* [PATCH v3 01/14] arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 02/14] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
` (12 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-doc, Catalin Marinas, Dave Hansen, linux-riscv,
Will Deacon, Christoph Hellwig, linux-arch, Jonathan Corbet,
Masahiro Yamada, Huacai Chen, Russell King, amd-gfx, Ingo Molnar,
Nicolas Schier, linux-kbuild, Nathan Chancellor, Borislav Petkov,
loongarch, Thomas Gleixner, linux-kernel, Samuel Holland,
linuxppc-dev
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@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- Add documentation explaining the built-time and runtime APIs
- Add a linux/fpu.h header for generic isolation enforcement
Documentation/core-api/floating-point.rst | 78 +++++++++++++++++++++++
Documentation/core-api/index.rst | 1 +
Makefile | 5 ++
arch/Kconfig | 6 ++
include/linux/fpu.h | 12 ++++
5 files changed, 102 insertions(+)
create mode 100644 Documentation/core-api/floating-point.rst
create mode 100644 include/linux/fpu.h
diff --git a/Documentation/core-api/floating-point.rst b/Documentation/core-api/floating-point.rst
new file mode 100644
index 000000000000..a8d0d4b05052
--- /dev/null
+++ b/Documentation/core-api/floating-point.rst
@@ -0,0 +1,78 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Floating-point API
+==================
+
+Kernel code is normally prohibited from using floating-point (FP) registers or
+instructions, including the C float and double data types. This rule reduces
+system call overhead, because the kernel does not need to save and restore the
+userspace floating-point register state.
+
+However, occasionally drivers or library functions may need to include FP code.
+This is supported by isolating the functions containing FP code to a separate
+translation unit (a separate source file), and saving/restoring the FP register
+state around calls to those functions. This creates "critical sections" of
+floating-point usage.
+
+The reason for this isolation is to prevent the compiler from generating code
+touching the FP registers outside these critical sections. Compilers sometimes
+use FP registers to optimize inlined ``memcpy`` or variable assignment, as
+floating-point registers may be wider than general-purpose registers.
+
+Usability of floating-point code within the kernel is architecture-specific.
+Additionally, because a single kernel may be configured to support platforms
+both with and without a floating-point unit, FPU availability must be checked
+both at build time and at run time.
+
+Several architectures implement the generic kernel floating-point API from
+``linux/fpu.h``, as described below. Some other architectures implement their
+own unique APIs, which are documented separately.
+
+Build-time API
+--------------
+
+Floating-point code may be built if the option ``ARCH_HAS_KERNEL_FPU_SUPPORT``
+is enabled. For C code, such code must be placed in a separate file, and that
+file must have its compilation flags adjusted using the following pattern::
+
+ CFLAGS_foo.o += $(CC_FLAGS_FPU)
+ CFLAGS_REMOVE_foo.o += $(CC_FLAGS_NO_FPU)
+
+Architectures are expected to define one or both of these variables in their
+top-level Makefile as needed. For example::
+
+ CC_FLAGS_FPU := -mhard-float
+
+or::
+
+ CC_FLAGS_NO_FPU := -msoft-float
+
+Normal kernel code is assumed to use the equivalent of ``CC_FLAGS_NO_FPU``.
+
+Runtime API
+-----------
+
+The runtime API is provided in ``linux/fpu.h``. This header cannot be included
+from files implementing FP code (those with their compilation flags adjusted as
+above). Instead, it must be included when defining the FP critical sections.
+
+.. c:function:: bool kernel_fpu_available( void )
+
+ This function reports if floating-point code can be used on this CPU or
+ platform. The value returned by this function is not expected to change
+ at runtime, so it only needs to be called once, not before every
+ critical section.
+
+.. c:function:: void kernel_fpu_begin( void )
+ void kernel_fpu_end( void )
+
+ These functions create a floating-point critical section. It is only
+ valid to call ``kernel_fpu_begin()`` after a previous call to
+ ``kernel_fpu_available()`` returned ``true``. These functions are only
+ guaranteed to be callable from (preemptible or non-preemptible) process
+ context.
+
+ Preemption may be disabled inside critical sections, so their size
+ should be minimized. They are *not* required to be reentrant. If the
+ caller expects to nest critical sections, it must implement its own
+ reference counting.
diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst
index 7a3a08d81f11..974beccd671f 100644
--- a/Documentation/core-api/index.rst
+++ b/Documentation/core-api/index.rst
@@ -48,6 +48,7 @@ Library functionality that is used throughout the kernel.
errseq
wrappers/atomic_t
wrappers/atomic_bitops
+ floating-point
Low level entry and exit
========================
diff --git a/Makefile b/Makefile
index 763b6792d3d5..710f65e4249d 100644
--- a/Makefile
+++ b/Makefile
@@ -964,6 +964,11 @@ KBUILD_CFLAGS += $(CC_FLAGS_CFI)
export CC_FLAGS_CFI
endif
+# Architectures can define flags to add/remove for floating-point support
+CC_FLAGS_FPU += -D_LINUX_FPU_COMPILATION_UNIT
+export CC_FLAGS_FPU
+export CC_FLAGS_NO_FPU
+
ifneq ($(CONFIG_FUNCTION_ALIGNMENT),0)
# Set the minimal function alignment. Use the newer GCC option
# -fmin-function-alignment if it is available, or fall back to -falign-funtions.
diff --git a/arch/Kconfig b/arch/Kconfig
index 9f066785bb71..8e34b3acf73d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1569,6 +1569,12 @@ 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
+ Architectures that select this option can run floating-point code in
+ the kernel, as described in Documentation/core-api/floating-point.rst.
+
source "kernel/gcov/Kconfig"
source "scripts/gcc-plugins/Kconfig"
diff --git a/include/linux/fpu.h b/include/linux/fpu.h
new file mode 100644
index 000000000000..2fb63e22913b
--- /dev/null
+++ b/include/linux/fpu.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_FPU_H
+#define _LINUX_FPU_H
+
+#ifdef _LINUX_FPU_COMPILATION_UNIT
+#error FP code must be compiled separately. See Documentation/core-api/floating-point.rst.
