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![Masahiro Yamada](/assets/img/avatar_default.png)
At first, the ARM64 Linux booting requirement recommended that the kernel image be placed text_offset bytes from 2MB aligned base near the start of usable system RAM because memory below that base address was unusable at that time. This requirement was relaxed by Linux commit a7f8de168ace ("arm64: allow kernel Image to be loaded anywhere in physical memory"). Since then, the bit 3 of the flags field indicates the tolerance of the kernel physical placement. If this bit is set, the 2MB aligned base may be anywhere in physical memory. For details, see Documentation/arm64/booting.txt of Linux. The booti command should be also relaxed. If the bit 3 is set, images->ep is respected, and the image is placed at the nearest bootable location. Otherwise, it is relocated to the start of the system RAM to keep the original behavior. Another wrinkle we need to take care of is the unknown endianness of text_offset for a kernel older than commit a2c1d73b94ed (i.e. v3.16). We can detect this based on the image_size field. If the field is zero, just use a fixed offset 0x80000. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
182 lines
4.5 KiB
C
182 lines
4.5 KiB
C
/*
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* (C) Copyright 2000-2009
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <bootm.h>
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#include <command.h>
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#include <image.h>
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#include <lmb.h>
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#include <mapmem.h>
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#include <linux/kernel.h>
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#include <linux/sizes.h>
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DECLARE_GLOBAL_DATA_PTR;
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/* See Documentation/arm64/booting.txt in the Linux kernel */
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struct Image_header {
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uint32_t code0; /* Executable code */
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uint32_t code1; /* Executable code */
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uint64_t text_offset; /* Image load offset, LE */
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uint64_t image_size; /* Effective Image size, LE */
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uint64_t flags; /* Kernel flags, LE */
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uint64_t res2; /* reserved */
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uint64_t res3; /* reserved */
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uint64_t res4; /* reserved */
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uint32_t magic; /* Magic number */
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uint32_t res5;
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};
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#define LINUX_ARM64_IMAGE_MAGIC 0x644d5241
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static int booti_setup(bootm_headers_t *images)
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{
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struct Image_header *ih;
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uint64_t dst;
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uint64_t image_size, text_offset;
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ih = (struct Image_header *)map_sysmem(images->ep, 0);
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if (ih->magic != le32_to_cpu(LINUX_ARM64_IMAGE_MAGIC)) {
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puts("Bad Linux ARM64 Image magic!\n");
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return 1;
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}
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/*
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* Prior to Linux commit a2c1d73b94ed, the text_offset field
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* is of unknown endianness. In these cases, the image_size
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* field is zero, and we can assume a fixed value of 0x80000.
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*/
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if (ih->image_size == 0) {
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puts("Image lacks image_size field, assuming 16MiB\n");
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image_size = 16 << 20;
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text_offset = 0x80000;
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} else {
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image_size = le64_to_cpu(ih->image_size);
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text_offset = le64_to_cpu(ih->text_offset);
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}
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/*
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* If bit 3 of the flags field is set, the 2MB aligned base of the
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* kernel image can be anywhere in physical memory, so respect
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* images->ep. Otherwise, relocate the image to the base of RAM
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* since memory below it is not accessible via the linear mapping.
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*/
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if (le64_to_cpu(ih->flags) & BIT(3))
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dst = images->ep - text_offset;
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else
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dst = gd->bd->bi_dram[0].start;
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dst = ALIGN(dst, SZ_2M) + text_offset;
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unmap_sysmem(ih);
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if (images->ep != dst) {
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void *src;
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debug("Moving Image from 0x%lx to 0x%llx\n", images->ep, dst);
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src = (void *)images->ep;
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images->ep = dst;
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memmove((void *)dst, src, image_size);
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}
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return 0;
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}
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/*
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* Image booting support
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*/
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static int booti_start(cmd_tbl_t *cmdtp, int flag, int argc,
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char * const argv[], bootm_headers_t *images)
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{
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int ret;
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struct Image_header *ih;
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ret = do_bootm_states(cmdtp, flag, argc, argv, BOOTM_STATE_START,
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images, 1);
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/* Setup Linux kernel Image entry point */
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if (!argc) {
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images->ep = load_addr;
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debug("* kernel: default image load address = 0x%08lx\n",
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load_addr);
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} else {
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images->ep = simple_strtoul(argv[0], NULL, 16);
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debug("* kernel: cmdline image address = 0x%08lx\n",
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images->ep);
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}
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ret = booti_setup(images);
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if (ret != 0)
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return 1;
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ih = (struct Image_header *)map_sysmem(images->ep, 0);
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lmb_reserve(&images->lmb, images->ep, le32_to_cpu(ih->image_size));
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unmap_sysmem(ih);
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/*
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* Handle the BOOTM_STATE_FINDOTHER state ourselves as we do not
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* have a header that provide this informaiton.
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*/
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if (bootm_find_images(flag, argc, argv))
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return 1;
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return 0;
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}
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int do_booti(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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int ret;
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/* Consume 'booti' */
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argc--; argv++;
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if (booti_start(cmdtp, flag, argc, argv, &images))
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return 1;
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/*
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* We are doing the BOOTM_STATE_LOADOS state ourselves, so must
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* disable interrupts ourselves
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*/
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bootm_disable_interrupts();
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images.os.os = IH_OS_LINUX;
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images.os.arch = IH_ARCH_ARM64;
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ret = do_bootm_states(cmdtp, flag, argc, argv,
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#ifdef CONFIG_SYS_BOOT_RAMDISK_HIGH
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BOOTM_STATE_RAMDISK |
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#endif
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BOOTM_STATE_OS_PREP | BOOTM_STATE_OS_FAKE_GO |
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BOOTM_STATE_OS_GO,
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&images, 1);
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return ret;
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}
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#ifdef CONFIG_SYS_LONGHELP
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static char booti_help_text[] =
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"[addr [initrd[:size]] [fdt]]\n"
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" - boot arm64 Linux Image stored in memory\n"
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"\tThe argument 'initrd' is optional and specifies the address\n"
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"\tof an initrd in memory. The optional parameter ':size' allows\n"
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"\tspecifying the size of a RAW initrd.\n"
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#if defined(CONFIG_OF_LIBFDT)
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"\tSince booting a Linux kernel requires a flat device-tree, a\n"
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"\tthird argument providing the address of the device-tree blob\n"
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"\tis required. To boot a kernel with a device-tree blob but\n"
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"\twithout an initrd image, use a '-' for the initrd argument.\n"
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#endif
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"";
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#endif
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U_BOOT_CMD(
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booti, CONFIG_SYS_MAXARGS, 1, do_booti,
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"boot arm64 Linux Image image from memory", booti_help_text
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);
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