From: Daniel Allred d-allred@ti.com

The next stage boot loader image and the selected FDT can be post-processed by board/platform/device-specific code, which can include modifying the size and altering the starting source address before copying these binary blobs to their final desitination. This might be desired to do things like strip headers or footers attached to the images before they were packeaged into the FIT, or to perform operations such as decryption or authentication.

Signed-off-by: Daniel Allred d-allred@ti.com Signed-off-by: Andreas Dannenberg dannenberg@ti.com --- common/spl/spl_fit.c | 21 ++++++++++++++++----- include/image.h | 15 +++++++++++++++ 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c index 9874708..ecbcb97 100644 --- a/common/spl/spl_fit.c +++ b/common/spl/spl_fit.c @@ -121,6 +121,10 @@ static int get_aligned_image_size(struct spl_load_info *info, int data_size, return (data_size + info->bl_len - 1) / info->bl_len; }

+void __weak board_fit_image_post_process(void **p_src, size_t *p_size) +{ +} + int spl_load_simple_fit(struct spl_load_info *info, ulong sector, void *fit) { int sectors; @@ -132,7 +136,7 @@ int spl_load_simple_fit(struct spl_load_info *info, ulong sector, void *fit) int data_offset, data_size; int base_offset, align_len = ARCH_DMA_MINALIGN - 1; int src_sector; - void *dst; + void *dst, *src;

/* * Figure out where the external images start. This is the base for the @@ -206,8 +210,11 @@ int spl_load_simple_fit(struct spl_load_info *info, ulong sector, void *fit) return -EIO; debug("image: dst=%p, data_offset=%x, size=%x\n", dst, data_offset, data_size); - memcpy(dst, dst + get_aligned_image_overhead(info, data_offset), - data_size); + src = dst + get_aligned_image_overhead(info, data_offset); + + board_fit_image_post_process((void **)&src, (size_t *)&data_size); + + memcpy(dst, src, data_size);

/* Figure out which device tree the board wants to use */ fdt_len = spl_fit_select_fdt(fit, images, &fdt_offset); @@ -236,8 +243,12 @@ int spl_load_simple_fit(struct spl_load_info *info, ulong sector, void *fit) */ debug("fdt: dst=%p, data_offset=%x, size=%x\n", dst, fdt_offset, fdt_len); - memcpy(load_ptr + data_size, - dst + get_aligned_image_overhead(info, fdt_offset), fdt_len); + src = dst + get_aligned_image_overhead(info, fdt_offset); + dst = load_ptr + data_size; + + board_fit_image_post_process((void **)&src, (size_t *)&fdt_len); + + memcpy(dst, src, fdt_len);

return 0; } diff --git a/include/image.h b/include/image.h index a8f6bd1..9536874 100644 --- a/include/image.h +++ b/include/image.h @@ -1172,4 +1172,19 @@ ulong android_image_get_kload(const struct andr_img_hdr *hdr); */ int board_fit_config_name_match(const char *name);

+/** + * board_fit_image_post_process() - Do any post-process on FIT binary data + * + * This is used to do any sort of image manipulation, verification, decryption + * etc. in a platform or board specific way. Obviously, anything done here would + * need to be comprehended in how the images were prepared before being injected + * into the FIT creation (i.e. the binary blobs would have been pre-processed + * before being added to the FIT image). + * + * @image: pointer to the image start pointer + * @size: pointer to the image size + * @return no return value (failure should be handled internally) + */ +void board_fit_image_post_process(void **p_image, size_t *p_size); + #endif /* __IMAGE_H__ */

From: Daniel Allred d-allred@ti.com

Add an interface for calling secure ROM APIs across a range of OMAP and OMAP compatible high-security (HS) device variants. While at it, also perform minor cleanup/alignment without any change in functionality.