+#endif
+
+#include <asm/fpu.h>
+
+#endif
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 02/14] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
2024-03-27 20:00 ` [PATCH v3 01/14] arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 03/14] ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
` (11 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
Russell King, linux-riscv, linuxppc-dev, Christoph Hellwig
ARM provides an equivalent to the common kernel-mode FPU API, but in a
different header and using different function names. Add a wrapper
header, and export CFLAGS adjustments as found in lib/raid6/Makefile.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- Remove file name from header comment
arch/arm/Kconfig | 1 +
arch/arm/Makefile | 7 +++++++
arch/arm/include/asm/fpu.h | 15 +++++++++++++++
3 files changed, 23 insertions(+)
create mode 100644 arch/arm/include/asm/fpu.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b14aed3a17ab..b1751c2cab87 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -15,6 +15,7 @@ config ARM
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index d82908b1b1bb..71afdd98ddf2 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -130,6 +130,13 @@ endif
# Accept old syntax despite ".syntax unified"
AFLAGS_NOWARN :=$(call as-option,-Wa$(comma)-mno-warn-deprecated,-Wa$(comma)-W)
+# The GCC option -ffreestanding is required in order to compile code containing
+# ARM/NEON intrinsics in a non C99-compliant environment (such as the kernel)
+CC_FLAGS_FPU := -ffreestanding
+# Enable <arm_neon.h>
+CC_FLAGS_FPU += -isystem $(shell $(CC) -print-file-name=include)
+CC_FLAGS_FPU += -march=armv7-a -mfloat-abi=softfp -mfpu=neon
+
ifeq ($(CONFIG_THUMB2_KERNEL),y)
CFLAGS_ISA :=-Wa,-mimplicit-it=always $(AFLAGS_NOWARN)
AFLAGS_ISA :=$(CFLAGS_ISA) -Wa$(comma)-mthumb
diff --git a/arch/arm/include/asm/fpu.h b/arch/arm/include/asm/fpu.h
new file mode 100644
index 000000000000..2ae50bdce59b
--- /dev/null
+++ b/arch/arm/include/asm/fpu.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef __ASM_FPU_H
+#define __ASM_FPU_H
+
+#include <asm/neon.h>
+
+#define kernel_fpu_available() cpu_has_neon()
+#define kernel_fpu_begin() kernel_neon_begin()
+#define kernel_fpu_end() kernel_neon_end()
+
+#endif /* ! __ASM_FPU_H */
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 03/14] ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
2024-03-27 20:00 ` [PATCH v3 01/14] arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-27 20:00 ` [PATCH v3 02/14] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 04/14] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
` (10 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
Russell King, linux-riscv, linuxppc-dev, Christoph Hellwig
Now that CC_FLAGS_FPU is exported and can be used anywhere in the source
tree, use it instead of duplicating the flags here.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v1)
arch/arm/lib/Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 650404be6768..0ca5aae1bcc3 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -40,8 +40,7 @@ $(obj)/csumpartialcopy.o: $(obj)/csumpartialcopygeneric.S
$(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S
ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
- NEON_FLAGS := -march=armv7-a -mfloat-abi=softfp -mfpu=neon
- CFLAGS_xor-neon.o += $(NEON_FLAGS)
+ CFLAGS_xor-neon.o += $(CC_FLAGS_FPU)
obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o
endif
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 04/14] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (2 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 03/14] ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 05/14] arm64: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
` (9 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, Will Deacon, Catalin Marinas, linux-kernel, amd-gfx,
Samuel Holland, loongarch, linux-riscv, linuxppc-dev,
Christoph Hellwig
arm64 provides an equivalent to the common kernel-mode FPU API, but in a
different header and using different function names. Add a wrapper
header, and export CFLAGS adjustments as found in lib/raid6/Makefile.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- Remove file name from header comment
arch/arm64/Kconfig | 1 +
arch/arm64/Makefile | 9 ++++++++-
arch/arm64/include/asm/fpu.h | 15 +++++++++++++++
3 files changed, 24 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/include/asm/fpu.h
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7b11c98b3e84..67f0d3b5b7df 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -30,6 +30,7 @@ config ARM64
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 0e075d3c546b..3e863e5b0169 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -36,7 +36,14 @@ ifeq ($(CONFIG_BROKEN_GAS_INST),y)
$(warning Detected assembler with broken .inst; disassembly will be unreliable)
endif
-KBUILD_CFLAGS += -mgeneral-regs-only \
+# The GCC option -ffreestanding is required in order to compile code containing
+# ARM/NEON intrinsics in a non C99-compliant environment (such as the kernel)
+CC_FLAGS_FPU := -ffreestanding
+# Enable <arm_neon.h>
+CC_FLAGS_FPU += -isystem $(shell $(CC) -print-file-name=include)
+CC_FLAGS_NO_FPU := -mgeneral-regs-only
+
+KBUILD_CFLAGS += $(CC_FLAGS_NO_FPU) \
$(compat_vdso) $(cc_has_k_constraint)
KBUILD_CFLAGS += $(call cc-disable-warning, psabi)
KBUILD_AFLAGS += $(compat_vdso)
diff --git a/arch/arm64/include/asm/fpu.h b/arch/arm64/include/asm/fpu.h
new file mode 100644
index 000000000000..2ae50bdce59b
--- /dev/null
+++ b/arch/arm64/include/asm/fpu.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef __ASM_FPU_H
+#define __ASM_FPU_H
+
+#include <asm/neon.h>
+
+#define kernel_fpu_available() cpu_has_neon()
+#define kernel_fpu_begin() kernel_neon_begin()
+#define kernel_fpu_end() kernel_neon_end()
+
+#endif /* ! __ASM_FPU_H */
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 05/14] arm64: crypto: Use CC_FLAGS_FPU for NEON CFLAGS
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (3 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 04/14] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 06/14] lib/raid6: " Samuel Holland
` (8 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, Will Deacon, Catalin Marinas, linux-kernel, amd-gfx,
