构建安卓内核

编程问答 2022-06-02

问题描述

两周以来，我尝试为我的 htc 设备构建内核。获得正确的来源不是问题，但由于 gcc 已从工具链中删除，这真是一场噩梦。遵循使用 clang 的建议总是以大量错误消息结束。

到目前为止我做了什么？

  1. 正确安装最新的 android-ndk (21.3.6528147)
  2. 通过命令行成功测试交叉编译（只是一个简单的程序）
  3. 为内核构建设置 ENV 变量：（仅在尚未设置时导出命令）
$ cd <kernel-source-root>
($ make mrproper) // just after Failed attempt to build
$ export ARCH=arm64
$ export SUBARCH=arm64
$ export CROSS_COMPILE=<path-to-toolchain-llvm-bin-folder>
  1. 修改 Makefile 和 AndroidKernel.mk
// replace all occurences of 'gcc' with 'clang'
-gcc 
+clang
  1. 生成.config
$ make msm-perf_defconfig
  1. 执行构建
$ make V=1
  1. 获取错误消息：
// ...
../kernel/bounds.c:18:2: error: unexpected token at start of statement
        DEFINE(NR_PAGEFLAGS,__NR_PAGEFLAGS);
        ^
../include/linux/kbuild.h:5:25: note: expanded from macro 'DEFINE'
        asm volatile("\n->" #sym " %0 " #val : : "i" (val))
                        ^
<inline asm>:2:1: note: instantiated into assembly here
->NR_PAGEFLAGS 21 __NR_PAGEFLAGS
^
../kernel/bounds.c:19:2: error: unexpected token at start of statement
        DEFINE(MAX_NR_ZOnes,__MAX_NR_ZOnes);
        ^
../include/linux/kbuild.h:5:25: note: expanded from macro 'DEFINE'
        asm volatile("\n->" #sym " %0 " #val : : "i" (val))
                        ^
<inline asm>:2:1: note: instantiated into assembly here
->MAX_NR_ZOnes 3 __MAX_NR_ZOnes
^
../kernel/bounds.c:21:2: error: unexpected token at start of statement
        DEFINE(NR_cpuS_BITS,ilog2(CONfig_NR_cpuS));
        ^
../include/linux/kbuild.h:5:25: note: expanded from macro 'DEFINE'
        asm volatile("\n->" #sym " %0 " #val : : "i" (val))
                        ^
<inline asm>:2:1: note: instantiated into assembly here
->NR_cpuS_BITS 3 ilog2(CONfig_NR_cpuS)
^
../kernel/bounds.c:23:2: error: unexpected token at start of statement
        DEFINE(SPINLOCK_SIZE,sizeof(spinlock_t));
        ^
../include/linux/kbuild.h:5:25: note: expanded from macro 'DEFINE'
        asm volatile("\n->" #sym " %0 " #val : : "i" (val))
                        ^
<inline asm>:2:1: note: instantiated into assembly here
->SPINLOCK_SIZE 4 sizeof(spinlock_t)
^
4 errors generated.
make[2]: *** [kernel/bounds.s] Error 1
make[1]: *** [prepare0] Error 2
make: *** [sub-make] Error 2

有人看到出了什么问题吗？

解决方法

在构建命令中添加 -no-integrated-as 修复了它。

根据 clang 开发人员的说法：

添加-no-integrated-as。这是一种已知的滥用编译器来输出程序集以外的内容。

reference

make ARCH=arm64 -j64 -no-integrated-as

androidandroidandroid-kernelmacostoolchain