From: Michel Lespinasse <michel@lespinasse.org>
To: Linux-MM <linux-mm@kvack.org>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Cc: kernel-team@fb.com, Laurent Dufour <ldufour@linux.ibm.com>,
Jerome Glisse <jglisse@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
Davidlohr Bueso <dave@stgolabs.net>,
Matthew Wilcox <willy@infradead.org>,
Liam Howlett <liam.howlett@oracle.com>,
Rik van Riel <riel@surriel.com>,
Paul McKenney <paulmck@kernel.org>,
Song Liu <songliubraving@fb.com>,
Suren Baghdasaryan <surenb@google.com>,
Minchan Kim <minchan@google.com>,
Joel Fernandes <joelaf@google.com>,
David Rientjes <rientjes@google.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Andy Lutomirski <luto@kernel.org>,
Michel Lespinasse <michel@lespinasse.org>
Subject: [PATCH v2 35/35] powerpc/mm: attempt speculative mm faults first
Date: Fri, 28 Jan 2022 05:10:06 -0800 [thread overview]
Message-ID: <20220128131006.67712-36-michel@lespinasse.org> (raw)
In-Reply-To: <20220128131006.67712-1-michel@lespinasse.org>
Attempt speculative mm fault handling first, and fall back to the
existing (non-speculative) code if that fails.
This follows the lines of the x86 speculative fault handling code,
but with some minor arch differences such as the way that the
access_pkey_error case is handled
Signed-off-by: Michel Lespinasse <michel@lespinasse.org>
---
arch/powerpc/mm/fault.c | 64 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index eb8ecd7343a9..3f039504e8fd 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -395,6 +395,10 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
int is_write = page_fault_is_write(error_code);
vm_fault_t fault, major = 0;
bool kprobe_fault = kprobe_page_fault(regs, 11);
+#ifdef CONFIG_SPECULATIVE_PAGE_FAULT
+ struct vm_area_struct pvma;
+ unsigned long seq;
+#endif
if (unlikely(debugger_fault_handler(regs) || kprobe_fault))
return 0;
@@ -451,6 +455,63 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
if (is_exec)
flags |= FAULT_FLAG_INSTRUCTION;
+#ifdef CONFIG_SPECULATIVE_PAGE_FAULT
+ /*
+ * No need to try speculative faults for kernel or
+ * single threaded user space.
+ */
+ if (!(flags & FAULT_FLAG_USER) || atomic_read(&mm->mm_users) == 1)
+ goto no_spf;
+
+ count_vm_event(SPF_ATTEMPT);
+ seq = mmap_seq_read_start(mm);
+ if (seq & 1) {
+ count_vm_spf_event(SPF_ABORT_ODD);
+ goto spf_abort;
+ }
+ rcu_read_lock();
+ vma = __find_vma(mm, address);
+ if (!vma || vma->vm_start > address) {
+ rcu_read_unlock();
+ count_vm_spf_event(SPF_ABORT_UNMAPPED);
+ goto spf_abort;
+ }
+ if (!vma_is_anonymous(vma)) {
+ rcu_read_unlock();
+ count_vm_spf_event(SPF_ABORT_NO_SPECULATE);
+ goto spf_abort;
+ }
+ pvma = *vma;
+ rcu_read_unlock();
+ if (!mmap_seq_read_check(mm, seq, SPF_ABORT_VMA_COPY))
+ goto spf_abort;
+ vma = &pvma;
+#ifdef CONFIG_PPC_MEM_KEYS
+ if (unlikely(access_pkey_error(is_write, is_exec,
+ (error_code & DSISR_KEYFAULT), vma))) {
+ count_vm_spf_event(SPF_ABORT_ACCESS_ERROR);
+ goto spf_abort;
+ }
+#endif /* CONFIG_PPC_MEM_KEYS */
+ if (unlikely(access_error(is_write, is_exec, vma))) {
+ count_vm_spf_event(SPF_ABORT_ACCESS_ERROR);
+ goto spf_abort;
+ }
+ fault = do_handle_mm_fault(vma, address,
+ flags | FAULT_FLAG_SPECULATIVE, seq, regs);
+ major |= fault & VM_FAULT_MAJOR;
+
+ if (fault_signal_pending(fault, regs))
+ return user_mode(regs) ? 0 : SIGBUS;
+ if (!(fault & VM_FAULT_RETRY))
+ goto done;
+
+spf_abort:
+ count_vm_event(SPF_ABORT);
+no_spf:
+
+#endif /* CONFIG_SPECULATIVE_PAGE_FAULT */
+
/* 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
@@ -522,6 +583,9 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
}
mmap_read_unlock(current->mm);
+#ifdef CONFIG_SPECULATIVE_PAGE_FAULT
+done:
+#endif
if (unlikely(fault & VM_FAULT_ERROR))
return mm_fault_error(regs, address, fault);
--
2.20.1
next prev parent reply other threads:[~2022-01-28 13:20 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 13:09 [PATCH v2 00/35] Speculative page faults Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 01/35] mm: export dump_mm Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 02/35] mmap locking API: mmap_lock_is_contended returns a bool Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 03/35] mmap locking API: name the return values Michel Lespinasse
2022-01-31 16:17 ` Liam Howlett