Samuel Holland, loongarch, linux-riscv, linuxppc-dev,
Christoph Hellwig
Now that CC_FLAGS_FPU is exported and can be used anywhere in the source
tree, use it instead of duplicating the flags here.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- New patch for v2
arch/arm64/lib/Makefile | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
index 29490be2546b..13e6a2829116 100644
--- a/arch/arm64/lib/Makefile
+++ b/arch/arm64/lib/Makefile
@@ -7,10 +7,8 @@ lib-y := clear_user.o delay.o copy_from_user.o \
ifeq ($(CONFIG_KERNEL_MODE_NEON), y)
obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o
-CFLAGS_REMOVE_xor-neon.o += -mgeneral-regs-only
-CFLAGS_xor-neon.o += -ffreestanding
-# Enable <arm_neon.h>
-CFLAGS_xor-neon.o += -isystem $(shell $(CC) -print-file-name=include)
+CFLAGS_xor-neon.o += $(CC_FLAGS_FPU)
+CFLAGS_REMOVE_xor-neon.o += $(CC_FLAGS_NO_FPU)
endif
lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 06/14] lib/raid6: Use CC_FLAGS_FPU for NEON CFLAGS
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (4 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 05/14] arm64: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 07/14] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
` (7 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, Will Deacon, Catalin Marinas, linux-kernel, amd-gfx,
Samuel Holland, loongarch, Russell King, linux-riscv,
linuxppc-dev, Christoph Hellwig
Now that CC_FLAGS_FPU is exported and can be used anywhere in the source
tree, use it instead of duplicating the flags here.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v1)
lib/raid6/Makefile | 31 ++++++++-----------------------
1 file changed, 8 insertions(+), 23 deletions(-)
diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile
index 385a94aa0b99..c71984e04c4d 100644
--- a/lib/raid6/Makefile
+++ b/lib/raid6/Makefile
@@ -33,25 +33,6 @@ CFLAGS_REMOVE_vpermxor8.o += -msoft-float
endif
endif
-# The GCC option -ffreestanding is required in order to compile code containing
-# ARM/NEON intrinsics in a non C99-compliant environment (such as the kernel)
-ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
-NEON_FLAGS := -ffreestanding
-# Enable <arm_neon.h>
-NEON_FLAGS += -isystem $(shell $(CC) -print-file-name=include)
-ifeq ($(ARCH),arm)
-NEON_FLAGS += -march=armv7-a -mfloat-abi=softfp -mfpu=neon
-endif
-CFLAGS_recov_neon_inner.o += $(NEON_FLAGS)
-ifeq ($(ARCH),arm64)
-CFLAGS_REMOVE_recov_neon_inner.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon2.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon4.o += -mgeneral-regs-only
-CFLAGS_REMOVE_neon8.o += -mgeneral-regs-only
-endif
-endif
-
quiet_cmd_unroll = UNROLL $@
cmd_unroll = $(AWK) -v N=$* -f $(srctree)/$(src)/unroll.awk < $< > $@
@@ -75,10 +56,14 @@ targets += vpermxor1.c vpermxor2.c vpermxor4.c vpermxor8.c
$(obj)/vpermxor%.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
$(call if_changed,unroll)
-CFLAGS_neon1.o += $(NEON_FLAGS)
-CFLAGS_neon2.o += $(NEON_FLAGS)
-CFLAGS_neon4.o += $(NEON_FLAGS)
-CFLAGS_neon8.o += $(NEON_FLAGS)
+CFLAGS_neon1.o += $(CC_FLAGS_FPU)
+CFLAGS_neon2.o += $(CC_FLAGS_FPU)
+CFLAGS_neon4.o += $(CC_FLAGS_FPU)
+CFLAGS_neon8.o += $(CC_FLAGS_FPU)
+CFLAGS_REMOVE_neon1.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_neon2.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_neon4.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_neon8.o += $(CC_FLAGS_NO_FPU)
targets += neon1.c neon2.c neon4.c neon8.c
$(obj)/neon%.c: $(src)/neon.uc $(src)/unroll.awk FORCE
$(call if_changed,unroll)
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 07/14] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (5 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 06/14] lib/raid6: " Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 08/14] powerpc: " Samuel Holland
` (6 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, Huacai Chen, linux-kernel, amd-gfx, Samuel Holland,
loongarch, WANG Xuerui, linux-riscv, linuxppc-dev,
Christoph Hellwig
LoongArch already provides kernel_fpu_begin() and kernel_fpu_end() in
asm/fpu.h, so it only needs to add kernel_fpu_available() and export
the CFLAGS adjustments.
Acked-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
Changes in v3:
- Rebase on v6.9-rc1
arch/loongarch/Kconfig | 1 +
arch/loongarch/Makefile | 5 ++++-
arch/loongarch/include/asm/fpu.h | 1 +
3 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index a5f300ec6f28..2266c6c41c38 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -18,6 +18,7 @@ config LOONGARCH
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if CPU_HAS_FPU
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_SPECIAL
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index df6caf79537a..efb5440a43ec 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -26,6 +26,9 @@ endif
32bit-emul = elf32loongarch
64bit-emul = elf64loongarch
+CC_FLAGS_FPU := -mfpu=64
+CC_FLAGS_NO_FPU := -msoft-float
+
ifdef CONFIG_UNWINDER_ORC
orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
orc_hash_sh := $(srctree)/scripts/orc_hash.sh
@@ -59,7 +62,7 @@ ld-emul = $(64bit-emul)
cflags-y += -mabi=lp64s
endif
-cflags-y += -pipe -msoft-float
+cflags-y += -pipe $(CC_FLAGS_NO_FPU)
LDFLAGS_vmlinux += -static -n -nostdlib
# When the assembler supports explicit relocation hint, we must use it.
diff --git a/arch/loongarch/include/asm/fpu.h b/arch/loongarch/include/asm/fpu.h
index c2d8962fda00..3177674228f8 100644
--- a/arch/loongarch/include/asm/fpu.h
+++ b/arch/loongarch/include/asm/fpu.h
@@ -21,6 +21,7 @@
struct sigcontext;
+#define kernel_fpu_available() cpu_has_fpu
extern void kernel_fpu_begin(void);
extern void kernel_fpu_end(void);
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 08/14] powerpc: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (6 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 07/14] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 09/14] x86: " Samuel Holland
` (5 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
linux-riscv, linuxppc-dev, Christoph Hellwig
PowerPC provides an equivalent to the common kernel-mode FPU API, but in
a different header and using different function names. The PowerPC API
also requires a non-preemptible context. Add a wrapper header, and
export the CFLAGS adjustments.
