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powerc/mm: try VMA lock-based page fault handling first

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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"

[ldufour@linux.ibm.com: powerpc/mm: fix mmap_lock bad unlock]
  Link: https://lkml.kernel.org/r/20230306154244.17560-1-ldufour@linux.ibm.com
  Link: https://lore.kernel.org/linux-mm/842502FB-F99C-417C-9648-A37D0ECDC9CE@linux.ibm.com
Link: https://lkml.kernel.org/r/20230227173632.3292573-32-surenb@google.com
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Sachin Sant <sachinp@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Laurent Dufour 2023-02-27 09:36:30 -08:00 committed by Andrew Morton
parent cd7f176aea
commit 70d4cbc80c
3 changed files with 39 additions and 0 deletions
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37
arch/powerpc/mm/fault.c
View File

@ -474,6 +474,40 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
if (is_exec) if (is_exec)
flags |= FAULT_FLAG_INSTRUCTION; 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))) {
vma_end_read(vma);
goto lock_mmap;
}
if (unlikely(access_error(is_write, is_exec, vma))) {
vma_end_read(vma);
goto lock_mmap;
}
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 /* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the * addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an * kernel and should generate an OOPS. Unfortunately, in the case of an
@ -550,6 +584,9 @@ retry:
mmap_read_unlock(current->mm); mmap_read_unlock(current->mm);
#ifdef CONFIG_PER_VMA_LOCK
done:
#endif
if (unlikely(fault & VM_FAULT_ERROR)) if (unlikely(fault & VM_FAULT_ERROR))
return mm_fault_error(regs, address, fault); return mm_fault_error(regs, address, fault);

1
arch/powerpc/platforms/powernv/Kconfig
View File

@ -16,6 +16,7 @@ config PPC_POWERNV
select PPC_DOORBELL select PPC_DOORBELL
select MMU_NOTIFIER select MMU_NOTIFIER
select FORCE_SMP select FORCE_SMP
select ARCH_SUPPORTS_PER_VMA_LOCK
default y default y
config OPAL_PRD config OPAL_PRD

1
arch/powerpc/platforms/pseries/Kconfig
View File

@ -22,6 +22,7 @@ config PPC_PSERIES
select HOTPLUG_CPU select HOTPLUG_CPU
select FORCE_SMP select FORCE_SMP
select SWIOTLB select SWIOTLB
select ARCH_SUPPORTS_PER_VMA_LOCK
default y default y
config PARAVIRT config PARAVIRT