diff options
Diffstat (limited to 'drivers/firmware/google/gsmi.c')
| -rw-r--r-- | drivers/firmware/google/gsmi.c | 1093 |
1 files changed, 1093 insertions, 0 deletions
diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c new file mode 100644 index 000000000..871bedf53 --- /dev/null +++ b/drivers/firmware/google/gsmi.c @@ -0,0 +1,1093 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2010 Google Inc. All Rights Reserved. + * Author: dlaurie@google.com (Duncan Laurie) + * + * Re-worked to expose sysfs APIs by mikew@google.com (Mike Waychison) + * + * EFI SMI interface for Google platforms + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/spinlock.h> +#include <linux/dma-mapping.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/panic_notifier.h> +#include <linux/ioctl.h> +#include <linux/acpi.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <linux/dmi.h> +#include <linux/kdebug.h> +#include <linux/reboot.h> +#include <linux/efi.h> +#include <linux/module.h> +#include <linux/ucs2_string.h> +#include <linux/suspend.h> + +#define GSMI_SHUTDOWN_CLEAN 0 /* Clean Shutdown */ +/* TODO(mikew@google.com): Tie in HARDLOCKUP_DETECTOR with NMIWDT */ +#define GSMI_SHUTDOWN_NMIWDT 1 /* NMI Watchdog */ +#define GSMI_SHUTDOWN_PANIC 2 /* Panic */ +#define GSMI_SHUTDOWN_OOPS 3 /* Oops */ +#define GSMI_SHUTDOWN_DIE 4 /* Die -- No longer meaningful */ +#define GSMI_SHUTDOWN_MCE 5 /* Machine Check */ +#define GSMI_SHUTDOWN_SOFTWDT 6 /* Software Watchdog */ +#define GSMI_SHUTDOWN_MBE 7 /* Uncorrected ECC */ +#define GSMI_SHUTDOWN_TRIPLE 8 /* Triple Fault */ + +#define DRIVER_VERSION "1.0" +#define GSMI_GUID_SIZE 16 +#define GSMI_BUF_SIZE 1024 +#define GSMI_BUF_ALIGN sizeof(u64) +#define GSMI_CALLBACK 0xef + +/* SMI return codes */ +#define GSMI_SUCCESS 0x00 +#define GSMI_UNSUPPORTED2 0x03 +#define GSMI_LOG_FULL 0x0b +#define GSMI_VAR_NOT_FOUND 0x0e +#define GSMI_HANDSHAKE_SPIN 0x7d +#define GSMI_HANDSHAKE_CF 0x7e +#define GSMI_HANDSHAKE_NONE 0x7f +#define GSMI_INVALID_PARAMETER 0x82 +#define GSMI_UNSUPPORTED 0x83 +#define GSMI_BUFFER_TOO_SMALL 0x85 +#define GSMI_NOT_READY 0x86 +#define GSMI_DEVICE_ERROR 0x87 +#define GSMI_NOT_FOUND 0x8e + +#define QUIRKY_BOARD_HASH 0x78a30a50 + +/* Internally used commands passed to the firmware */ +#define GSMI_CMD_GET_NVRAM_VAR 0x01 +#define GSMI_CMD_GET_NEXT_VAR 0x02 +#define GSMI_CMD_SET_NVRAM_VAR 0x03 +#define GSMI_CMD_SET_EVENT_LOG 0x08 +#define GSMI_CMD_CLEAR_EVENT_LOG 0x09 +#define GSMI_CMD_LOG_S0IX_SUSPEND 0x0a +#define GSMI_CMD_LOG_S0IX_RESUME 0x0b +#define GSMI_CMD_CLEAR_CONFIG 0x20 +#define GSMI_CMD_HANDSHAKE_TYPE 0xC1 +#define GSMI_CMD_RESERVED 0xff + +/* Magic entry type for kernel events */ +#define GSMI_LOG_ENTRY_TYPE_KERNEL 0xDEAD + +/* SMI buffers must be in 32bit physical address space */ +struct gsmi_buf { + u8 *start; /* start of buffer */ + size_t length; /* length of buffer */ + u32 address; /* physical address of buffer */ +}; + +static struct gsmi_device { + struct platform_device *pdev; /* platform device */ + struct gsmi_buf *name_buf; /* variable name buffer */ + struct gsmi_buf *data_buf; /* generic data buffer */ + struct gsmi_buf *param_buf; /* parameter buffer */ + spinlock_t lock; /* serialize access to SMIs */ + u16 smi_cmd; /* SMI command port */ + int handshake_type; /* firmware handler interlock type */ + struct kmem_cache *mem_pool; /* kmem cache for gsmi_buf allocations */ +} gsmi_dev; + +/* Packed structures for communicating with the firmware */ +struct gsmi_nvram_var_param { + efi_guid_t guid; + u32 name_ptr; + u32 attributes; + u32 data_len; + u32 data_ptr; +} __packed; + +struct