--- /dev/null
+/*
+ * Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <byteswap.h>
+#include <ipxe/image.h>
+#include <ipxe/memmap.h>
+#include <ipxe/uaccess.h>
+#include <ipxe/segment.h>
+#include <ipxe/io.h>
+#include <ipxe/fdt.h>
+#include <ipxe/lkrn.h>
+
+/** @file
+ *
+ * Linux kernel image format
+ *
+ */
+
+/**
+ * Parse kernel image
+ *
+ * @v image Kernel image
+ * @v ctx Kernel image context
+ * @ret rc Return status code
+ */
+static int lkrn_parse ( struct image *image, struct lkrn_context *ctx ) {
+ const struct lkrn_header *hdr;
+
+ /* Initialise context */
+ memset ( ctx, 0, sizeof ( *ctx ) );
+
+ /* Read image header */
+ if ( image->len < sizeof ( *hdr ) ) {
+ DBGC ( image, "LKRN %s too short for header\n", image->name );
+ return -ENOEXEC;
+ }
+ hdr = image->data;
+
+ /* Check magic value */
+ if ( hdr->magic != cpu_to_le32 ( LKRN_MAGIC_ARCH ) ) {
+ DBGC ( image, "LKRN %s bad magic value %#08x\n",
+ image->name, le32_to_cpu ( hdr->magic ) );
+ return -ENOEXEC;
+ }
+
+ /* Record load offset */
+ ctx->offset = le64_to_cpu ( hdr->text_offset );
+
+ /* Record and check image size */
+ ctx->filesz = image->len;
+ ctx->memsz = le64_to_cpu ( hdr->image_size );
+ if ( ctx->filesz > ctx->memsz ) {
+ DBGC ( image, "LKRN %s invalid image size %#zx/%#zx\n",
+ image->name, ctx->filesz, ctx->memsz );
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
+
+/**
+ * Locate start of RAM
+ *
+ * @v image Kernel image
+ * @v ctx Kernel image context
+ * @ret rc Return status code
+ */
+static int lkrn_ram ( struct image *image, struct lkrn_context *ctx ) {
+ struct memmap_region region;
+
+ /* Locate start of RAM */
+ for_each_memmap ( ®ion, 0 ) {
+ memmap_dump ( ®ion );
+ if ( ! ( region.flags & MEMMAP_FL_MEMORY ) )
+ continue;
+ ctx->ram = region.addr;
+ DBGC ( image, "LKRN %s RAM starts at %#08lx\n",
+ image->name, ctx->ram );
+ return 0;
+ }
+
+ DBGC ( image, "LKRN %s found no RAM\n", image->name );
+ return -ENOTSUP;
+}
+
+/**
+ * Load kernel image
+ *
+ * @v image Kernel image
+ * @v ctx Kernel image context
+ * @ret rc Return status code
+ */
+static int lkrn_load ( struct image *image, struct lkrn_context *ctx ) {
+ void *dest;
+ int rc;
+
+ /* Record entry point */
+ ctx->entry = ( ctx->ram + ctx->offset );
+ dest = phys_to_virt ( ctx->entry );
+ DBGC ( image, "LKRN %s loading to [%#08lx,%#08lx,%#08lx)\n",
+ image->name, ctx->entry, ( ctx->entry + ctx->filesz ),
+ ( ctx->entry + ctx->memsz ) );
+
+ /* Prepare segment */
+ if ( ( rc = prep_segment ( dest, ctx->filesz, ctx->memsz ) ) != 0 ) {
+ DBGC ( image, "LKRN %s could not prepare kernel "
+ "segment: %s\n", image->name, strerror ( rc ) );
+ return rc;
+ }
+
+ /* Copy to segment */
+ memcpy ( dest, image->data, ctx->filesz );
+
+ return 0;
+}
+
+/**
+ * Construct device tree
+ *
+ * @v image Kernel image
+ * @v ctx Kernel image context
+ * @ret rc Return status code
+ */
+static int lkrn_fdt ( struct image *image, struct lkrn_context *ctx ) {
+ struct fdt_header *fdt;
+ void *dest;
+ size_t len;
+ int rc;
+
+ /* Build device tree (which may change system memory map) */
+ if ( ( rc = fdt_create ( &fdt, image->cmdline ) ) != 0 )
+ goto err_create;
+ len = be32_to_cpu ( fdt->totalsize );
+
+ /* Place device tree after kernel, rounded up to a page boundary */
+ ctx->fdt = ( ( ctx->ram + ctx->offset + ctx->memsz + PAGE_SIZE - 1 ) &
+ ~( PAGE_SIZE - 1 ) );
+ dest = phys_to_virt ( ctx->fdt );
+ DBGC ( image, "LKRN %s FDT at [%#08lx,%#08lx)\n",
+ image->name, ctx->fdt, ( ctx->fdt + len ) );
+
+ /*
+ * No further allocations are permitted after this point,
+ * since we are about to start loading segments.
+ *
+ */
+
+ /* Prepare segment */
+ if ( ( rc = prep_segment ( dest, len, len ) ) != 0 ) {
+ DBGC ( image, "LKRN %s could not prepare FDT segment: %s\n",
+ image->name, strerror ( rc ) );
+ goto err_segment;
+ }
+
+ /* Copy to segment */
+ memcpy ( dest, fdt, len );
+
+ /* Success */
+ rc = 0;
+
+ err_segment:
+ fdt_remove ( fdt );
+ err_create:
+ return rc;
+}
+
+/**
+ * Execute kernel image
+ *
+ * @v image Kernel image
+ * @ret rc Return status code
+ */
+static int lkrn_exec ( struct image *image ) {
+ struct lkrn_context ctx;
+ int rc;
+
+ /* Parse header */
+ if ( ( rc = lkrn_parse ( image, &ctx ) ) != 0 )
+ return rc;
+
+ /* Locate start of RAM */
+ if ( ( rc = lkrn_ram ( image, &ctx ) ) != 0 )
+ return rc;
+
+ /* Create device tree (which may change system memory map) */
+ if ( ( rc = lkrn_fdt ( image, &ctx ) ) != 0 )
+ return rc;
+
+ /* Load kernel image (after all allocations are finished) */
+ if ( ( rc = lkrn_load ( image, &ctx ) ) != 0 )
+ return rc;
+
+ /* Jump to kernel entry point */
+ DBGC ( image, "LKRN %s jumping to kernel at %#08lx\n",
+ image->name, ctx.entry );
+ lkrn_jump ( ctx.entry, ctx.fdt );
+
+ /* There is no way for the image to return, since we provide
+ * no return address.
+ */
+ assert ( 0 );
+
+ return -ECANCELED; /* -EIMPOSSIBLE */
+}
+
+/**
+ * Probe kernel image
+ *
+ * @v image Kernel image
+ * @ret rc Return status code
+ */
+static int lkrn_probe ( struct image *image ) {
+ struct lkrn_context ctx;
+ int rc;
+
+ /* Parse header */
+ if ( ( rc = lkrn_parse ( image, &ctx ) ) != 0 )
+ return rc;
+
+ DBGC ( image, "LKRN %s is a Linux kernel\n", image->name );
+ return 0;
+}
+
+/** Linux kernel image type */
+struct image_type lkrn_image_type __image_type ( PROBE_NORMAL ) = {
+ .name = "lkrn",
+ .probe = lkrn_probe,
+ .exec = lkrn_exec,
+};
projects / thirdparty / ipxe.git / commitdiff
