On Fri, Oct 23, 2020 at 05:14:37PM +0800, Miles Chen wrote: > Since kernel no longer writes to the vector, try to replace > the vector mem type with read-only type and remove L_PTE_MT_VECTORS. > > from Catalin in [1]: > " > > I don't think this matters since the kernel no longer writes to the > > vectors page at run-time but it needs cleaning up a bit (and testing in > > case I missed something). IOW, do we still need a dedicated mapping type > > for the vectors or we can simply use the read-only user page attributes? > "
Catalin is incorrect. If CONFIG_KUSER_HELPERS is enabled, then the vectors page is definitely written to - it's a user interface, so it's not going to change: #ifdef CONFIG_KUSER_HELPERS /* * User space must never try to access this * directly. Expect your app to break * eventually if you do so. The user helper * at 0xffff0fe0 must be used instead. (see * entry-armv.S for details) */ *((unsigned int *)0xffff0ff0) = val; #endif -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!