gsmi_get_next_var_param { + u8 guid[GSMI_GUID_SIZE]; + u32 name_ptr; + u32 name_len; +} __packed; + +struct gsmi_set_eventlog_param { + u32 data_ptr; + u32 data_len; + u32 type; +} __packed; + +/* Event log formats */ +struct gsmi_log_entry_type_1 { + u16 type; + u32 instance; +} __packed; + +/* + * Some platforms don't have explicit SMI handshake + * and need to wait for SMI to complete. + */ +#define GSMI_DEFAULT_SPINCOUNT 0x10000 +static unsigned int spincount = GSMI_DEFAULT_SPINCOUNT; +module_param(spincount, uint, 0600); +MODULE_PARM_DESC(spincount, + "The number of loop iterations to use when using the spin handshake."); + +/* + * Some older platforms with Apollo Lake chipsets do not support S0ix logging + * in their GSMI handlers, and behaved poorly when resuming via power button + * press if the logging was attempted. Updated firmware with proper behavior + * has long since shipped, removing the need for this opt-in parameter. It + * now exists as an opt-out parameter for folks defiantly running old + * firmware, or unforeseen circumstances. After the change from opt-in to + * opt-out has baked sufficiently, this parameter should probably be removed + * entirely. + */ +static bool s0ix_logging_enable = true; +module_param(s0ix_logging_enable, bool, 0600); + +static struct gsmi_buf *gsmi_buf_alloc(void) +{ + struct gsmi_buf *smibuf; + + smibuf = kzalloc(sizeof(*smibuf), GFP_KERNEL); + if (!smibuf) { + printk(KERN_ERR "gsmi: out of memory\n"); + return NULL; + } + + /* allocate buffer in 32bit address space */ + smibuf->start = kmem_cache_alloc(gsmi_dev.mem_pool, GFP_KERNEL); + if (!smibuf->start) { + printk(KERN_ERR "gsmi: failed to allocate name buffer\n"); + kfree(smibuf); + return NULL; + } + + /* fill in the buffer handle */ + smibuf->length = GSMI_BUF_SIZE; + smibuf->address = (u32)virt_to_phys(smibuf->start); + + return smibuf; +} + +static void gsmi_buf_free(struct gsmi_buf *smibuf) +{ + if (smibuf) { + if (smibuf->start) + kmem_cache_free(gsmi_dev.mem_pool, smibuf->start); + kfree(smibuf); + } +} + +/* + * Make a call to gsmi func(sub). GSMI error codes are translated to + * in-kernel errnos (0 on success, -ERRNO on error). + */ +static int gsmi_exec(u8 func, u8 sub) +{ + u16 cmd = (sub << 8) | func; + u16 result = 0; + int rc = 0; + + /* + * AH : Subfunction number + * AL : Function number + * EBX : Parameter block address + * DX : SMI command port + * + * Three protocols here. See also the comment in gsmi_init(). + */ + if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_CF) { + /* + * If handshake_type == HANDSHAKE_CF then set CF on the + * way in and wait for the handler to clear it; this avoids + * corrupting register state on those chipsets which have + * a delay between writing the SMI trigger register and + * entering SMM. + */ + asm volatile ( + "stc\n" + "outb %%al, %%dx\n" + "1: jc 1b\n" + : "=a" (result) + : "0" (cmd), + "d" (gsmi_dev.smi_cmd), + "b" (gsmi_dev.param_buf->address) + : "memory", "cc" + ); + } else if (gsmi_dev.handshake_type == GSMI_HANDSHAKE_SPIN) { + /* + * If handshake_type == HANDSHAKE_SPIN we spin a + * hundred-ish usecs to ensure the SMI has triggered. + */ + asm volatile ( + "outb %%al, %%dx\n" + "1: loop 1b\n" + : "=a" (result) + : "0" (cmd), + "d" (gsmi_dev.smi_cmd), + "b" (gsmi_dev.param_buf->address), + "c" (spincount) + : "memory", "cc" + ); + } else { + /* + * If handshake_type == HANDSHAKE_NONE we do nothing; + * either we don't need to or it's legacy firmware that + * doesn't understand the CF protocol. + */ + asm volatile ( + "outb %%al, %%dx\n\t" + : "=a" (result) + : "0" (cmd), + "d" (gsmi_dev.smi_cmd), + "b" (gsmi_dev.param_buf->address) + : "memory", "cc" + ); + } + + /* check return code from SMI handler */ + switch (result) { + case GSMI_SUCCESS: + break; + case GSMI_VAR_NOT_FOUND: + /* not really an error, but let the caller know */ + rc = 1; + break; + case GSMI_INVALID_PARAMETER: + printk(KERN_ERR "gsmi: exec 0x%04x: Invalid parameter\n", cmd); + rc = -EINVAL; + break; + case GSMI_BUFFER_TOO_SMALL: + printk(KERN_ERR "gsmi: exec 0x%04x: Buffer too small\n", cmd); + rc = -ENOMEM; + break; + case GSMI_UNSUPPORTED: + case GSMI_UNSUPPORTED2: + if (sub != GSMI_CMD_HANDSHAKE_TYPE) + printk(KERN_ERR "gsmi: exec 0x%04x: Not supported\n", + cmd); + rc = -ENOSYS; + break; + case GSMI_NOT_READY: + printk(KERN_ERR "gsmi: exec 0x%04x: Not ready\n", cmd); + rc = -EBUSY; + break; + case GSMI_DEVICE_ERROR: + printk(KERN_ERR "gsmi: exec 0x%04x: Device error\n", cmd); + rc = -EFAULT; + break; + case GSMI_NOT_FOUND: + printk(KERN_ERR "gsmi: exec 0x%04x: Data not found\n", cmd); + rc = -ENOENT; + break; + case GSMI_LOG_FULL: + printk(KERN_ERR "gsmi: exec 0x%04x: Log full\n", cmd); + rc = -ENOSPC; + break; + case GSMI_HANDSHAKE_CF: + case GSMI_HANDSHAKE_SPIN: + case GSMI_HANDSHAKE_NONE: + rc = result; + break; + default: + printk(KERN_ERR "gsmi: exec 0x%04x: Unknown error 0x%04x\n", + cmd, result); + rc = -ENXIO; + } + + return rc; +} + +#ifdef CONFIG_EFI + +static struct efivars efivars; + +static efi_status_t gsmi_get_variable(efi_char16_t *name, + efi_guid_t *vendor, u32 *attr, + unsigned long *data_size, + void *data) +{ + struct gsmi_nvram_var_param param = { + .name_ptr = gsmi_dev.name_buf->address, + .data_ptr = gsmi_dev.data_buf->address, + .data_len = (u32)*data_size, + }; + efi_status_t ret = EFI_SUCCESS; + unsigned long flags; + size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2); + int rc; + + if (name_len >= GSMI_BUF_SIZE / 2) + return EFI_BAD_BUFFER_SIZE; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + /* Vendor guid */ + memcpy(¶m.guid, vendor, sizeof(param.guid)); + + /* variable name, already in UTF-16 */ + memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length); + memcpy(gsmi_dev.name_buf->start, name, name_len * 2); + + /* data pointer */ + memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); + + /* parameter buffer */ + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NVRAM_VAR); + if (rc < 0) { + printk(KERN_ERR "gsmi: Get Variable failed\n"); + ret = EFI_LOAD_ERROR; + } else if (rc == 1) { + /* variable was not found */ + ret = EFI_NOT_FOUND; + } else { + /* Get the arguments back */ + memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param)); + + /* The size reported is the min of all of our buffers */ + *data_size = min_t(unsigned long, *data_size, + gsmi_dev.data_buf->length); + *data_size = min_t(unsigned long, *data_size, param.data_len); + + /* Copy data back to return buffer. */ + memcpy(data, gsmi_dev.data_buf->start, *data_size); + + /* All variables are have the following attributes */ + if (attr) + *attr = EFI_VARIABLE_NON_VOLATILE | + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS; + } + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + return ret; +} + +static efi_status_t gsmi_get_next_variable(unsigned long *name_size, + efi_char16_t *name, + efi_guid_t *vendor) +{ + struct gsmi_get_next_var_param param = { + .name_ptr = gsmi_dev.name_buf->address, + .name_len = gsmi_dev.name_buf->length, + }; + efi_status_t ret = EFI_SUCCESS; + int rc; + unsigned long flags; + + /* For the moment, only support buffers that exactly match in size */ + if (*name_size != GSMI_BUF_SIZE) + return EFI_BAD_BUFFER_SIZE; + + /* Let's make sure the thing is at least null-terminated */ + if (ucs2_strnlen(name, GSMI_BUF_SIZE / 2) == GSMI_BUF_SIZE / 2) + return EFI_INVALID_PARAMETER; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + /* guid */ + memcpy(¶m.guid, vendor, sizeof(param.guid)); + + /* variable name, already in UTF-16 */ + memcpy(gsmi_dev.name_buf->start, name, *name_size); + + /* parameter buffer */ + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_GET_NEXT_VAR); + if (rc < 0) { + printk(KERN_ERR "gsmi: Get Next Variable Name failed\n"); + ret = EFI_LOAD_ERROR; + } else if (rc == 1) { + /* variable not found -- end of list */ + ret = EFI_NOT_FOUND; + } else { + /* copy variable data back to return buffer */ + memcpy(¶m, gsmi_dev.param_buf->start, sizeof(param)); + + /* Copy the name back */ + memcpy(name, gsmi_dev.name_buf->start, GSMI_BUF_SIZE); + *name_size = ucs2_strnlen(name, GSMI_BUF_SIZE / 2) * 2; + + /* copy guid to return buffer */ + memcpy(vendor, ¶m.guid, sizeof(param.guid)); + ret = EFI_SUCCESS; + } + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + return ret; +} + +static efi_status_t gsmi_set_variable(efi_char16_t *name, + efi_guid_t *vendor, + u32 attr, + unsigned long data_size, + void *data) +{ + struct gsmi_nvram_var_param param = { + .name_ptr = gsmi_dev.name_buf->address, + .data_ptr = gsmi_dev.data_buf->address, + .data_len = (u32)data_size, + .attributes = EFI_VARIABLE_NON_VOLATILE | + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS, + }; + size_t name_len = ucs2_strnlen(name, GSMI_BUF_SIZE / 2); + efi_status_t ret = EFI_SUCCESS; + int rc; + unsigned long flags; + + if (name_len >= GSMI_BUF_SIZE / 2) + return EFI_BAD_BUFFER_SIZE; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + /* guid */ + memcpy(¶m.guid, vendor, sizeof(param.guid)); + + /* variable name, already in UTF-16 */ + memset(gsmi_dev.name_buf->start, 0, gsmi_dev.name_buf->length); + memcpy(gsmi_dev.name_buf->start, name, name_len * 2); + + /* data pointer */ + memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); + memcpy(gsmi_dev.data_buf->start, data, data_size); + + /* parameter buffer */ + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_NVRAM_VAR); + if (rc < 0) { + printk(KERN_ERR "gsmi: Set Variable failed\n"); + ret = EFI_INVALID_PARAMETER; + } + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + return ret; +} + +static const struct efivar_operations efivar_ops = { + .get_variable = gsmi_get_variable, + .set_variable = gsmi_set_variable, + .get_next_variable = gsmi_get_next_variable, +}; + +#endif /* CONFIG_EFI */ + +static ssize_t eventlog_write(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct gsmi_set_eventlog_param param = { + .data_ptr = gsmi_dev.data_buf->address, + }; + int rc = 0; + unsigned long flags; + + /* Pull the type out */ + if (count < sizeof(u32)) + return -EINVAL; + param.type = *(u32 *)buf; + buf += sizeof(u32); + + /* The remaining buffer is the data payload */ + if ((count - sizeof(u32)) > gsmi_dev.data_buf->length) + return -EINVAL; + param.data_len = count - sizeof(u32); + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + /* data pointer */ + memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); + memcpy(gsmi_dev.data_buf->start, buf, param.data_len); + + /* parameter buffer */ + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG); + if (rc < 0) + printk(KERN_ERR "gsmi: Set Event Log failed\n"); + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + return (rc == 0) ? count : rc; + +} + +static struct bin_attribute eventlog_bin_attr = { + .attr = {.name = "append_to_eventlog", .mode = 0200}, + .write = eventlog_write, +}; + +static ssize_t gsmi_clear_eventlog_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int rc; + unsigned long flags; + unsigned long val; + struct { + u32 percentage; + u32 data_type; + } param; + + rc = kstrtoul(buf, 0, &val); + if (rc) + return rc; + + /* + * Value entered is a percentage, 0 through 100, anything else + * is invalid. + */ + if (val > 100) + return -EINVAL; + + /* data_type here selects the smbios event log. */ + param.percentage = val; + param.data_type = 0; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + /* parameter buffer */ + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_EVENT_LOG); + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + if (rc) + return rc; + return count; +} + +static struct kobj_attribute gsmi_clear_eventlog_attr = { + .attr = {.name = "clear_eventlog", .mode = 0200}, + .store = gsmi_clear_eventlog_store, +}; + +static ssize_t gsmi_clear_config_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int rc; + unsigned long flags; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + /* clear parameter buffer */ + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_CLEAR_CONFIG); + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + if (rc) + return rc; + return count; +} + +static struct kobj_attribute gsmi_clear_config_attr = { + .attr = {.name = "clear_config", .mode = 0200}, + .store = gsmi_clear_config_store, +}; + +static const struct attribute *gsmi_attrs[] = { + &gsmi_clear_config_attr.attr, + &gsmi_clear_eventlog_attr.attr, + NULL, +}; + +static int gsmi_shutdown_reason(int reason) +{ + struct gsmi_log_entry_type_1 entry = { + .type = GSMI_LOG_ENTRY_TYPE_KERNEL, + .instance = reason, + }; + struct gsmi_set_eventlog_param param = { + .data_len = sizeof(entry), + .type = 1, + }; + static int saved_reason; + int rc = 0; + unsigned long flags; + + /* avoid duplicate entries in the log */ + if (saved_reason & (1 << reason)) + return 0; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + saved_reason |= (1 << reason); + + /* data pointer */ + memset(gsmi_dev.data_buf->start, 0, gsmi_dev.data_buf->length); + memcpy(gsmi_dev.data_buf->start, &entry, sizeof(entry)); + + /* parameter buffer */ + param.data_ptr = gsmi_dev.data_buf->address; + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + memcpy(gsmi_dev.param_buf->start, ¶m, sizeof(param)); + + rc = gsmi_exec(GSMI_CALLBACK, GSMI_CMD_SET_EVENT_LOG); + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + if (rc < 0) + printk(KERN_ERR "gsmi: Log Shutdown Reason failed\n"); + else + printk(KERN_EMERG "gsmi: Log Shutdown Reason 0x%02x\n", + reason); + + return rc; +} + +static int gsmi_reboot_callback(struct notifier_block *nb, + unsigned long reason, void *arg) +{ + gsmi_shutdown_reason(GSMI_SHUTDOWN_CLEAN); + return NOTIFY_DONE; +} + +static struct notifier_block gsmi_reboot_notifier = { + .notifier_call = gsmi_reboot_callback +}; + +static int gsmi_die_callback(struct notifier_block *nb, + unsigned long reason, void *arg) +{ + if (reason == DIE_OOPS) + gsmi_shutdown_reason(GSMI_SHUTDOWN_OOPS); + return NOTIFY_DONE; +} + +static struct notifier_block gsmi_die_notifier = { + .notifier_call = gsmi_die_callback +}; + +static int gsmi_panic_callback(struct notifier_block *nb, + unsigned long reason, void *arg) +{ + + /* + * Panic callbacks are executed with all other CPUs stopped, + * so we must not attempt to spin waiting for gsmi_dev.lock + * to be released. + */ + if (spin_is_locked(&gsmi_dev.lock)) + return