From d58541d25d4f1bd980ce40dd307d1f20dca7d237 Mon Sep 17 00:00:00 2001 From: Seiji Aguchi Date: Wed, 14 Nov 2012 20:26:21 +0000 Subject: [PATCH] efi_pstore: Add a logic erasing entries to an erase callback [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 Acked-by: Mike Waychison Signed-off-by: Tony Luck --- drivers/firmware/efivars.c | 46 +++++++++++++++++++++++++++++++++++++- 1 file changed, 45 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 37ac21a08751..bee14cc47c03 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -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; } -- 2.39.2