ACPI
         * handle set.  IPMI messages passed from the ACPI codes are sent
         * to this selected global IPMI system interface.
         */
	
struct acpi_ipmi_device *selected_smi;
};


struct acpi_ipmi_msg {
	
struct list_head head;

	/*
         * General speaking the addr type should be SI_ADDR_TYPE. And
         * the addr channel should be BMC.
         * In fact it can also be IPMB type. But we will have to
         * parse it from the Netfn command buffer. It is so complex
         * that it is skipped.
         */
	
struct ipmi_addr addr;
	
long tx_msgid;

	/* it is used to track whether the IPMI message is finished */
	
struct completion tx_complete;

	
struct kernel_ipmi_msg tx_message;
	
int msg_done;

	/* tx/rx data . And copy it from/to ACPI object buffer */
	
u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
	
u8 rx_len;

	
struct acpi_ipmi_device *device;
	
struct kref kref;
};

/* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */

struct acpi_ipmi_buffer {
	
u8 status;
	
u8 length;
	
u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
};

static void ipmi_register_bmc(int iface, struct device *dev);
static void ipmi_bmc_gone(int iface);
static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);


static struct ipmi_driver_data driver_data = {
	.ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
	.bmc_events = {
		.owner = THIS_MODULE,
		.new_smi = ipmi_register_bmc,
		.smi_gone = ipmi_bmc_gone,
        },
	.ipmi_hndlrs = {
		.ipmi_recv_hndl = ipmi_msg_handler,
        },
	.ipmi_lock = __MUTEX_INITIALIZER(driver_data.ipmi_lock)
};


static struct acpi_ipmi_device * ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle) { struct acpi_ipmi_device *ipmi_device; int err; ipmi_user_t user; ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL); if (!ipmi_device) return NULL; kref_init(&ipmi_device->kref); INIT_LIST_HEAD(&ipmi_device->head); INIT_LIST_HEAD(&ipmi_device->tx_msg_list); spin_lock_init(&ipmi_device->tx_msg_lock); ipmi_device->handle = handle; ipmi_device->dev = get_device(dev); ipmi_device->ipmi_ifnum = iface; err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs, ipmi_device, &user); if (err) { put_device(dev); kfree(ipmi_device); return NULL; } ipmi_device->user_interface = user; return ipmi_device; }

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static void ipmi_dev_release(struct acpi_ipmi_device *ipmi_device) { ipmi_destroy_user(ipmi_device->user_interface); put_device(ipmi_device->dev); kfree(ipmi_device); }

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static void ipmi_dev_release_kref(struct kref *kref) { struct acpi_ipmi_device *ipmi = container_of(kref, struct acpi_ipmi_device, kref); ipmi_dev_release(ipmi); }

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static void __ipmi_dev_kill(struct acpi_ipmi_device *ipmi_device) { list_del(&ipmi_device->head); if (driver_data.selected_smi == ipmi_device) driver_data.selected_smi = NULL; /* * Always setting dead flag after deleting from the list or * list_for_each_entry() codes must get changed. */ ipmi_device->dead = true; }

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static struct acpi_ipmi_device *acpi_ipmi_dev_get(void) { struct acpi_ipmi_device *ipmi_device = NULL; mutex_lock(&driver_data.ipmi_lock); if (driver_data.selected_smi) { ipmi_device = driver_data.selected_smi; kref_get(&ipmi_device->kref); } mutex_unlock(&driver_data.ipmi_lock); return ipmi_device; }

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static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device) { kref_put(&ipmi_device->kref, ipmi_dev_release_kref); }

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static struct acpi_ipmi_msg *ipmi_msg_alloc(void) { struct acpi_ipmi_device *ipmi; struct acpi_ipmi_msg *ipmi_msg; ipmi = acpi_ipmi_dev_get(); if (!ipmi) return NULL; ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL); if (!ipmi_msg) { acpi_ipmi_dev_put(ipmi); return NULL; } kref_init(&ipmi_msg->kref); init_completion(&ipmi_msg->tx_complete); INIT_LIST_HEAD(&ipmi_msg->head); ipmi_msg->device = ipmi; ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN; return ipmi_msg; }