NOTIFY_DONE; + + gsmi_shutdown_reason(GSMI_SHUTDOWN_PANIC); + return NOTIFY_DONE; +} + +static struct notifier_block gsmi_panic_notifier = { + .notifier_call = gsmi_panic_callback, +}; + +/* + * This hash function was blatantly copied from include/linux/hash.h. + * It is used by this driver to obfuscate a board name that requires a + * quirk within this driver. + * + * Please do not remove this copy of the function as any changes to the + * global utility hash_64() function would break this driver's ability + * to identify a board and provide the appropriate quirk -- mikew@google.com + */ +static u64 __init local_hash_64(u64 val, unsigned bits) +{ + u64 hash = val; + + /* Sigh, gcc can't optimise this alone like it does for 32 bits. */ + u64 n = hash; + n <<= 18; + hash -= n; + n <<= 33; + hash -= n; + n <<= 3; + hash += n; + n <<= 3; + hash -= n; + n <<= 4; + hash += n; + n <<= 2; + hash += n; + + /* High bits are more random, so use them. */ + return hash >> (64 - bits); +} + +static u32 __init hash_oem_table_id(char s[8]) +{ + u64 input; + memcpy(&input, s, 8); + return local_hash_64(input, 32); +} + +static const struct dmi_system_id gsmi_dmi_table[] __initconst = { + { + .ident = "Google Board", + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "Google, Inc."), + }, + }, + { + .ident = "Coreboot Firmware", + .matches = { + DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"), + }, + }, + {} +}; +MODULE_DEVICE_TABLE(dmi, gsmi_dmi_table); + +static __init int gsmi_system_valid(void) +{ + u32 hash; + u16 cmd, result; + + if (!dmi_check_system(gsmi_dmi_table)) + return -ENODEV; + + /* + * Only newer firmware supports the gsmi interface. All older + * firmware that didn't support this interface used to plug the + * table name in the first four bytes of the oem_table_id field. + * Newer firmware doesn't do that though, so use that as the + * discriminant factor. We have to do this in order to + * whitewash our board names out of the public driver. + */ + if (!strncmp(acpi_gbl_FADT.header.oem_table_id, "FACP", 4)) { + printk(KERN_INFO "gsmi: Board is too old\n"); + return -ENODEV; + } + + /* Disable on board with 1.0 BIOS due to Google bug 2602657 */ + hash = hash_oem_table_id(acpi_gbl_FADT.header.oem_table_id); + if (hash == QUIRKY_BOARD_HASH) { + const char *bios_ver = dmi_get_system_info(DMI_BIOS_VERSION); + if (strncmp(bios_ver, "1.0", 3) == 0) { + pr_info("gsmi: disabled on this board's BIOS %s\n", + bios_ver); + return -ENODEV; + } + } + + /* check for valid SMI command port in ACPI FADT */ + if (acpi_gbl_FADT.smi_command == 0) { + pr_info("gsmi: missing smi_command\n"); + return -ENODEV; + } + + /* Test the smihandler with a bogus command. If it leaves the + * calling argument in %ax untouched, there is no handler for + * GSMI commands. + */ + cmd = GSMI_CALLBACK | GSMI_CMD_RESERVED << 8; + asm volatile ( + "outb %%al, %%dx\n\t" + : "=a" (result) + : "0" (cmd), + "d" (acpi_gbl_FADT.smi_command) + : "memory", "cc" + ); + if (cmd == result) { + pr_info("gsmi: no gsmi handler in firmware\n"); + return -ENODEV; + } + + /* Found */ + return 0; +} + +static struct kobject *gsmi_kobj; + +static const struct platform_device_info gsmi_dev_info = { + .name = "gsmi", + .id = -1, + /* SMI callbacks require 32bit addresses */ + .dma_mask = DMA_BIT_MASK(32), +}; + +#ifdef CONFIG_PM +static void gsmi_log_s0ix_info(u8 cmd) +{ + unsigned long flags; + + /* + * If platform has not enabled S0ix logging, then no action is + * necessary. + */ + if (!s0ix_logging_enable) + return; + + spin_lock_irqsave(&gsmi_dev.lock, flags); + + memset(gsmi_dev.param_buf->start, 