diff options
| -rw-r--r-- | payloads/libpayload/arch/x86/boot_media.c | 17 | ||||
| -rw-r--r-- | payloads/libpayload/include/boot_device.h | 22 |
2 files changed, 39 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/x86/boot_media.c b/payloads/libpayload/arch/x86/boot_media.c new file mode 100644 index 0000000000..ce0283273d --- /dev/null +++ b/payloads/libpayload/arch/x86/boot_media.c @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ + +#include <boot_device.h> +#include <commonlib/bsd/cb_err.h> +#include <stddef.h> +#include <string.h> +#include <sysinfo.h> + +__attribute__((weak)) ssize_t boot_device_read(void *buf, size_t offset, size_t size) +{ + /* Memory-mapping usually only works for the top 16MB. */ + if (!lib_sysinfo.boot_media_size || lib_sysinfo.boot_media_size - offset > 16 * MiB) + return CB_ERR_ARG; + void *ptr = (void *)(uintptr_t)(0 - lib_sysinfo.boot_media_size + offset); + memcpy(buf, ptr, size); + return size; +} diff --git a/payloads/libpayload/include/boot_device.h b/payloads/libpayload/include/boot_device.h new file mode 100644 index 0000000000..a946545792 --- /dev/null +++ b/payloads/libpayload/include/boot_device.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ + +#ifndef _BOOT_DEVICE_H +#define _BOOT_DEVICE_H + +#include <stddef.h> + +/** + * This is a boot device access function, which is used by libpayload to read data from + * the flash memory (or other boot device). It has to be implemented by payloads that want + * to use FMAP or libcbfs. + * + * @param buf The output buffer to which the data should be written to. + * @param offset Absolute offset in bytes of the requested boot device memory area. Not aligned. + * @param size Size in bytes of the requested boot device memory area. Not aligned. + * + * @returns Number of bytes returned to the buffer, or negative value on error. Typically should + * be equal to the `size`, and not aligned forcefully. + */ +ssize_t boot_device_read(void *buf, size_t offset, size_t size); + +#endif /* _BOOT_DEVICE_H */ |