RISC-V反汇编程序与峰值运行结果不符？ [英] RISC-V disassembler doesn't match with spike running results?
问题描述
我建立了一个hello world程序来测试我的 riscv32-unknown-elf 工具链， spike ， pk 等。尽管我设法使用 spike --isa = RV32 pk hello.elf ，我发现如果我为调试添加了 -d 标志，我会得到以下说明（整体的一部分）：
I've set up a hello world program just for testing my riscv32-unknown-elf toolchain, spike, pk etc. Though I managed to get the hello world printed using spike --isa=RV32 pk hello.elf, I found out that if I added the -d flag for debugging, I was given following instructions (a section of the whole):
core 0: 0x0000000000001000 (0x7ffff297) auipc t0, 0x7ffff
:
core 0: 0x0000000000001004 (0x00028067) jr t0
:
core 0: 0xffffffff80000000 (0x1b00006f) j pc + 0x1b0
:
core 0: 0xffffffff800001b0 (0x00000093) li ra, 0
:
core 0: 0xffffffff800001b4 (0x00000113) li sp, 0
:
core 0: 0xffffffff800001b8 (0x00000193) li gp, 0
:
core 0: 0xffffffff800001bc (0x00000213) li tp, 0
:
core 0: 0xffffffff800001c0 (0x00000293) li t0, 0
:
core 0: 0xffffffff800001c4 (0x00000313) li t1, 0
:
core 0: 0xffffffff800001c8 (0x00000393) li t2, 0
:
core 0: 0xffffffff800001cc (0x00000413) li s0, 0
:
core 0: 0xffffffff800001d0 (0x00000493) li s1, 0
:
core 0: 0xffffffff800001d4 (0x00000513) li a0, 0
:
core 0: 0xffffffff800001d8 (0x00000593) li a1, 0
:
core 0: 0xffffffff800001dc (0x00000613) li a2, 0
:
core 0: 0xffffffff800001e0 (0x00000693) li a3, 0
:
core 0: 0xffffffff800001e4 (0x00000713) li a4, 0
:
core 0: 0xffffffff800001e8 (0x00000793) li a5, 0
:
core 0: 0xffffffff800001ec (0x00000813) li a6, 0
:
core 0: 0xffffffff800001f0 (0x00000893) li a7, 0
:
core 0: 0xffffffff800001f4 (0x00000913) li s2, 0
:
core 0: 0xffffffff800001f8 (0x00000993) li s3, 0
:
core 0: 0xffffffff800001fc (0x00000a13) li s4, 0
:
core 0: 0xffffffff80000200 (0x00000a93) li s5, 0
:
core 0: 0xffffffff80000204 (0x00000b13) li s6, 0
:
core 0: 0xffffffff80000208 (0x00000b93) li s7, 0
:
core 0: 0xffffffff8000020c (0x00000c13) li s8, 0
:
core 0: 0xffffffff80000210 (0x00000c93) li s9, 0
:
core 0: 0xffffffff80000214 (0x00000d13) li s10, 0
:
core 0: 0xffffffff80000218 (0x00000d93) li s11, 0
:
core 0: 0xffffffff8000021c (0x00000e13) li t3, 0
:
core 0: 0xffffffff80000220 (0x00000e93) li t4, 0
:
core 0: 0xffffffff80000224 (0x00000f13) li t5, 0
:
core 0: 0xffffffff80000228 (0x00000f93) li t6, 0
:
core 0: 0xffffffff8000022c (0x34001073) csrw mscratch, zero
:
core 0: 0xffffffff80000230 (0x00000297) auipc t0, 0x0
:
core 0: 0xffffffff80000234 (0xdd828293) addi t0, t0, -552
:
core 0: 0xffffffff80000238 (0x30529073) csrw mtvec, t0
:
core 0: 0xffffffff8000023c (0x30502373) csrr t1, mtvec
:
core 0: 0xffffffff80000240 (0x00629063) bne t0, t1, pc + 0
:
core 0: 0xffffffff80000244 (0x00012117) auipc sp, 0x12
无论如何，它与从产生的反汇编程序不匹配（也是开始部分）：
Anyway it doesn't match the disassembler produced from riscv32-unknown-elf-objdump -d hello.elf > hello.dump (also a section on the beginning):
hello.elf: file format elf32-littleriscv
Disassembly of section .text:
00010074 <_start>:
10074: 00005197 auipc gp,0x5
10078: fcc18193 addi gp,gp,-52 # 15040 <_gp>
1007c: 00004517 auipc a0,0x4
10080: 7d850513 addi a0,a0,2008 # 14854 <_edata>
10084: 00005617 auipc a2,0x5
10088: 83060613 addi a2,a2,-2000 # 148b4 <_end>