Signed-off-by: Daniel Allred d-allred@ti.com Signed-off-by: Andreas Dannenberg dannenberg@ti.com Reviewed-by: Simon Glass sjg@chromium.org --- arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 45 ++++++++++++++++++++------ arch/arm/include/asm/omap_common.h | 6 ++++ 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/arch/arm/cpu/armv7/omap-common/lowlevel_init.S b/arch/arm/cpu/armv7/omap-common/lowlevel_init.S index 5283135..66a3b3d 100644 --- a/arch/arm/cpu/armv7/omap-common/lowlevel_init.S +++ b/arch/arm/cpu/armv7/omap-common/lowlevel_init.S @@ -16,9 +16,10 @@ #include <asm/arch/spl.h> #include <linux/linkage.h>

+.arch_extension sec + #ifdef CONFIG_SPL ENTRY(save_boot_params) - ldr r1, =OMAP_SRAM_SCRATCH_BOOT_PARAMS str r0, [r1] b save_boot_params_ret @@ -26,14 +27,40 @@ ENDPROC(save_boot_params) #endif

ENTRY(omap_smc1) - PUSH {r4-r12, lr} @ save registers - ROM code may pollute + push {r4-r12, lr} @ save registers - ROM code may pollute @ our registers - MOV r12, r0 @ Service - MOV r0, r1 @ Argument - DSB - DMB - .word 0xe1600070 @ SMC #0 - hand assembled for GCC versions - @ call ROM Code API for the service requested + mov r12, r0 @ Service + mov r0, r1 @ Argument

- POP {r4-r12, pc} + dsb + dmb + smc 0 @ SMC #0 to enter monitor mode + @ call ROM Code API for the service requested + pop {r4-r12, pc} ENDPROC(omap_smc1) + +ENTRY(omap_smc_sec) + push {r4-r12, lr} @ save registers - ROM code may pollute + @ our registers + mov r6, #0xFF @ Indicate new Task call + mov r12, #0x00 @ Secure Service ID in R12 + + dsb + dmb + smc 0 @ SMC #0 to enter monitor mode + + b omap_smc_sec_end @ exit at end of the service execution + nop + + @ In case of IRQ happening in Secure, then ARM will branch here. + @ At that moment, IRQ will be pending and ARM will jump to Non Secure + @ IRQ handler + mov r12, #0xFE + + dsb + dmb + smc 0 @ SMC #0 to enter monitor mode + +omap_smc_sec_end: + pop {r4-r12, pc} +ENDPROC(omap_smc_sec) diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h index 07f3848..605c549 100644 --- a/arch/arm/include/asm/omap_common.h +++ b/arch/arm/include/asm/omap_common.h @@ -627,6 +627,12 @@ void recalibrate_iodelay(void);

void omap_smc1(u32 service, u32 val);

+/* + * Low-level helper function used when performing secure ROM calls on high- + * security (HS) device variants by doing a specially-formed smc entry. + */ +u32 omap_smc_sec(u32 service, u32 proc_id, u32 flag, u32 *params); + void enable_edma3_clocks(void); void disable_edma3_clocks(void);

Adds a generic C-callable API for making secure ROM calls on OMAP and OMAP-compatible devices. This API provides the important function of flushing the ROM call arguments to memory from the cache, so that the secure world will have a coherent view of those arguments. Then is simply calls the omap_smc_sec routine.

Signed-off-by: Daniel Allred d-allred@ti.com Signed-off-by: Andreas Dannenberg dannenberg@ti.com Reviewed-by: Simon Glass sjg@chromium.org --- arch/arm/cpu/armv7/omap-common/Makefile | 2 ++ arch/arm/cpu/armv7/omap-common/sec-common.c | 49 +++++++++++++++++++++++++++++ arch/arm/include/asm/omap_common.h | 7 +++++ 3 files changed, 58 insertions(+) create mode 100644 arch/arm/cpu/armv7/omap-common/sec-common.c

