[PATCH 1/3 v2] arm: init: save previous bootloader data
Dzmitry Sankouski
dsankouski at gmail.com
Sun Jan 30 11:40:16 CET 2022
When u-boot is used as a chain-loaded bootloader (replacing OS kernel),
previous bootloader leaves data in RAM, that can be reused.
For example, on recent arm linux system, when chainloading u-boot,
there are initramfs and fdt in RAM prepared for OS booting. Initramfs
may be modified to store u-boot's payload, thus providing the ability to
use chainloaded u-boot to boot OS without any storage support.
Two config options added:
- SAVE_PREV_BL_INITRAMFS_START_ADDR
saves initramfs start address to 'prevbl_initrd_start_addr' environment
variable
- SAVE_PREV_BL_FDT_ADDR
saves fdt address to 'prevbl_fdt_addr' environment variable
Signed-off-by: Dzmitry Sankouski <dsankouski at gmail.com>
Cc: Tom Rini <trini at konsulko.com>
---
Changes for v2:
- change signed off line
arch/arm/lib/Makefile | 2 +
arch/arm/lib/save_prev_bl_data.c | 93 ++++++++++++++++++++++++++++++++
boot/Kconfig | 79 +++++++++++++++++----------
include/init.h | 13 +++++
4 files changed, 160 insertions(+), 27 deletions(-)
create mode 100644 arch/arm/lib/save_prev_bl_data.c
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index c48e1f622d..aacd2253da 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -48,6 +48,8 @@ obj-$(CONFIG_$(SPL_TPL_)USE_ARCH_MEMCPY) += memcpy.o
endif
obj-$(CONFIG_SEMIHOSTING) += semihosting.o
+obj-$(filter y, $(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR) $(CONFIG_SAVE_PREV_BL_FDT_ADDR)) += save_prev_bl_data.o
+# obj-$(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR) += save_prev_bl_data.o
obj-y += bdinfo.o
obj-y += sections.o
CFLAGS_REMOVE_sections.o := $(LTO_CFLAGS)
diff --git a/arch/arm/lib/save_prev_bl_data.c b/arch/arm/lib/save_prev_bl_data.c
new file mode 100644
index 0000000000..2f88874484
--- /dev/null
+++ b/arch/arm/lib/save_prev_bl_data.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * save_prev_bl_data - saving previous bootloader data
+ * to environment variables.
+ *
+ * Copyright (c) 2022 Dzmitry Sankouski (dsankouski at gmail.com)
+ */
+#include <init.h>
+#include <env.h>
+#include <fdtdec.h>
+#include <fdt_support.h>
+#include <fdt.h>
+#include <common.h>
+#include <linux/errno.h>
+#include <asm/system.h>
+#include <asm/armv8/mmu.h>
+
+static ulong reg0 __section(".data");
+
+/**
+ * Save x0 register value, assuming previous bootloader set it to
+ * point on loaded fdt or (for older linux kernels)atags.
+ */
+void save_boot_params(ulong r0)
+{
+ reg0 = r0;
+ save_boot_params_ret();
+}
+
+bool is_addr_accessible(phys_addr_t addr)
+{
+ struct mm_region *mem = mem_map;
+ phys_addr_t bank_start;
+ phys_addr_t bank_end;
+
+ while (mem->size) {
+ bank_start = mem->phys;
+ bank_end = bank_start + mem->size;
+ debug("check if block %pap - %pap includes %pap\n", &bank_start, &bank_end, &addr);
+ if (addr > bank_start && addr < bank_end)
+ return true;
+ mem++;
+ }
+
+ return false;
+}
+
+int save_prev_bl_data(void)
+{
+ struct fdt_header *fdt_blob;
+ int node;
+ u64 initrd_start_prop;
+
+ if (!is_addr_accessible((phys_addr_t)reg0))
+ return -ENODATA;
+
+ fdt_blob = (struct fdt_header *)reg0;
+ if (!fdt_valid(&fdt_blob)) {
+ pr_warn("%s: address 0x%lx is not a valid fdt\n", __func__, reg0);
+ return -ENODATA;
+ }
+
+ #if defined(CONFIG_SAVE_PREV_BL_FDT_ADDR)
+ env_set_addr("prevbl_fdt_addr", (void *)reg0);
+ #endif
+ #if !defined(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR)
+ return 0;
+ #endif
+
+ node = fdt_path_offset(fdt_blob, "/chosen");
+ if (!node) {
+ pr_warn("%s: chosen node not found in device tree at addr: 0x%lx\n",
+ __func__, reg0);
+ return -ENODATA;
+ }
+ /*
+ * linux,initrd-start property might be either 64 or 32 bit,
+ * depending on primary bootloader implementation.
