On Tue, Apr 20, 2021 at 04:50:12PM +0000, Liam Howlett wrote: > arm64_notify_segfault() was written to decide on the si_code from the > assembly emulation of the swp_handler(), but was also used for the > signal generation from failed access_ok() and unaligned instructions. > > When access_ok() fails, there is no need to search for the offending > address in the VMA space. Instead, simply set the error to SIGSEGV with > si_code SEGV_ACCERR. > > Change the return code from emulate_swpX() when there is an unaligned > pointer so the caller can differentiate from the EFAULT. It is > unnecessary to search the VMAs in the case of an unaligned pointer. > This change uses SIGSEGV and SEGV_ACCERR instead of SIGBUS to keep with > what was returned before. > > Fixes: bd35a4adc413 (arm64: Port SWP/SWPB emulation support from arm) > Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> > --- > arch/arm64/kernel/armv8_deprecated.c | 20 +++++++++++++------- Can you give an example of something that is fixed by this, please? At first glance, it doesn't look like it changes the user-visible behaviour. We should also be compatible with arch/arm/ here (see set_segfault()). Will
