linux-kernel - [PATCH v9 3/3] arm64: kexec

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Date:   Thu, 22 Aug 2019 15:15:23 +0800
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     linux-arm-kernel@...ts.infradead.org,
        "Theodore Y . Ts'o" <tytso@....edu>
Cc:     Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        "David S . Miller" <davem@...emloft.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Arnd Bergmann <arnd@...db.de>, Marc Zyngier <maz@...nel.org>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Wei Li <liwei391@...wei.com>,
        Anders Roxell <anders.roxell@...aro.org>,
        Rob Herring <robh@...nel.org>,
        Aaro Koskinen <aaro.koskinen@...ia.com>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Rik van Riel <riel@...riel.com>,
        Waiman Long <longman@...hat.com>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Armijn Hemel <armijn@...ldur.nl>,
        Grzegorz Halat <ghalat@...hat.com>,
        Len Brown <len.brown@...el.com>,
        Shaokun Zhang <zhangshaokun@...ilicon.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Kees Cook <keescook@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Yury Norov <ynorov@...vell.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Jiri Kosina <jkosina@...e.cz>,
        Mukesh Ojha <mojha@...eaurora.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v9 3/3] arm64: kexec_file: add rng-seed support

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@...omium.org>
Reviewed-by: Stephen Boyd <swboyd@...omium.org>
---
No change since v7.
---
 arch/arm64/kernel/machine_kexec_file.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index ba78ee7ca990..7b08bf9499b6 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 +104,19 @@ static int setup_dtb(struct kimage *image,
 				FDT_PROP_KASLR_SEED);
 	}
 
+	/* add rng-seed */
+	if (rng_is_initialized()) {
+		u8 rng_seed[RNG_SEED_SIZE];
+		get_random_bytes(rng_seed, RNG_SEED_SIZE);
+		ret = fdt_setprop(dtb, off, FDT_PROP_RNG_SEED, rng_seed,
+				RNG_SEED_SIZE);
+		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 +125,8 @@ 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
 
-- 
2.20.1