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v1)
arch/powerpc/Kconfig | 1 +
arch/powerpc/Makefile | 5 ++++-
arch/powerpc/include/asm/fpu.h | 28 ++++++++++++++++++++++++++++
3 files changed, 33 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/include/asm/fpu.h
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 1c4be3373686..c42a57b6839d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -137,6 +137,7 @@ config PPC
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_HUGEPD if HUGETLB_PAGE
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if PPC_FPU
select ARCH_HAS_MEMBARRIER_CALLBACKS
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_MEMREMAP_COMPAT_ALIGN if PPC_64S_HASH_MMU
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 65261cbe5bfd..93d89f055b70 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -153,6 +153,9 @@ CFLAGS-$(CONFIG_PPC32) += $(call cc-option, $(MULTIPLEWORD))
CFLAGS-$(CONFIG_PPC32) += $(call cc-option,-mno-readonly-in-sdata)
+CC_FLAGS_FPU := $(call cc-option,-mhard-float)
+CC_FLAGS_NO_FPU := $(call cc-option,-msoft-float)
+
ifdef CONFIG_FUNCTION_TRACER
ifdef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
@@ -174,7 +177,7 @@ asinstr := $(call as-instr,lis 9$(comma)foo@high,-DHAVE_AS_ATHIGH=1)
KBUILD_CPPFLAGS += -I $(srctree)/arch/powerpc $(asinstr)
KBUILD_AFLAGS += $(AFLAGS-y)
-KBUILD_CFLAGS += $(call cc-option,-msoft-float)
+KBUILD_CFLAGS += $(CC_FLAGS_NO_FPU)
KBUILD_CFLAGS += $(CFLAGS-y)
CPP = $(CC) -E $(KBUILD_CFLAGS)
diff --git a/arch/powerpc/include/asm/fpu.h b/arch/powerpc/include/asm/fpu.h
new file mode 100644
index 000000000000..ca584e4bc40f
--- /dev/null
+++ b/arch/powerpc/include/asm/fpu.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef _ASM_POWERPC_FPU_H
+#define _ASM_POWERPC_FPU_H
+
+#include <linux/preempt.h>
+
+#include <asm/cpu_has_feature.h>
+#include <asm/switch_to.h>
+
+#define kernel_fpu_available() (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
+
+static inline void kernel_fpu_begin(void)
+{
+ preempt_disable();
+ enable_kernel_fp();
+}
+
+static inline void kernel_fpu_end(void)
+{
+ disable_kernel_fp();
+ preempt_enable();
+}
+
+#endif /* ! _ASM_POWERPC_FPU_H */
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 09/14] x86: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (7 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 08/14] powerpc: " Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 10/14] riscv: Add support for kernel-mode FPU Samuel Holland
` (4 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, Thomas Gleixner, Dave Hansen, linux-kernel, amd-gfx,
Samuel Holland, Ingo Molnar, Borislav Petkov, loongarch,
linux-riscv, linuxppc-dev, Christoph Hellwig
x86 already provides kernel_fpu_begin() and kernel_fpu_end(), but in a
different header. Add a wrapper header, and export the CFLAGS
adjustments as found in lib/Makefile.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v1)
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 20 ++++++++++++++++++++
arch/x86/include/asm/fpu.h | 13 +++++++++++++
3 files changed, 34 insertions(+)
create mode 100644 arch/x86/include/asm/fpu.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 39886bab943a..7c9d032ee675 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -83,6 +83,7 @@ config X86
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV if X86_64
+ select ARCH_HAS_KERNEL_FPU_SUPPORT
select ARCH_HAS_MEM_ENCRYPT
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 662d9d4033e6..5a5f5999c505 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -74,6 +74,26 @@ KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
+#
+# CFLAGS for compiling floating point code inside the kernel.
+#
+CC_FLAGS_FPU := -msse -msse2
+ifdef CONFIG_CC_IS_GCC
+# Stack alignment mismatch, proceed with caution.
+# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
+# (8B stack alignment).
+# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
+#
+# The "-msse" in the first argument is there so that the
+# -mpreferred-stack-boundary=3 build error:
+#
+# -mpreferred-stack-boundary=3 is not between 4 and 12
+#
+# can be triggered. Otherwise gcc doesn't complain.
+CC_FLAGS_FPU += -mhard-float
+CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
+endif
+
ifeq ($(CONFIG_X86_KERNEL_IBT),y)
#
# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
diff --git a/arch/x86/include/asm/fpu.h b/arch/x86/include/asm/fpu.h
new file mode 100644
index 000000000000..b2743fe19339
--- /dev/null
+++ b/arch/x86/include/asm/fpu.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef _ASM_X86_FPU_H
+#define _ASM_X86_FPU_H
+
+#include <asm/fpu/api.h>
+
+#define kernel_fpu_available() true
+
+#endif /* ! _ASM_X86_FPU_H */
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 10/14] riscv: Add support for kernel-mode FPU
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (8 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 09/14] x86: " Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 11/14] drm/amd/display: Only use hard-float, not altivec on powerpc Samuel Holland
` (3 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland,
Palmer Dabbelt, loongarch, linux-riscv, linuxppc-dev,
Christoph Hellwig
This is motivated by the amdgpu DRM driver, which needs floating-point
code to support recent hardware. That code is not performance-critical,
so only provide a minimal non-preemptible implementation for now.
Support is limited to riscv64 because riscv32 requires runtime (libgcc)
assistance to convert between doubles and 64-bit integers.
