b3624e40df
Add extension that enables 32-bit compat vDSO for arm64 kernels. Without vDSO, 32-bit applications using gettimeofday() syscall heavily suffer significant performance penalty on arm64 systems. The extension: - Adds gcc-arm-linux-gnueabi as build dependency - Sets CROSS_COMPILE_COMPAT for kernel make - Enables CONFIG_COMPAT_VDSO in kernel config Enable with: ENABLE_EXTENSIONS=arm64-compat-vdso Refs: https://github.com/armbian/build/issues/9216 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
55 lines
1.9 KiB
Bash
55 lines
1.9 KiB
Bash
# Enable 32-bit compat vDSO for arm64 kernels with GCC or clang.
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# Requirements:
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# - arm64 build target (ARCH=arm64, ARCHITECTURE=arm64).
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# - For GCC builds: a 32-bit ARM cross-compiler (default prefix arm-linux-gnueabi-),
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# available as ${CROSS_COMPILE_COMPAT}gcc; install gcc-arm-linux-gnueabi or set CROSS_COMPILE_COMPAT.
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# - For clang builds: clang present; compat vDSO is built via clang --target=arm-linux-gnueabi.
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function extension_prepare_config__arm64_compat_vdso() {
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if [[ "${ARCH}" != "arm64" || "${ARCHITECTURE}" != "arm64" ]]; then
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exit_with_error "arm64-only extension: ARCH=${ARCH} ARCHITECTURE=${ARCHITECTURE}"
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fi
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}
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function add_host_dependencies__arm64_compat_vdso() {
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if [[ "${KERNEL_COMPILER}" == "clang" ]]; then
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EXTRA_BUILD_DEPS+=" clang "
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else
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EXTRA_BUILD_DEPS+=" gcc-arm-linux-gnueabi "
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fi
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}
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function host_dependencies_ready__arm64_compat_vdso() {
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if [[ "${KERNEL_COMPILER}" == "clang" ]]; then
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return 0
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fi
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local compat_gcc_prefix="${CROSS_COMPILE_COMPAT:-"arm-linux-gnueabi-"}"
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if ! command -v "${compat_gcc_prefix}gcc" >/dev/null 2>&1; then
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exit_with_error "Missing 32-bit compiler '${compat_gcc_prefix}gcc' for COMPAT_VDSO; install gcc-arm-linux-gnueabi or set CROSS_COMPILE_COMPAT"
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fi
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}
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function custom_kernel_make_params__arm64_compat_vdso() {
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if [[ "${KERNEL_COMPILER}" == "clang" ]]; then
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return 0
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fi
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local compat_gcc_compiler="${CROSS_COMPILE_COMPAT:-"arm-linux-gnueabi-"}"
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common_make_params_quoted+=("CROSS_COMPILE_COMPAT=${compat_gcc_compiler}")
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display_alert "arm64-compat-vdso" "Adding CROSS_COMPILE_COMPAT=${compat_gcc_compiler}" "info"
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}
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function custom_kernel_config__arm64_compat_vdso() {
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local kconfig_hit=""
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opts_y+=("COMPAT" "COMPAT_VDSO" "ARM64_32BIT_EL0")
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if [[ -f .config ]]; then
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kconfig_hit="$(grep -R -n -m1 "COMPAT_VDSO" arch/arm64 Kconfig* 2>/dev/null || true)"
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if [[ -z "${kconfig_hit}" ]]; then
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exit_with_error "Selected kernel tree lacks COMPAT_VDSO support for arm64"
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fi
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fi
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}
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