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<p><span style="color: rgb(33, 33, 33); font-size: 12pt;">>I have just checked it, the startup.elf and realmode.elf are fine. Only few changes are required for mainline kernel and one >commit has to be reverted from lld and a few patches have to be applied.</span><br>
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<div>> </div>
<div>>The only step when I have used BFD is linking vmlinux. I have manually set LD variable in vmlinux_link() function. The vmlinux >produced by lld doesn't work yet. I will compare it to the one produced by GNU ld and try to figure out what is wrong (maybe
>you can suggest some useful objdump flags?)</div>
<div>> </div>
<div>>Regards,</div>
<div>>Dmitry<br>
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<div>Just want to share latest results of investigation from my side. </div>
<div>I traced kernel linked with LLD to find where it fails.<br>
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<div>LLD linked kernel starts execution and then <span style="font-size: 12pt;">I came up to </span><span style="font-size: 12pt;">protected_mode_jump</span><span style="font-size: 12pt;"> fun</span><span style="font-size: 12pt;">ction, which intention to
jump to </span><span style="font-size: 12pt;">startup_64</span><span style="font-size: 12pt;">:</span></div>
<div> jmpl<span class="Apple-tab-span" style="white-space:pre"> </span>*%eax<span class="Apple-tab-span" style="white-space:pre">
</span># Jump to the 32-bit entrypoint<br>
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<div>(<a href="https://github.com/torvalds/linux/blob/5924bbecd0267d87c24110cbe2041b5075173a25/arch/x86/boot/pmjump.S#L76" style="font-size: 12pt;">https://github.com/torvalds/linux/blob/5924bbecd0267d87c24110cbe2041b5075173a25/arch/x86/boot/pmjump.S#L76</a>)<br>
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<div>(https://github.com/torvalds/linux/blob/5924bbecd0267d87c24110cbe2041b5075173a25/arch/x86/kernel/head_64.S#L48)<br>
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<div>It does not happen. Code executes right before jmpl and then fail on this call for me, so <span style="color: rgb(33, 33, 33); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);">startup_64</span>
never called.<br>
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<div>startup_64 is a part of vmlinux binary. So as you said vmlinux has troubles and a<span style="font-size: 12pt;">fter doi</span><span style="font-size: 12pt;">ng readelf -a on LLD linked and bfd linked ones, I found that LLD outputs <span style="color: rgb(33, 33, 33); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);">vmlinux</span> as executable
and bfd output is DSO. Had no chance to investigate why that happens, </span><span style="font-size: 12pt;">but pretty sure that is t</span><span style="font-size: 12pt;">he
</span><span style="font-size: 12pt;">not fine</span><span style="font-size: 12pt;">.</span></div>
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<div>Invocation line for us does not contain -shared:<br>
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<div>-m elf_x86_64</div>
<div>--script home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/vmlinux.lds</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/head_64.o</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/misc.o</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/string.o</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/cmdline.o</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/error.o</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/piggy.o</div>
<div>home/umb/linux_kernel/linux/linux/arch/x86/boot/compressed/cpuflags.o</div>
<div>-o vmlinux<br>
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<div>George.<br>
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