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
Changes in v3:
- Rebase on v6.9-rc1
- Limit ARCH_HAS_KERNEL_FPU_SUPPORT to 64BIT
Changes in v2:
- Remove RISC-V architecture-specific preprocessor check
arch/riscv/Kconfig | 1 +
arch/riscv/Makefile | 3 +++
arch/riscv/include/asm/fpu.h | 16 ++++++++++++++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/kernel_mode_fpu.c | 28 ++++++++++++++++++++++++++++
5 files changed, 49 insertions(+)
create mode 100644 arch/riscv/include/asm/fpu.h
create mode 100644 arch/riscv/kernel/kernel_mode_fpu.c
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index be09c8836d56..3bcd0d250810 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -27,6 +27,7 @@ config RISCV
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if 64BIT && FPU
select ARCH_HAS_MEMBARRIER_CALLBACKS
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_MMIOWB
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 252d63942f34..76ff4033c854 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -84,6 +84,9 @@ KBUILD_CFLAGS += -march=$(shell echo $(riscv-march-y) | sed -E 's/(rv32ima|rv64i
KBUILD_AFLAGS += -march=$(riscv-march-y)
+# For C code built with floating-point support, exclude V but keep F and D.
+CC_FLAGS_FPU := -march=$(shell echo $(riscv-march-y) | sed -E 's/(rv32ima|rv64ima)([^v_]*)v?/\1\2/')
+
KBUILD_CFLAGS += -mno-save-restore
KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
diff --git a/arch/riscv/include/asm/fpu.h b/arch/riscv/include/asm/fpu.h
new file mode 100644
index 000000000000..91c04c244e12
--- /dev/null
+++ b/arch/riscv/include/asm/fpu.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef _ASM_RISCV_FPU_H
+#define _ASM_RISCV_FPU_H
+
+#include <asm/switch_to.h>
+
+#define kernel_fpu_available() has_fpu()
+
+void kernel_fpu_begin(void);
+void kernel_fpu_end(void);
+
+#endif /* ! _ASM_RISCV_FPU_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 81d94a8ee10f..5b243d46f4b1 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_RISCV_MISALIGNED) += unaligned_access_speed.o
obj-$(CONFIG_RISCV_PROBE_UNALIGNED_ACCESS) += copy-unaligned.o
obj-$(CONFIG_FPU) += fpu.o
+obj-$(CONFIG_FPU) += kernel_mode_fpu.o
obj-$(CONFIG_RISCV_ISA_V) += vector.o
obj-$(CONFIG_RISCV_ISA_V) += kernel_mode_vector.o
obj-$(CONFIG_SMP) += smpboot.o
diff --git a/arch/riscv/kernel/kernel_mode_fpu.c b/arch/riscv/kernel/kernel_mode_fpu.c
new file mode 100644
index 000000000000..0ac8348876c4
--- /dev/null
+++ b/arch/riscv/kernel/kernel_mode_fpu.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#include <linux/export.h>
+#include <linux/preempt.h>
+
+#include <asm/csr.h>
+#include <asm/fpu.h>
+#include <asm/processor.h>
+#include <asm/switch_to.h>
+
+void kernel_fpu_begin(void)
+{
+ preempt_disable();
+ fstate_save(current, task_pt_regs(current));
+ csr_set(CSR_SSTATUS, SR_FS);
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_begin);
+
+void kernel_fpu_end(void)
+{
+ csr_clear(CSR_SSTATUS, SR_FS);
+ fstate_restore(current, task_pt_regs(current));
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_end);
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 11/14] drm/amd/display: Only use hard-float, not altivec on powerpc
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (9 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 10/14] riscv: Add support for kernel-mode FPU Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 12/14] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
` (2 subsequent siblings)
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
Alex Deucher, linux-riscv, linuxppc-dev, Christoph Hellwig
From: Michael Ellerman <mpe@ellerman.id.au>
The compiler flags enable altivec, but that is not required; hard-float
is sufficient for the code to build and function.
Drop altivec from the compiler flags and adjust the enable/disable code
to only enable FPU use.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- New patch for v2
drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 12 ++----------
drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
drivers/gpu/drm/amd/display/dc/dml2/Makefile | 2 +-
3 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
index 4ae4720535a5..0de16796466b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
@@ -92,11 +92,7 @@ void dc_fpu_begin(const char *function_name, const int line)
#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
kernel_fpu_begin();
#elif defined(CONFIG_PPC64)
- if (cpu_has_feature(CPU_FTR_VSX_COMP))
- enable_kernel_vsx();
- else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP))
- enable_kernel_altivec();
- else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
+ if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
enable_kernel_fp();
#elif defined(CONFIG_ARM64)
kernel_neon_begin();
@@ -125,11 +121,7 @@ void dc_fpu_end(const char *function_name, const int line)
#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
kernel_fpu_end();
#elif defined(CONFIG_PPC64)
- if (cpu_has_feature(CPU_FTR_VSX_COMP))
- disable_kernel_vsx();
- else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP))
- disable_kernel_altivec();
- else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
+ if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
disable_kernel_fp();
#elif defined(CONFIG_ARM64)
kernel_neon_end();
diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
index c4a5efd2dda5..59d3972341d2 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
@@ -31,7 +31,7 @@ dml_ccflags := $(dml_ccflags-y) -msse
endif
ifdef CONFIG_PPC64
-dml_ccflags := -mhard-float -maltivec
+dml_ccflags := -mhard-float
endif
ifdef CONFIG_ARM64
diff --git a/drivers/gpu/drm/amd/display/dc/dml2/Makefile b/drivers/gpu/drm/amd/display/dc/dml2/Makefile
index acff3449b8d7..7b51364084b5 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml2/Makefile
@@ -30,7 +30,7 @@ dml2_ccflags := $(dml2_ccflags-y) -msse
endif
ifdef CONFIG_PPC64
-dml2_ccflags := -mhard-float -maltivec
+dml2_ccflags := -mhard-float
endif
ifdef CONFIG_ARM64
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 12/14] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (10 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 11/14] drm/amd/display: Only use hard-float, not altivec on powerpc Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 21:25 ` Andrew Morton
2024-03-27 20:00 ` [PATCH v3 13/14] selftests/fpu: Move FP code to a separate translation unit Samuel Holland
2024-03-27 20:00 ` [PATCH v3 14/14] selftests/fpu: Allow building on other architectures Samuel Holland
13 siblings, 1 reply; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
Alex Deucher, linux-riscv, linuxppc-dev, Christoph Hellwig
Now that all previously-supported architectures select
ARCH_HAS_KERNEL_FPU_SUPPORT, this code can depend on that symbol instead
of the existing list of architectures. It can also take advantage of the
common kernel-mode FPU API and method of adjusting CFLAGS.
