Messages in this thread | | | Date | Mon, 20 Jun 2011 17:56:27 -0700 | From | Mike Waychison <> | Subject | Re: [PATCH 3/3] efi: Add support for using efivars as a pstore backend |
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On 06/06/11 12:38, Matthew Garrett wrote: > 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.
How do I configure this thing?
Inline notes below. Sorry for the delayed response.
> > Signed-off-by: Matthew Garrett<mjg@redhat.com> > --- > drivers/firmware/efivars.c | 158 +++++++++++++++++++++++++++++++++++++++++++- > include/linux/efi.h | 3 + > 2 files changed, 159 insertions(+), 2 deletions(-) > > diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c > index 5f29aaf..89e6a3a 100644 > --- a/drivers/firmware/efivars.c > +++ b/drivers/firmware/efivars.c > @@ -78,6 +78,7 @@ > #include<linux/kobject.h> > #include<linux/device.h> > #include<linux/slab.h> > +#include<linux/pstore.h> > > #include<asm/uaccess.h> > > @@ -89,6 +90,8 @@ MODULE_DESCRIPTION("sysfs interface to EFI Variables"); > MODULE_LICENSE("GPL"); > MODULE_VERSION(EFIVARS_VERSION); > > +#define DUMP_NAME_LEN 52 > + > /* > * The maximum size of VariableName + Data = 1024 > * Therefore, it's reasonable to save that much > @@ -161,18 +164,28 @@ utf8_strsize(efi_char16_t *data, unsigned long maxlength) > } > > static efi_status_t > -get_var_data(struct efivars *efivars, struct efi_variable *var) > +get_var_data_locked(struct efivars *efivars, struct efi_variable *var) > { > efi_status_t status; > > - spin_lock(&efivars->lock); > var->DataSize = 1024; > status = efivars->ops->get_variable(var->VariableName, > &var->VendorGuid, > &var->Attributes, > &var->DataSize, > var->Data); > + return status; > +} > + > +static efi_status_t > +get_var_data(struct efivars *efivars, struct efi_variable *var) > +{ > + efi_status_t status; > + > + spin_lock(&efivars->lock); > + status = get_var_data_locked(efivars, var); > spin_unlock(&efivars->lock); > + > if (status != EFI_SUCCESS) { > printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n", > status); > @@ -387,12 +400,145 @@ static struct kobj_type efivar_ktype = { > .default_attrs = def_attrs, > }; > > +static struct efivar_entry *walk_entry; > + > +static struct pstore_info efi_pstore_info;
Can you move these into struct efivars in efi.h?
> + > static inline void > efivar_unregister(struct efivar_entry *var) > { > kobject_put(&var->kobj); > } > > +static int efi_pstore_open(struct pstore_info *psi) > +{ > + struct efivars *efivars = psi->data; > + > + spin_lock(&efivars->lock); > + walk_entry = list_first_entry(&efivars->list, struct efivar_entry, > + list); > + return 0; > +} > + > +static int efi_pstore_close(struct pstore_info *psi) > +{ > + struct efivars *efivars = psi->data; > + > + spin_unlock(&efivars->lock); > + return 0; > +} > + > +static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, > + struct timespec *timespec, struct pstore_info *psi) > +{ > + efi_guid_t vendor = LINUX_EFI_CRASH_GUID; > + struct efivars *efivars = psi->data; > + char name[DUMP_NAME_LEN]; > + int i; > + unsigned int part, size; > + unsigned long time; > + > + while (&walk_entry->list !=&efivars->list) { > + if (!efi_guidcmp(walk_entry->var.VendorGuid, vendor)) { > + for (i = 0; i< DUMP_NAME_LEN; i++) { > + name[i] = walk_entry->var.VariableName[i]; > + } > + if (sscanf(name, "dump-type%u-%u-%lu", type,&part,&time) == 3) { > + *id = part; > + timespec->tv_sec = time; > + timespec->tv_nsec = 0; > + get_var_data_locked(efivars,&walk_entry->var); > + size = walk_entry->var.DataSize; > + memcpy(psi->buf, walk_entry->var.Data, size); > + walk_entry = list_entry(walk_entry->list.next, > + struct efivar_entry, list); > + return size; > + } > + } > + walk_entry = list_entry(walk_entry->list.next, > + struct efivar_entry, list); > + } > + return 0; > +} > + > +static u64 efi_pstore_write(enum pstore_type_id type, int part, size_t size, > + struct pstore_info *psi) > +{ > + char name[DUMP_NAME_LEN]; > + char stub_name[DUMP_NAME_LEN]; > + efi_char16_t efi_name[DUMP_NAME_LEN]; > + efi_guid_t vendor = LINUX_EFI_CRASH_GUID; > + struct efivars *efivars = psi->data; > + struct efivar_entry *entry, *found = NULL; > + int i; > + > + sprintf(stub_name, "dump-type%u-%u-", type, part);
The format specifier here uses an unsigned, but your series passes part around as a signed int. If part is truely non-negative, consider changing it to unsigned?
