Linux 4.14, 4.19, 5.0+ compat: SIMD save/restore

[zfs] / config / kernel-fpu.m4

diff --git a/config/kernel-fpu.m4 b/config/kernel-fpu.m4
index a2c47d65a5aa23c6550a9388cf98394296c36351..3c7933413d18c765d57ae99a9a96d8f3f7fadbb6 100644 (file)
--- a/config/kernel-fpu.m4
+++ b/config/kernel-fpu.m4
@@ -2,15 +2,9 @@ dnl #
 dnl # Handle differences in kernel FPU code.
 dnl #
 dnl # Kernel
-dnl # 5.2:     The fpu->initialized flag was replaced by TIF_NEED_FPU_LOAD.
-dnl #          HAVE_KERNEL_TIF_NEED_FPU_LOAD
-dnl #
-dnl # 5.0:     As an optimization SIMD operations performed by kernel
-dnl #          threads can skip saving and restoring their FPU context.
-dnl #          Wrappers have been introduced to determine the running
-dnl #          context and use either the SIMD or generic implementation.
+dnl # 5.0:     Wrappers have been introduced to save/restore the FPU state.
 dnl #          This change was made to the 4.19.38 and 4.14.120 LTS kernels.
-dnl #          HAVE_KERNEL_FPU_INITIALIZED
+dnl #          HAVE_KERNEL_FPU_INTERNAL
 dnl #
 dnl # 4.2:     Use __kernel_fpu_{begin,end}()
 dnl #          HAVE_UNDERSCORE_KERNEL_FPU & KERNEL_EXPORTS_X86_FPU
@@ -38,6 +32,7 @@ AC_DEFUN([ZFS_AC_KERNEL_FPU_HEADER], [
 
 AC_DEFUN([ZFS_AC_KERNEL_SRC_FPU], [
        ZFS_LINUX_TEST_SRC([kernel_fpu], [
+               #include <linux/types.h>
                #ifdef HAVE_KERNEL_FPU_API_HEADER
                #include <asm/fpu/api.h>
                #else
@@ -50,6 +45,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_FPU], [
        ], [], [$ZFS_META_LICENSE])
 
        ZFS_LINUX_TEST_SRC([__kernel_fpu], [
+               #include <linux/types.h>
                #ifdef HAVE_KERNEL_FPU_API_HEADER
                #include <asm/fpu/api.h>
                #else
@@ -61,22 +57,41 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_FPU], [
                __kernel_fpu_end();
        ], [], [$ZFS_META_LICENSE])
 
-       ZFS_LINUX_TEST_SRC([fpu_initialized], [
-               #include <linux/module.h>
-               #include <linux/sched.h>
-       ],[
-               struct fpu *fpu = &current->thread.fpu;
-               if (fpu->initialized) { return (0); };
-       ])
+       ZFS_LINUX_TEST_SRC([fpu_internal], [
+               #if defined(__x86_64) || defined(__x86_64__) || \
+                   defined(__i386) || defined(__i386__)
+               #if !defined(__x86)
+               #define __x86
+               #endif
+               #endif
 
-       ZFS_LINUX_TEST_SRC([tif_need_fpu_load], [
-               #include <linux/module.h>
-               #include <asm/thread_info.h>
+               #if !defined(__x86)
+               #error Unsupported architecture
+               #endif
 
-               #if !defined(TIF_NEED_FPU_LOAD)
-               #error "TIF_NEED_FPU_LOAD undefined"
+               #include <linux/types.h>
+               #ifdef HAVE_KERNEL_FPU_API_HEADER
+               #include <asm/fpu/api.h>
+               #include <asm/fpu/internal.h>
+               #else
+               #include <asm/i387.h>
+               #include <asm/xcr.h>
+               #endif
+
+               #if !defined(XSTATE_XSAVE)
+               #error XSTATE_XSAVE not defined
                #endif
-       ],[])
+
+               #if !defined(XSTATE_XRESTORE)
+               #error XSTATE_XRESTORE not defined
+               #endif
+       ],[
+               struct fpu *fpu = &current->thread.fpu;
+               union fpregs_state *st = &fpu->state;
+               struct fregs_state *fr __attribute__ ((unused)) = &st->fsave;
+               struct fxregs_state *fxr __attribute__ ((unused)) = &st->fxsave;
+               struct xregs_state *xr __attribute__ ((unused)) = &st->xsave;
+       ])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_FPU], [
@@ -104,25 +119,12 @@ AC_DEFUN([ZFS_AC_KERNEL_FPU], [
                        AC_DEFINE(KERNEL_EXPORTS_X86_FPU, 1,
                            [kernel exports FPU functions])
                ],[
-                       dnl #
-                       dnl # Linux 5.0 kernel
-                       dnl #
-                       ZFS_LINUX_TEST_RESULT([fpu_initialized], [
-                               AC_MSG_RESULT(fpu.initialized)
-                               AC_DEFINE(HAVE_KERNEL_FPU_INITIALIZED, 1,
-                                   [kernel fpu.initialized exists])
+                       ZFS_LINUX_TEST_RESULT([fpu_internal], [
+                               AC_MSG_RESULT(internal)
+                               AC_DEFINE(HAVE_KERNEL_FPU_INTERNAL, 1,
+                                   [kernel fpu internal])
                        ],[
-                               dnl #
-                               dnl # Linux 5.2 kernel
-                               dnl #
-                               ZFS_LINUX_TEST_RESULT([tif_need_fpu_load], [
-                                       AC_MSG_RESULT(TIF_NEED_FPU_LOAD)
-                                       AC_DEFINE(
-                                           HAVE_KERNEL_TIF_NEED_FPU_LOAD, 1,
-                                           [kernel TIF_NEED_FPU_LOAD exists])
-                               ],[
-                                       AC_MSG_RESULT(unavailable)
-                               ])
+                               AC_MSG_RESULT(unavailable)
                        ])
                ])
        ])