diff --git a/arch/arm/cpu/armv7/omap-common/Makefile b/arch/arm/cpu/armv7/omap-common/Makefile index 87a7ac0..3172bae 100644 --- a/arch/arm/cpu/armv7/omap-common/Makefile +++ b/arch/arm/cpu/armv7/omap-common/Makefile @@ -36,3 +36,5 @@ obj-y += boot-common.o obj-y += lowlevel_init.o

obj-y += mem-common.o + +obj-$(CONFIG_TI_SECURE_DEVICE) += sec-common.o diff --git a/arch/arm/cpu/armv7/omap-common/sec-common.c b/arch/arm/cpu/armv7/omap-common/sec-common.c new file mode 100644 index 0000000..b9c0a42 --- /dev/null +++ b/arch/arm/cpu/armv7/omap-common/sec-common.c @@ -0,0 +1,49 @@ +/* + * + * Common security related functions for OMAP devices + * + * (C) Copyright 2016 + * Texas Instruments, <www.ti.com> + * + * Daniel Allred d-allred@ti.com + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <stdarg.h> + +#include <asm/arch/sys_proto.h> +#include <asm/omap_common.h> + +static uint32_t secure_rom_call_args[5] __aligned(ARCH_DMA_MINALIGN); + +u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...) +{ + int i; + u32 num_args; + va_list ap; + + va_start(ap, flag); + + num_args = va_arg(ap, u32); + + if (num_args > 4) + return 1; + + /* Copy args to aligned args structure */ + for (i = 0; i < num_args; i++) + secure_rom_call_args[i + 1] = va_arg(ap, u32); + + secure_rom_call_args[0] = num_args; + + va_end(ap); + + /* if data cache is enabled, flush the aligned args structure */ + flush_dcache_range( + (unsigned int)&secure_rom_call_args[0], + (unsigned int)&secure_rom_call_args[0] + + roundup(sizeof(secure_rom_call_args), ARCH_DMA_MINALIGN)); + + return omap_smc_sec(service, proc_id, flag, secure_rom_call_args); +} diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h index 605c549..293fc72 100644 --- a/arch/arm/include/asm/omap_common.h +++ b/arch/arm/include/asm/omap_common.h @@ -633,6 +633,13 @@ void omap_smc1(u32 service, u32 val); */ u32 omap_smc_sec(u32 service, u32 proc_id, u32 flag, u32 *params);

+/* + * Invoke secure ROM API on high-security (HS) device variants. It formats + * the variable argument list into the format expected by the ROM code before + * triggering the actual low-level smc entry. + */ +u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...); + void enable_edma3_clocks(void); void disable_edma3_clocks(void);

Adds an API that verifies a signature attached to an image (binary blob). This API is basically a entry to a secure ROM service provided by the device and accessed via an SMC call, using a particular calling convention.

Signed-off-by: Daniel Allred d-allred@ti.com Signed-off-by: Andreas Dannenberg dannenberg@ti.com --- arch/arm/cpu/armv7/omap-common/sec-common.c | 76 +++++++++++++++++++++++++++++ arch/arm/include/asm/omap_common.h | 9 ++++ 2 files changed, 85 insertions(+)

diff --git a/arch/arm/cpu/armv7/omap-common/sec-common.c b/arch/arm/cpu/armv7/omap-common/sec-common.c index b9c0a42..dbb9078 100644 --- a/arch/arm/cpu/armv7/omap-common/sec-common.c +++ b/arch/arm/cpu/armv7/omap-common/sec-common.c @@ -16,6 +16,9 @@ #include <asm/arch/sys_proto.h> #include <asm/omap_common.h>

+/* Index for signature verify ROM API */ +#define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX (0x0000000E) + static uint32_t secure_rom_call_args[5] __aligned(ARCH_DMA_MINALIGN);

u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...) @@ -47,3 +50,76 @@ u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...)

