Date: Sun, 13 Mar 2016 22:50:56 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 207898] kernel linker behaves differently on amd64 vs. i386 Message-ID: <bug-207898-8-1i4IIOjM4k@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-207898-8@https.bugs.freebsd.org/bugzilla/> References: <bug-207898-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D207898 Jilles Tjoelker <jilles@FreeBSD.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jilles@FreeBSD.org --- Comment #2 from Jilles Tjoelker <jilles@FreeBSD.org> --- There is another MD aspect of the kernel linker: whether kernel modules are object files (file says "ELF xx-bit yyy relocatable") or DSOs (file says "E= LF xx-bit yyy shared object"). Of the architectures you are looking at, i386 u= ses DSOs and amd64 uses object files. Using object files may reduce overhead slightly but bypasses functionality = that may be useful. For example, DSOs have a symbol table for dynamic linking separate from the one for debugging, while object files only have a single symbol table. Although there is a flag for static (local) symbols, the kern= el linker ignores it and some code may have started abusing this ignoring. Note that, although i386 kernel modules are DSOs, they are not PIC and do n= ot use a GOT and PLT. Therefore, there is no overhead from the DSO format while running the code. --=20 You are receiving this mail because: You are the assignee for the bug.=
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