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Some improvements to remap-the-kernel and allocating-frames

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Philipp Oppermann
2016-02-13 22:44:09 +01:00
parent d321982755
commit ac9044bd96
2 changed files with 6 additions and 4 deletions
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posts/2015-11-15-allocating-frames.md
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@@ -128,7 +128,9 @@ for section in elf_sections_tag.sections() {
```
This should print out the start address and size of all kernel sections. If the section is writable, the `0x1` bit is set in `flags`. The `0x4` bit marks an executable section and the `0x2` bit indicates that the section was loaded in memory. For example, the `.text` section is executable but not writable and the `.data` section just the opposite.
But when we execute it, tons of really small sections are printed. We can use the `objdump -h build/kernel-x86_64.bin` command to list the sections with name. There seem to be over 200 sections and many of them start with `.text.*` or `.data.rel.ro.local.*`. This is because the Rust compiler puts e.g. each function in its own `.text` subsection. To merge these subsections, we need to update our linker script:
But when we execute it, tons of really small sections are printed. We can use the `objdump -h build/kernel-x86_64.bin` command to list the sections with name. There seem to be over 200 sections and many of them start with `.text.*` or `.data.rel.ro.local.*`. This is because the Rust compiler puts e.g. each function in its own `.text` subsection. That way, unused functions are removed when the linker omits unused sections.
To merge these subsections, we need to update our linker script:
```
SECTIONS {