Function rmodule_cbfs_allocator

src/lib/rmodule.c:194–247

}

static void *rmodule_cbfs_allocator(void *rsl_arg, size_t unused,
				    const union cbfs_mdata *mdata)
{
	struct rmod_stage_load *rsl = rsl_arg;

	assert(IS_POWER_OF_2(region_alignment) &&
	       region_alignment >= sizeof(struct rmodule_header));

	/* The CBFS core just passes us the decompressed size of the file, but
	   we need to know the memlen of the binary image. We need to find and
	   parse the stage header explicitly. */
	const struct cbfs_file_attr_stageheader *sattr = cbfs_find_attr(mdata,
			CBFS_FILE_ATTR_TAG_STAGEHEADER, sizeof(*sattr));
	if (!sattr) {
		printk(BIOS_ERR, "rmodule '%s' has no stage header!\n",
		       rsl->prog->name);
		return NULL;
	}

	const size_t memlen = be32toh(sattr->memlen);

	/* Place the rmodule according to alignment. The rmodule files
	 * themselves are packed as a header and a payload, however the rmodule
	 * itself is linked along with the header. The header starts at address
	 * 0. Immediately following the header in the file is the program,
	 * however its starting address is determined by the rmodule linker
	 * script. In short, sizeof(struct rmodule_header) can be less than
	 * or equal to the linked address of the program. Therefore we want
	 * to place the rmodule so that the program falls on the aligned
	 * address with the header just before it. Therefore, we need at least
	 * a page to account for the size of the header. */
	size_t region_size = ALIGN_UP(memlen + region_alignment, 4096);
	/* The program starts immediately after the header. However,
	 * it needs to be aligned to a 4KiB boundary. Therefore, adjust the
	 * program location so that the program lands on a page boundary.  The
	 * layout looks like the following:
	 *
	 * +--------------------------------+  region_alignment + region_size
	 * |  >= 0 bytes from alignment     |
	 * +--------------------------------+  program end (4KiB aligned)
	 * |  program size                  |
	 * +--------------------------------+  program_begin (4KiB aligned)
	 * |  sizeof(struct rmodule_header) |
	 * +--------------------------------+  rmodule header start
	 * |  >= 0 bytes from alignment     |
	 * +--------------------------------+  region_alignment
	 */

	uint8_t *stage_region = cbmem_add(rsl->cbmem_id, region_size);
	if (stage_region == NULL)
		return NULL;

	return stage_region + region_alignment - sizeof(struct rmodule_header);
}

int rmodule_stage_load(struct rmod_stage_load *rsl)
{