On Mon, 2024-10-07 at 09:49 +0200, Julian Vetter wrote:
The um arch is the only architecture that sets the config 'NO_IOMEM',
(you did note this, for the comment below)
No, I think you're understanding the series correctly. It doesn't work. I will revert this.
OK.
You're adding these inlines unconditionally, so if this included logic_io.h, you should get symbol conflicts? Also not sure these functions should/need to do anything at all, there's no IO memory on ARCH=um in case of not having logic_io.h. Maybe even BUG_ON() or something? It can't be reachable (under correct drivers) since ioremap() always returns NULL (without logic_iomem).
Thanks. You're right. I added this patch because there was a build robot on some mailinglist building a random config with 'ARCH=um' and with some MTD drivers that actually use memcpy_fromio or memcpy_toio. These drivers are not guarded by a 'depends on HAS_IOMEM'. I thought I could simply fix it by adding stub functions to the um arch. Because I saw there are A LOT of drivers that use IO functions without being guarded by 'depends on HAS_IOMEM'. Not sure though, how to handle this case.
Right, well, as you noted above ARCH=um is the only architecture that has NO_IOMEM, so I suppose drivers are just broken. But e.g. kernel/iomem.c is also only ever built if you have HAS_IOMEM, so devm_* functions related to this are not available. So I don't know. On the one hand, it feels correct to have NO_IOMEM and HAS_IOMEM, on the other hand that's a bit of a fight against windmills? What happens now though? Seems it should _already_ not build with ARCH=um and memcpy_*io() being used? No, I guess it picked up the asm- generic version? Hm. I'm almost thinking we should let such drivers not build, and then see that they add appropriate HAS_IOMEM dependencies, but ... windmills? johannes
