On Wed, 25 Sept 2024 at 20:54, Uros Bizjak <ubizjak@xxxxxxxxx> wrote: > > On Wed, Sep 25, 2024 at 5:02 PM Ard Biesheuvel <ardb+git@xxxxxxxxxx> wrote: > > > > From: Ard Biesheuvel <ardb@xxxxxxxxxx> > > > > Build the kernel as a Position Independent Executable (PIE). This > > results in more efficient relocation processing for the virtual > > displacement of the kernel (for KASLR). More importantly, it instructs > > the linker to generate what is actually needed (a program that can be > > moved around in memory before execution), which is better than having to > > rely on the linker to create a position dependent binary that happens to > > tolerate being moved around after poking it in exactly the right manner. > > > > Note that this means that all codegen should be compatible with PIE, > > including Rust objects, so this needs to switch to the small code model > > with the PIE relocation model as well. > > I think that related to this work is the patch series [1] that > introduces the changes necessary to build the kernel as Position > Independent Executable (PIE) on x86_64 [1]. There are some more places > that need to be adapted for PIE. The patch series also introduces > objtool functionality to add validation for x86 PIE. > > [1] "[PATCH RFC 00/43] x86/pie: Make kernel image's virtual address flexible" > https://lore.kernel.org/lkml/cover.1682673542.git.houwenlong.hwl@xxxxxxxxxxxx/ > Hi Uros, I am aware of that discussion, as I took part in it as well. I don't think any of those changes are actually needed now - did you notice anything in particular that is missing?
