[U-Boot] [PATCH v2] imx: Support i.MX6 High Assurance Boot authentication

Nitin Garg nitin.garg at freescale.com
Wed Sep 3 03:30:36 CEST 2014


When CONFIG_SECURE_BOOT is enabled, the signed images
like kernel and dtb can be authenticated using iMX6 CAAM.
The added command hab_auth_img can be used for HAB
authentication of images. The command takes the image
DDR location, IVT (Image Vector Table) offset inside
image as parameters. Detailed info about signing images
can be found in Freescale AppNote AN4581.

Signed-off-by: Nitin Garg <nitin.garg at freescale.com>

---

Changes in v2:
- Cleaned up clock code as per review comments
- Removed dead code as per review comments
- Re-written commit log as per review comments

 arch/arm/cpu/armv7/mx6/clock.c            |   32 +++++-
 arch/arm/cpu/armv7/mx6/hab.c              |  165 ++++++++++++++++++++++++++++-
 arch/arm/cpu/armv7/mx6/soc.c              |   15 +++
 arch/arm/include/asm/arch-mx6/clock.h     |    4 +
 arch/arm/include/asm/arch-mx6/sys_proto.h |    2 +-
 5 files changed, 215 insertions(+), 3 deletions(-)

diff --git a/arch/arm/cpu/armv7/mx6/clock.c b/arch/arm/cpu/armv7/mx6/clock.c
index 820b8d5..db6a8fc 100644
--- a/arch/arm/cpu/armv7/mx6/clock.c
+++ b/arch/arm/cpu/armv7/mx6/clock.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2011 Freescale Semiconductor, Inc.
+ * Copyright (C) 2010-2014 Freescale Semiconductor, Inc.
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */
@@ -543,6 +543,36 @@ int enable_pcie_clock(void)
 			       BM_ANADIG_PLL_ENET_ENABLE_PCIE);
 }
 
+#ifdef CONFIG_SECURE_BOOT
+void hab_caam_clock_enable(void)
+{
+	struct mxc_ccm_reg *const imx_ccm =
+		(struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	/*CG4 ~ CG6, enable CAAM clocks*/
+	setbits_le32(&imx_ccm->CCGR0, MXC_CCM_CCGR0_CAAM_WRAPPER_IPG_MASK |
+		     MXC_CCM_CCGR0_CAAM_WRAPPER_ACLK_MASK |
+		     MXC_CCM_CCGR0_CAAM_SECURE_MEM_MASK);
+
+	/* Enable EMI slow clk */
+	setbits_le32(&imx_ccm->CCGR6, MXC_CCM_CCGR6_EMI_SLOW_MASK);
+}
+
+void hab_caam_clock_disable(void)
+{
+	struct mxc_ccm_reg *const imx_ccm =
+		(struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	/*CG4 ~ CG6, disable CAAM clocks*/
+	clrbits_le32(&imx_ccm->CCGR0, MXC_CCM_CCGR0_CAAM_WRAPPER_IPG_MASK |
+		     MXC_CCM_CCGR0_CAAM_WRAPPER_ACLK_MASK |
+		     MXC_CCM_CCGR0_CAAM_SECURE_MEM_MASK);
+
+	/* Disable EMI slow clk */
+	clrbits_le32(&imx_ccm->CCGR6, MXC_CCM_CCGR6_EMI_SLOW_MASK);
+}
+#endif
+
 unsigned int mxc_get_clock(enum mxc_clock clk)
 {
 	switch (clk) {
diff --git a/arch/arm/cpu/armv7/mx6/hab.c b/arch/arm/cpu/armv7/mx6/hab.c
index f6810a6..61a94a1 100644
--- a/arch/arm/cpu/armv7/mx6/hab.c
+++ b/arch/arm/cpu/armv7/mx6/hab.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2013 Freescale Semiconductor, Inc.
+ * Copyright (C) 2010-2014 Freescale Semiconductor, Inc.
  *
  * SPDX-License-Identifier:    GPL-2.0+
  */
@@ -7,8 +7,12 @@
 #include <common.h>
 #include <asm/io.h>
 #include <asm/arch/hab.h>
+#include <asm/arch/clock.h>
 #include <asm/arch/sys_proto.h>
 
+/* HAB (High Assurance Boot) debug */
+#undef DEBUG_AUTHENTICATE_IMAGE
+
 /* -------- start of HAB API updates ------------*/
 
 #define hab_rvt_report_event_p					\
@@ -71,6 +75,41 @@
 	((hab_rvt_exit_t *)HAB_RVT_EXIT)			\
 )
 