> + sprintf(name, "%s%lu", stub_name, get_seconds()); > + > + spin_lock(&efivars->lock); > + > + for (i = 0; i< DUMP_NAME_LEN; i++) > + efi_name[i] = stub_name[i]; > + > + /* > + * Clean up any entries with the same name > + */ > + > + list_for_each_entry(entry,&efivars->list, list) { > + get_var_data_locked(efivars,&entry->var); > + > + for (i = 0; i< DUMP_NAME_LEN; i++) { > + if (efi_name[i] == 0) {
Test for entry->var.VariableName[i] == 0 too. Actually, could we just turn this string comparing loop into a strncmp test?
> + found = entry; > + efi.set_variable(entry->var.VariableName,&entry->var.VendorGuid,
space after comma
> + EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, > + 0, NULL);
We shouldn't be calling the global efi ops structure here. Instead, we should be using efivars->ops->set_variable(...)
> + break; > + } else if (efi_name[i] != entry->var.VariableName[i]) { > + break; > + } > + } > + } > + > + if (found) > + list_del(&found->list); > + > + for (i = 0; i< DUMP_NAME_LEN; i++) > + efi_name[i] = name[i]; > + > + efi.set_variable(efi_name,&vendor, > + EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, > + size, psi->buf);
efivars->ops->set_variable.
> + > + spin_unlock(&efivars->lock); > + > + if (found) > + efivar_unregister(found); > + > + if (size) > + efivar_create_sysfs_entry(efivars, utf8_strsize(efi_name, DUMP_NAME_LEN * 2), > + efi_name,&vendor); > + > + return part; > +}; > + > +static int efi_pstore_erase(enum pstore_type_id type, u64 id, > + struct pstore_info *psi) > +{ > + efi_pstore_write(type, id, 0, psi); > + > + return 0; > +} > + > +static struct pstore_info efi_pstore_info = { > + .owner = THIS_MODULE, > + .name = "efi", > + .open = efi_pstore_open, > + .close = efi_pstore_close, > + .read = efi_pstore_read, > + .write = efi_pstore_write, > + .erase = efi_pstore_erase, > +}; > > static ssize_t efivar_create(struct file *filp, struct kobject *kobj, > struct bin_attribute *bin_attr, > @@ -763,6 +909,14 @@ int register_efivars(struct efivars *efivars, > if (error) > unregister_efivars(efivars); > > + efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL); > + if (efi_pstore_info.buf) { > + efi_pstore_info.bufsize = 1024; > + efi_pstore_info.data = efivars; > + mutex_init(&efi_pstore_info.buf_mutex); > + pstore_register(&efi_pstore_info); > + } > +
Hmm. pstore doesn't have a pstore_unregister? This is unfortunate because this breaks efivars module unloading :(
> out: > kfree(variable_name); > > diff --git a/include/linux/efi.h b/include/linux/efi.h > index ec25726..8dd9a01 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -232,6 +232,9 @@ typedef efi_status_t efi_query_capsule_caps_t(efi_capsule_header_t **capsules, > #define UV_SYSTEM_TABLE_GUID \ > EFI_GUID( 0x3b13a7d4, 0x633e, 0x11dd, 0x93, 0xec, 0xda, 0x25, 0x56, 0xd8, 0x95, 0x93 ) > > +#define LINUX_EFI_CRASH_GUID \ > + EFI_GUID( 0xcfc8fc79, 0xbe2e, 0x4ddc, 0x97, 0xf0, 0x9f, 0x98, 0xbf, 0xe2, 0x98, 0xa0 ) > + > typedef struct { > efi_guid_t guid; > unsigned long table;
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