cbfs.h

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#ifndef _CBFS_H_
#define _CBFS_H_
 
#include <cbmem.h>
#include <commonlib/bsd/cbfs_mdata.h>
#include <commonlib/mem_pool.h>
#include <commonlib/region.h>
#include <endian.h>
#include <program_loading.h>
#include <types.h>
#include <vb2_sha.h>
 
 
/**********************************************************************************************
 *                                  CBFS FILE ACCESS APIs                                     *
 **********************************************************************************************/
 
/*
 * These are the APIs used to access files in CBFS. In order to keep the calls simple and free
 * of clutter in the common cases, but still offer all advanced functionality when needed, there
 * are many different variations that are implemented by wrapping the same underlying API with
 * static inlines. All accessors have in common that they look up files by name, and will
 * transparently decompress files that are compressed.
 *
 * There are three main flavors of CBFS accessors:
 *
 * size_t cbfs_load(char *name, void *buf, size_t size): Loads the contents of a CBFS file into
 *      a buffer provided by the caller (by providing pointer and size to it). Will return the
 *      amount of bytes loaded on success, or 0 on error.
 *
 * void *cbfs_map(char *name, size_t *size_out): Maps a file into the address space. If the file
 *      is not compressed and the platform supports direct memory-mapping for the boot medium,
 *      a pointer to the platform mapping is returned directly. In all other cases, memory will
 *      be allocated from the cbfs_cache and file data will be loaded into there. Returns a
 *      pointer to the mapping on success, or NULL on error. If an optional size_out parameter
 *      is passed in, it will be filled out with the size of the mapped data. Caller should call
 *      cbfs_unmap() after it is done using the mapping to free up the cbfs_cache if possible.
 *
 * void *cbfs_alloc(char *name, cbfs_allocator_t allocator, void *arg, size_t *size_out): Loads
 *      file data into memory provided by a custom allocator function that the caller passes in.
 *      The caller may pass an argument that is passed through verbatim to the allocator.
 *      Returns the pointer returned by the allocator (where the file data was loaded to) on
 *      success, or NULL on error. If an optional size_out parameter is passed in, it will be
 *      filled out with the size of the loaded data.
 *
 * void *cbfs_cbmem_alloc(char *name, uint32_t cbmem_id, size_t *size_out): Wrapper around
 *      cbfs_alloc() that will provide an allocator function for allocating space for the file
 *      data in CBMEM, with the provided CBMEM ID.
 *
 * All of these flavors have variations with any of the following optional parameters added:
 *
 * ..._ro_...: Will force looking up the CBFS file in the read-only CBFS (the "COREBOOT" FMAP
 *      section), even when running in an RW stage from one of the RW CBFSs. Only relevant if
 *      CONFIG(VBOOT) is set.
 *
 * ..._unverified_area_...: Will look for the CBFS file in the named FMAP area, rather than
 *      any of the default (RO or RW) CBFSs. Files accessed this way are *not* verified in any
 *      way (even if CONFIG(CBFS_VERIFICATION) is enabled) and should always be treated as
 *      untrusted (potentially malicious) data. Mutually exclusive with the ..._ro_... variant.
 *
 * ..._type_...: May pass in an extra enum cbfs_type *type parameter. If the value it points to
 *      is CBFS_TYPE_QUERY, it will be replaced with the actual CBFS type of the found file. If
 *      it is anything else, the type will be compared with the actually found type, and the
 *      operation will fail if they don't match.
 */
 
