Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-03 17:41:22 +00:00
Code Issues Packages Projects Releases Wiki Activity

efi_pstore: Add a logic erasing entries to an erase callback

Browse Source 
[Issue]

Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.

 1. kernel panics.
 2. efi_pstore is kicked and writes panic messages to NVRAM.
 3. system reboots.
 4. kernel panics again before a user checks the 1st panic messages in NVRAM.

[Solution]

A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.

This patch freshly adds a logic erasing existing entries, which shared with a write callback,
to an erase callback.
To support holding multiple logs, the write callback doesn't need to erase any entries and
it will be removed in a subsequent patch.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Seiji Aguchi 2012-11-14 20:26:21 +00:00 committed by Tony Luck
parent d80a361d77
commit dd230fecab
1 changed files with 45 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
drivers/firmware/efivars.c
View File

@ -784,7 +784,51 @@ static int efi_pstore_write(enum pstore_type_id type,
static int efi_pstore_erase(enum pstore_type_id type, u64 id,
struct pstore_info *psi)
{
efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
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, (unsigned int)id);
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);
if (efi_guidcmp(entry->var.VendorGuid, vendor))
continue;
if (utf16_strncmp(entry->var.VariableName, efi_name,
utf16_strlen(efi_name)))
continue;
/* Needs to be a prefix */
if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
continue;
/* found */
found = entry;
efivars->ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
PSTORE_EFI_ATTRIBUTES,
0, NULL);
}
if (found)
list_del(&found->list);
spin_unlock(&efivars->lock);
if (found)
efivar_unregister(found);
return 0;
}