25 lines
1.3 KiB
Markdown
25 lines
1.3 KiB
Markdown
# Failed modificatons
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## LTO
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Enabling LTO via `-flto` flag, leads to the error `MAX_NR_ZONES undefined` on kernel compilation. Disabling LTO for kernel leads to a linker error at some point (maybe some things are dynamically linked?).
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## Changing march
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Changing march flag leads to compiler error with missing headers (tried only with `-march=24kec`)
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## Optimizing unlikely/likely branches
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Setting `CONFIG_JUMP_LABEL=y` in kernel config causes kernel compilation to fail with:
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```c
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arch/mips/kernel/jump_label.c: In function 'arch_jump_label_transform':
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arch/mips/kernel/jump_label.c:46:37: error: implicit declaration of function 'msk_isa16_mode' [-Werror=implicit-function-declaration]
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insn_p = (union mips_instruction *)msk_isa16_mode(e->code);
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^~~~~~~~~~~~~~
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arch/mips/kernel/jump_label.c:55:38: error: 'mm_j32_op' undeclared (first use in this function); did you mean 'dsra32_op'?
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insn.j_format.opcode = J_ISA_BIT ? mm_j32_op : j_op;
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^~~~~~~~~
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dsra32_op
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```
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## Updating userspace apps and kernel
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Padavan uses old Linux kernel (3.4.3), as well as outdated versions of some apps, it would be the best to update them.
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Unfortunately it seems kernel and apps contain certain modifications, which I don't have knowledge to determine and port.
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