+#define IVT_SIZE		0x20
+#define ALIGN_SIZE		0x1000
+#define CSF_PAD_SIZE		0x2000
+
+/*
+ * +------------+  0x0 (DDR_UIMAGE_START) -
+ * |   Header   |                          |
+ * +------------+  0x40                    |
+ * |            |                          |
+ * |            |                          |
+ * |            |                          |
+ * |            |                          |
+ * | Image Data |                          |
+ * .            |                          |
+ * .            |                           > Stuff to be authenticated ----+
+ * .            |                          |                                |
+ * |            |                          |                                |
+ * |            |                          |                                |
+ * +------------+                          |                                |
+ * |            |                          |                                |
+ * | Fill Data  |                          |                                |
+ * |            |                          |                                |
+ * +------------+ Align to ALIGN_SIZE      |                                |
+ * |    IVT     |                          |                                |
+ * +------------+ + IVT_SIZE              -                                 |
+ * |            |                                                           |
+ * |  CSF DATA  | <---------------------------------------------------------+
+ * |            |
+ * +------------+
+ * |            |
+ * | Fill Data  |
+ * |            |
+ * +------------+ + CSF_PAD_SIZE
+ */
+
 bool is_hab_enabled(void)
 {
 	struct ocotp_regs *ocotp = (struct ocotp_regs *)OCOTP_BASE_ADDR;
@@ -144,6 +183,105 @@ int get_hab_status(void)
 	return 0;
 }
 
+uint32_t authenticate_image(uint32_t ddr_start, uint32_t image_size)
+{
+	uint32_t load_addr = 0;
+	size_t bytes;
+	ptrdiff_t ivt_offset = 0;
+	int result = 0;
+	ulong start;
+	hab_rvt_authenticate_image_t *hab_rvt_authenticate_image;
+	hab_rvt_entry_t *hab_rvt_entry;
+	hab_rvt_exit_t *hab_rvt_exit;
+
+	hab_rvt_authenticate_image = hab_rvt_authenticate_image_p;
+	hab_rvt_entry = hab_rvt_entry_p;
+	hab_rvt_exit = hab_rvt_exit_p;
+
+	if (is_hab_enabled()) {
+		printf("\nAuthenticate image from DDR location 0x%x...\n",
+		       ddr_start);
+
+		hab_caam_clock_enable();
+
+		if (hab_rvt_entry() == HAB_SUCCESS) {
+			/* If not already aligned, Align to ALIGN_SIZE */
+			ivt_offset = (image_size + ALIGN_SIZE - 1) &
+					~(ALIGN_SIZE - 1);
+
+			start = ddr_start;
+			bytes = ivt_offset + IVT_SIZE + CSF_PAD_SIZE;
+
+#ifdef DEBUG_AUTHENTICATE_IMAGE
+			printf("\nivt_offset = 0x%x, ivt addr = 0x%x\n",
+			       ivt_offset, ddr_start + ivt_offset);
+			printf("Dumping IVT\n");
+			print_buffer(ddr_start + ivt_offset,
+				     (void *)(ddr_start + ivt_offset),
+				     4, 0x8, 0);
+
+			printf("Dumping CSF Header\n");
+			print_buffer(ddr_start + ivt_offset+IVT_SIZE,
+				     (void *)(ddr_start + ivt_offset+IVT_SIZE),
+				     4, 0x10, 0);
+
+			get_hab_status();
+
+			printf("\nCalling authenticate_image in ROM\n");
+			printf("\tivt_offset = 0x%x\n", ivt_offset);
+			printf("\tstart = 0x%08lx\n", start);
+			printf("\tbytes = 0x%x\n", bytes);
+#endif
+			/*
+			 * If the MMU is enabled, we have to notify the ROM
+			 * code, or it won't flush the caches when needed.
+			 * This is done, by setting the "pu_irom_mmu_enabled"
+			 * word to 1. You can find its address by looking in
+			 * the ROM map. This is critical for
+			 * authenticate_image(). If MMU is enabled, without
+			 * setting this but, authentication will fail and may
+			 * crash.
+			 */
+			if (is_cpu_type(MXC_CPU_MX6Q) ||
+			    is_cpu_type(MXC_CPU_MX6D)) {
+				/*
+				 * This won't work on Rev 1.0.0 of i.MX6Q/D,
+				 * since their ROM doesn't do cache flushes.
+				 * I don't think any exist, so we ignore them.
+				 */
+				writel(1, 0x009024a8);
+			} else if (is_cpu_type(MXC_CPU_MX6DL) ||
+				   is_cpu_type(MXC_CPU_MX6SOLO)) {
+				writel(1, 0x00901dd0);
+			} else if (is_cpu_type(MXC_CPU_MX6SL)) {
+				writel(1, 0x00900a18);
+			}
+
+			load_addr = (uint32_t)hab_rvt_authenticate_image(
+					HAB_CID_UBOOT,
+					ivt_offset, (void **)&start,
+					(size_t *)&bytes, NULL);
+			if (hab_rvt_exit() != HAB_SUCCESS) {
+				printf("hab exit function fail\n");
+				load_addr = 0;
+			}
+		} else {
+			printf("hab entry function fail\n");
+		}
+
+		hab_caam_clock_disable();
+
+		get_hab_status();
+	} else {
+		printf("hab fuse not enabled\n");
+	}
+
+	if ((!is_hab_enabled()) || (load_addr != 0))
+		result = 1;
+
+	return result;
+}
+
 int do_hab_status(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	if ((argc != 1)) {
@@ -156,8 +294,33 @@ int do_hab_status(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	return 0;
 }
 