return omap_smc_sec(service, proc_id, flag, secure_rom_call_args); } + +static u32 find_sig_start(char *image, size_t size) +{ + char *image_end = image + size; + char *sig_start_magic = "CERT_"; + int magic_str_len = strlen(sig_start_magic); + char *ch; + + while (--image_end > image) { + if (*image_end == '_') { + ch = image_end - magic_str_len + 1; + if (!strncmp(ch, sig_start_magic, magic_str_len)) + return (u32)ch; + } + } + return 0; +} + +int secure_boot_verify_image(void **image, size_t *size) +{ + int result = 1; + u32 cert_addr, sig_addr; + size_t cert_size; + + /* Perform cache writeback on input buffer */ + flush_dcache_range( + (u32)*image, + (u32)*image + roundup(*size, ARCH_DMA_MINALIGN)); + + cert_addr = (uint32_t)*image; + sig_addr = find_sig_start((char *)*image, *size); + + if (sig_addr == 0) { + printf("No signature found in image.\n"); + result = 1; + goto auth_exit; + } + + *size = sig_addr - cert_addr; /* Subtract out the signature size */ + cert_size = *size; + + /* Check if image load address is 32-bit aligned */ + if (0 != (0x3 & cert_addr)) { + printf("Image is not 4-byte aligned.\n"); + result = 1; + goto auth_exit; + } + + /* Image size also should be multiple of 4 */ + if (0 != (0x3 & cert_size)) { + printf("Image size is not 4-byte aligned.\n"); + result = 1; + goto auth_exit; + } + + /* Call ROM HAL API to verify certificate signature */ + debug("%s: load_addr = %x, size = %x, sig_addr = %x\n", __func__, + cert_addr, cert_size, sig_addr); + + result = secure_rom_call( + API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX, 0, 0, + 4, cert_addr, cert_size, sig_addr, 0xFFFFFFFF); +auth_exit: + if (result != 0) { + printf("Authentication failed!\n"); + printf("Return Value = %08X\n", result); + hang(); + } + + printf("Authentication passed: %s\n", (char *)sig_addr); + + return result; +} diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h index 293fc72..8887335 100644 --- a/arch/arm/include/asm/omap_common.h +++ b/arch/arm/include/asm/omap_common.h @@ -640,6 +640,15 @@ u32 omap_smc_sec(u32 service, u32 proc_id, u32 flag, u32 *params); */ u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...);

+/* + * Invoke a secure ROM API on high-secure (HS) device variants that can be used + * to verify a secure blob by authenticating and optionally decrypting it. The + * exact operation performed depends on how the certificate that was embedded + * into the blob during the signing/encryption step when the secure blob was + * first created. + */ +int secure_boot_verify_image(void **p_image, size_t *p_size); + void enable_edma3_clocks(void); void disable_edma3_clocks(void);

Modify the SPL build procedure for AM57xx and DRA7xx high-security (HS) device variants to create a secure u-boot_HS.img FIT blob that contains U-Boot and DTB artifacts signed with a TI-specific process based on the CONFIG_TI_SECURE_DEVICE config option and the externally-provided image signing tool.

Also populate the corresponding FIT image post processing call to be performed during SPL runtime.

Signed-off-by: Daniel Allred d-allred@ti.com Signed-off-by: Andreas Dannenberg dannenberg@ti.com --- arch/arm/cpu/armv7/omap5/config.mk | 3 +++ board/ti/am57xx/board.c | 7 +++++++ board/ti/dra7xx/evm.c | 7 +++++++ 3 files changed, 17 insertions(+)

