selftests/fpu: move FP code to a separate translation unit

This ensures no compiler-generated floating-point code can appear outside
kernel_fpu_{begin,end}() sections, and some architectures enforce this
separation.

Link: https://lkml.kernel.org/r/20240329072441.591471-15-samuel.holland@sifive.com
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian König <christian.koenig@amd.com> 
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: WANG Xuerui <git@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 0 insertions, 89 deletions

diff --git a/lib/test_fpu.c b/lib/test_fpu.c
deleted file mode 100644
index e82db19fed84..000000000000
--- a/lib/test_fpu.c
+++ /dev/null
@@ -1,89 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * Test cases for using floating point operations inside a kernel module.
- *
- * This tests kernel_fpu_begin() and kernel_fpu_end() functions, especially
- * when userland has modified the floating point control registers. The kernel
- * state might depend on the state set by the userland thread that was active
- * before a syscall.
- *
- * To facilitate the test, this module registers file
- * /sys/kernel/debug/selftest_helpers/test_fpu, which when read causes a
- * sequence of floating point operations. If the operations fail, either the
- * read returns error status or the kernel crashes.
- * If the operations succeed, the read returns "1\n".
- */
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#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;
-}
-
-static int test_fpu_get(void *data, u64 *val)
-{
-	int status = -EINVAL;
-
-	kernel_fpu_begin();
-	status = test_fpu();
-	kernel_fpu_end();
-
-	*val = 1;
-	return status;
-}
-
-DEFINE_DEBUGFS_ATTRIBUTE(test_fpu_fops, test_fpu_get, NULL, "%lld\n");
-static struct dentry *selftest_dir;
-
-static int __init test_fpu_init(void)
-{
-	selftest_dir = debugfs_create_dir("selftest_helpers", NULL);
-	if (!selftest_dir)
-		return -ENOMEM;
-
-	debugfs_create_file_unsafe("test_fpu", 0444, selftest_dir, NULL,
-				   &test_fpu_fops);
-
-	return 0;
-}
-
-static void __exit test_fpu_exit(void)
-{
-	debugfs_remove(selftest_dir);
-}
-
-module_init(test_fpu_init);
-module_exit(test_fpu_exit);
-
-MODULE_LICENSE("GPL");