我是C和Linux的新手。我正在尝试编译以下代码,但在编译时会出现一些致命错误。修复此问题的任何帮助表示赞赏。
这是代码measurecpu.c
:
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/hardirq.h>
#include <linux/preempt.h>
#include <linux/sched.h>
#include<stdio.h>
int main() {
uint64_t start, end;
int i=0;
asm volatile ("CPUID \ n \ t" "RDTSC \ n \ t" "mov %%edx, %0 \ n \ t" "mov %%eax, %1 \ n \ t": "=r" (cycles_high), "=r" (cycles_low):: "%rax", "%rbx", "%rcx", "%rdx");
for(i=0; i<200000;i++) {}
asm volatile ("RDTSCP \ n \ t" "mov %%edx, %0 \ n \ t" "mov %%eax, %1 \ n \ t" "CPUID \ n \ t": "=r" (cycles_high1), "=r" (cycles_low1):: "%rax", "%rbx", "%rcx", "%rdx");
start = ( ((uint64_t)cycles_high << 32) | cycles_low );
end = ( ((uint64_t)cycles_high1 << 32) | cycles_low1 );
printk(KERN_INFO " \ n function execution time is %llu clock cycles",(end - start));
}
我正在尝试以这种方式进行编译:
gcc -c -O2 -W -Wall -isystem /lib/modules/'uname -r'/build/include -D_KERNEL_ -DMODULE measurecpu.c
我收到此错误:
measurecpu.c:1:32: fatal error: linux/module.h: No such file or directory
#include <linux/module.h>
^
compilation terminated.
最佳答案
通常,编译内核模块的方法是使用内核构建系统-即,您直接使用make
而不是gcc
。您需要创建一个Makefile
并指定对象,在您的情况下为obj-m := measurecpu.o
行。之后,在同一目录中,发出make
命令,该命令将生成内核目标文件 measurecpu.ko
# If KERNELRELEASE is defined, we've been invoked from the
# kernel build system and can use its language.
ifneq ($(KERNELRELEASE),)
obj-m := measurecpu.o
# Otherwise we were called directly from the command
# line; invoke the kernel build system.
else
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules clean
endif
请注意,内核模块不是用户空间程序,因此您不能仅运行它。您将需要通过
insmod
告知内核该内核模块,并通过dmesg
检查结果。关于c - 我们如何用C编译内核代码?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/34980880/