On Wed, Jan 12, 2022 at 05:29:03PM +0000, Daniel Thompson wrote: > On Mon, Jul 26, 2021 at 04:11:39PM +0200, Arnd Bergmann wrote: > > From: Arnd Bergmann <arnd@xxxxxxxx> > > > > These mimic the behavior of get_user and put_user, except > > for domain switching, address limit checking and handling > > of mismatched sizes, none of which are relevant here. > > > > To work with pre-Armv6 kernels, this has to avoid TUSER() > > inside of the new macros, the new approach passes the "t" > > string along with the opcode, which is a bit uglier but > > avoids duplicating more code. > > > > As there is no __get_user_asm_dword(), I work around it > > by copying 32 bit at a time, which is possible because > > the output size is known. > > > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > > I've just been bisecting some regressions running the kgdbts tests on > arm and this patch came up. So the software PAN code is working :) The kernel attempted to access an address that is in the userspace domain (NULL pointer) and took an exception. I suppose we should handle a domain fault more gracefully - what are the required semantics if the kernel attempts a userspace access using one of the _nofault() accessors? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
