coreboot-kgpe-d16/src/lib/rmodule.c

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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2012 Google LLC
*
* 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; version 2 of the License.
*
* 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.
*/
#include <assert.h>
#include <cbmem.h>
#include <cbfs.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <console/console.h>
#include <program_loading.h>
#include <rmodule.h>
/* Change this define to get more verbose debugging for module loading. */
#define PK_ADJ_LEVEL BIOS_NEVER
static inline int rmodule_is_loaded(const struct rmodule *module)
{
return module->location != NULL;
}
/* Calculate a loaded program address based on the blob address. */
static inline void *rmodule_load_addr(const struct rmodule *module,
uintptr_t blob_addr)
{
char *loc = module->location;
return &loc[blob_addr - module->header->module_link_start_address];
}
/* Initialize a rmodule structure based on raw data. */
int rmodule_parse(void *ptr, struct rmodule *module)
{
char *base;
struct rmodule_header *rhdr;
base = ptr;
rhdr = ptr;
if (rhdr == NULL)
return -1;
/* Sanity check the raw data. */
if (rhdr->magic != RMODULE_MAGIC)
return -1;
if (rhdr->version != RMODULE_VERSION_1)
return -1;
/* Indicate the module hasn't been loaded yet. */
module->location = NULL;
/* The rmodule only needs a reference to the reloc_header. */
module->header = rhdr;
/* The payload lives after the header. */
module->payload = &base[rhdr->payload_begin_offset];
module->payload_size = rhdr->payload_end_offset -
rhdr->payload_begin_offset;
module->relocations = &base[rhdr->relocations_begin_offset];
return 0;
}
int rmodule_memory_size(const struct rmodule *module)
{
return module->header->module_program_size;
}
void *rmodule_parameters(const struct rmodule *module)
{
if (!rmodule_is_loaded(module))
return NULL;
/* Indicate if there are no parameters. */
if (module->header->parameters_begin == module->header->parameters_end)
return NULL;
return rmodule_load_addr(module, module->header->parameters_begin);
}
int rmodule_entry_offset(const struct rmodule *module)
{
return module->header->module_entry_point -
module->header->module_link_start_address;
}
void *rmodule_entry(const struct rmodule *module)
{
if (!rmodule_is_loaded(module))
return NULL;
return rmodule_load_addr(module, module->header->module_entry_point);
}
static void rmodule_clear_bss(struct rmodule *module)
{
char *begin;
int size;
begin = rmodule_load_addr(module, module->header->bss_begin);
size = module->header->bss_end - module->header->bss_begin;
memset(begin, 0, size);
}
static inline size_t rmodule_number_relocations(const struct rmodule *module)
{
size_t r;
r = module->header->relocations_end_offset;
r -= module->header->relocations_begin_offset;
r /= sizeof(uintptr_t);
return r;
}
static void rmodule_copy_payload(const struct rmodule *module)
{
printk(BIOS_DEBUG, "Loading module at %p with entry %p. "
"filesize: 0x%x memsize: 0x%x\n",
module->location, rmodule_entry(module),
module->payload_size, rmodule_memory_size(module));
/* No need to copy the payload if the load location and the
* payload location are the same. */
if (module->location == module->payload)
return;
memcpy(module->location, module->payload, module->payload_size);
}
static int rmodule_relocate(const struct rmodule *module)
{
size_t num_relocations;
const uintptr_t *reloc;
uintptr_t adjustment;
/* Each relocation needs to be adjusted relative to the beginning of
* the loaded program. */
adjustment = (uintptr_t)rmodule_load_addr(module, 0);
reloc = module->relocations;
num_relocations = rmodule_number_relocations(module);
printk(BIOS_DEBUG, "Processing %zu relocs. Offset value of 0x%08lx\n",
num_relocations, (unsigned long)adjustment);
while (num_relocations > 0) {
uintptr_t *adjust_loc;
/* If the adjustment location is non-NULL adjust it. */
adjust_loc = rmodule_load_addr(module, *reloc);
printk(PK_ADJ_LEVEL, "Adjusting %p: 0x%08lx -> 0x%08lx\n",
adjust_loc, (unsigned long) *adjust_loc,
(unsigned long) (*adjust_loc + adjustment));
*adjust_loc += adjustment;
reloc++;
num_relocations--;
}
return 0;
}
int rmodule_load_alignment(const struct rmodule *module)
{
/* The load alignment is the start of the program's linked address.
* The base address where the program is loaded needs to be a multiple
* of the program's starting link address. That way all data alignment
* in the program is preserved. Default to 4KiB. */
return 4096;
}
int rmodule_load(void *base, struct rmodule *module)
{
/*
* In order to load the module at a given address, the following steps
* take place:
* 1. Copy payload to base address.
* 2. Adjust relocations within the module to new base address.
* 3. Clear the bss segment last since the relocations live where
* the bss is. If an rmodule is being loaded from its load
* address the relocations need to be processed before the bss.
*/
module->location = base;
rmodule_copy_payload(module);
if (rmodule_relocate(module))
return -1;
rmodule_clear_bss(module);
prog_segment_loaded((uintptr_t)module->location,
rmodule_memory_size(module), SEG_FINAL);
return 0;
}
int rmodule_calc_region(unsigned int region_alignment, size_t rmodule_size,
size_t *region_size, int *load_offset)
{
/* region_alignment must be a power of 2. */
if (region_alignment & (region_alignment - 1))
BUG();
if (region_alignment < 4096)
region_alignment = 4096;
/* Sanity check rmodule_header size. The code below assumes it is less
* than the minimum alignment required. */
if (region_alignment < sizeof(struct rmodule_header))
BUG();
/* 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. */
*region_size = ALIGN(rmodule_size + 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
*/
*load_offset = region_alignment;
return region_alignment - sizeof(struct rmodule_header);
}
int rmodule_stage_load(struct rmod_stage_load *rsl)
{
struct rmodule rmod_stage;
size_t region_size;
char *stage_region;
int rmodule_offset;
int load_offset;
struct cbfs_stage stage;
void *rmod_loc;
struct region_device *fh;
if (rsl->prog == NULL || prog_name(rsl->prog) == NULL)
return -1;
fh = prog_rdev(rsl->prog);
if (rdev_readat(fh, &stage, 0, sizeof(stage)) != sizeof(stage))
return -1;
rmodule_offset =
rmodule_calc_region(DYN_CBMEM_ALIGN_SIZE,
stage.memlen, &region_size, &load_offset);
stage_region = cbmem_add(rsl->cbmem_id, region_size);
if (stage_region == NULL)
return -1;
rmod_loc = &stage_region[rmodule_offset];
printk(BIOS_INFO, "Decompressing stage %s @ 0x%p (%d bytes)\n",
prog_name(rsl->prog), rmod_loc, stage.memlen);
if (!cbfs_load_and_decompress(fh, sizeof(stage), stage.len, rmod_loc,
stage.memlen, stage.compression))
return -1;
if (rmodule_parse(rmod_loc, &rmod_stage))
return -1;
if (rmodule_load(&stage_region[load_offset], &rmod_stage))
return -1;
prog_set_area(rsl->prog, rmod_stage.location,
rmodule_memory_size(&rmod_stage));
/* Allow caller to pick up parameters, if available. */
rsl->params = rmodule_parameters(&rmod_stage);
prog_set_entry(rsl->prog, rmodule_entry(&rmod_stage), rsl->params);
return 0;
}