Hi, This is an RFC to seed the random number pool earlier when using devicetree. The big issue this is trying to solve is the fact that the stack canary for ARM tends to be the same across bootups of the same device. This is because the random number pools do not get initialized until after the canary has been set up. The canary can be moved later, but in general there is still no way to reliably get random numbers early for other features (e.g. vector randomization). The goal here is to allow devices to add to the random pools via add_device_randomness or some other method of their chosing at FDT time. I realize that ARCH_RANDOM is already available but this didn't work because 1) ARCH_RANDOM is not multi-platform compatible without added infrastructure to ARM 2) There is no uniform way to generate the random numbers which would require an additional framework (same result as #1, different reasons) 3) Given there is no uniform way to generate the random numbers, it seems unlikely that 'early' random numbers would work the same as 'non-early' random number which adds another layer of complexity. The big reason to skip ARCH_RANDOM though is that the random number generation we have would be reasonable if only seeded earlier. Thanks, Laura Laura Abbott (3): of: Add early randomness hooks arm: Add ARCH_WANT_OF_RANDOMNESS init: Move stack canary initialization after setup_arch arch/arm/Kconfig | 3 ++ arch/arm/kernel/vmlinux.lds.S | 1 + drivers/of/Kconfig | 7 ++++++ drivers/of/Makefile | 1 + drivers/of/fdt.c | 7 ++++++ drivers/of/of_randomness.c | 43 +++++++++++++++++++++++++++++++++++++ include/asm-generic/vmlinux.lds.h | 5 ++++ include/linux/of_randomness.h | 42 ++++++++++++++++++++++++++++++++++++ init/main.c | 9 +++---- 9 files changed, 113 insertions(+), 5 deletions(-) create mode 100644 drivers/of/of_randomness.c create mode 100644 include/linux/of_randomness.h -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