diff --git a/arch/arm/cpu/armv7/omap5/config.mk b/arch/arm/cpu/armv7/omap5/config.mk index a7e55a5..d245572 100644 --- a/arch/arm/cpu/armv7/omap5/config.mk +++ b/arch/arm/cpu/armv7/omap5/config.mk @@ -15,5 +15,8 @@ else ALL-y += MLO endif else +ifeq ($(CONFIG_TI_SECURE_DEVICE),y) +ALL-y += u-boot_HS.img +endif ALL-y += u-boot.img endif diff --git a/board/ti/am57xx/board.c b/board/ti/am57xx/board.c index 08cf14d..8ded453 100644 --- a/board/ti/am57xx/board.c +++ b/board/ti/am57xx/board.c @@ -750,3 +750,10 @@ int board_fit_config_name_match(const char *name) return -1; } #endif + +#ifdef CONFIG_TI_SECURE_DEVICE +void board_fit_image_post_process(void **p_image, size_t *p_size) +{ + secure_boot_verify_image(p_image, p_size); +} +#endif diff --git a/board/ti/dra7xx/evm.c b/board/ti/dra7xx/evm.c index 0394e4e..a8176b8 100644 --- a/board/ti/dra7xx/evm.c +++ b/board/ti/dra7xx/evm.c @@ -830,3 +830,10 @@ int board_fit_config_name_match(const char *name) return -1; } #endif + +#ifdef CONFIG_TI_SECURE_DEVICE +void board_fit_image_post_process(void **p_image, size_t *p_size) +{ + secure_boot_verify_image(p_image, p_size); +} +#endif

From: Madan Srinivas madans@ti.com

Modify the SPL build procedure for AM437x high-security (HS) device variants to create a secure u-boot_HS.img FIT blob that contains U-Boot and DTB artifacts signed (and optionally encrypted) with a TI-specific process based on the CONFIG_TI_SECURE_DEVICE config option and the externally-provided image signing tool.

Also populate the corresponding FIT image post processing call to be performed during SPL runtime.

Signed-off-by: Madan Srinivas madans@ti.com Signed-off-by: Andreas Dannenberg dannenberg@ti.com --- arch/arm/cpu/armv7/am33xx/config.mk | 1 + board/ti/am43xx/board.c | 7 +++++++ 2 files changed, 8 insertions(+)

diff --git a/arch/arm/cpu/armv7/am33xx/config.mk b/arch/arm/cpu/armv7/am33xx/config.mk index 6d95d32..ab94708 100644 --- a/arch/arm/cpu/armv7/am33xx/config.mk +++ b/arch/arm/cpu/armv7/am33xx/config.mk @@ -26,6 +26,7 @@ endif else ifeq ($(CONFIG_TI_SECURE_DEVICE),y) ALL-$(CONFIG_QSPI_BOOT) += u-boot_HS_XIP_X-LOADER +ALL-y += u-boot_HS.img endif ALL-y += u-boot.img endif diff --git a/board/ti/am43xx/board.c b/board/ti/am43xx/board.c index f005762..fc0b38b 100644 --- a/board/ti/am43xx/board.c +++ b/board/ti/am43xx/board.c @@ -862,3 +862,10 @@ int board_fit_config_name_match(const char *name) return -1; } #endif + +#ifdef CONFIG_TI_SECURE_DEVICE +void board_fit_image_post_process(void **p_image, size_t *p_size) +{ + secure_boot_verify_image(p_image, p_size); +} +#endif

From: Daniel Allred d-allred@ti.com

Adds information regarding SPL handling the loading and processing of secured u-boot images as part of the second stage boot the SPL does. Introduces the description of a new interface script in the TI SECDEV Package which handles the creation and prep of secured binary images.

Signed-off-by: Daniel Allred d-allred@ti.com --- doc/README.ti-secure | 170 +++++++++++++++++++++++++++++++++++---------------- 1 file changed, 116 insertions(+), 54 deletions(-)

diff --git a/doc/README.ti-secure b/doc/README.ti-secure index 7fc9b9b..e9d212b 100644 --- a/doc/README.ti-secure +++ b/doc/README.ti-secure @@ -19,69 +19,80 @@ control restrictions. Access must be requested and granted by TI before the package is viewable and downloadable. Contact TI, either online or by way of a local TI representative, to request access.

