Large Page Support for Code Issue: 16198 #21064
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|
There was a problem hiding this comment. This file can probably be reduced to ~20 lines. It's pretty well hidden in all the definitions but I infer you really only care about the There was a problem hiding this comment. I dont see how it can be reduced to 20 lines. Much of it is what is used by the default linker script. Yes the only reason for me to modify it was to find the start of the actual text. I had trouble with moving the plt regions and wanted to avoid several of those regions. There was a problem hiding this comment. https://sourceware.org/binutils/docs/ld/Implicit-Linker-Scripts.html#Implicit-Linker-Scripts - instead of replacing the default linker script, you use an implicit linker script that works in addition to the default linker script. Replacing the default linker script isn't an option, IMO, because that will be a never-ending maintenance hassle for us. There was a problem hiding this comment. The implicit linker scripts wont really help as I cant do a symbol assignment for something that is already specified in the linker script. I will investigate if there is some other approach to get the address of the .text segment. There was a problem hiding this comment. I am able eliminate the ld.script by using the LD option The other way is to read the elf file and find the .text segment and determine the address. There was a problem hiding this comment. A fixed address is bad for security reasons and reading it from the ELF header won't work when ASLR is enabled. I guess you could compute the ASLR slide at run-time but that gets complicated fast when code and data is spread across several segments. Another issue with that approach: two segments with different protection might be located within < 2 MB from each other. Are you sure implicit linker scripts don't work? I remember using that to put symbols at fixed locations. What about retrieving the path to the default linker script with There was a problem hiding this comment. Thanks. Let me look into the implicit linker script some more. Another option is to generate the linker script using the There was a problem hiding this comment. I was able to figure this out. GNU ld has the INSERT option which makes the externally supported script not override the default script but insert the code into the default. So I will delete the ld.script and insert a new ld.implicit.script PROVIDE (_nodetext = .); |
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too low level for me to review, how do we make sure its correctness? are there documentations around this?
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There were 3 line modification to the default ld.script to create a variable name(s) for the start of actual node text segment.