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10fa254539
Contrary to initial testing we cannot rely on these kernels to invalidate the per-cpu FPU state and restore the FPU registers. Nor can we guarantee that the kernel won't modify the FPU state which we saved in the task struck. Therefore, the kfpu_begin() and kfpu_end() functions have been updated to save and restore the FPU state using our own dedicated per-cpu FPU state variables. This has the additional advantage of allowing us to use the FPU again in user threads. So we remove the code which was added to use task queues to ensure some functions ran in kernel threads. Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #9346 Closes #9403
132 lines
3.3 KiB
Plaintext
132 lines
3.3 KiB
Plaintext
dnl #
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dnl # Handle differences in kernel FPU code.
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dnl #
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dnl # Kernel
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dnl # 5.0: Wrappers have been introduced to save/restore the FPU state.
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dnl # This change was made to the 4.19.38 and 4.14.120 LTS kernels.
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dnl # HAVE_KERNEL_FPU_INTERNAL
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dnl #
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dnl # 4.2: Use __kernel_fpu_{begin,end}()
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dnl # HAVE_UNDERSCORE_KERNEL_FPU & KERNEL_EXPORTS_X86_FPU
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dnl #
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dnl # Pre-4.2: Use kernel_fpu_{begin,end}()
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dnl # HAVE_KERNEL_FPU & KERNEL_EXPORTS_X86_FPU
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dnl #
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dnl # N.B. The header check is performed before all other checks since it
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dnl # depends on HAVE_KERNEL_FPU_API_HEADER being set in confdefs.h.
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dnl #
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AC_DEFUN([ZFS_AC_KERNEL_FPU_HEADER], [
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AC_MSG_CHECKING([whether fpu headers are available])
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ZFS_LINUX_TRY_COMPILE([
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#include <linux/module.h>
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#include <asm/fpu/api.h>
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],[
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],[
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AC_DEFINE(HAVE_KERNEL_FPU_API_HEADER, 1,
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[kernel has asm/fpu/api.h])
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AC_MSG_RESULT(asm/fpu/api.h)
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],[
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AC_MSG_RESULT(i387.h & xcr.h)
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])
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])
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AC_DEFUN([ZFS_AC_KERNEL_SRC_FPU], [
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ZFS_LINUX_TEST_SRC([kernel_fpu], [
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#include <linux/types.h>
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#ifdef HAVE_KERNEL_FPU_API_HEADER
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#include <asm/fpu/api.h>
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#else
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#include <asm/i387.h>
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#include <asm/xcr.h>
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#endif
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], [
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kernel_fpu_begin();
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kernel_fpu_end();
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], [], [$ZFS_META_LICENSE])
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ZFS_LINUX_TEST_SRC([__kernel_fpu], [
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#include <linux/types.h>
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#ifdef HAVE_KERNEL_FPU_API_HEADER
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#include <asm/fpu/api.h>
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#else
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#include <asm/i387.h>
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#include <asm/xcr.h>
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#endif
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], [
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__kernel_fpu_begin();
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__kernel_fpu_end();
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], [], [$ZFS_META_LICENSE])
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ZFS_LINUX_TEST_SRC([fpu_internal], [
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#if defined(__x86_64) || defined(__x86_64__) || \
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defined(__i386) || defined(__i386__)
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#if !defined(__x86)
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#define __x86
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#endif
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#endif
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#if !defined(__x86)
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#error Unsupported architecture
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#endif
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#include <linux/types.h>
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#ifdef HAVE_KERNEL_FPU_API_HEADER
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#include <asm/fpu/api.h>
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#include <asm/fpu/internal.h>
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#else
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#include <asm/i387.h>
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#include <asm/xcr.h>
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#endif
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#if !defined(XSTATE_XSAVE)
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#error XSTATE_XSAVE not defined
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#endif
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#if !defined(XSTATE_XRESTORE)
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#error XSTATE_XRESTORE not defined
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#endif
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],[
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struct fpu *fpu = ¤t->thread.fpu;
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union fpregs_state *st = &fpu->state;
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struct fregs_state *fr __attribute__ ((unused)) = &st->fsave;
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struct fxregs_state *fxr __attribute__ ((unused)) = &st->fxsave;
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struct xregs_state *xr __attribute__ ((unused)) = &st->xsave;
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])
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])
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AC_DEFUN([ZFS_AC_KERNEL_FPU], [
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dnl #
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dnl # Legacy kernel
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dnl #
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AC_MSG_CHECKING([whether kernel fpu is available])
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ZFS_LINUX_TEST_RESULT_SYMBOL([kernel_fpu_license],
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[kernel_fpu_begin], [arch/x86/kernel/fpu/core.c], [
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AC_MSG_RESULT(kernel_fpu_*)
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AC_DEFINE(HAVE_KERNEL_FPU, 1,
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[kernel has kernel_fpu_* functions])
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AC_DEFINE(KERNEL_EXPORTS_X86_FPU, 1,
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[kernel exports FPU functions])
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],[
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dnl #
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dnl # Linux 4.2 kernel
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dnl #
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ZFS_LINUX_TEST_RESULT_SYMBOL([__kernel_fpu_license],
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[__kernel_fpu_begin],
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[arch/x86/kernel/fpu/core.c arch/x86/kernel/i387.c], [
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AC_MSG_RESULT(__kernel_fpu_*)
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AC_DEFINE(HAVE_UNDERSCORE_KERNEL_FPU, 1,
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[kernel has __kernel_fpu_* functions])
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AC_DEFINE(KERNEL_EXPORTS_X86_FPU, 1,
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[kernel exports FPU functions])
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],[
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ZFS_LINUX_TEST_RESULT([fpu_internal], [
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AC_MSG_RESULT(internal)
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AC_DEFINE(HAVE_KERNEL_FPU_INTERNAL, 1,
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[kernel fpu internal])
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],[
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AC_MSG_RESULT(unavailable)
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])
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])
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])
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])
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