+ */
+ initrd_start_prop = fdtdec_get_uint64(fdt_blob, node, "linux,initrd-start", 0);
+ if (!initrd_start_prop) {
+ debug("%s: attempt to get uint64 linux,initrd-start property failed, trying uint\n",
+ __func__);
+ initrd_start_prop = fdtdec_get_uint(fdt_blob, node, "linux,initrd-start", 0);
+ if (!initrd_start_prop) {
+ debug("%s: attempt to get uint failed, too\n", __func__);
+ return -ENODATA;
+ }
+ }
+ env_set_addr("prevbl_initrd_start_addr", (void *)initrd_start_prop);
+
+ return 0;
+}
diff --git a/boot/Kconfig b/boot/Kconfig
index c8d5906cd3..da2f0797e0 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -135,10 +135,10 @@ config FIT_IMAGE_POST_PROCESS
processed before being added to the FIT image).
config FIT_PRINT
- bool "Support FIT printing"
- default y
- help
- Support printing the content of the fitImage in a verbose manner.
+ bool "Support FIT printing"
+ default y
+ help
+ Support printing the content of the fitImage in a verbose manner.
if SPL
@@ -207,12 +207,12 @@ config SPL_LOAD_FIT
This path has the following limitations:
1. "loadables" images, other than FDTs, which do not have a "load"
- property will not be loaded. This limitation also applies to FPGA
- images with the correct "compatible" string.
+ property will not be loaded. This limitation also applies to FPGA
+ images with the correct "compatible" string.
2. For FPGA images, only the "compatible" = "u-boot,fpga-legacy"
- loading method is supported.
+ loading method is supported.
3. FDTs are only loaded for images with an "os" property of "u-boot".
- "linux" images are also supported with Falcon boot mode.
+ "linux" images are also supported with Falcon boot mode.
config SPL_LOAD_FIT_ADDRESS
hex "load address of fit image"
@@ -345,8 +345,8 @@ config SYS_EXTRA_OPTIONS
The old configuration infrastructure (= mkconfig + boards.cfg)
provided the extra options field. If you have something like
"HAS_BAR,BAZ=64", the optional options
- #define CONFIG_HAS
- #define CONFIG_BAZ 64
+ #define CONFIG_HAS
+ #define CONFIG_BAZ 64
will be defined in include/config.h.
This option was prepared for the smooth migration from the old
configuration to Kconfig. Since this option will be removed sometime,
@@ -380,7 +380,7 @@ config SYS_CLK_FREQ
int "CPU clock frequency"
default 125000000 if ARCH_LS1012A
default 100000000 if ARCH_P2020 || ARCH_T1024 || ARCH_T1042 || \
- ARCH_LS1021A || FSL_LSCH2 || FSL_LSCH3
+ ARCH_LS1021A || FSL_LSCH2 || FSL_LSCH3
default 66666666 if ARCH_P1010 || ARCH_P1020 || ARCH_T4240
default 66660000 if ARCH_T2080
default 33333333 if RCAR_GEN3
@@ -485,15 +485,15 @@ config BOOTSTAGE_REPORT
boot process. The report looks something like this:
Timer summary in microseconds:
- Mark Elapsed Stage
- 0 0 reset
+ Mark Elapsed Stage
+ 0 0 reset
3,575,678 3,575,678 board_init_f start
- 3,575,695 17 arch_cpu_init A9
- 3,575,777 82 arch_cpu_init done
- 3,659,598 83,821 board_init_r start
- 3,910,375 250,777 main_loop
+ 3,575,695 17 arch_cpu_init A9
+ 3,575,777 82 arch_cpu_init done
+ 3,659,598 83,821 board_init_r start
+ 3,910,375 250,777 main_loop
29,916,167 26,005,792 bootm_start
- 30,361,327 445,160 start_kernel
+ 30,361,327 445,160 start_kernel
config BOOTSTAGE_RECORD_COUNT
int "Number of boot stage records to store"
@@ -580,24 +580,24 @@ config SHOW_BOOT_PROGRESS
Legacy uImage format:
