fit_payload.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
 
#include <commonlib/bsd/compression.h>
#include <console/console.h>
#include <bootmem.h>
#include <program_loading.h>
#include <fit.h>
#include <endian.h>
 
/* Implements a Berkeley Boot Loader (BBL) compatible payload loading */
 
#define MAX_KERNEL_SIZE (64*MiB)
 
#if CONFIG(ARCH_RISCV_RV32)
#define SECTION_ALIGN (4 * MiB)
#endif
#if CONFIG(ARCH_RISCV_RV64)
#define SECTION_ALIGN (2 * MiB)
#endif
 
static size_t get_kernel_size(const struct fit_image_node *node)
{
        /*
         * Since we don't have a way to determine the uncompressed size of the
         * kernel, we have to keep as much memory as possible free for use by
         * the kernel immediately after the end of the kernel image. The amount
         * of space required will vary depending on selected features, and is
         * effectively unbound.
         */
 
        printk(BIOS_INFO,
               "FIT: Leaving additional %u MiB of free space after kernel.\n",
               MAX_KERNEL_SIZE >> 20);
 
        return node->size + MAX_KERNEL_SIZE;
}
 
/**
 * Place the region in free memory range.
 *
 * The caller has to set region->offset to the minimum allowed address.
 */
static bool fit_place_mem(const struct range_entry *r, void *arg)
{
        struct region *region = arg;
        resource_t start;
 
        if (range_entry_tag(r) != BM_MEM_RAM)
                return true;
 
        /* Section must be aligned at page boundary */
        start = ALIGN_UP(MAX(region->offset, range_entry_base(r)), SECTION_ALIGN);
 
        if (start + region->size < range_entry_end(r)) {
                region->offset = (size_t)start;
                return false;
        }
 
        return true;
}
 
bool fit_payload_arch(struct prog *payload, struct fit_config_node *config,
                      struct region *kernel,
                      struct region *fdt,
                      struct region *initrd)
{
        void *arg = NULL;
 
        if (!config->fdt || !fdt) {
                printk(BIOS_CRIT, "CRIT: Providing a valid FDT is mandatory to "
                       "boot a RISC-V kernel!\n");
                return false;
                /* TODO: Fall back to the ROM FDT? */
        }
 
        /* Update kernel size from image header, if possible */
        kernel->size = get_kernel_size(config->kernel);
        printk(BIOS_DEBUG, "FIT: Using kernel size of 0x%zx bytes\n",
               kernel->size);
 
        /*
         * The code assumes that bootmem_walk provides a sorted list of memory
         * regions, starting from the lowest address.
         * The order of the calls here doesn't matter, as the placement is
         * enforced in the called functions.
         * For details check code on top.
         */
        kernel->offset = 0;
        if (!bootmem_walk(fit_place_mem, kernel))
                return false;
 
        /* Mark as reserved for future allocations. */
        bootmem_add_range(kernel->offset, kernel->size, BM_MEM_PAYLOAD);
 
        /* Place FDT and INITRD after kernel. */
 
        /* Place INITRD */
        if (config->ramdisk) {
                initrd->offset = kernel->offset + kernel->size;
 
                if (!bootmem_walk(fit_place_mem, initrd))
                        return false;
                /* Mark as reserved for future allocations. */
                bootmem_add_range(initrd->offset, initrd->size, BM_MEM_PAYLOAD);
        }
 
        /* Place FDT */
        fdt->offset = kernel->offset + kernel->size;
 
        if (!bootmem_walk(fit_place_mem, fdt))
                return false;
        /* Mark as reserved for future allocations. */
        bootmem_add_range(fdt->offset, fdt->size, BM_MEM_PAYLOAD);
 
        /* Kernel expects FDT as argument */
        arg = (void *)fdt->offset;
 
        prog_set_entry(payload, (void *)kernel->offset, arg);
 
        bootmem_dump_ranges();
 
        return true;
}