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- Split altivec removal to a separate patch
- Use linux/fpu.h instead of asm/fpu.h in consumers
drivers/gpu/drm/amd/display/Kconfig | 2 +-
.../gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 27 ++------------
drivers/gpu/drm/amd/display/dc/dml/Makefile | 36 ++-----------------
drivers/gpu/drm/amd/display/dc/dml2/Makefile | 36 ++-----------------
4 files changed, 7 insertions(+), 94 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/display/Kconfig
index 901d1961b739..5fcd4f778dc3 100644
--- a/drivers/gpu/drm/amd/display/Kconfig
+++ b/drivers/gpu/drm/amd/display/Kconfig
@@ -8,7 +8,7 @@ config DRM_AMD_DC
depends on BROKEN || !CC_IS_CLANG || ARM64 || RISCV || SPARC64 || X86_64
select SND_HDA_COMPONENT if SND_HDA_CORE
# !CC_IS_CLANG: https://github.com/ClangBuiltLinux/linux/issues/1752
- select DRM_AMD_DC_FP if (X86 || LOONGARCH || (PPC64 && ALTIVEC) || (ARM64 && KERNEL_MODE_NEON && !CC_IS_CLANG))
+ select DRM_AMD_DC_FP if ARCH_HAS_KERNEL_FPU_SUPPORT && (!ARM64 || !CC_IS_CLANG)
help
Choose this option if you want to use the new display engine
support for AMDGPU. This adds required support for Vega and
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
index 0de16796466b..e46f8ce41d87 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
@@ -26,16 +26,7 @@
#include "dc_trace.h"
-#if defined(CONFIG_X86)
-#include <asm/fpu/api.h>
-#elif defined(CONFIG_PPC64)
-#include <asm/switch_to.h>
-#include <asm/cputable.h>
-#elif defined(CONFIG_ARM64)
-#include <asm/neon.h>
-#elif defined(CONFIG_LOONGARCH)
-#include <asm/fpu.h>
-#endif
+#include <linux/fpu.h>
/**
* DOC: DC FPU manipulation overview
@@ -87,16 +78,9 @@ void dc_fpu_begin(const char *function_name, const int line)
WARN_ON_ONCE(!in_task());
preempt_disable();
depth = __this_cpu_inc_return(fpu_recursion_depth);
-
if (depth == 1) {
-#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
+ BUG_ON(!kernel_fpu_available());
kernel_fpu_begin();
-#elif defined(CONFIG_PPC64)
- if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
- enable_kernel_fp();
-#elif defined(CONFIG_ARM64)
- kernel_neon_begin();
-#endif
}
TRACE_DCN_FPU(true, function_name, line, depth);
@@ -118,14 +102,7 @@ void dc_fpu_end(const char *function_name, const int line)
depth = __this_cpu_dec_return(fpu_recursion_depth);
if (depth == 0) {
-#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
kernel_fpu_end();
-#elif defined(CONFIG_PPC64)
- if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
- disable_kernel_fp();
-#elif defined(CONFIG_ARM64)
- kernel_neon_end();
-#endif
} else {
WARN_ON_ONCE(depth < 0);
}
diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
index 59d3972341d2..a94b6d546cd1 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
@@ -25,40 +25,8 @@
# It provides the general basic services required by other DAL
# subcomponents.
-ifdef CONFIG_X86
-dml_ccflags-$(CONFIG_CC_IS_GCC) := -mhard-float
-dml_ccflags := $(dml_ccflags-y) -msse
-endif
-
-ifdef CONFIG_PPC64
-dml_ccflags := -mhard-float
-endif
-
-ifdef CONFIG_ARM64
-dml_rcflags := -mgeneral-regs-only
-endif
-
-ifdef CONFIG_LOONGARCH
-dml_ccflags := -mfpu=64
-dml_rcflags := -msoft-float
-endif
-
-ifdef CONFIG_CC_IS_GCC
-ifneq ($(call gcc-min-version, 70100),y)
-IS_OLD_GCC = 1
-endif
-endif
-
-ifdef CONFIG_X86
-ifdef IS_OLD_GCC
-# Stack alignment mismatch, proceed with caution.
-# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
-# (8B stack alignment).
-dml_ccflags += -mpreferred-stack-boundary=4
-else
-dml_ccflags += -msse2
-endif
-endif
+dml_ccflags := $(CC_FLAGS_FPU)
+dml_rcflags := $(CC_FLAGS_NO_FPU)
ifneq ($(CONFIG_FRAME_WARN),0)
ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y)
diff --git a/drivers/gpu/drm/amd/display/dc/dml2/Makefile b/drivers/gpu/drm/amd/display/dc/dml2/Makefile
index 7b51364084b5..4f6c804a26ad 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml2/Makefile
@@ -24,40 +24,8 @@
#
# Makefile for dml2.
-ifdef CONFIG_X86
-dml2_ccflags-$(CONFIG_CC_IS_GCC) := -mhard-float
-dml2_ccflags := $(dml2_ccflags-y) -msse
-endif
-
-ifdef CONFIG_PPC64
-dml2_ccflags := -mhard-float
-endif
-
-ifdef CONFIG_ARM64
-dml2_rcflags := -mgeneral-regs-only
-endif
-
-ifdef CONFIG_LOONGARCH
-dml2_ccflags := -mfpu=64
-dml2_rcflags := -msoft-float
-endif
-
-ifdef CONFIG_CC_IS_GCC
-ifeq ($(call cc-ifversion, -lt, 0701, y), y)
-IS_OLD_GCC = 1
-endif
-endif
-
-ifdef CONFIG_X86
-ifdef IS_OLD_GCC
-# Stack alignment mismatch, proceed with caution.
-# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
-# (8B stack alignment).
-dml2_ccflags += -mpreferred-stack-boundary=4
-else
-dml2_ccflags += -msse2
-endif
-endif
+dml2_ccflags := $(CC_FLAGS_FPU)
+dml2_rcflags := $(CC_FLAGS_NO_FPU)
ifneq ($(CONFIG_FRAME_WARN),0)
ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y)
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* Re: [PATCH v3 12/14] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 20:00 ` [PATCH v3 12/14] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
@ 2024-03-27 21:25 ` Andrew Morton
2024-03-27 22:08 ` Samuel Holland
0 siblings, 1 reply; 17+ messages in thread
From: Andrew Morton @ 2024-03-27 21:25 UTC (permalink / raw)
To: Samuel Holland
Cc: linux-arch, x86, linux-kernel, amd-gfx, loongarch, Alex Deucher,
linux-riscv, linuxppc-dev, Christoph Hellwig, linux-arm-kernel
On Wed, 27 Mar 2024 13:00:43 -0700 Samuel Holland <samuel.holland@sifive.com> wrote:
> Now that all previously-supported architectures select
> ARCH_HAS_KERNEL_FPU_SUPPORT, this code can depend on that symbol instead
> of the existing list of architectures. It can also take advantage of the
> common kernel-mode FPU API and method of adjusting CFLAGS.
>
> ...
>
> @@ -87,16 +78,9 @@ void dc_fpu_begin(const char *function_name, const int line)
> WARN_ON_ONCE(!in_task());
> preempt_disable();
> depth = __this_cpu_inc_return(fpu_recursion_depth);
> -
> if (depth == 1) {
> -#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
> + BUG_ON(!kernel_fpu_available());
> kernel_fpu_begin();
For some reason kernel_fpu_available() was undefined in my x86_64
allmodconfig build. I just removed the statement.
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v3 12/14] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT
2024-03-27 21:25 ` Andrew Morton
@ 2024-03-27 22:08 ` Samuel Holland
0 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 22:08 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-arch, x86, linux-kernel, amd-gfx, loongarch, Alex Deucher,
linux-riscv, linuxppc-dev, Christoph Hellwig, linux-arm-kernel
On 2024-03-27 4:25 PM, Andrew Morton wrote:
> On Wed, 27 Mar 2024 13:00:43 -0700 Samuel Holland <samuel.holland@sifive.com> wrote:
>
>> Now that all previously-supported architectures select
>> ARCH_HAS_KERNEL_FPU_SUPPORT, this code can depend on that symbol instead
>> of the existing list of architectures. It can also take advantage of the
>> common kernel-mode FPU API and method of adjusting CFLAGS.
>>
>> ...
>>
>> @@ -87,16 +78,9 @@ void dc_fpu_begin(const char *function_name, const int line)
>> WARN_ON_ONCE(!in_task());
>> preempt_disable();
>> depth = __this_cpu_inc_return(fpu_recursion_depth);
>> -
>> if (depth == 1) {
>> -#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
>> + BUG_ON(!kernel_fpu_available());
>> kernel_fpu_begin();
>
> For some reason kernel_fpu_available() was undefined in my x86_64
> allmodconfig build. I just removed the statement.
This is because the include guard in asm/fpu.h conflicts with the existing one
in asm/fpu/types.h (which doesn't match its filename), so the definition of
kernel_fpu_available() is not seen. I can fix up the include guard in
asm/fpu/types.h in the next version:
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index ace9aa3b78a3..75a3910d867a 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -2,8 +2,8 @@
/*
* FPU data structures:
*/
-#ifndef _ASM_X86_FPU_H
-#define _ASM_X86_FPU_H
+#ifndef _ASM_X86_FPU_TYPES_H
+#define _ASM_X86_FPU_TYPES_H
#include <asm/page_types.h>
@@ -596,4 +596,4 @@ struct fpu_state_config {
/* FPU state configuration information */
extern struct fpu_state_config fpu_kernel_cfg, fpu_user_cfg;
-#endif /* _ASM_X86_FPU_H */
+#endif /* _ASM_X86_FPU_TY{ES_H */
Regards,
Samuel
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 13/14] selftests/fpu: Move FP code to a separate translation unit
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (11 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 12/14] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
2024-03-27 20:00 ` [PATCH v3 14/14] selftests/fpu: Allow building on other architectures Samuel Holland
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
linux-riscv, linuxppc-dev, Christoph Hellwig
This ensures no compiler-generated floating-point code can appear
outside kernel_fpu_{begin,end}() sections, and some architectures
enforce this separation.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v2)
Changes in v2:
- Declare test_fpu() in a header
lib/Makefile | 3 ++-
lib/test_fpu.h | 8 +++++++
lib/{test_fpu.c => test_fpu_glue.c} | 32 +------------------------
lib/test_fpu_impl.c | 37 +++++++++++++++++++++++++++++
4 files changed, 48 insertions(+), 32 deletions(-)
create mode 100644 lib/test_fpu.h
rename lib/{test_fpu.c => test_fpu_glue.c} (71%)
create mode 100644 lib/test_fpu_impl.c
diff --git a/lib/Makefile b/lib/Makefile
index ffc6b2341b45..fcb35bf50979 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -133,7 +133,8 @@ FPU_CFLAGS += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-st
endif
obj-$(CONFIG_TEST_FPU) += test_fpu.o
-CFLAGS_test_fpu.o += $(FPU_CFLAGS)
+test_fpu-y := test_fpu_glue.o test_fpu_impl.o
+CFLAGS_test_fpu_impl.o += $(FPU_CFLAGS)
# Some KUnit files (hooks.o) need to be built-in even when KUnit is a module,
# so we can't just use obj-$(CONFIG_KUNIT).
diff --git a/lib/test_fpu.h b/lib/test_fpu.h
new file mode 100644
index 000000000000..4459807084bc
--- /dev/null
+++ b/lib/test_fpu.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef _LIB_TEST_FPU_H
+#define _LIB_TEST_FPU_H
+
+int test_fpu(void);
+
+#endif
diff --git a/lib/test_fpu.c b/lib/test_fpu_glue.c
similarity index 71%
rename from lib/test_fpu.c
rename to lib/test_fpu_glue.c
index e82db19fed84..85963d7be826 100644
--- a/lib/test_fpu.c
+++ b/lib/test_fpu_glue.c
@@ -19,37 +19,7 @@
#include <linux/debugfs.h>
#include <asm/fpu/api.h>
-static int test_fpu(void)
-{
- /*
- * This sequence of operations tests that rounding mode is
- * to nearest and that denormal numbers are supported.