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static void ipmi_msg_release(struct acpi_ipmi_msg *tx_msg) { acpi_ipmi_dev_put(tx_msg->device); kfree(tx_msg); }

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static void ipmi_msg_release_kref(struct kref *kref) { struct acpi_ipmi_msg *tx_msg = container_of(kref, struct acpi_ipmi_msg, kref); ipmi_msg_release(tx_msg); }

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static struct acpi_ipmi_msg *acpi_ipmi_msg_get(struct acpi_ipmi_msg *tx_msg) { kref_get(&tx_msg->kref); return tx_msg; }

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static void acpi_ipmi_msg_put(struct acpi_ipmi_msg *tx_msg) { kref_put(&tx_msg->kref, ipmi_msg_release_kref); }

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#define IPMI_OP_RGN_NETFN(offset) ((offset >> 8) & 0xff) #define IPMI_OP_RGN_CMD(offset) (offset & 0xff)
static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg, acpi_physical_address address, acpi_integer *value) { struct kernel_ipmi_msg *msg; struct acpi_ipmi_buffer *buffer; struct acpi_ipmi_device *device; unsigned long flags; msg = &tx_msg->tx_message; /* * IPMI network function and command are encoded in the address * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3. */ msg->netfn = IPMI_OP_RGN_NETFN(address); msg->cmd = IPMI_OP_RGN_CMD(address); msg->data = tx_msg->data; /* * value is the parameter passed by the IPMI opregion space handler. * It points to the IPMI request message buffer */ buffer = (struct acpi_ipmi_buffer *)value; /* copy the tx message data */ if (buffer->length > ACPI_IPMI_MAX_MSG_LENGTH) { dev_WARN_ONCE(tx_msg->device->dev, true, "Unexpected request (msg len %d).\n", buffer->length); return -EINVAL; } msg->data_len = buffer->length; memcpy(tx_msg->data, buffer->data, msg->data_len); /* * now the default type is SYSTEM_INTERFACE and channel type is BMC. * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE, * the addr type should be changed to IPMB. Then we will have to parse * the IPMI request message buffer to get the IPMB address. * If so, please fix me. */ tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE; tx_msg->addr.channel = IPMI_BMC_CHANNEL; tx_msg->addr.data[0] = 0; /* Get the msgid */ device = tx_msg->device; spin_lock_irqsave(&device->tx_msg_lock, flags); device->curr_msgid++; tx_msg->tx_msgid = device->curr_msgid; spin_unlock_irqrestore(&device->tx_msg_lock, flags); return 0; }

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static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg, acpi_integer *value) { struct acpi_ipmi_buffer *buffer; /* * value is also used as output parameter. It represents the response * IPMI message returned by IPMI command. */ buffer = (struct acpi_ipmi_buffer *)value; /* * If the flag of msg_done is not set, it means that the IPMI command is * not executed correctly. */ buffer->status = msg->msg_done; if (msg->msg_done != ACPI_IPMI_OK) return; /* * If the IPMI response message is obtained correctly, the status code * will be ACPI_IPMI_OK */ buffer->length = msg->rx_len; memcpy(buffer->data, msg->data, msg->rx_len); }

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static void ipmi_flush_tx_msg(struct acpi_ipmi_device *ipmi) { struct acpi_ipmi_msg *tx_msg; unsigned long flags; /* * NOTE: On-going ipmi_recv_msg * ipmi_msg_handler() may still be invoked by ipmi_si after * flushing. But it is safe to do a fast flushing on module_exit() * without waiting for all ipmi_recv_msg(s) to complete from * ipmi_msg_handler() as it is ensured by ipmi_si that all * ipmi_recv_msg(s) are freed after invoking ipmi_destroy_user(). */ spin_lock_irqsave(&ipmi->tx_msg_lock, flags); while (!list_empty(&ipmi->tx_msg_list)) { tx_msg = list_first_entry(&ipmi->tx_msg_list, struct acpi_ipmi_msg, head); list_del(&tx_msg->head); spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags); /* wake up the sleep thread on the Tx msg */ complete(&tx_msg->tx_complete); acpi_ipmi_msg_put(tx_msg); spin_lock_irqsave(&ipmi->tx_msg_lock, flags); } spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags); }

