Re: [tip:efi/core] efibc: Add EFI Bootloader Control module

Ingo Molnar
2016-04-29T19:46:21Z

* Compostella, Jeremy <jeremy.compostella@intel.com> wrote:

> -static void efibc_set_variable(const char *name, const char *value)
> +static int efibc_set_variable(const char *name, const char *value)
> {
> int ret;
> efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
> - struct efivar_entry entry;
> + struct efivar_entry *entry;
> size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
>
> - if (size > sizeof(entry.var.Data))
> + if (size > sizeof(entry->var.Data)) {
> pr_err("value is too large");
> + return -1;
> + }
>
> - efibc_str_to_str16(name, entry.var.VariableName);
> - efibc_str_to_str16(value, (efi_char16_t *)entry.var.Data);
> - memcpy(&entry.var.VendorGuid, &guid, sizeof(guid));
> + entry = kmalloc(sizeof(*entry), GFP_KERNEL);
> + if (!entry) {
> + pr_err("failed to allocate efivar entry");
> + return -1;
> + }
>
> - ret = efivar_entry_set(&entry,
> + efibc_str_to_str16(name, entry->var.VariableName);
> + efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
> + memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
> +
> + ret = efivar_entry_set(entry,
> EFI_VARIABLE_NON_VOLATILE
> | EFI_VARIABLE_BOOTSERVICE_ACCESS
> | EFI_VARIABLE_RUNTIME_ACCESS,
> - size, entry.var.Data, NULL);
> + size, entry->var.Data, NULL);
> if (ret)
> pr_err("failed to set %s EFI variable: 0x%x\n",
> name, ret);
> +
> + kfree(entry);
> + return ret;
> }
>
> static int efibc_reboot_notifier_call(struct notifier_block *notifier,
> unsigned long event, void *data)
> {
> const char *reason = "shutdown";
> + int ret;
>
> if (event == SYS_RESTART)
> reason = "reboot";
>
> - efibc_set_variable("LoaderEntryRebootReason", reason);
> -
> - if (!data)
> - return NOTIFY_DONE;
> + ret = efibc_set_variable("LoaderEntryRebootReason", reason);
> + if (ret || !data)
> + return NOTIFY_DONE;
>
> efibc_set_variable("LoaderEntryOneShot", (char *)data);

Hm, can reboot notifiers do non-atomic allocations?

Why is efivar_entry so huge?

Thanks,

Ingo