- * Volatile variables are used to avoid compiler optimizing
- * the calculations away.
- */
- volatile double a, b, c, d, e, f, g;
-
- a = 4.0;
- b = 1e-15;
- c = 1e-310;
-
- /* Sets precision flag */
- d = a + b;
-
- /* Result depends on rounding mode */
- e = a + b / 2;
-
- /* Denormal and very large values */
- f = b / c;
-
- /* Depends on denormal support */
- g = a + c * f;
-
- if (d > a && e > a && g > a)
- return 0;
- else
- return -EINVAL;
-}
+#include "test_fpu.h"
static int test_fpu_get(void *data, u64 *val)
{
diff --git a/lib/test_fpu_impl.c b/lib/test_fpu_impl.c
new file mode 100644
index 000000000000..777894dbbe86
--- /dev/null
+++ b/lib/test_fpu_impl.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/errno.h>
+
+#include "test_fpu.h"
+
+int test_fpu(void)
+{
+ /*
+ * This sequence of operations tests that rounding mode is
+ * to nearest and that denormal numbers are supported.
+ * Volatile variables are used to avoid compiler optimizing
+ * the calculations away.
+ */
+ volatile double a, b, c, d, e, f, g;
+
+ a = 4.0;
+ b = 1e-15;
+ c = 1e-310;
+
+ /* Sets precision flag */
+ d = a + b;
+
+ /* Result depends on rounding mode */
+ e = a + b / 2;
+
+ /* Denormal and very large values */
+ f = b / c;
+
+ /* Depends on denormal support */
+ g = a + c * f;
+
+ if (d > a && e > a && g > a)
+ return 0;
+ else
+ return -EINVAL;
+}
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread
* [PATCH v3 14/14] selftests/fpu: Allow building on other architectures
2024-03-27 20:00 [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API Samuel Holland
` (12 preceding siblings ...)
2024-03-27 20:00 ` [PATCH v3 13/14] selftests/fpu: Move FP code to a separate translation unit Samuel Holland
@ 2024-03-27 20:00 ` Samuel Holland
13 siblings, 0 replies; 17+ messages in thread
From: Samuel Holland @ 2024-03-27 20:00 UTC (permalink / raw)
To: Andrew Morton, linux-arm-kernel, x86
Cc: linux-arch, linux-kernel, amd-gfx, Samuel Holland, loongarch,
linux-riscv, linuxppc-dev, Christoph Hellwig
Now that ARCH_HAS_KERNEL_FPU_SUPPORT provides a common way to compile
and run floating-point code, this test is no longer x86-specific.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v1)
lib/Kconfig.debug | 2 +-
lib/Makefile | 25 ++-----------------------
lib/test_fpu_glue.c | 5 ++++-
3 files changed, 7 insertions(+), 25 deletions(-)
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c63a5fbf1f1c..f93e778e0405 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2890,7 +2890,7 @@ config TEST_FREE_PAGES
config TEST_FPU
tristate "Test floating point operations in kernel space"
- depends on X86 && !KCOV_INSTRUMENT_ALL
+ depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
help
Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
which will trigger a sequence of floating point operations. This is used
diff --git a/lib/Makefile b/lib/Makefile
index fcb35bf50979..e44ad11f77b5 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -110,31 +110,10 @@ CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE)
obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o
obj-$(CONFIG_TEST_OBJPOOL) += test_objpool.o
-#
-# CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns
-# off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGS
-# get appended last to CFLAGS and thus override those previous compiler options.
-#
-FPU_CFLAGS := -msse -msse2
-ifdef CONFIG_CC_IS_GCC
-# Stack alignment mismatch, proceed with caution.
-# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
-# (8B stack alignment).
-# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
-#
-# The "-msse" in the first argument is there so that the
-# -mpreferred-stack-boundary=3 build error:
-#
-# -mpreferred-stack-boundary=3 is not between 4 and 12
-#
-# can be triggered. Otherwise gcc doesn't complain.
-FPU_CFLAGS += -mhard-float
-FPU_CFLAGS += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
-endif
-
obj-$(CONFIG_TEST_FPU) += test_fpu.o
test_fpu-y := test_fpu_glue.o test_fpu_impl.o
-CFLAGS_test_fpu_impl.o += $(FPU_CFLAGS)
+CFLAGS_test_fpu_impl.o += $(CC_FLAGS_FPU)
+CFLAGS_REMOVE_test_fpu_impl.o += $(CC_FLAGS_NO_FPU)
# Some KUnit files (hooks.o) need to be built-in even when KUnit is a module,
# so we can't just use obj-$(CONFIG_KUNIT).
diff --git a/lib/test_fpu_glue.c b/lib/test_fpu_glue.c
index 85963d7be826..eef282a2715f 100644
--- a/lib/test_fpu_glue.c
+++ b/lib/test_fpu_glue.c
@@ -17,7 +17,7 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/debugfs.h>
-#include <asm/fpu/api.h>
+#include <linux/fpu.h>
#include "test_fpu.h"
@@ -38,6 +38,9 @@ static struct dentry *selftest_dir;
static int __init test_fpu_init(void)
{
+ if (!kernel_fpu_available())
+ return -EINVAL;
+
selftest_dir = debugfs_create_dir("selftest_helpers", NULL);
if (!selftest_dir)
return -ENOMEM;
--
2.43.1
^ permalink raw reply related [flat|nested] 17+ messages in thread