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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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efi: Add support for using efivars as a pstore backend
EFI provides an area of nonvolatile storage managed by the firmware. We can use this as a pstore backend to maintain copies of oopses, aiding diagnosis. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Matthew Garrett
Tony Luck
parent
dee28e72b6
commit
5ee9c198a4
2 changed files with 195 additions and 2 deletions
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@ -78,6 +78,7 @@
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#include <linux/kobject.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/pstore.h>
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#include <asm/uaccess.h>
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@ -89,6 +90,8 @@ MODULE_DESCRIPTION("sysfs interface to EFI Variables");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(EFIVARS_VERSION);
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#define DUMP_NAME_LEN 52
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/*
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* The maximum size of VariableName + Data = 1024
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* Therefore, it's reasonable to save that much
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@ -161,18 +164,28 @@ utf8_strsize(efi_char16_t *data, unsigned long maxlength)
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}
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static efi_status_t
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get_var_data(struct efivars *efivars, struct efi_variable *var)
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get_var_data_locked(struct efivars *efivars, struct efi_variable *var)
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{
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efi_status_t status;
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spin_lock(&efivars->lock);
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var->DataSize = 1024;
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status = efivars->ops->get_variable(var->VariableName,
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&var->VendorGuid,
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&var->Attributes,
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&var->DataSize,
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var->Data);
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return status;
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}
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static efi_status_t
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get_var_data(struct efivars *efivars, struct efi_variable *var)
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{
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efi_status_t status;
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spin_lock(&efivars->lock);
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status = get_var_data_locked(efivars, var);
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spin_unlock(&efivars->lock);
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if (status != EFI_SUCCESS) {
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printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
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status);
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@ -387,12 +400,176 @@ static struct kobj_type efivar_ktype = {
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.default_attrs = def_attrs,
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};
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static struct pstore_info efi_pstore_info;
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static inline void
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efivar_unregister(struct efivar_entry *var)
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{
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kobject_put(&var->kobj);
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}
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#ifdef CONFIG_PSTORE
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static int efi_pstore_open(struct pstore_info *psi)
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{
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struct efivars *efivars = psi->data;
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spin_lock(&efivars->lock);
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efivars->walk_entry = list_first_entry(&efivars->list,
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struct efivar_entry, list);
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return 0;
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}
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static int efi_pstore_close(struct pstore_info *psi)
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{
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struct efivars *efivars = psi->data;
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spin_unlock(&efivars->lock);
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return 0;
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}
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static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
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struct timespec *timespec, struct pstore_info *psi)
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{
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efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
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struct efivars *efivars = psi->data;
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char name[DUMP_NAME_LEN];
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int i;
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unsigned int part, size;
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unsigned long time;
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while (&efivars->walk_entry->list != &efivars->list) {
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if (!efi_guidcmp(efivars->walk_entry->var.VendorGuid,
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vendor)) {
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for (i = 0; i < DUMP_NAME_LEN; i++) {
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name[i] = efivars->walk_entry->var.VariableName[i];
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}
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if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
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*id = part;
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timespec->tv_sec = time;
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timespec->tv_nsec = 0;
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get_var_data_locked(efivars, &efivars->walk_entry->var);
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size = efivars->walk_entry->var.DataSize;
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memcpy(psi->buf, efivars->walk_entry->var.Data, size);
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efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
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struct efivar_entry, list);
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return size;
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}
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}
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efivars->walk_entry = list_entry(efivars->walk_entry->list.next,
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struct efivar_entry, list);
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}
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return 0;
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}
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static u64 efi_pstore_write(enum pstore_type_id type, unsigned int part,
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size_t size, struct pstore_info *psi)
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{
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char name[DUMP_NAME_LEN];
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char stub_name[DUMP_NAME_LEN];
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efi_char16_t efi_name[DUMP_NAME_LEN];
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efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
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struct efivars *efivars = psi->data;
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struct efivar_entry *entry, *found = NULL;
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int i;
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sprintf(stub_name, "dump-type%u-%u-", type, part);
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sprintf(name, "%s%lu", stub_name, get_seconds());