0, gsmi_dev.param_buf->length); + + gsmi_exec(GSMI_CALLBACK, cmd); + + spin_unlock_irqrestore(&gsmi_dev.lock, flags); +} + +static int gsmi_log_s0ix_suspend(struct device *dev) +{ + /* + * If system is not suspending via firmware using the standard ACPI Sx + * types, then make a GSMI call to log the suspend info. + */ + if (!pm_suspend_via_firmware()) + gsmi_log_s0ix_info(GSMI_CMD_LOG_S0IX_SUSPEND); + + /* + * Always return success, since we do not want suspend + * to fail just because of logging failure. + */ + return 0; +} + +static int gsmi_log_s0ix_resume(struct device *dev) +{ + /* + * If system did not resume via firmware, then make a GSMI call to log + * the resume info and wake source. + */ + if (!pm_resume_via_firmware()) + gsmi_log_s0ix_info(GSMI_CMD_LOG_S0IX_RESUME); + + /* + * Always return success, since we do not want resume + * to fail just because of logging failure. + */ + return 0; +} + +static const struct dev_pm_ops gsmi_pm_ops = { + .suspend_noirq = gsmi_log_s0ix_suspend, + .resume_noirq = gsmi_log_s0ix_resume, +}; + +static int gsmi_platform_driver_probe(struct platform_device *dev) +{ + return 0; +} + +static struct platform_driver gsmi_driver_info = { + .driver = { + .name = "gsmi", + .pm = &gsmi_pm_ops, + }, + .probe = gsmi_platform_driver_probe, +}; +#endif + +static __init int gsmi_init(void) +{ + unsigned long flags; + int ret; + + ret = gsmi_system_valid(); + if (ret) + return ret; + + gsmi_dev.smi_cmd = acpi_gbl_FADT.smi_command; + +#ifdef CONFIG_PM + ret = platform_driver_register(&gsmi_driver_info); + if (unlikely(ret)) { + printk(KERN_ERR "gsmi: unable to register platform driver\n"); + return ret; + } +#endif + + /* register device */ + gsmi_dev.pdev = platform_device_register_full(&gsmi_dev_info); + if (IS_ERR(gsmi_dev.pdev)) { + printk(KERN_ERR "gsmi: unable to register platform device\n"); + return PTR_ERR(gsmi_dev.pdev); + } + + /* SMI access needs to be serialized */ + spin_lock_init(&gsmi_dev.lock); + + ret = -ENOMEM; + + /* + * SLAB cache is created using SLAB_CACHE_DMA32 to ensure that the + * allocations for gsmi_buf come from the DMA32 memory zone. These + * buffers have nothing to do with DMA. They are required for + * communication with firmware executing in SMI mode which can only + * access the bottom 4GiB of physical memory. Since DMA32 memory zone + * guarantees allocation under the 4GiB boundary, this driver creates + * a SLAB cache with SLAB_CACHE_DMA32 flag. + */ + gsmi_dev.mem_pool = kmem_cache_create("gsmi", GSMI_BUF_SIZE, + GSMI_BUF_ALIGN, + SLAB_CACHE_DMA32, NULL); + if (!gsmi_dev.mem_pool) + goto out_err; + + /* + * pre-allocate buffers because sometimes we are called when + * this is not feasible: oops, panic, die, mce, etc + */ + gsmi_dev.name_buf = gsmi_buf_alloc(); + if (!gsmi_dev.name_buf) { + printk(KERN_ERR "gsmi: failed to allocate name buffer\n"); + goto out_err; + } + + gsmi_dev.data_buf = gsmi_buf_alloc(); + if (!gsmi_dev.data_buf) { + printk(KERN_ERR "gsmi: failed to allocate data buffer\n"); + goto out_err; + } + + gsmi_dev.param_buf = gsmi_buf_alloc(); + if (!gsmi_dev.param_buf) { + printk(KERN_ERR "gsmi: failed to allocate param buffer\n"); + goto out_err; + } + + /* + * Determine type of handshake used to serialize the SMI + * entry. See also gsmi_exec(). + * + * There's a "behavior" present on some chipsets where writing the + * SMI trigger register in the southbridge doesn't result in an + * immediate SMI. Rather, the processor can execute "a few" more + * instructions before the SMI takes effect. To ensure synchronous + * behavior, implement a handshake between the kernel driver