-When CONFIG_TI_SECURE_DEVICE is set, the U-Boot SPL build process requires -the presence and use of these tools in order to create a viable boot image. -The build process will look for the environment variable TI_SECURE_DEV_PKG, -which should be the path of the installed SECDEV package. If the -TI_SECURE_DEV_PKG variable is not defined or if it is defined but doesn't -point to a valid SECDEV package, a warning is issued during the build to -indicate that a final secure bootable image was not created. - -Within the SECDEV package exists an image creation script: - -${TI_SECURE_DEV_PKG}/scripts/create-boot-image.sh - -This is called as part of the SPL/u-boot build process. As the secure boot -image formats and requirements differ between secure SOC from TI, the -purpose of this script is to abstract these details as much as possible. - -The script is basically the only required interface to the TI SECDEV package -for secure TI devices. - -Invoking the script for AM43xx Secure Devices -============================================= - -create-boot-image.sh <IMAGE_FLAG> <INPUT_FILE> <OUTPUT_FILE> <SPL_LOAD_ADDR> - -<IMAGE_FLAG> is a value that specifies the type of the image to generate OR -the action the image generation tool will take. Valid values are: - SPI_X-LOADER - Generates an image for SPI flash (byte swapped) - XIP_X-LOADER - Generates a single stage u-boot for NOR/QSPI XiP - ISSW - Generates an image for all other boot modes - -<INPUT_FILE> is the full path and filename of the public world boot loader -binary file (depending on the boot media, this is usually either -u-boot-spl.bin or u-boot.bin). - -<OUTPUT_FILE> is the full path and filename of the final secure image. The -output binary images should be used in place of the standard non-secure -binary images (see the platform-specific user's guides and releases notes -for how the non-secure images are typically used) +Booting of U-Boot SPL +===================== + + When CONFIG_TI_SECURE_DEVICE is set, the U-Boot SPL build process + requires the presence and use of these tools in order to create a + viable boot image. The build process will look for the environment + variable TI_SECURE_DEV_PKG, which should be the path of the installed + SECDEV package. If the TI_SECURE_DEV_PKG variable is not defined or + if it is defined but doesn't point to a valid SECDEV package, a + warning is issued during the build to indicate that a final secure + bootable image was not created. + + Within the SECDEV package exists an image creation script: + + ${TI_SECURE_DEV_PKG}/scripts/create-boot-image.sh + + This is called as part of the SPL/u-boot build process. As the secure + boot image formats and requirements differ between secure SOC from TI, + the purpose of this script is to abstract these details as much as + possible. + + The script is basically the only required interface to the TI SECDEV + package for creating a bootable SPL image for secure TI devices. + + Invoking the script for AM43xx Secure Devices + ============================================= + + create-boot-image.sh \ + <IMAGE_FLAG> <INPUT_FILE> <OUTPUT_FILE> <SPL_LOAD_ADDR> + + <IMAGE_FLAG> is a value that specifies the type of the image to + generate OR the action the image generation tool will take. Valid + values are: + SPI_X-LOADER - Generates an image for SPI flash (byte + swapped) + XIP_X-LOADER - Generates a single stage u-boot for + NOR/QSPI XiP + ISSW - Generates an image for all other boot modes + + <INPUT_FILE> is the full path and filename of the public world boot + loaderbinary file (depending on the boot media, this is usually + either u-boot-spl.bin or u-boot.bin). + + <OUTPUT_FILE> is the full path and filename of the final secure + image. The output binary images should be used in place of the standard + non-secure binary images (see the platform-specific user's guides and + releases notes for how the non-secure images are typically used) u-boot-spl_HS_SPI_X-LOADER - byte swapped boot image for SPI flash u-boot_HS_XIP_X-LOADER - boot image for NOR or QSPI flash u-boot-spl_HS_ISSW - boot image for all other boot media

-<SPL_LOAD_ADDR> is the address at which SOC ROM should load the <INPUT_FILE> + <SPL_LOAD_ADDR> is the address at which SOC ROM should load the + <INPUT_FILE>

-Invoking the script for DRA7xx/AM57xx Secure Devices -==================================================== + Invoking the script for DRA7xx/AM57xx Secure Devices + ====================================================

