linux: update fpu patches for 5.3

At the moment we experience bad instabilities with linux 5.3:

openzfs/zfs#9346

as the zfs-native method of disabling the FPU is buggy.

(cherry picked from commit 96097ab)

pkgs/os-specific/linux/kernel/export_kernel_fpu_functions_5_3.patch

@@ -0,0 +1,42 @@
+From 1e010beda2896bdf3082fb37a3e49f8ce20e04d8 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <[email protected]>
+Date: Thu, 2 May 2019 05:28:08 +0100
+Subject: [PATCH] x86/fpu: Export kernel_fpu_{begin,end}() with
+ EXPORT_SYMBOL_GPL
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+We need these symbols in zfs as the fpu implementation breaks userspace:
+
+https://github.com/zfsonlinux/zfs/issues/9346
+Signed-off-by: Jörg Thalheim <[email protected]>
+---
+ arch/x86/kernel/fpu/core.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
+index 12c70840980e..352538b3bb5d 100644
+--- a/arch/x86/kernel/fpu/core.c
++++ b/arch/x86/kernel/fpu/core.c
+@@ -102,7 +102,7 @@ void kernel_fpu_begin(void)
+ 	}
+ 	__cpu_invalidate_fpregs_state();
+ }
+-EXPORT_SYMBOL_GPL(kernel_fpu_begin);
++EXPORT_SYMBOL(kernel_fpu_begin);
+
+ void kernel_fpu_end(void)
+ {
+@@ -111,7 +111,7 @@ void kernel_fpu_end(void)
+ 	this_cpu_write(in_kernel_fpu, false);
+ 	preempt_enable();
+ }
+-EXPORT_SYMBOL_GPL(kernel_fpu_end);
++EXPORT_SYMBOL(kernel_fpu_end);
+
+ /*
+  * Save the FPU state (mark it for reload if necessary):
+-- 
+2.23.0
+

pkgs/os-specific/linux/kernel/patches.nix

@@ -59,8 +59,14 @@
   };
 
   export_kernel_fpu_functions = {
-    name = "export_kernel_fpu_functions";
-    patch = ./export_kernel_fpu_functions.patch;
+    "4.14" = {
+      name = "export_kernel_fpu_functions";
+      patch = ./export_kernel_fpu_functions_4_14.patch;
+    };
+    "5.3" = {
+      name = "export_kernel_fpu_functions";
+      patch = ./export_kernel_fpu_functions_5_3.patch;
+    };
   };
 
   # patches from https://lkml.org/lkml/2019/7/15/1748

pkgs/top-level/all-packages.nix

@@ -15747,21 +15747,24 @@ in
         # when adding a new linux version
         kernelPatches.cpu-cgroup-v2."4.11"
         kernelPatches.modinst_arg_list_too_long
-        kernelPatches.export_kernel_fpu_functions
+        kernelPatches.export_kernel_fpu_functions."4.14"
       ];
   };
 
   linux_4_19 = callPackage ../os-specific/linux/kernel/linux-4.19.nix {
     kernelPatches =
       [ kernelPatches.bridge_stp_helper
         kernelPatches.modinst_arg_list_too_long
-        kernelPatches.export_kernel_fpu_functions
+        kernelPatches.export_kernel_fpu_functions."4.14"
       ];
   };
 
   # Update this when adding the newest kernel major version!
   linux_latest = callPackage ../os-specific/linux/kernel/linux-5.4.nix {
-    kernelPatches = [ kernelPatches.bridge_stp_helper ];
+    kernelPatches = [
+      kernelPatches.bridge_stp_helper
+      kernelPatches.export_kernel_fpu_functions."5.3"
+    ];
   };
 
   linux_testing = callPackage ../os-specific/linux/kernel/linux-testing.nix {