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spin_lock(&efivars->lock);
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for (i = 0; i < DUMP_NAME_LEN; i++)
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efi_name[i] = stub_name[i];
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/*
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* Clean up any entries with the same name
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*/
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list_for_each_entry(entry, &efivars->list, list) {
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get_var_data_locked(efivars, &entry->var);
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for (i = 0; i < DUMP_NAME_LEN; i++) {
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if (efi_name[i] == 0) {
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found = entry;
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efivars->ops->set_variable(entry->var.VariableName,
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&entry->var.VendorGuid,
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EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
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0, NULL);
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break;
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} else if (efi_name[i] != entry->var.VariableName[i]) {
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break;
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}
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}
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}
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if (found)
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list_del(&found->list);
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for (i = 0; i < DUMP_NAME_LEN; i++)
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efi_name[i] = name[i];
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efivars->ops->set_variable(efi_name, &vendor,
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EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
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size, psi->buf);
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spin_unlock(&efivars->lock);
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if (found)
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efivar_unregister(found);
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if (size)
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efivar_create_sysfs_entry(efivars, utf8_strsize(efi_name, DUMP_NAME_LEN * 2),
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efi_name, &vendor);
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return part;
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};
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static int efi_pstore_erase(enum pstore_type_id type, u64 id,
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struct pstore_info *psi)
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{
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efi_pstore_write(type, id, 0, psi);
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return 0;
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}
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#else
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static int efi_pstore_open(struct pstore_info *psi)
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{
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return 0;
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}
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static int efi_pstore_close(struct pstore_info *psi)
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{
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return 0;
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}
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static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
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struct timespec *time, struct pstore_info *psi)
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{
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return -1;
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}
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static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size,
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struct pstore_info *psi)
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{
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return 0;
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}
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static int efi_pstore_erase(enum pstore_type_id type, u64 id,
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struct pstore_info *psi)
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{
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return 0;
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}
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#endif
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static struct pstore_info efi_pstore_info = {
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.owner = THIS_MODULE,
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.name = "efi",
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.open = efi_pstore_open,
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.close = efi_pstore_close,
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.read = efi_pstore_read,
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.write = efi_pstore_write,
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.erase = efi_pstore_erase,
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};
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static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr,
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@ -763,6 +940,16 @@ int register_efivars(struct efivars *efivars,
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if (error)
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unregister_efivars(efivars);
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efivars->efi_pstore_info = efi_pstore_info;
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efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
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if (efivars->efi_pstore_info.buf) {
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efivars->efi_pstore_info.bufsize = 1024;
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efivars->efi_pstore_info.data = efivars;
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mutex_init(&efivars->efi_pstore_info.buf_mutex);
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pstore_register(&efivars->efi_pstore_info);
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}
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out:
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kfree(variable_name);
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@ -19,6 +19,7 @@
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#include <linux/rtc.h>
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#include <linux/ioport.h>
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#include <linux/pfn.h>
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#include <linux/pstore.h>
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#include <asm/page.h>
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#include <asm/system.h>
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@ -211,6 +212,9 @@ typedef efi_status_t efi_set_virtual_address_map_t (unsigned long memory_map_siz
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#define UV_SYSTEM_TABLE_GUID \
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EFI_GUID( 0x3b13a7d4, 0x633e, 0x11dd, 0x93, 0xec, 0xda, 0x25, 0x56, 0xd8, 0x95, 0x93 )
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#define LINUX_EFI_CRASH_GUID \
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EFI_GUID( 0xcfc8fc79, 0xbe2e, 0x4ddc, 0x97, 0xf0, 0x9f, 0x98, 0xbf, 0xe2, 0x98, 0xa0 )
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typedef struct {
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efi_guid_t guid;
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unsigned long table;
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@ -426,6 +430,8 @@ struct efivars {
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struct kset *kset;
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struct bin_attribute *new_var, *del_var;
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const struct efivar_operations *ops;
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struct efivar_entry *walk_entry;
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struct pstore_info efi_pstore_info;
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};
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int register_efivars(struct efivars *efivars,
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