From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hsin-Yi Wang Subject: [PATCH v8 2/3] fdt: add support for rng-seed Date: Mon, 19 Aug 2019 15:16:04 +0800 Message-ID: <20190819071602.139014-3-hsinyi@chromium.org> References: <20190819071602.139014-1-hsinyi@chromium.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190819071602.139014-1-hsinyi@chromium.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Frank Rowand , Catalin Marinas , Will Deacon , Andrew Morton , Mike Rapoport , Ard Biesheuvel , Miles Chen , Hsin-Yi Wang , James Morse , Andrew Murray , Mark Rutland , Jun Yao , Yu Zhao , Robin Murphy , Laura Abbott , Stephen Boyd , Kees Cook List-Id: devicetree@vger.kernel.org Introducing a chosen node, rng-seed, which is an entropy that can be passed to kernel called very early to increase initial device randomness. Bootloader should provide this entropy and the value is read from /chosen/rng-seed in DT. Obtain of_fdt_crc32 for CRC check after early_init_dt_scan_nodes(), since early_init_dt_scan_chosen() would modify fdt to erase rng-seed. Signed-off-by: Hsin-Yi Wang Reviewed-by: Stephen Boyd Reviewed-by: Rob Herring --- Change from v7: obtain of_fdt_crc32 after early_init_dt_scan_nodes(). --- drivers/of/fdt.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 9cdf14b9aaab..97a75996993c 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -24,6 +24,7 @@ #include #include #include +#include #include /* for COMMAND_LINE_SIZE */ #include @@ -1044,6 +1045,7 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, { int l; const char *p; + const void *rng_seed; pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname); @@ -1078,6 +1080,14 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, pr_debug("Command line is: %s\n", (char*)data); + rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); + if (rng_seed && l > 0) { + add_device_randomness(rng_seed, l); + + /* try to clear seed so it won't be found. */ + fdt_nop_property(initial_boot_params, node, "rng-seed"); + } + /* break now */ return 1; } @@ -1166,8 +1176,6 @@ bool __init early_init_dt_verify(void *params) /* Setup flat device-tree pointer */ initial_boot_params = params; - of_fdt_crc32 = crc32_be(~0, initial_boot_params, - fdt_totalsize(initial_boot_params)); return true; } @@ -1197,6 +1205,8 @@ bool __init early_init_dt_scan(void *params) return false; early_init_dt_scan_nodes(); + of_fdt_crc32 = crc32_be(~0, initial_boot_params, + fdt_totalsize(initial_boot_params)); return true; } -- 2.20.1