diff options
| -rw-r--r-- | common/Kconfig | 14 | ||||
| -rw-r--r-- | common/fdt_support.c | 13 | ||||
| -rw-r--r-- | include/fdt_support.h | 13 |
3 files changed, 40 insertions, 0 deletions
diff --git a/common/Kconfig b/common/Kconfig index e7914ca..ebee856 100644 --- a/common/Kconfig +++ b/common/Kconfig @@ -768,6 +768,20 @@ config TPL_STACKPROTECTOR bool "Stack Protector buffer overflow detection for TPL" depends on STACKPROTECTOR && TPL +config BOARD_RNG_SEED + bool "Provide /chosen/rng-seed property to the linux kernel" + help + Selecting this option requires the board to define a + board_rng_seed() function, which should return a buffer + which will be used to populate the /chosen/rng-seed property + in the device tree for the OS being booted. + + It is up to the board code (and more generally the whole + BSP) where and how to store (or generate) such a seed, how + to ensure a given seed is only used once, how to create a + new seed for use on subsequent boots, and whether or not the + kernel should account any entropy from the given seed. + endmenu menu "Update support" diff --git a/common/fdt_support.c b/common/fdt_support.c index 8c18af2..baf7fb7 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -7,6 +7,7 @@ */ #include <common.h> +#include <abuf.h> #include <env.h> #include <log.h> #include <mapmem.h> @@ -279,6 +280,7 @@ __weak char *board_fdt_chosen_bootargs(void) int fdt_chosen(void *fdt) { + struct abuf buf = {}; int nodeoffset; int err; char *str; /* used to set string properties */ @@ -294,6 +296,17 @@ int fdt_chosen(void *fdt) if (nodeoffset < 0) return nodeoffset; + if (IS_ENABLED(CONFIG_BOARD_RNG_SEED) && !board_rng_seed(&buf)) { + err = fdt_setprop(fdt, nodeoffset, "rng-seed", + abuf_data(&buf), abuf_size(&buf)); + abuf_uninit(&buf); + if (err < 0) { + printf("WARNING: could not set rng-seed %s.\n", + fdt_strerror(err)); + return err; + } + } + str = board_fdt_chosen_bootargs(); if (str) { diff --git a/include/fdt_support.h b/include/fdt_support.h index ac76939..b838071 100644 --- a/include/fdt_support.h +++ b/include/fdt_support.h @@ -11,6 +11,7 @@ #include <asm/u-boot.h> #include <linux/libfdt.h> +#include <abuf.h> /** * arch_fixup_fdt() - Write arch-specific information to fdt @@ -187,6 +188,18 @@ int fdt_find_or_add_subnode(void *fdt, int parentoffset, const char *name); int ft_board_setup(void *blob, struct bd_info *bd); /** + * board_rng_seed() - Provide a seed to be passed via /chosen/rng-seed + * + * This function is called if CONFIG_BOARD_RNG_SEED is set, and must + * be provided by the board. It should return, via @buf, some suitable + * seed value to pass to the kernel. + * + * @param buf A struct abuf for returning the seed and its size. + * @return 0 if ok, negative on error. + */ +int board_rng_seed(struct abuf *buf); + +/** * board_fdt_chosen_bootargs() - Arbitrarily amend fdt kernel command line * * This is used for late modification of kernel command line arguments just |