1008c: 40a60633 sub a2,a2,a0
10090: 00000593 li a1,0
10094: 2c0000ef jal ra,10354 <memset>
10098: 00000517 auipc a0,0x0
1009c: 1bc50513 addi a0,a0,444 # 10254 <__libc_fini_array>
100a0: 16c000ef jal ra,1020c <atexit>
100a4: 210000ef jal ra,102b4 <__libc_init_array>
100a8: 00012503 lw a0,0(sp)
100ac: 00410593 addi a1,sp,4
100b0: 00000613 li a2,0
100b4: 124000ef jal ra,101d8 <main>
100b8: 1680006f j 10220 <exit>
000100bc <_fini>:
100bc: 00008067 ret
000100c0 <deregister_tm_clones>:
100c0: 00015537 lui a0,0x15
100c4: 000157b7 lui a5,0x15
100c8: 84050713 addi a4,a0,-1984 # 14840 <__TMC_END__>
100cc: 84378793 addi a5,a5,-1981 # 14843 <__TMC_END__+0x3>
100d0: 40e787b3 sub a5,a5,a4
100d4: 00600713 li a4,6
100d8: 00f77c63 bleu a5,a4,100f0 <deregister_tm_clones+0x30>
100dc: 00000337 lui t1,0x0
100e0: 00030313 mv t1,t1
100e4: 00030663 beqz t1,100f0 <deregister_tm_clones+0x30>
100e8: 84050513 addi a0,a0,-1984
100ec: 00030067 jr t1
100f0: 00008067 ret
000100f4 <register_tm_clones>:
100f4: 00015537 lui a0,0x15
100f8: 000155b7 lui a1,0x15
100fc: 84050793 addi a5,a0,-1984 # 14840 <__TMC_END__>
10100: 84058593 addi a1,a1,-1984 # 14840 <__TMC_END__>
10104: 40f585b3 sub a1,a1,a5
10108: 4025d593 srai a1,a1,0x2
1010c: 01f5d793 srli a5,a1,0x1f
10110: 00b785b3 add a1,a5,a1
10114: 4015d593 srai a1,a1,0x1
10118: 00058c63 beqz a1,10130 <register_tm_clones+0x3c>
1011c: 00000337 lui t1,0x0
10120: 00030313 mv t1,t1
10124: 00030663 beqz t1,10130 <register_tm_clones+0x3c>
10128: 84050513 addi a0,a0,-1984
1012c: 00030067 jr t1
10130: 00008067 ret
我很困惑，因为地址和机器代码之间存在很大差异。如果你能给我一些想法，我会很感激。谢谢！
I am confused since there's a big difference between both the addresses and machine code. I'd really appreciate it if you could give me some thoughts. Thanks!
祝好，
Cy
Best regards, Cy
推荐答案
我认为你会发现启动过程开始以及 pk 二进制文件（物理地址）。并且在 objdump 输出中，您从入口点反汇编了ELF。所以hello binary可能会在稍后的秒杀输出中出现...
I think that in spike you see start of boot process and the pk binary (in physical addresses). And in objdump output you have ELF disassembled from the entry point. So hello binary may be somewhere later in spike output...
您从秒杀中看到的内容与我的机器init代码类似： https://github.com/riscv/riscv-pk/blob/6c1d0604dcabf36a6a8d8d9a839b2d4634e202d2/machine/mentry .S＃L183
What you see from spike resemble me this code of machine init: https://github.com/riscv/riscv-pk/blob/6c1d0604dcabf36a6a8d8d9a839b2d4634e202d2/machine/mentry.S#L183
core 0: 0x0000000000001000 (0x7ffff297) auipc t0, 0x7ffff
:
core 0: 0x0000000000001004 (0x00028067) jr t0
reset_vector:
j do_reset
，然后确切 do_reset of machine / mentry.S （行183），它仍然在在加载和运行用户应用程序 hello 之前， pk 代码：
and then exact do_reset of machine/mentry.S (line 183), it is still before main pk code, before loading and running user app hello:
do_reset:
li x1, 0
li x2, 0
li x3, 0
li x4, 0
li x5, 0
li x6, 0
li x7, 0
li x8, 0
li x9, 0
li x10, 0
li x11, 0
li x12, 0
li x13, 0
li x14, 0
li x15, 0
li x16, 0
li x17, 0
li x18, 0
li x19, 0
li x20, 0
li x21, 0
li x22, 0
li x23, 0
li x24, 0
li x25, 0
li x26, 0
li x27, 0
li x28, 0
li x29, 0
li x30, 0
li x31, 0
csrw mscratch, x0
# write mtvec and make sure it sticks
la t0, trap_vector
csrw mtvec, t0
csrr t1, mtvec
1:bne t0, t1, 1b
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