[PATCH v2 1/4] fdt: common API to populate kaslr seed
Simon Glass
sjg at chromium.org
Thu Aug 31 21:02:00 CEST 2023
Hi Sean,
On Tue, 29 Aug 2023 at 14:37, <seanedmond at linux.microsoft.com> wrote:
>
> From: Dhananjay Phadke <dphadke at linux.microsoft.com>
>
> fdt_fixup_kaslr_seed() will update given ofnode with random seed value.
> Source for random seed can be TPM or RNG driver in u-boot or sec
> firmware (ARM).
>
> Signed-off-by: Dhananjay Phadke <dphadke at linux.microsoft.com>
> Signed-off-by: Sean Edmond <senaedmond at microsoft.com>
> ---
> arch/arm/cpu/armv8/sec_firmware.c | 39 +++++++++++--------------------
> common/fdt_support.c | 19 +++++++++++++++
> drivers/core/ofnode.c | 17 ++++++++++++++
> include/dm/ofnode.h | 12 ++++++++++
> include/fdt_support.h | 9 +++++++
> 5 files changed, 71 insertions(+), 25 deletions(-)
>
> diff --git a/arch/arm/cpu/armv8/sec_firmware.c b/arch/arm/cpu/armv8/sec_firmware.c
> index c0e8726346..5f04cd8aec 100644
> --- a/arch/arm/cpu/armv8/sec_firmware.c
> +++ b/arch/arm/cpu/armv8/sec_firmware.c
> @@ -411,46 +411,35 @@ int sec_firmware_init(const void *sec_firmware_img,
> /*
> * fdt_fix_kaslr - Add kalsr-seed node in Device tree
> * @fdt: Device tree
> - * @eret: 0 in case of error, 1 for success
> + * @eret: 0 for success
> */
> int fdt_fixup_kaslr(void *fdt)
Is it possible to put this code in an EVT_FT_FIXUP spy? I was rather
hoping not to add new fixup functions.
> {
> - int nodeoffset;
> - int err, ret = 0;
> - u8 rand[8];
> + int ret = 0;
>
> #if defined(CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT)
> + u8 rand[8];
> + ofnode root;
> +
> /* Check if random seed generation is supported */
> if (sec_firmware_support_hwrng() == false) {
> printf("WARNING: SEC firmware not running, no kaslr-seed\n");
> - return 0;
> + return -EOPNOTSUPP;
> }
>
> - err = sec_firmware_get_random(rand, 8);
> - if (err < 0) {
> + ret = sec_firmware_get_random(rand, 8);
> + if (ret < 0) {
> printf("WARNING: No random number to set kaslr-seed\n");
> - return 0;
> + return ret;
> }
>
> - err = fdt_check_header(fdt);
> - if (err < 0) {
> - printf("fdt_chosen: %s\n", fdt_strerror(err));
> - return 0;
> + ret = root_ofnode_from_fdt(fdt, &root);
> + if (ret < 0) {
> + printf("WARNING: Unable to get root ofnode\n");
> + return ret;
> }
>
> - /* find or create "/chosen" node. */
> - nodeoffset = fdt_find_or_add_subnode(fdt, 0, "chosen");
> - if (nodeoffset < 0)
> - return 0;
> -
> - err = fdt_setprop(fdt, nodeoffset, "kaslr-seed", rand,
> - sizeof(rand));
> - if (err < 0) {
> - printf("WARNING: can't set kaslr-seed %s.\n",
> - fdt_strerror(err));
> - return 0;
> - }
> - ret = 1;
> + ret = fdt_fixup_kaslr_seed(root, rand, sizeof(rand));
> #endif
>
> return ret;
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 5e49078f8c..52be4375b4 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -631,6 +631,25 @@ void fdt_fixup_ethernet(void *fdt)
> }
> }
>
> +int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len)
> +{
> + ofnode chosen;
> + int ret;
> +
> + /* find or create "/chosen" node. */
> + ret = ofnode_add_subnode(node, "chosen", &chosen);
> + if (ret && ret != -EEXIST)
> + return -ENOENT;
> +
> + ret = ofnode_write_prop(chosen, "kaslr-seed", seed, len, true);
> + if (ret) {
> + printf("WARNING: can't set kaslr-seed\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> int fdt_record_loadable(void *blob, u32 index, const char *name,
> uintptr_t load_addr, u32 size, uintptr_t entry_point,
> const char *type, const char *os, const char *arch)
> diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
> index 8df16e56af..4be21133b8 100644
> --- a/drivers/core/ofnode.c
> +++ b/drivers/core/ofnode.c
> @@ -870,6 +870,23 @@ ofnode oftree_path(oftree tree, const char *path)
> }
> }
>
> +int root_ofnode_from_fdt(void *fdt, ofnode *root_node)
> +{
> + oftree tree;
> + /* If OFNODE_MULTI_TREE is not set, and if fdt is not the control FDT,
> + * oftree_from_fdt() will return NULL
> + */
> + tree = oftree_from_fdt(fdt);
> +
> + if (!oftree_valid(tree)) {
> + printf("Cannot create oftree\n");
> + return -EINVAL;
> + }
> + *root_node = oftree_root(tree);
> +
> + return 0;
> +}
> +
> const void *ofnode_read_chosen_prop(const char *propname, int *sizep)
> {
> ofnode chosen_node;
> diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
> index 0f38b3e736..e79bb62be8 100644
> --- a/include/dm/ofnode.h
> +++ b/include/dm/ofnode.h
> @@ -901,6 +901,18 @@ ofnode oftree_path(oftree tree, const char *path);
> */
> ofnode oftree_root(oftree tree);
>
> +/**
> + * root_ofnode_from_fdt() - Gets the root ofnode given an FDT blob.
> + * Note, this will fail if OFNODE_MULTI_TREE
> + * is not set.
> + *
> + * @fdt: Device tree to use
> + * @root_node : Root ofnode
> + *
> + * Return: 0 if OK, -ve on error
> + */
> +int root_ofnode_from_fdt(void *fdt, ofnode *root_node);
> +
> /**
> * ofnode_read_chosen_prop() - get the value of a chosen property
> *
> diff --git a/include/fdt_support.h b/include/fdt_support.h
> index 2cd8366898..d967118bed 100644
> --- a/include/fdt_support.h
> +++ b/include/fdt_support.h
> @@ -11,6 +11,7 @@
> !defined(USE_HOSTCC)
>
> #include <asm/u-boot.h>
> +#include <dm/ofnode.h>
> #include <linux/libfdt.h>
> #include <abuf.h>
>
> @@ -121,6 +122,14 @@ static inline int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[],
> #endif
>
> void fdt_fixup_ethernet(void *fdt);
> +
> +/*
> + * fdt_fixup_kaslr_seed - Add kaslr-seed node in Device tree
> + * @node: ofnode
> + * @eret: 0 for success
> + */
> +int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len);
> +
> int fdt_find_and_setprop(void *fdt, const char *node, const char *prop,
> const void *val, int len, int create);
> void fdt_fixup_qe_firmware(void *fdt);
> --
> 2.40.0
>
Regards,
Simon
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