d1-wip-kernel-issue.c

/*
Hello, I'm using d1-wip kernel from https://github.com/smaeul/linux/commits/riscv/d1-wip.

My rootfs is archriscv from https://mirrors.wsyu.edu.cn/archriscv/images/archriscv-20210601.tar.zst.

I found some programs running on this kernel will get SEGV, such as curl.

I delve into this problem and found the root cause is about pthread. It just trap at "amoswap.w.aq a5,a5,(s1)". And the value of register s1 is an address on the stack.

Here is a simple program with pthread. using gcc -lpthread to compile and run on D1-board with work in progress kernel is fine.

But if you comment the printf line in function main, you will get SEGV. And the cause is 0x7.

I guess this issue related to cache or TLB didn't flush properly. So I add some "sfence.vma x0,x0" to the kernel which I think should get TLB flush, but it doesn't work.
*/
#include <stdio.h>
#include <pthread.h>

void hello() {
        printf("Hello from thread\n");
        return;
}

int main() {
        pthread_t t1;
        printf("pthread create\n"); // try to comment this line, you will get segv
        if ( pthread_create(&t1,NULL,hello,NULL) ) {
                return 1;
        }
        pthread_join(t1,NULL);
        return 0;
}

d1 kernel有各种问题，一不小心就重启。