2022-02-07 17:39 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 04/35] do_anonymous_page: use update_mmu_tlb() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 05/35] do_anonymous_page: reduce code duplication Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 06/35] mm: introduce CONFIG_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 07/35] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 08/35] mm: add FAULT_FLAG_SPECULATIVE flag Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 09/35] mm: add do_handle_mm_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 10/35] mm: add per-mm mmap sequence counter for speculative page fault handling Michel Lespinasse
2022-08-25 11:23 ` Pavan Kondeti
2022-01-28 13:09 ` [PATCH v2 11/35] mm: rcu safe vma freeing Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 12/35] mm: separate mmap locked assertion from find_vma Michel Lespinasse
2022-01-29 0:08 ` kernel test robot
2022-01-29 0:33 ` Michel Lespinasse
2022-01-31 14:44 ` Matthew Wilcox
2022-02-04 22:41 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 13/35] x86/mm: attempt speculative mm faults first Michel Lespinasse
2022-02-01 17:16 ` Liam Howlett
2022-02-07 17:39 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 14/35] mm: add speculative_page_walk_begin() and speculative_page_walk_end() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 15/35] mm: refactor __handle_mm_fault() / handle_pte_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 16/35] mm: implement speculative handling in __handle_mm_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 17/35] mm: add pte_map_lock() and pte_spinlock() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 18/35] mm: implement speculative handling in do_anonymous_page() Michel Lespinasse
2022-01-28 21:03 ` kernel test robot
2022-01-28 22:08 ` Michel Lespinasse
2022-01-30 2:54 ` [mm] fa5331bae2: canonical_address#:#[##] kernel test robot
2022-01-30 5:08 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 19/35] mm: enable speculative fault handling through do_anonymous_page() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 20/35] mm: implement speculative handling in do_numa_page() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 21/35] mm: enable speculative fault " Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 22/35] percpu-rwsem: enable percpu_sem destruction in atomic context Michel Lespinasse
[not found] ` <20220129121319.3593-1-hdanton@sina.com>
2022-01-31 18:04 ` Suren Baghdasaryan
[not found] ` <20220201020958.3720-1-hdanton@sina.com>
2022-02-07 19:31 ` Suren Baghdasaryan
[not found] ` <20220208002059.2670-1-hdanton@sina.com>
2022-02-08 1:31 ` Suren Baghdasaryan
2022-01-28 13:09 ` [PATCH v2 23/35] mm: add mmu_notifier_lock Michel Lespinasse
2022-07-27 7:34 ` Pavan Kondeti
2022-07-27 20:30 ` Suren Baghdasaryan
2022-01-28 13:09 ` [PATCH v2 24/35] mm: write lock mmu_notifier_lock when registering mmu notifiers Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 25/35] mm: add mmu_notifier_trylock() and mmu_notifier_unlock() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 26/35] mm: implement speculative handling in wp_page_copy() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 27/35] mm: implement and enable speculative fault handling in handle_pte_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 28/35] mm: disable speculative faults for single threaded user space Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 29/35] mm: disable rcu safe vma freeing " Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 30/35] mm: create new include/linux/vm_event.h header file Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 31/35] mm: anon spf statistics Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 32/35] arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 33/35] arm64/mm: attempt speculative mm faults first Michel Lespinasse
2022-01-30 9:13 ` Mike Rapoport
2022-01-31 8:07 ` Michel Lespinasse
2022-02-01 8:58 ` Mike Rapoport
2022-02-07 17:39 ` Michel Lespinasse
2022-02-08 9:07 ` Mike Rapoport
2022-01-28 13:10 ` [PATCH v2 34/35] powerpc/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:10 ` Michel Lespinasse [this message]
2022-01-31 9:56 ` [PATCH v2 00/35] Speculative page faults David Hildenbrand
2022-01-31 17:00 ` Suren Baghdasaryan
2022-02-01 1:14 ` Andrew Morton
2022-02-01 2:20 ` Matthew Wilcox
2022-02-07 17:39 ` Michel Lespinasse
2022-02-01 17:17 ` Sebastian Andrzej Siewior
2022-02-23 16:11 ` Mel Gorman
2022-03-08 5:37 ` Suren Baghdasaryan
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