+static int do_authenticate_image(cmd_tbl_t *cmdtp, int flag, int argc,
+				char * const argv[])
+{
+	ulong	addr, ivt_offset;
+	int	rcode = 0;
+
+	if (argc < 3)
+		return CMD_RET_USAGE;
+
+	addr = simple_strtoul(argv[1], NULL, 16);
+	ivt_offset = simple_strtoul(argv[2], NULL, 16);
+
+	rcode = authenticate_image(addr, ivt_offset);
+
+	return rcode;
+}
+
 U_BOOT_CMD(
 		hab_status, CONFIG_SYS_MAXARGS, 1, do_hab_status,
 		"display HAB status",
 		""
 	  );
+
+U_BOOT_CMD(
+		hab_auth_img, 3, 1, do_authenticate_image,
+		"authenticate image via HAB",
+		"addr ivt_offset\n"
+		"addr - image hex address\n"
+		"ivt_offset - hex offset of IVT in the image"
+	  );
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index b0c1306..9842efb 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -409,10 +409,25 @@ int board_postclk_init(void)
 #ifndef CONFIG_SYS_DCACHE_OFF
 void enable_caches(void)
 {
+#if defined(CONFIG_SYS_ARM_CACHE_WRITETHROUGH)
+	enum dcache_option option = DCACHE_WRITETHROUGH;
+#else
+	enum dcache_option option = DCACHE_WRITEBACK;
+#endif
+
 	/* Avoid random hang when download by usb */
 	invalidate_dcache_all();
+
 	/* Enable D-cache. I-cache is already enabled in start.S */
 	dcache_enable();
+
+	/* Enable caching on OCRAM and ROM */
+	mmu_set_region_dcache_behaviour(ROMCP_ARB_BASE_ADDR,
+					ROMCP_ARB_END_ADDR,
+					option);
+	mmu_set_region_dcache_behaviour(IRAM_BASE_ADDR,
+					IRAM_SIZE,
+					option);
 }
 #endif
 
diff --git a/arch/arm/include/asm/arch-mx6/clock.h b/arch/arm/include/asm/arch-mx6/clock.h
index 339c789..2482e1a 100644
--- a/arch/arm/include/asm/arch-mx6/clock.h
+++ b/arch/arm/include/asm/arch-mx6/clock.h
@@ -2,6 +2,8 @@
  * (C) Copyright 2009
  * Stefano Babic, DENX Software Engineering, sbabic at denx.de.
  *
+ * (C) Copyright 2014 Freescale Semiconductor, Inc.
+ *
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
@@ -60,4 +62,6 @@ int enable_i2c_clk(unsigned char enable, unsigned i2c_num);
 int enable_spi_clk(unsigned char enable, unsigned spi_num);
 void enable_ipu_clock(void);
 int enable_fec_anatop_clock(enum enet_freq freq);
+void hab_caam_clock_enable(void);
+void hab_caam_clock_disable(void);
 #endif /* __ASM_ARCH_CLOCK_H */
diff --git a/arch/arm/include/asm/arch-mx6/sys_proto.h b/arch/arm/include/asm/arch-mx6/sys_proto.h
index 306d699..0528453 100644
--- a/arch/arm/include/asm/arch-mx6/sys_proto.h
+++ b/arch/arm/include/asm/arch-mx6/sys_proto.h
@@ -11,7 +11,7 @@
 #include <asm/imx-common/regs-common.h>
 #include "../arch-imx/cpu.h"
 
-#define soc_rev() (get_cpu_rev() & 0xFF)
+#define soc_rev() ((int)(get_cpu_rev() & 0xFF))
 #define is_soc_rev(rev)        (soc_rev() - rev)
 
 u32 get_nr_cpus(void);
-- 
1.7.9.5



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