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Toolchain Management

This document describes how spksrc manages Synology cross-compilation toolchains.

Overview

Synology provides official cross-compilation toolchains for each DSM version and architecture. spksrc downloads, extracts, and configures these toolchains automatically.

Toolchain Directory Structure

toolchain/
├── syno-x64-7.2/
│   ├── Makefile
│   ├── digests
│   └── work/
│       ├── x86_64-pc-linux-gnu/    # Extracted toolchain
│       ├── tc_vars.mk              # Generated variables
│       ├── tc_vars.autotools.mk
│       ├── tc_vars.flags.mk
│       ├── tc_vars.cmake
│       └── tc_vars.meson-*
├── syno-aarch64-7.2/
├── syno-armv7-7.2/
└── ...

Toolchain Naming

Toolchains follow the pattern syno-<arch>-<tcversion>:

  • arch - Target architecture (x64, aarch64, armv7, etc.)
  • tcversion - DSM version (7.2, 7.1, 6.2.4, etc.)

Examples: - syno-x64-7.2 - Intel 64-bit for DSM 7.2 - syno-aarch64-7.1 - ARM 64-bit for DSM 7.1 - syno-armv7-6.2.4 - ARM 32-bit for DSM 6.2.4

Toolchain Makefile

Each toolchain directory contains a Makefile with:

TC_NAME  = x86_64-pc-linux-gnu
TC_VERS  = 7.2
TC_ARCH  = x64
TC_DIST_SITE_PATH = $(SYNOLOGY_DOWNLOAD_URL)/toolchain/DSM$(TC_VERS)
TC_DIST_NAME = $(TC_DIST_SITE_PATH)/Intel%20x86%20Linux%204.4.302%20%28x86_64-GPL%29.txz

include ../../mk/spksrc.toolchain.mk

tc_vars Files

The toolchain build generates several tc_vars*.mk files that configure cross-compilation:

tc_vars.mk

Core toolchain identity:

TC_NAME     = x86_64-pc-linux-gnu
TC_PREFIX   = /path/to/toolchain/work/x86_64-pc-linux-gnu/bin/
TC_PATH     = $(TC_PREFIX)/bin
TC_SYSROOT  = $(TC_PREFIX)/x86_64-pc-linux-gnu/sysroot
TC_CC       = $(TC_PREFIX)x86_64-pc-linux-gnu-gcc
TC_CXX      = $(TC_PREFIX)x86_64-pc-linux-gnu-g++
TC_AR       = $(TC_PREFIX)x86_64-pc-linux-gnu-ar
TC_LD       = $(TC_PREFIX)x86_64-pc-linux-gnu-ld
TC_STRIP    = $(TC_PREFIX)x86_64-pc-linux-gnu-strip

tc_vars.autotools.mk

Autotools (configure) adapter:

GNU_CONFIGURE = 1
CONFIGURE_ARGS = --host=$(TC_NAME) --build=$(TC_BUILD)

tc_vars.flags.mk

Compiler and linker flags:

CFLAGS   = -I$(STAGING_INSTALL_PREFIX)/include
CXXFLAGS = $(CFLAGS)
LDFLAGS  = -L$(STAGING_INSTALL_PREFIX)/lib -Wl,-rpath,$(INSTALL_PREFIX)/lib

tc_vars.cmake

CMake toolchain file for cross-compilation:

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR x86_64)
set(CMAKE_C_COMPILER /path/to/x86_64-pc-linux-gnu-gcc)
set(CMAKE_CXX_COMPILER /path/to/x86_64-pc-linux-gnu-g++)
set(CMAKE_SYSROOT /path/to/sysroot)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

tc_vars.meson-cross and tc_vars.meson-native

Meson cross and native files:

# tc_vars.meson-cross
[binaries]
c = '/path/to/x86_64-pc-linux-gnu-gcc'
cpp = '/path/to/x86_64-pc-linux-gnu-g++'
ar = '/path/to/x86_64-pc-linux-gnu-ar'
strip = '/path/to/x86_64-pc-linux-gnu-strip'
pkgconfig = '/usr/bin/pkg-config'

[host_machine]
system = 'linux'
cpu_family = 'x86_64'
cpu = 'x86_64'
endian = 'little'

tc_vars.rust.mk

Rust cross-compilation settings:

CARGO_TARGET = x86_64-unknown-linux-gnu
RUSTFLAGS = -C linker=$(TC_CC)

Supported Architectures

spksrc supports the following architecture families:

64-bit Architectures

Architecture CPU Family Common Models
x64 Intel 64-bit DS923+, DS1621+, RS1221+
aarch64 ARM 64-bit DS223, DS423+, RS422+

32-bit Architectures (Legacy)

Architecture CPU Family Common Models
armv7 ARM 32-bit DS218, DS418
i686 Intel 32-bit DS216j, DS218j

Generic Architectures

Generic architectures build for multiple targets:

Generic Expands To
arm5 88f6281, 88f6282
arm7 alpine, alpine4k, armada370, armada375, armada38x, armadaxp, comcerto2k, monaco
arm8 rtd1296, rtd1619b, armv8
ppc ppc853x, ppc854x, qoriq

Adding New Toolchain Support

When Synology releases a new DSM version:

  1. Create toolchain directory: 

    mkdir toolchain/syno-x64-8.0

  2. Create Makefile: 

    TC_NAME  = x86_64-pc-linux-gnu
TC_VERS  = 8.0
TC_ARCH  = x64
TC_DIST_SITE_PATH = $(SYNOLOGY_DOWNLOAD_URL)/toolchain/DSM$(TC_VERS)
TC_DIST_NAME = $(TC_DIST_SITE_PATH)/Intel%20x86%20Linux%20...%20%28x86_64-GPL%29.txz

include ../../mk/spksrc.toolchain.mk

  3. Create digests file with SHA256 checksums

  4. Test build: 

    make -C spk/transmission ARCH=x64 TCVERSION=8.0

Toolchain Build Process

The toolchain build follows this process:

  1. Download - Fetches toolchain archive from Synology
  2. Checksum - Verifies archive integrity
  3. Extract - Unpacks to work/ directory
  4. Normalize - Applies patches for compatibility
  5. Rust - Installs Rust toolchain components if needed
  6. tcvars - Generates tc_vars*.mk files

Caching

Toolchains are cached in the distrib/ directory:

distrib/
└── toolchain/
    ├── Intel x86 Linux 4.4.302 (x86_64-GPL).txz
    ├── Realtek RTD1296 Linux 4.4.180 (aarch64-GPL).txz
    └── ...

Once downloaded, toolchains are reused across builds. Delete from distrib/ to force re-download.

Troubleshooting

Toolchain Download Fails

Check if the URL is still valid: 

grep TC_DIST_NAME toolchain/syno-x64-7.2/Makefile
# Verify URL accessibility

tc_vars Not Generated

Remove the tcvars cookie and rebuild: 

rm toolchain/syno-x64-7.2/work/.tcvars_done
make -C toolchain/syno-x64-7.2 tcvars

Cross-Compiler Not Found

Ensure the toolchain is fully extracted: 

ls toolchain/syno-x64-7.2/work/x86_64-pc-linux-gnu/bin/