ARMv8/sec_firmware : Update chosen/kaslr-seed with random number

kASLR support in kernel requires a random number to be passed via
chosen/kaslr-seed propert. sec_firmware generates this random seed
which can then be passed in the device tree node.

sec_firmware reserves JR3 for it's own usage. Node for JR3 is
removed from device-tree.

Signed-off-by: Ruchika Gupta <ruchika.gupta@nxp.com>

2 files changed, 133 insertions, 3 deletions

diff --git a/arch/arm/cpu/armv8/fsl-layerscape/fdt.c b/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
index f5f4840f194..c9252751dbc 100644
--- a/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
+++ b/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
@@ -345,11 +345,38 @@ static void fdt_fixup_msi(void *blob)
 }
 #endif
 
+#ifdef CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT
+/* Remove JR node used by SEC firmware */
+void fdt_fixup_remove_jr(void *blob)
+{
+	int jr_node, addr_cells, len;
+	int crypto_node = fdt_path_offset(blob, "crypto");
+	u64 jr_offset, used_jr;
+	fdt32_t *reg;
+
+	used_jr = sec_firmware_used_jobring_offset();
+	fdt_support_default_count_cells(blob, crypto_node, &addr_cells, NULL);
+
+	jr_node = fdt_node_offset_by_compatible(blob, crypto_node,
+						"fsl,sec-v4.0-job-ring");
+
+	while (jr_node != -FDT_ERR_NOTFOUND) {
+		reg = (fdt32_t *)fdt_getprop(blob, jr_node, "reg", &len);
+		jr_offset = fdt_read_number(reg, addr_cells);
+		if (jr_offset == used_jr) {
+			fdt_del_node(blob, jr_node);
+			break;
+		}
+		jr_node = fdt_node_offset_by_compatible(blob, jr_node,
+							"fsl,sec-v4.0-job-ring");
+	}
+}
+#endif
+
 void ft_cpu_setup(void *blob, bd_t *bd)
 {
-#ifdef CONFIG_FSL_LSCH2
 	struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_FSL_GUTS_ADDR);
-	unsigned int svr = in_be32(&gur->svr);
+	unsigned int svr = gur_in32(&gur->svr);
 
 	/* delete crypto node if not on an E-processor */
 	if (!IS_E_PROCESSOR(svr))
@@ -358,11 +385,15 @@ void ft_cpu_setup(void *blob, bd_t *bd)
 	else {
 		ccsr_sec_t __iomem *sec;
 
+#ifdef CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT
+		if (fdt_fixup_kaslr(blob))
+			fdt_fixup_remove_jr(blob);
+#endif
+
 		sec = (void __iomem *)CONFIG_SYS_FSL_SEC_ADDR;
 		fdt_fixup_crypto_node(blob, sec_in32(&sec->secvid_ms));
 	}
 #endif
-#endif
 
 #ifdef CONFIG_MP
 	ft_fixup_cpu(blob);
diff --git a/arch/arm/cpu/armv8/sec_firmware.c b/arch/arm/cpu/armv8/sec_firmware.c
index fffce712d38..0e7483437a9 100644
--- a/arch/arm/cpu/armv8/sec_firmware.c
+++ b/arch/arm/cpu/armv8/sec_firmware.c
@@ -232,6 +232,59 @@ unsigned int sec_firmware_support_psci_version(void)
 #endif
 
 /*
+ * Check with sec_firmware if it supports random number generation
+ * via HW RNG
+ *
+ * The return value will be true if it is supported
+ */
+bool sec_firmware_support_hwrng(void)
+{
+	uint8_t rand[8];
+	if (sec_firmware_addr & SEC_FIRMWARE_RUNNING) {
+		if (!sec_firmware_get_random(rand, 8))
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * sec_firmware_get_random - Get a random number from SEC Firmware
+ * @rand:		random number buffer to be filled
+ * @bytes:		Number of bytes of random number to be supported
+ * @eret:		-1 in case of error, 0 for success
+ */
+int sec_firmware_get_random(uint8_t *rand, int bytes)
+{
+	unsigned long long num;
+	struct pt_regs regs;
+	int param1;
+
+	if (!bytes || bytes > 8) {
+		printf("Max Random bytes genration supported is 8\n");
+		return -1;
+	}
+#define SIP_RNG_64 0xC200FF11
+	regs.regs[0] = SIP_RNG_64;
+
+	if (bytes <= 4)
+		param1 = 0;
+	else
+		param1 = 1;
+	regs.regs[1] = param1;
+
+	smc_call(&regs);
+
+	if (regs.regs[0])
+		return -1;
+
+	num = regs.regs[1];
+	memcpy(rand, &num, bytes);
+
+	return 0;
+}
+
+/*
  * sec_firmware_init - Initialize the SEC Firmware
  * @sec_firmware_img:	the SEC Firmware image address
  * @eret_hold_l:	the address to hold exception return address low
@@ -278,3 +331,49 @@ int sec_firmware_init(const void *sec_firmware_img,
 
 	return 0;
 }
+
+/*
+ * fdt_fix_kaslr - Add kalsr-seed node in Device tree
+ * @fdt:		Device tree
+ * @eret:		0 in case of error, 1 for success
+ */
+int fdt_fixup_kaslr(void *fdt)
+{
+	int nodeoffset;
+	int err, ret = 0;
+	u8 rand[8];
+
+#if defined(CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT)
+	/* Check if random seed generation is  supported */
+	if (sec_firmware_support_hwrng() == false)
+		return 0;
+
+	ret = sec_firmware_get_random(rand, 8);
+	if (ret < 0) {
+		printf("WARNING: No random number to set kaslr-seed\n");
+		return 0;
+	}
+
+	err = fdt_check_header(fdt);
+	if (err < 0) {
+		printf("fdt_chosen: %s\n", fdt_strerror(err));
+		return 0;
+	}
+
+	/* 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;
+#endif
+
+	return ret;
+}