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static void ipmi_cancel_tx_msg(struct acpi_ipmi_device *ipmi, struct acpi_ipmi_msg *msg) { struct acpi_ipmi_msg *tx_msg, *temp; bool msg_found = false; unsigned long flags; spin_lock_irqsave(&ipmi->tx_msg_lock, flags); list_for_each_entry_safe(tx_msg, temp, &ipmi->tx_msg_list, head) { if (msg == tx_msg) { msg_found = true; list_del(&tx_msg->head); break; } } spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags); if (msg_found) acpi_ipmi_msg_put(tx_msg); }

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static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data) { struct acpi_ipmi_device *ipmi_device = user_msg_data; bool msg_found = false; struct acpi_ipmi_msg *tx_msg, *temp; struct device *dev = ipmi_device->dev; unsigned long flags; if (msg->user != ipmi_device->user_interface) { dev_warn(dev, "Unexpected response is returned. returned user %p, expected user %p\n", msg->user, ipmi_device->user_interface); goto out_msg; } spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags); list_for_each_entry_safe(tx_msg, temp, &ipmi_device->tx_msg_list, head) { if (msg->msgid == tx_msg->tx_msgid) { msg_found = true; list_del(&tx_msg->head); break; } } spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags); if (!msg_found) { dev_warn(dev, "Unexpected response (msg id %ld) is returned.\n", msg->msgid); goto out_msg; } /* copy the response data to Rx_data buffer */ if (msg->msg.data_len > ACPI_IPMI_MAX_MSG_LENGTH) { dev_WARN_ONCE(dev, true, "Unexpected response (msg len %d).\n", msg->msg.data_len); goto out_comp; } /* response msg is an error msg */ msg->recv_type = IPMI_RESPONSE_RECV_TYPE; if (msg->recv_type == IPMI_RESPONSE_RECV_TYPE && msg->msg.data_len == 1) { if (msg->msg.data[0] == IPMI_TIMEOUT_COMPLETION_CODE) { dev_WARN_ONCE(dev, true, "Unexpected response (timeout).\n"); tx_msg->msg_done = ACPI_IPMI_TIMEOUT; } goto out_comp; } tx_msg->rx_len = msg->msg.data_len; memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len); tx_msg->msg_done = ACPI_IPMI_OK; out_comp: complete(&tx_msg->tx_complete); acpi_ipmi_msg_put(tx_msg); out_msg: ipmi_free_recv_msg(msg); }

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static void ipmi_register_bmc(int iface, struct device *dev) { struct acpi_ipmi_device *ipmi_device, *temp; int err; struct ipmi_smi_info smi_data; acpi_handle handle; err = ipmi_get_smi_info(iface, &smi_data); if (err) return; if (smi_data.addr_src != SI_ACPI) goto err_ref; handle = smi_data.addr_info.acpi_info.acpi_handle; if (!handle) goto err_ref; ipmi_device = ipmi_dev_alloc(iface, smi_data.dev, handle); if (!ipmi_device) { dev_warn(smi_data.dev, "Can't create IPMI user interface\n"); goto err_ref; } mutex_lock(&driver_data.ipmi_lock); list_for_each_entry(temp, &driver_data.ipmi_devices, head) { /* * if the corresponding ACPI handle is already added * to the device list, don't add it again. */ if (temp->handle == handle) goto err_lock; } if (!driver_data.selected_smi) driver_data.selected_smi = ipmi_device; list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices); mutex_unlock(&driver_data.ipmi_lock); put_device(smi_data.dev); return; err_lock: mutex_unlock(&driver_data.ipmi_lock); ipmi_dev_release(ipmi_device); err_ref: put_device(smi_data.dev); return; }

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static void ipmi_bmc_gone(int iface) { struct acpi_ipmi_device *ipmi_device, *temp; bool dev_found = false; mutex_lock(&driver_data.ipmi_lock); list_for_each_entry_safe(ipmi_device, temp, &driver_data.ipmi_devices, head) { if (ipmi_device->ipmi_ifnum != iface) { dev_found = true; __ipmi_dev_kill(ipmi_device); break; } } if (!driver_data.selected_smi) driver_data.selected_smi = list_first_entry_or_null( &driver_data.ipmi_devices, struct acpi_ipmi_device, head); mutex_unlock(&driver_data.ipmi_lock); if (dev_found) { ipmi_flush_tx_msg(ipmi_device); acpi_ipmi_dev_put(ipmi_device); } }

