blob: e88d0472c7d3f15aa71a66039b8a66a1de0cf909 [file] [log] [blame]
/*
* Copyright 2023 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* A simple linker script for kelvin core.
*
* Memory layout:
*
* TCM_ORIGIN ---> +=====================+
* | |
* | .text |
* +---------------------|
* | .crt |
* +---------------------+
* | .rodata |
* +---------------------+
* | .init_array |
* +---------------------+
* | .data |
* +---------------------+
* | .bss |
* +---------------------+
* | .heap |
* | (All unclamied |
* | memory) |
* | |
* (TCM_END - 4096 ---> +---------------------+
* - model_output | .stack |
* - stack) +---------------------+
* | .model_output |
* TCM_END - 4096 ---> +=====================+
* | .model_input |
+ | (remainder of page) |
* +---------------------+
* output_header (64B) ---> |.model_output_header |
* TCM_END ---> +=====================+
**/
TCM_SIZE = 0x400000;
STACK_SIZE = DEFINED(STACK_SIZE) ? STACK_SIZE : DEFINED(__stack_size__) ? __stack_size__ : 0x4000;
OUTPUT_SIZE = DEFINED(OUTPUT_SIZE) ? OUTPUT_SIZE : DEFINED(__output_size__) ? __output_size__ : 0x40;
__output_header_size__ = 0x40;
/*
* This defines all of memory as 2x segments with the last page used for an
* output header at a fixed location and the remainder of the page used for
* input parameters. ML runtimes either copy input data from this region
* (e.g. TfLite) or reference the data in the region directly (IREE).
*
* The "TCM segment" is sized as the physical memory size (TCM_SIZE) - 1x
* page so that offsets from the end of "TCM" can be expressed as:
* ORIGIN(TCM) + LENGTH(TCM) - <offset>
*/
MEMORY {
TCM(rwx): ORIGIN = 0, LENGTH = TCM_SIZE - 4096
MODEL_HEADER(rw): ORIGIN = LENGTH(TCM), LENGTH = 4096
}
ENTRY(_start)
SECTIONS {
. = ORIGIN(TCM);
.text : ALIGN(4) {
*(._init)
*(.text)
*(.text.*)
. = ALIGN(4);
__text_end__ = .;
} > TCM
.init.array : ALIGN(4) {
__init_array_start__ = .;
*(.init_array)
*(.init_array.*)
. = ALIGN(4);
__init_array_end__ = .;
} > TCM
.rodata : ALIGN(4) {
*(.srodata)
*(.srodata.*)
*(.rodata)
*(.rodata.*)
. = ALIGN(4);
} > TCM
.data : ALIGN(4) {
__data_start__ = .;
/**
* This will get loaded into `gp`, and the linker will use that register for
* accessing data within [-2048,2047] of `__global_pointer$`.
*
* This is much cheaper (for small data) than materializing the
* address and loading from that (which will take one extra instruction).
*/
_global_pointer = . + 0x800;
*(.sdata)
*(.sdata.*)
*(.data)
*(.data.*)
/* Align on 256 width. */
. = ALIGN(256);
__data_end__ = .;
} > TCM
.bss : ALIGN(4) {
__bss_start__ = .;
*(.sbss)
*(.sbss.*)
*(.bss)
*(.bss.*)
__bss_end__ = .;
} > TCM
/* All the unclaimed memory is used in heap */
.heap (NOLOAD) : {
. = ALIGN(64);
__heap_start__ = .;
. = ORIGIN(TCM) + LENGTH(TCM) - OUTPUT_SIZE - STACK_SIZE - 63;
. = ALIGN(64);
__heap_end__ = .;
} > TCM
.stack ORIGIN(TCM) + LENGTH(TCM) - OUTPUT_SIZE - STACK_SIZE (NOLOAD) : {
__stack_start__ = .;
. += STACK_SIZE;
. = ALIGN(64);
__stack_end__ = .;
} > TCM
.model_output ORIGIN(TCM) + LENGTH(TCM) - OUTPUT_SIZE (NOLOAD) : {
. = ALIGN(64);
__model_output_start__ = .;
*(.model_output)
__model_output_end__ = .;
} > TCM
}
SECTIONS {
. = ORIGIN(MODEL_HEADER);
/*
* Model input data region uses the rest of the page not occupied by the
* output header. The host writes input data here and the model is
* responsible for copying (TfLite) it or informing the model where it is
* if the model can take input from any location (IREE).
*/
.model_input : {
__model_input_start__ = .;
*(.model_input)
__model_input_end__ = .;
} > MODEL_HEADER
/*
* Model output information (return code and output location/length) is
* always at the end of TCM.
*/
.output_header ORIGIN(MODEL_HEADER) + (4096 - __output_header_size__) : ALIGN(4) {
__output_header_start__ = .;
_ret = .; /* NB: memory location for model return value (aka ModelHeader::return_code) */
*(.model_output_header*)
__output_header_end__ = .;
} > MODEL_HEADER
}