Arg Where When
- 1 common/cmd_bootm.c before attempting to boot an image
+ 1 common/cmd_bootm.c before attempting to boot an image
-1 common/cmd_bootm.c Image header has bad magic number
- 2 common/cmd_bootm.c Image header has correct magic number
+ 2 common/cmd_bootm.c Image header has correct magic number
-2 common/cmd_bootm.c Image header has bad checksum
- 3 common/cmd_bootm.c Image header has correct checksum
+ 3 common/cmd_bootm.c Image header has correct checksum
-3 common/cmd_bootm.c Image data has bad checksum
- 4 common/cmd_bootm.c Image data has correct checksum
+ 4 common/cmd_bootm.c Image data has correct checksum
-4 common/cmd_bootm.c Image is for unsupported architecture
- 5 common/cmd_bootm.c Architecture check OK
+ 5 common/cmd_bootm.c Architecture check OK
-5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
- 6 common/cmd_bootm.c Image Type check OK
+ 6 common/cmd_bootm.c Image Type check OK
-6 common/cmd_bootm.c gunzip uncompression error
-7 common/cmd_bootm.c Unimplemented compression type
- 7 common/cmd_bootm.c Uncompression OK
- 8 common/cmd_bootm.c No uncompress/copy overwrite error
+ 7 common/cmd_bootm.c Uncompression OK
+ 8 common/cmd_bootm.c No uncompress/copy overwrite error
-9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
- 9 common/image.c Start initial ramdisk verification
+ 9 common/image.c Start initial ramdisk verification
-10 common/image.c Ramdisk header has bad magic number
-11 common/image.c Ramdisk header has bad checksum
10 common/image.c Ramdisk header is OK
@@ -1067,4 +1067,29 @@ config DEFAULT_FDT_FILE
help
This option is used to set the default fdt file to boot OS.
+config SAVE_PREV_BL_FDT_ADDR
+ depends on ARM
+ bool "Saves fdt address, passed by the previous bootloader, to env var"
+ default n
+ help
+ When u-boot is used as a chain-loaded bootloader (replacing OS kernel),
+ enable this option to save fdt address, passed by the
+ previous bootloader for future use.
+ Address is saved to `prevbl_fdt_addr` environment variable.
+
+ If no fdt was provided by previous bootloader, no env variables
+ will be created.
+
+config SAVE_PREV_BL_INITRAMFS_START_ADDR
+ depends on ARM
+ bool "Saves initramfs address, passed by the previous bootloader, to env var"
+ default n
+ help
+ When u-boot is used as a chain-loaded bootloader(replacing OS kernel),
+ enable this option to save initramfs address, passed by the
+ previous bootloader for future use.
+ Address is saved to `prevbl_initrd_start_addr` environment variable.
+
+ If no initramfs was provided by previous bootloader, no env variables
+ will be created.
endmenu # Booting
diff --git a/include/init.h b/include/init.h
index 20c3976af0..1a55a0e2e4 100644
--- a/include/init.h
+++ b/include/init.h
@@ -166,6 +166,19 @@ int arch_setup_bdinfo(void);
*/
int setup_bdinfo(void);
+#if defined(CONFIG_SAVE_PREV_BL_INITRAMFS_START_ADDR) || \
+defined(CONFIG_SAVE_PREV_BL_FDT_ADDR)
+/**
+ * save_prev_bl_data - Save prev bl data in env vars.
+ *
+ * When u-boot is chain-loaded, save previous bootloader data,
+ * like initramfs address to environment variables.
+ *
+ * Return: 0 if ok; -ENODATA on error
+ */
+int save_prev_bl_data(void);
+#endif
+
/**
* cpu_secondary_init_r() - CPU-specific secondary initialization
*
--
2.20.1
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