/*
 * An allocator function for passing to cbfs_alloc(). Takes the argument that was originally
 * passed to cbfs_alloc(), the size of the file to be loaded, and a pointer to the already
 * loaded and verified file metadata (for rare cases where the allocator needs to check custom
 * attributes). Must return a pointer to space of the requested size where the file data should
 * be loaded, or NULL to make the operation fail.
 */
typedef void *(*cbfs_allocator_t)(void *arg, size_t size, const union cbfs_mdata *mdata);
 
static inline size_t cbfs_load(const char *name, void *buf, size_t size);
static inline size_t cbfs_ro_load(const char *name, void *buf, size_t size);
static inline size_t cbfs_type_load(const char *name, void *buf, size_t size,
                                    enum cbfs_type *type);
static inline size_t cbfs_ro_type_load(const char *name, void *buf, size_t size,
                                    enum cbfs_type *type);
static inline size_t cbfs_unverified_area_load(const char *area, const char *name,
                                               void *buf, size_t size);
 
static inline void *cbfs_map(const char *name, size_t *size_out);
static inline void *cbfs_ro_map(const char *name, size_t *size_out);
static inline void *cbfs_type_map(const char *name, size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_ro_type_map(const char *name, size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_unverified_area_map(const char *area, const char *name,
                                              size_t *size_out);
 
static inline void *cbfs_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                               size_t *size_out);
static inline void *cbfs_ro_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                                  size_t *size_out);
static inline void *cbfs_type_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                                    size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_ro_type_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                                       size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_unverified_area_alloc(const char *area, const char *name,
                                                cbfs_allocator_t allocator, void *arg,
                                                size_t *size_out);
 
static inline void *cbfs_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out);
static inline void *cbfs_ro_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out);
static inline void *cbfs_type_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out,
                                          enum cbfs_type *type);
static inline void *cbfs_ro_type_cbmem_alloc(const char *name, uint32_t cbmem_id,
                                             size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_unverified_area_cbmem_alloc(const char *area, const char *name,
                                                      uint32_t cbmem_id, size_t *size_out);
 
/*
 * Starts the processes of preloading a file into RAM.
 *
 * This method depends on COOP_MULTITASKING to parallelize the loading. This method is only
 * effective when the underlying rdev supports DMA operations.
 *
 * When `cbfs_load`, `cbfs_alloc`, or `cbfs_map` are called after a preload has been started,
 * they will wait for the preload to complete (if it hasn't already) and then perform
 * verification and/or decompression.
 *
 * This method does not have a return value because the system should boot regardless if this
 * method succeeds or fails.
 */
void cbfs_preload(const char *name);
 
/* Removes a previously allocated CBFS mapping. Should try to unmap mappings in strict LIFO
   order where possible, since mapping backends often don't support more complicated cases. */
void cbfs_unmap(void *mapping);
 
/* Load stage into memory filling in prog. Return 0 on success. < 0 on error. */
enum cb_err cbfs_prog_stage_load(struct prog *prog);
 
/* Returns the size of a CBFS file, or 0 on error. Avoid using this function to allocate space,
   and instead use cbfs_alloc() so the file only needs to be looked up once. */
static inline size_t cbfs_get_size(const char *name);
static inline size_t cbfs_ro_get_size(const char *name);
 
/* Returns the type of a CBFS file, or CBFS_TYPE_NULL on error. Use cbfs_type_load() instead of
   this where possible to avoid looking up the file more than once. */
static inline enum cbfs_type cbfs_get_type(const char *name);
static inline enum cbfs_type cbfs_ro_get_type(const char *name);
 
/* Check whether a CBFS file exists. */
static inline bool cbfs_file_exists(const char *name);
static inline bool cbfs_ro_file_exists(const char *name);
 
 
/**********************************************************************************************
 *                                BOOT DEVICE HELPER APIs                                     *
 **********************************************************************************************/
 
/*
 * The shared memory pool for backing mapped CBFS files, and other CBFS allocation needs.
 */
extern struct mem_pool cbfs_cache;
 
/*
 * Data structure that represents "a" CBFS boot device, with optional metadata cache. Generally
 * we only have one of these, or two (RO and RW) when CONFIG(VBOOT) is set. The region device
 * stored here must always be a subregion of boot_device_ro().
 */
struct cbfs_boot_device {
        struct region_device rdev;
        void *mcache;
        size_t mcache_size;
};
 
/* Helper to fill out |mcache| and |mcache_size| in a cbfs_boot_device. */
void cbfs_boot_device_find_mcache(struct cbfs_boot_device *cbd, uint32_t id);
 
