diff mbox series

[v5,3/3] arm64: kexec_file: add rng-seed support

Message ID 20190527043336.112854-3-hsinyi@chromium.org (mailing list archive)
State New, archived
Headers show
Series [v5,1/3] arm64: map FDT as RW for early_init_dt_scan() | expand

Commit Message

Hsin-Yi Wang May 27, 2019, 4:33 a.m. UTC 
Adding "rng-seed" to dtb. It's fine to add this property if original
fdt doesn't contain it. Since original seed will be wiped after
read, so use a default size 128 bytes here.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
 arch/arm64/kernel/machine_kexec_file.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

Comments

Stephen Boyd May 28, 2019, 3:55 p.m. UTC | #1 
Quoting Hsin-Yi Wang (2019-05-26 21:33:36)
> Adding "rng-seed" to dtb. It's fine to add this property if original
> fdt doesn't contain it. Since original seed will be wiped after
> read, so use a default size 128 bytes here.
> 
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
diff mbox series

Patch

diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 58871333737a..d40fde72a023 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -27,6 +27,8 @@ 
 #define FDT_PROP_INITRD_END	"linux,initrd-end"
 #define FDT_PROP_BOOTARGS	"bootargs"
 #define FDT_PROP_KASLR_SEED	"kaslr-seed"
+#define FDT_PROP_RNG_SEED	"rng-seed"
+#define RNG_SEED_SIZE		128
 
 const struct kexec_file_ops * const kexec_file_loaders[] = {
 	&kexec_image_ops,
@@ -102,6 +104,23 @@  static int setup_dtb(struct kimage *image,
 				FDT_PROP_KASLR_SEED);
 	}
 
+	/* add rng-seed */
+	if (rng_is_initialized()) {
+		void *rng_seed = kmalloc(RNG_SEED_SIZE, GFP_ATOMIC);
+		get_random_bytes(rng_seed, RNG_SEED_SIZE);
+
+		ret = fdt_setprop(dtb, off, FDT_PROP_RNG_SEED, rng_seed,
+				RNG_SEED_SIZE);
+		kfree(rng_seed);
+
+		if (ret)
+			goto out;
+
+	} else {
+		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
+				FDT_PROP_RNG_SEED);
+	}
+
 out:
 	if (ret)
 		return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;
@@ -110,7 +129,8 @@  static int setup_dtb(struct kimage *image,
 }
 
 /*
- * More space needed so that we can add initrd, bootargs and kaslr-seed.
+ * More space needed so that we can add initrd, bootargs, kaslr-seed, and
+ * rng-seed.
  */
 #define DTB_EXTRA_SPACE 0x1000