On Mon, Feb 27, 2023 at 9:37 AM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote: > > From: Laurent Dufour <ldufour@xxxxxxxxxxxxx> > > Attempt VMA lock-based page fault handling first, and fall back to the > existing mmap_lock-based handling if that fails. > Copied from "x86/mm: try VMA lock-based page fault handling first" Hi Andrew, Laurent posted a fix for this patch at https://lore.kernel.org/all/20230306154244.17560-1-ldufour@xxxxxxxxxxxxx/. Could you please squash the fix into this patch? Thanks, Suren. > > Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxx> > Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > --- > arch/powerpc/mm/fault.c | 41 ++++++++++++++++++++++++++ > arch/powerpc/platforms/powernv/Kconfig | 1 + > arch/powerpc/platforms/pseries/Kconfig | 1 + > 3 files changed, 43 insertions(+) > > diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > index 2bef19cc1b98..c7ae86b04b8a 100644 > --- a/arch/powerpc/mm/fault.c > +++ b/arch/powerpc/mm/fault.c > @@ -469,6 +469,44 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address, > if (is_exec) > flags |= FAULT_FLAG_INSTRUCTION; > > +#ifdef CONFIG_PER_VMA_LOCK > + if (!(flags & FAULT_FLAG_USER)) > + goto lock_mmap; > + > + vma = lock_vma_under_rcu(mm, address); > + if (!vma) > + goto lock_mmap; > + > + if (unlikely(access_pkey_error(is_write, is_exec, > + (error_code & DSISR_KEYFAULT), vma))) { > + int rc = bad_access_pkey(regs, address, vma); > + > + vma_end_read(vma); > + return rc; > + } > + > + if (unlikely(access_error(is_write, is_exec, vma))) { > + int rc = bad_access(regs, address); > + > + vma_end_read(vma); > + return rc; > + } > + > + fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); > + vma_end_read(vma); > + > + if (!(fault & VM_FAULT_RETRY)) { > + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); > + goto done; > + } > + count_vm_vma_lock_event(VMA_LOCK_RETRY); > + > + if (fault_signal_pending(fault, regs)) > + return user_mode(regs) ? 0 : SIGBUS; > + > +lock_mmap: > +#endif /* CONFIG_PER_VMA_LOCK */ > + > /* When running in the kernel we expect faults to occur only to > * addresses in user space. All other faults represent errors in the > * kernel and should generate an OOPS. Unfortunately, in the case of an > @@ -545,6 +583,9 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address, > > mmap_read_unlock(current->mm); > > +#ifdef CONFIG_PER_VMA_LOCK > +done: > +#endif > if (unlikely(fault & VM_FAULT_ERROR)) > return mm_fault_error(regs, address, fault); > > diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig > index ae248a161b43..70a46acc70d6 100644 > --- a/arch/powerpc/platforms/powernv/Kconfig > +++ b/arch/powerpc/platforms/powernv/Kconfig > @@ -16,6 +16,7 @@ config PPC_POWERNV > select PPC_DOORBELL > select MMU_NOTIFIER > select FORCE_SMP > + select ARCH_SUPPORTS_PER_VMA_LOCK > default y > > config OPAL_PRD > diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig > index b481c5c8bae1..9c205fe0e619 100644 > --- a/arch/powerpc/platforms/pseries/Kconfig > +++ b/arch/powerpc/platforms/pseries/Kconfig > @@ -21,6 +21,7 @@ config PPC_PSERIES > select HOTPLUG_CPU > select FORCE_SMP > select SWIOTLB > + select ARCH_SUPPORTS_PER_VMA_LOCK > default y > > config PARAVIRT > -- > 2.39.2.722.g9855ee24e9-goog >
