Re: [PATCH v4 1/5] fdt: common API to populate kaslr seed

Hi Sean,

On Fri, 3 Nov 2023 at 12:39, seanedmond@linux.microsoft.com wrote:

From: Dhananjay Phadke dphadke@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@linux.microsoft.com Signed-off-by: Sean Edmond senaedmond@microsoft.com

---

arch/arm/cpu/armv8/sec_firmware.c | 39 +++++++++++-------------------- boot/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 c0e8726346f..5f04cd8aecd 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) {

•   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/boot/fdt_support.c b/boot/fdt_support.c index 5e49078f8c3..52be4375b46 100644 --- a/boot/fdt_support.c +++ b/boot/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 29a42945102..55291f0202b 100644 --- a/drivers/core/ofnode.c +++ b/drivers/core/ofnode.c @@ -966,6 +966,23 @@ 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 19e97a90327..5759cac5b30 100644 --- a/include/dm/ofnode.h +++ b/include/dm/ofnode.h @@ -936,6 +936,18 @@ 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 2cd83668982..d967118bedf 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>

I believe you only need dm/ofnode-decl.h here. That avoids pulling in ofnode.h which ends up with of.h which includes asm/global_data.h which causes a warning for qemu_arm64 for me.

Perhaps that last include could be dropped? But in any case, we should use ofnode-decl.h in preference to ofnode.h if possible

#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); -- 2.42.0

Regards, Simon