and the + * firmware handler to spin until released. This ioctl determines + * the type of handshake. + * + * NONE: The firmware handler does not implement any + * handshake. Either it doesn't need to, or it's legacy firmware + * that doesn't know it needs to and never will. + * + * CF: The firmware handler will clear the CF in the saved + * state before returning. The driver may set the CF and test for + * it to clear before proceeding. + * + * SPIN: The firmware handler does not implement any handshake + * but the driver should spin for a hundred or so microseconds + * to ensure the SMI has triggered. + * + * Finally, the handler will return -ENOSYS if + * GSMI_CMD_HANDSHAKE_TYPE is unimplemented, which implies + * HANDSHAKE_NONE. + */ + spin_lock_irqsave(&gsmi_dev.lock, flags); + gsmi_dev.handshake_type = GSMI_HANDSHAKE_SPIN; + gsmi_dev.handshake_type = + gsmi_exec(GSMI_CALLBACK, GSMI_CMD_HANDSHAKE_TYPE); + if (gsmi_dev.handshake_type == -ENOSYS) + gsmi_dev.handshake_type = GSMI_HANDSHAKE_NONE; + spin_unlock_irqrestore(&gsmi_dev.lock, flags); + + /* Remove and clean up gsmi if the handshake could not complete. */ + if (gsmi_dev.handshake_type == -ENXIO) { + printk(KERN_INFO "gsmi version " DRIVER_VERSION + " failed to load\n"); + ret = -ENODEV; + goto out_err; + } + + /* Register in the firmware directory */ + ret = -ENOMEM; + gsmi_kobj = kobject_create_and_add("gsmi", firmware_kobj); + if (!gsmi_kobj) { + printk(KERN_INFO "gsmi: Failed to create firmware kobj\n"); + goto out_err; + } + + /* Setup eventlog access */ + ret = sysfs_create_bin_file(gsmi_kobj, &eventlog_bin_attr); + if (ret) { + printk(KERN_INFO "gsmi: Failed to setup eventlog"); + goto out_err; + } + + /* Other attributes */ + ret = sysfs_create_files(gsmi_kobj, gsmi_attrs); + if (ret) { + printk(KERN_INFO "gsmi: Failed to add attrs"); + goto out_remove_bin_file; + } + +#ifdef CONFIG_EFI + ret = efivars_register(&efivars, &efivar_ops, gsmi_kobj); + if (ret) { + printk(KERN_INFO "gsmi: Failed to register efivars\n"); + sysfs_remove_files(gsmi_kobj, gsmi_attrs); + goto out_remove_bin_file; + } +#endif + + register_reboot_notifier(&gsmi_reboot_notifier); + register_die_notifier(&gsmi_die_notifier); + atomic_notifier_chain_register(&panic_notifier_list, + &gsmi_panic_notifier); + + printk(KERN_INFO "gsmi version " DRIVER_VERSION " loaded\n"); + + return 0; + +out_remove_bin_file: + sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr); +out_err: + kobject_put(gsmi_kobj); + gsmi_buf_free(gsmi_dev.param_buf); + gsmi_buf_free(gsmi_dev.data_buf); + gsmi_buf_free(gsmi_dev.name_buf); + kmem_cache_destroy(gsmi_dev.mem_pool); + platform_device_unregister(gsmi_dev.pdev); + pr_info("gsmi: failed to load: %d\n", ret); +#ifdef CONFIG_PM + platform_driver_unregister(&gsmi_driver_info); +#endif + return ret; +} + +static void __exit gsmi_exit(void) +{ + unregister_reboot_notifier(&gsmi_reboot_notifier); + unregister_die_notifier(&gsmi_die_notifier); + atomic_notifier_chain_unregister(&panic_notifier_list, + &gsmi_panic_notifier); +#ifdef CONFIG_EFI + efivars_unregister(&efivars); +#endif + + sysfs_remove_files(gsmi_kobj, gsmi_attrs); + sysfs_remove_bin_file(gsmi_kobj, &eventlog_bin_attr); + kobject_put(gsmi_kobj); + gsmi_buf_free(gsmi_dev.param_buf); + gsmi_buf_free(gsmi_dev.data_buf); + gsmi_buf_free(gsmi_dev.name_buf); + kmem_cache_destroy(gsmi_dev.mem_pool); + platform_device_unregister(gsmi_dev.pdev); +#ifdef CONFIG_PM + platform_driver_unregister(&gsmi_driver_info); +#endif +} + +module_init(gsmi_init); +module_exit(gsmi_exit); + +MODULE_AUTHOR("Google, Inc."); +MODULE_LICENSE("GPL"); |