git.openwrt.org Git - openwrt/staging/stintel.git/blob

   1 From ed4ae7386257aa66455e330234e513d098a36f84 Mon Sep 17 00:00:00 2001
   2 From: Alex Shumsky <alexthreed@gmail.com>
   3 Date: Wed, 16 Oct 2024 13:02:03 +0300
   4 Subject: [PATCH] rockchip: board: Increase rng-seed size to make it sufficient
   5  for modern Linux
   6
   7 Increase rng-seed size to make Linux happy and initialize rng pool instantly.
   8 Linux 5.19+ requires 32 bytes of entropy to initialize random pool, but u-boot
   9 currently provides only 8 bytes.
  10 Linux 5.18 and probably some versions before it used to require 64 bytes.
  11 Bump min value to 64 bytes to be on a safe side.
  12
  13 Boot with 8 byte rng-seed (Linux 6.11):
  14     # dmesg | grep crng
  15     [   12.089286] random: crng init done
  16 Boot with 32 byte rng-seed (Linux 6.11):
  17     # dmesg | grep crng
  18     [    0.000000] random: crng init done
  19
  20 Linux source references:
  21 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/char/random.c?h=v5.19#n551
  22 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/char/random.c?h=v5.18#n236
  23
  24 Signed-off-by: Alex Shumsky <alexthreed@gmail.com>
  25 Fixes: d2048bafae40 ("rockchip: board: Add board_rng_seed() for all Rockchip devices")
  26 Reviewed-by: Dragan Simic <dsimic@manjaro.org>
  27 Reviewed-by: Marek Vasut <marex@denx.de>
  28 Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
  29 Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
  30 ---
  31  arch/arm/mach-rockchip/board.c | 11 ++++++++++-
  32  common/Kconfig                 |  3 +++
  33  doc/usage/environment.rst      |  5 +++++
  34  include/fdt_support.h          |  3 ++-
  35  4 files changed, 20 insertions(+), 2 deletions(-)
  36
  37 --- a/arch/arm/mach-rockchip/board.c
  38 +++ b/arch/arm/mach-rockchip/board.c
  39 @@ -480,9 +480,18 @@ __weak int misc_init_r(void)
  40  __weak int board_rng_seed(struct abuf *buf)
  41  {
  42         struct udevice *dev;
  43 -       size_t len = 0x8;
  44 +       ulong len = env_get_ulong("rng_seed_size", 10, 64);
  45         u64 *data;
  46
  47 +       if (len < 64) {
  48 +               /*
  49 +                * rng_seed_size should be at least 32 bytes for Linux 5.19+,
  50 +                * or 64 for older Linux kernel versions
  51 +                */
  52 +               log_warning("Value for rng_seed_size (%lu) too low, Linux kernel RNG may fail to initialize early\n",
  53 +                           len);
  54 +       }
  55 +
  56         data = malloc(len);
  57         if (!data) {
  58                 printf("Out of memory\n");
  59 --- a/common/Kconfig
  60 +++ b/common/Kconfig
  61 @@ -927,6 +927,9 @@ config BOARD_RNG_SEED
  62           new seed for use on subsequent boots, and whether or not the
  63           kernel should account any entropy from the given seed.
  64
  65 +         Default seed size (64 bytes) can be overridden by a decimal
  66 +         environment variable rng_seed_size.
  67 +
  68  endmenu
  69
  70  menu "Update support"
  71 --- a/doc/usage/environment.rst
  72 +++ b/doc/usage/environment.rst
  73 @@ -323,6 +323,11 @@ netretry
  74      Useful on scripts which control the retry operation
  75      themselves.
  76
  77 +rng_seed_size
  78 +    Size of random value added to device-tree node /chosen/rng-seed.
  79 +    This variable is given as a decimal number.
  80 +    If unset, 64 bytes is used as the default.
  81 +
  82  silent_linux
  83      If set then Linux will be told to boot silently, by
  84      adding 'console=' to its command line. If "yes" it will be
  85 --- a/include/fdt_support.h
  86 +++ b/include/fdt_support.h
  87 @@ -202,7 +202,8 @@ int ft_board_setup(void *blob, struct bd
  88   *
  89   * This function is called if CONFIG_BOARD_RNG_SEED is set, and must
  90   * be provided by the board. It should return, via @buf, some suitable
  91 - * seed value to pass to the kernel.
  92 + * seed value to pass to the kernel. Seed size could be set in a decimal
  93 + * environment variable rng_seed_size and it defaults to 64 bytes.
  94   *
  95   * @param buf         A struct abuf for returning the seed and its size.
  96   * @return            0 if ok, negative on error.