-create-boot-image.sh <IMAGE_TYPE> <INPUT_FILE> <OUTPUT_FILE> + create-boot-image.sh <IMAGE_TYPE> <INPUT_FILE> <OUTPUT_FILE>

-<IMAGE_TYPE> is a value that specifies the type of the image to generate OR -the action the image generation tool will take. Valid values are: - X-LOADER - Generates an image for NOR or QSPI boot modes - MLO - Generates an image for SD/MMC/eMMC boot modes - ULO - Generates an image for USB/UART peripheral boot modes - Note: ULO is not yet used by the u-boot build process + <IMAGE_TYPE> is a value that specifies the type of the image to + generate OR the action the image generation tool will take. Valid + values are: + X-LOADER - Generates an image for NOR or QSPI boot modes + MLO - Generates an image for SD/MMC/eMMC boot modes + ULO - Generates an image for USB/UART peripheral boot modes + Note: ULO is not yet used by the u-boot build process

-<INPUT_FILE> is the full path and filename of the public world boot loader -binary file (for this platform, this is always u-boot-spl.bin). + <INPUT_FILE> is the full path and filename of the public world boot + loader binary file (for this platform, this is always u-boot-spl.bin).

-<OUTPUT_FILE> is the full path and filename of the final secure image. The -output binary images should be used in place of the standard non-secure -binary images (see the platform-specific user's guides and releases notes -for how the non-secure images are typically used) + <OUTPUT_FILE> is the full path and filename of the final secure image. + The output binary images should be used in place of the standard + non-secure binary images (see the platform-specific user's guides + and releases notes for how the non-secure images are typically used) u-boot-spl_HS_MLO - boot image for SD/MMC/eMMC. This image is copied to a file named MLO, which is the name that the device ROM bootloader requires for loading from @@ -89,3 +100,54 @@ for how the non-secure images are typically used) non-secure devices) u-boot-spl_HS_X-LOADER - boot image for all other flash memories including QSPI and NOR flash + +Booting of Primary U-Boot (u-boot.img) +====================================== + + The SPL image is responsible for loading the next stage boot loader, + which is the main u-boot image. For secure TI devices, the SPL will + be authenticated, as described above, as part of the particular + device's ROM boot process. In order to continue the secure boot + process, the authenticated SPL must authenticate the main u-boot + image that it loads. + + The configurations for secure TI platforms are written to make the boot + process use the FIT image format for the u-boot.img (CONFIG_SPL_FRAMEWORK + and CONFIG_SPL_LOAD_FIT). With these configurations the binary + components that the SPL loads include a specific DTB image and u-boot + image. These DTB image may be one of many available to the boot + process. In order to secure these components so that they can be + authenticated by the SPL as they are loaded from the FIT image, the + build procedure for secure TI devices will secure these images before + they are integrated into the FIT image. When those images are extracted + from the FIT image at boot time, they are post-processed to verify that + they are still secure. + + The exact details of the how the images are secured is handled by the + SECDEV package. Within the SECDEV package exists a script to process + an input binary image: + + ${TI_SECURE_DEV_PKG}/scripts/secure-binary-image.sh + + This is called as part of the u-boot build process. As the secure + image formats and requirements can differ between the various secure + SOCs from TI, this script in the SECDEV package abstracts these + details. This script is essentially the only required interface to the + TI SECDEV package for creating a u-boot.img image for secure TI + devices. + + The SPL/u-boot code contains calls to dedicated secure ROM functions + to perform the validation on the secured images. The details of the + interface to those functions is shown in the code. The summary + is that they are accessed by invoking an ARM secure monitor call to + the device's secure ROM (fixed read-only-memory that is secure and + only accessible when the ARM core is operating in the secure mode). + + Invoking the secure-binary-image script for Secure Devices + ========================================================== + + secure-binary-image.sh <INPUT_FILE> <OUTPUT_FILE> + + <INPUT_FILE> is the full path and filename of the input binary image + + <OUTPUT_FILE> is the full path and filename of the output secure image.