调用invlpg指令时出现段错误 [英] Segfault when invlpg instruction is called

问题描述

我正在尝试实现tlb刷新功能.对于刷新，我使用INVLPG指令，但不幸的是，它始终会导致分段错误.您能帮我解决这个问题吗?

I am trying to implement tlb flush function. For flushing I use INVLPG instruction, but unfortunately it always cause segmentation fault. Could you help me with this issue?

这是代码:

#include "stdlib.h"

inline void tlb_flush_entry(int *m) 
{
    asm volatile ("invlpg %0"::"m"(*m):"memory");
}

int main(int argc, char **argv)
{
    int *memory = (int *)malloc(100);
    tlb_flush_entry(memory);
}

推荐答案

发生SIGSEGV的原因是INVLPG是特权指令，只能从内核代码中调用. 这意味着您不能以这种方式将用户空间页面逐出TLB. 但是我写了一个小内核模块，演示了invlpg的用法: 如何在x86-64体系结构上使用INVLPG? a>

The SIGSEGV happens because INVLPG is a privileged instruction and can only be called out of kernel code. This means you can't evict a userspace page out of the TLB that way. However I wrote a litte kernel module demonstrating the usage of invlpg: How to use INVLPG on x86-64 architecture?

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