Merge pull request #196502 from r-burns/mips-darwin-cross

linuxHeaders: fix darwin -> linux-mips cross-compilation

1 files changed, 30 insertions, 0 deletions

diff --git a/pkgs/os-specific/linux/kernel-headers/default.nix b/pkgs/os-specific/linux/kernel-headers/default.nix
index ebf20a015c0..d8bfb59bf12 100644
--- a/pkgs/os-specific/linux/kernel-headers/default.nix
+++ b/pkgs/os-specific/linux/kernel-headers/default.nix
@@ -1,11 +1,37 @@
 { stdenvNoCC, lib, buildPackages, fetchurl, perl, elf-header
 , bison ? null, flex ? null, python ? null, rsync ? null
+, writeTextFile
 }:
 
 assert stdenvNoCC.hostPlatform.isAndroid ->
   (flex != null && bison != null && python != null && rsync != null);
 
 let
+
+  # As part of building a hostPlatform=mips kernel, Linux creates and runs a
+  # tiny utility `arch/mips/boot/tools/relocs_main.c` for the buildPlatform.
+  # This utility references a glibc-specific header `byteswap.h`.  There is a
+  # compatibility header in gnulib for most BSDs, but not for Darwin, so we
+  # synthesize one here.
+  darwin-endian-h = writeTextFile {
+    name = "endian-h";
+    text = ''
+      #include <byteswap.h>
+    '';
+    destination = "/include/endian.h";
+  };
+  darwin-byteswap-h = writeTextFile {
+    name = "byteswap-h";
+    text = ''
+      #pragma once
+      #include <libkern/OSByteOrder.h>
+      #define bswap_16 OSSwapInt16
+      #define bswap_32 OSSwapInt32
+      #define bswap_64 OSSwapInt64
+    '';
+    destination = "/include/byteswap.h";
+  };
+
   makeLinuxHeaders = { src, version, patches ? [] }: stdenvNoCC.mkDerivation {
     inherit src;
 
@@ -25,6 +51,10 @@ let
       perl elf-header
     ] ++ lib.optionals stdenvNoCC.hostPlatform.isAndroid [
       flex bison python rsync
+    ] ++ lib.optionals (stdenvNoCC.buildPlatform.isDarwin &&
+                        stdenvNoCC.hostPlatform.isMips) [
+      darwin-endian-h
+      darwin-byteswap-h
     ];
 
     extraIncludeDirs = lib.optionals (with stdenvNoCC.hostPlatform; isPower && is32bit && isBigEndian) ["ppc"];