Several architectures provide an API to enable the FPU and run floating-point SIMD code in kernel space. However, the function names, header locations, and semantics are inconsistent across architectures, and FPU support may be gated behind other Kconfig options. Provide a standard way for architectures to declare that kernel space FPU support is available. Architectures selecting this option must implement what is currently the most common API (kernel_fpu_begin() and kernel_fpu_end(), plus a new function kernel_fpu_available()) and provide the appropriate CFLAGS for compiling floating-point C code. Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx> Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx> --- Makefile | 4 ++++ arch/Kconfig | 9 +++++++++ 2 files changed, 13 insertions(+) diff --git a/Makefile b/Makefile index 511b5616aa41..e65c186cf2c9 100644 --- a/Makefile +++ b/Makefile @@ -969,6 +969,10 @@ KBUILD_CFLAGS += $(CC_FLAGS_CFI) export CC_FLAGS_CFI endif +# Architectures can define flags to add/remove for floating-point support +export CC_FLAGS_FPU +export CC_FLAGS_NO_FPU + ifneq ($(CONFIG_FUNCTION_ALIGNMENT),0) KBUILD_CFLAGS += -falign-functions=$(CONFIG_FUNCTION_ALIGNMENT) endif diff --git a/arch/Kconfig b/arch/Kconfig index f4b210ab0612..6df834e18e9c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1478,6 +1478,15 @@ config ARCH_HAS_NONLEAF_PMD_YOUNG address translations. Page table walkers that clear the accessed bit may use this capability to reduce their search space. +config ARCH_HAS_KERNEL_FPU_SUPPORT + bool + help + An architecture should select this option if it supports running + floating-point code in kernel space. It must export the functions + kernel_fpu_available(), kernel_fpu_begin(), and kernel_fpu_end() from + <asm/fpu.h>, and define CC_FLAGS_FPU and/or CC_FLAGS_NO_FPU as + necessary in its Makefile. + source "kernel/gcov/Kconfig" source "scripts/gcc-plugins/Kconfig" -- 2.42.0
