On Wed, Aug 02, 2023 at 05:28:10PM +0100, James Morse wrote: > Hi Luis, > > On 01/08/2023 18:14, Luis Chamberlain wrote: > > On Tue, Aug 01, 2023 at 02:54:06PM +0000, James Morse wrote: > >> Adam reports that Yocto can't load modules on arm64. This turns out to be due > >> to the arch code disagreeing with the core code when it comes to the layout > >> of the modules exit text, resulting in a shortage of PLTs and a bunch of > >> warnings. > >> > >> arm and arm64 are unusual here as they are counting the PLTs based on the > >> section name. This series exposes the helper that core code uses to decide > >> the layout. > >> > >> I've been unable to reproduce the behaviour on 32bit - but it looks like > >> its possible to reach the BUG_ON() in get_module_plt(). To test this, disable > >> CONFIG_MODULE_UNLOAD, and try to load modules with relocations in their exit > >> text. > >> > >> This series is based on v6.5-rc4, and can be retrieved from: > >> https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git arm64/modules/exit_sections/v1 > >> > > > > Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> > > Thanks! > > > > Do you want this to go through the modules tree or do you want to take > > this in your tree? Either way is fine by me, at this point there should > > be no conflicts. > > If Russell agrees the problem exists on 32bit arm, then I think it would be best to keep > these three together - going via the modules tree would make the most sense. > > This has been broken for a while, so it can wait for v6.6-rc1. > I think the yocto folk plan to carry this out of tree until its in their chosen stable > version. The thing about PLTs is that it's something I've never had the need to make use of - because I've never been in the situation where the arm32 module space has been close to overflowing. The addition of PLT support for 32-bit arm did make my eyebrows raise for this very reason, but I guess there are a small number of people who want to use really large modules. As such, I couldn't say whether it's broken or not - but it seems sensible to keep both the 64-bit and 32-bit code tracking each other. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
