2023-11-27 11:41:05 +01:00
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# NixOS on RISC-V
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2023-02-16 13:23:11 +01:00
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2024-01-17 18:24:36 +01:00
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To boot the system in QEMU, first enter the development shell:
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2023-02-16 13:23:11 +01:00
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2024-01-17 18:24:36 +01:00
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```
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$ nix develop
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```
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2023-02-16 13:23:11 +01:00
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2024-01-17 18:24:36 +01:00
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Then run the boot script:
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```
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$ ./boot.sh
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```
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2024-01-18 18:19:29 +01:00
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2024-01-19 16:27:58 +01:00
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## Use more than 1 CPU
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2024-01-19 13:41:35 +01:00
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2024-01-19 16:27:58 +01:00
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With only 1 CPU some thigs are soo slow to work. For example, the ttyS0 device
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doesn't arrive on time and the login fails. Or the SSH daemon doesn't start
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until the third try. With -smp 32 seems to work ok.
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## Compressed instructions
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To see if a binary has compressed instructions or not, you can use objdump:
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hut% nix shell -vL nixpkgs#pkgsCross.riscv64.bintools
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hut% objdump -M no-aliases -D result/u-boot | grep 'c\.' | head -5
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80200000: 822a c.mv tp,a0
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80200002: 84ae c.mv s1,a1
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80200018: 52c1 c.li t0,-16
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8020001e: 0356 c.slli t1,0x15
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80200024: 850a c.mv a0,sp
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To dump a ROM without the ELF header:
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hut% objdump -b binary -m riscv:rv64 -M no-aliases -D result/u-boot.bin
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