/*
 * Retrieves the currently active CBFS boot device. If |force_ro| is set, will always return the
 * read-only CBFS instead (this only makes a difference when CONFIG(VBOOT) is enabled). May
 * perform certain CBFS initialization tasks. Returns NULL on error (e.g. boot device IO error).
 */
const struct cbfs_boot_device *cbfs_get_boot_device(bool force_ro);
 
/*
 * Builds the mcache (if |cbd->mcache| is set) and verifies |metadata_hash| (if it is not NULL).
 * If CB_CBFS_CACHE_FULL is returned, the mcache is incomplete but still valid and the metadata
 * hash was still verified. Should be called once per *boot* (not once per stage) before the
 * first CBFS access.
 */
enum cb_err cbfs_init_boot_device(const struct cbfs_boot_device *cbd,
                                  struct vb2_hash *metadata_hash);
 
 
/**********************************************************************************************
 *                         INTERNAL HELPERS FOR INLINES, DO NOT USE.                          *
 **********************************************************************************************/
enum cb_err _cbfs_boot_lookup(const char *name, bool force_ro,
                              union cbfs_mdata *mdata, struct region_device *rdev);
 
void *_cbfs_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                  size_t *size_out, bool force_ro, enum cbfs_type *type);
 
void *_cbfs_unverified_area_alloc(const char *area, const char *name,
                                  cbfs_allocator_t allocator, void *arg, size_t *size_out);
 
struct _cbfs_default_allocator_arg {
        void *buf;
        size_t buf_size;
};
void *_cbfs_default_allocator(void *arg, size_t size, const union cbfs_mdata *unused);
 
void *_cbfs_cbmem_allocator(void *arg, size_t size, const union cbfs_mdata *unused);
 
/**********************************************************************************************
 *                                  INLINE IMPLEMENTATIONS                                    *
 **********************************************************************************************/
static inline void *cbfs_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                               size_t *size_out)
{
        return cbfs_type_alloc(name, allocator, arg, size_out, NULL);
}
 
static inline void *cbfs_ro_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                                  size_t *size_out)
{
        return cbfs_ro_type_alloc(name, allocator, arg, size_out, NULL);
}
 
static inline void *cbfs_type_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                                    size_t *size_out, enum cbfs_type *type)
{
        return _cbfs_alloc(name, allocator, arg, size_out, false, type);
}
 
static inline void *cbfs_ro_type_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
                                       size_t *size_out, enum cbfs_type *type)
{
        return _cbfs_alloc(name, allocator, arg, size_out, true, type);
}
 
static inline void *cbfs_unverified_area_alloc(const char *area, const char *name,
                                               cbfs_allocator_t allocator, void *arg,
                                               size_t *size_out)
{
        return _cbfs_unverified_area_alloc(area, name, allocator, arg, size_out);
}
 
static inline void *cbfs_map(const char *name, size_t *size_out)
{
        return cbfs_type_map(name, size_out, NULL);
}
 
static inline void *cbfs_ro_map(const char *name, size_t *size_out)
{
        return cbfs_ro_type_map(name, size_out, NULL);
}
 
static inline void *cbfs_type_map(const char *name, size_t *size_out, enum cbfs_type *type)
{
        return cbfs_type_alloc(name, NULL, NULL, size_out, type);
}
 
static inline void *cbfs_ro_type_map(const char *name, size_t *size_out, enum cbfs_type *type)
{
        return cbfs_ro_type_alloc(name, NULL, NULL, size_out, type);
}
 
static inline void *cbfs_unverified_area_map(const char *area, const char *name,
                                             size_t *size_out)
{
        return _cbfs_unverified_area_alloc(area, name, NULL, NULL, size_out);
}
 
static inline size_t _cbfs_load(const char *name, void *buf, size_t size, bool force_ro,
                                enum cbfs_type *type)
{
        struct _cbfs_default_allocator_arg arg = { .buf = buf, .buf_size = size };
        if (_cbfs_alloc(name, _cbfs_default_allocator, &arg, &size, force_ro, type))
                return size;
        else
                return 0;
}
 
