2 
#include<stdio.h>
int main()
{
int src = 5;
int dst = 0;

asm ("mv %0,%1":"=X"(dst):"r"(src));
asm("mv a0,a1");

printf(" %d\n", dst);
return 0;
}

prashantravi@ubuntu:~/rocket-chip$ riscv64-unknown-linux-gnu-gcc -o asm_test asm_test.c prashantravi@ubuntu:~/rocket-chip$ spike riscv/bin/pk asm_test z 0000000000000000 ra 0000000000000000 sp 00000000fefffb50 gp 0000000000801fb8 tp 0000000000000000 t0 0000000000000000 t1 0000000000000008 t2 00000000008012e0 s0 0000000000000000 s1 0000000000000000 a0 0000000000800430 a1 0000000000000001 a2 00000000fefffb58 a3 0000000000800484 a4 0000000000800514 a5 0000000000000000 a6 00000000fefffb50 a7 0000000000000000 s2 0000000000000000 s3 0000000000000000 s4 0000000000000000 s5 0000000000000000 s6 0000000000000000 s7 0000000000000000 s8 0000000000000000 s9 0000000000000000 sA 0000000000000000 sB 0000000000000000 t3 ffffffffffffffff t4 0000000000000000 t5 0000000000000000 t6 0000000000000000 pc fffffffffffffffe va fffffffffffffffe insn ffffffff sr 8000000000003008 User fetch segfault @ 0xfffffffffffffffe

当我在尖峰中使用 riscv64-unknown-linux-gnu-gcc 编译程序时出现上述错误。

使用 riscv64-unknown-elf gcc 运行时，相同的代码可以完美执行

4

1 回答 1

2

您不能在代理内核上运行动态链接的程序。

如果要在代理内核上运行程序，则必须静态链接程序。这是默认使用 riscv64-unknown-elf-gcc 编译器执行的。如果你打算使用 riscv64-unknown-linux-gnu-gcc 编译器，你必须要么通过，要么-static必须在 Linux 内核上运行它。

$ riscv64-unknown-elf-gcc -o asm_test asm_test.c [or...]
$ riscv64-unknown-linux-gnu-gcc -static -o asm_test asm_test.c 
$ spike pk asm_test

更详细地说，在我记得上述限制之前我是如何调试的：

通过运行$ spike -d pk asm_test 2> output.txt，我们可以看到程序的踪迹：

<snippet>
374618 : core   0: 0x0000000000800320 (0x00002197) auipc   gp, 0x2                  
374619 : core   0: 0x0000000000800324 (0xc9818193) addi    gp, gp, -872             
374620 : core   0: 0x0000000000800328 (0x00050793) mv      a5, a0                   
374621 : core   0: 0x000000000080032c (0x00000517) auipc   a0, 0x0                  
374622 : core   0: 0x0000000000800330 (0x10450513) addi    a0, a0, 260              
374623 : core   0: 0x0000000000800334 (0x00013583) ld      a1, 0(sp)                
374624 : core   0: 0x0000000000800338 (0x00810613) addi    a2, sp, 8                
374625 : core   0: 0x000000000080033c (0xff017113) andi    sp, sp, -16              
374626 : core   0: 0x0000000000800340 (0x00000697) auipc   a3, 0x0                  
374627 : core   0: 0x0000000000800344 (0x14468693) addi    a3, a3, 324              
374628 : core   0: 0x0000000000800348 (0x00000717) auipc   a4, 0x0                  
374629 : core   0: 0x000000000080034c (0x1cc70713) addi    a4, a4, 460              
374630 : core   0: 0x0000000000800350 (0x00010813) mv      a6, sp                   
374631 : core   0: 0x0000000000800354 (0xfbdff06f) j       pc - 0x44                
374632 : core   0: 0x0000000000800310 (0x00001e17) auipc   t3, 0x1                  
374633 : core   0: 0x0000000000800314 (0x498e3e03) ld      t3, 1176(t3)             
374634 : core   0: 0x0000000000800318 (0x000e0367) jalr    t1, t3, 0                
374635 : core   0: 0x00000000008002e0 (0x00001397) auipc   t2, 0x1                  
374636 : core   0: 0x00000000008002e4 (0x41c30333) sub     t1, t1, t3               
374637 : core   0: 0x00000000008002e8 (0x4b03be03) ld      t3, 1200(t2)             
374638 : core   0: 0x00000000008002ec (0xfd430313) addi    t1, t1, -44              
374639 : core   0: 0x00000000008002f0 (0x4b038293) addi    t0, t2, 1200             
374640 : core   0: 0x00000000008002f4 (0x00135313) srli    t1, t1, 1                
374641 : core   0: 0x00000000008002f8 (0x0082b283) ld      t0, 8(t0)                
374642 : core   0: 0x00000000008002fc (0x000e0067) jr      t3                       
374643 : core   0: exception trap_instruction_access_fault, epc 0xfffffffffffffffe  
374644 core   0: 0x0000000000000100 (0x34011173) csrrw   sp, mscratch, sp           
374645 : core   0: 0x0000000000000104 (0x04a13823) sd      a0, 80(sp)               
374646 : core   0: 0x0000000000000108 (0x04b13c23) sd      a1, 88(sp)

如果你 objdump asm_test，你会看到它在_start，然后__libc_start_main，然后是__libc_start_main@plt(0x800310)，然后是_PROCEDURE_LINKAGE_TABLE_(0x8002e0)。

从那里，它尝试 a jr，然后跳转到0xfffffffffffffffe，这是一个未对齐的提取地址。因此崩溃。

于 2015-10-13T07:34:35.797 回答