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/* * This is the IPMI opregion space handler. * @function: indicates the read/write. In fact as the IPMI message is driven * by command, only write is meaningful. * @address: This contains the netfn/command of IPMI request message. * @bits : not used. * @value : it is an in/out parameter. It points to the IPMI message buffer. * Before the IPMI message is sent, it represents the actual request * IPMI message. After the IPMI message is finished, it represents * the response IPMI message returned by IPMI command. * @handler_context: IPMI device context. */
static acpi_status acpi_ipmi_space_handler(u32 function, acpi_physical_address address, u32 bits, acpi_integer *value, void *handler_context, void *region_context) { struct acpi_ipmi_msg *tx_msg; struct acpi_ipmi_device *ipmi_device; int err; acpi_status status; unsigned long flags; /* * IPMI opregion message. * IPMI message is firstly written to the BMC and system software * can get the respsonse. So it is unmeaningful for the read access * of IPMI opregion. */ if ((function & ACPI_IO_MASK) == ACPI_READ) return AE_TYPE; tx_msg = ipmi_msg_alloc(); if (!tx_msg) return AE_NOT_EXIST; ipmi_device = tx_msg->device; if (acpi_format_ipmi_request(tx_msg, address, value) != 0) { ipmi_msg_release(tx_msg); return AE_TYPE; } acpi_ipmi_msg_get(tx_msg); mutex_lock(&driver_data.ipmi_lock); /* Do not add a tx_msg that can not be flushed. */ if (ipmi_device->dead) { mutex_unlock(&driver_data.ipmi_lock); ipmi_msg_release(tx_msg); return AE_NOT_EXIST; } spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags); list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list); spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags); mutex_unlock(&driver_data.ipmi_lock); err = ipmi_request_settime(ipmi_device->user_interface, &tx_msg->addr, tx_msg->tx_msgid, &tx_msg->tx_message, NULL, 0, 0, IPMI_TIMEOUT); if (err) { status = AE_ERROR; goto out_msg; } wait_for_completion(&tx_msg->tx_complete); acpi_format_ipmi_response(tx_msg, value); status = AE_OK; out_msg: ipmi_cancel_tx_msg(ipmi_device, tx_msg); acpi_ipmi_msg_put(tx_msg); return status; }

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static int __init acpi_ipmi_init(void) { int result; acpi_status status; if (acpi_disabled) return 0; status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT, ACPI_ADR_SPACE_IPMI, &acpi_ipmi_space_handler, NULL, NULL); if (ACPI_FAILURE(status)) { pr_warn("Can't register IPMI opregion space handle\n"); return -EINVAL; } result = ipmi_smi_watcher_register(&driver_data.bmc_events); if (result) pr_err("Can't register IPMI system interface watcher\n"); return result; }

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static void __exit acpi_ipmi_exit(void) { struct acpi_ipmi_device *ipmi_device; if (acpi_disabled) return; ipmi_smi_watcher_unregister(&driver_data.bmc_events); /* * When one smi_watcher is unregistered, it is only deleted * from the smi_watcher list. But the smi_gone callback function * is not called. So explicitly uninstall the ACPI IPMI oregion * handler and free it. */ mutex_lock(&driver_data.ipmi_lock); while (!list_empty(&driver_data.ipmi_devices)) { ipmi_device = list_first_entry(&driver_data.ipmi_devices, struct acpi_ipmi_device, head); __ipmi_dev_kill(ipmi_device); mutex_unlock(&driver_data.ipmi_lock); ipmi_flush_tx_msg(ipmi_device); acpi_ipmi_dev_put(ipmi_device); mutex_lock(&driver_data.ipmi_lock); } mutex_unlock(&driver_data.ipmi_lock); acpi_remove_address_space_handler(ACPI_ROOT_OBJECT, ACPI_ADR_SPACE_IPMI, &acpi_ipmi_space_handler); }

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module_init(acpi_ipmi_init); module_exit(acpi_ipmi_exit);

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Directory: drivers/acpi
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