static inline size_t cbfs_load(const char *name, void *buf, size_t size)
{
        return cbfs_type_load(name, buf, size, NULL);
}
 
static inline size_t cbfs_type_load(const char *name, void *buf, size_t size,
                                    enum cbfs_type *type)
{
        return _cbfs_load(name, buf, size, false, type);
}
 
static inline size_t cbfs_ro_load(const char *name, void *buf, size_t size)
{
        return cbfs_ro_type_load(name, buf, size, NULL);
}
 
static inline size_t cbfs_ro_type_load(const char *name, void *buf, size_t size,
                                    enum cbfs_type *type)
{
        return _cbfs_load(name, buf, size, true, type);
}
 
static inline size_t cbfs_unverified_area_load(const char *area, const char *name,
                                               void *buf, size_t size)
{
        struct _cbfs_default_allocator_arg arg = { .buf = buf, .buf_size = size };
        if (_cbfs_unverified_area_alloc(area, name, _cbfs_default_allocator, &arg, &size))
                return size;
        else
                return 0;
}
 
static inline void *cbfs_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out)
{
        return cbfs_type_cbmem_alloc(name, cbmem_id, size_out, NULL);
}
 
static inline void *cbfs_ro_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out)
{
        return cbfs_ro_type_cbmem_alloc(name, cbmem_id, size_out, NULL);
}
 
static inline void *cbfs_type_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out,
                                          enum cbfs_type *type)
{
        return cbfs_type_alloc(name, _cbfs_cbmem_allocator, (void *)(uintptr_t)cbmem_id,
                               size_out, type);
}
 
static inline void *cbfs_ro_type_cbmem_alloc(const char *name, uint32_t cbmem_id,
                                             size_t *size_out, enum cbfs_type *type)
{
        return cbfs_ro_type_alloc(name, _cbfs_cbmem_allocator, (void *)(uintptr_t)cbmem_id,
                                  size_out, type);
}
 
static inline void *cbfs_unverified_area_cbmem_alloc(const char *area, const char *name,
                                                     uint32_t cbmem_id, size_t *size_out)
{
        return _cbfs_unverified_area_alloc(area, name, _cbfs_cbmem_allocator,
                                           (void *)(uintptr_t)cbmem_id, size_out);
}
 
static inline size_t cbfs_get_size(const char *name)
{
        union cbfs_mdata mdata;
        struct region_device rdev;
        if (_cbfs_boot_lookup(name, false, &mdata, &rdev) != CB_SUCCESS)
                return 0;
        return be32toh(mdata.h.len);
}
 
static inline size_t cbfs_ro_get_size(const char *name)
{
        union cbfs_mdata mdata;
        struct region_device rdev;
        if (_cbfs_boot_lookup(name, true, &mdata, &rdev) != CB_SUCCESS)
                return 0;
        return be32toh(mdata.h.len);
}
 
static inline enum cbfs_type cbfs_get_type(const char *name)
{
        union cbfs_mdata mdata;
        struct region_device rdev;
        if (_cbfs_boot_lookup(name, false, &mdata, &rdev) != CB_SUCCESS)
                return CBFS_TYPE_NULL;
        return be32toh(mdata.h.type);
}
 
static inline enum cbfs_type cbfs_ro_get_type(const char *name)
{
        union cbfs_mdata mdata;
        struct region_device rdev;
        if (_cbfs_boot_lookup(name, true, &mdata, &rdev) != CB_SUCCESS)
                return CBFS_TYPE_NULL;
        return be32toh(mdata.h.type);
}
 
static inline bool cbfs_file_exists(const char *name)
{
        union cbfs_mdata mdata;
        struct region_device rdev;
        if (_cbfs_boot_lookup(name, false, &mdata, &rdev) != CB_SUCCESS)
                return false;
        return true;
}
 
static inline bool cbfs_ro_file_exists(const char *name)
{
        union cbfs_mdata mdata;
        struct region_device rdev;
        if (_cbfs_boot_lookup(name, true, &mdata, &rdev) != CB_SUCCESS)
                return false;
        return true;
}
 
#endif