於 四，2013-09-05 於 11:31 +0100，Matt Fleming 提到： > On Thu, 05 Sep, at 06:13:36PM, joeyli wrote: > > This S4WakeKey is a VOLATILE variable that could not modify by > > SetVariable() at runtime. So, it's read only even through efivars. > > > > Does it what your concern? > > No, the UEFI spec probibits certain runtime functions from being > executed concurrently on separate cpus and the spinlock used in the > efivars code ensures that we adhere to that restriction. See table 31 in > section 7.1 of the UEFI 2.4 spec for the list of services that are > non-reentrant. > > The problem isn't that we want to avoid simultaneous access to > S4WakeKey, it's that we can't invoke any of the variable runtime service > functions concurrently. > I see! I will use efivar api to access EFI variable. Thanks a lot! Joey Lee -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
