[RFC PATCH 7/7] powerpc/64s/radix: Only flush local TLB for spurious fault flushes
Nicholas Piggin
npiggin at gmail.com
Tue Oct 31 18:18:28 AEDT 2017
When permissiveness is relaxed, or found to have been relaxed by
another thread, we flush that address out of the TLB to avoid a
future fault or micro-fault due to a stale TLB entry.
Currently for processes with TLBs on other CPUs, this flush is always
done with a global tlbie. Although that could reduce faults on remote
CPUs, a broadcast operation seems to be wasteful for something that
can be handled in-core by the remote CPU if it comes to it.
XXX: This still needs some consideration with accelerators, not for
merge yet
---
.../powerpc/include/asm/book3s/64/tlbflush-radix.h | 5 +++
arch/powerpc/include/asm/book3s/64/tlbflush.h | 11 ++++++
arch/powerpc/mm/pgtable-book3s64.c | 5 ++-
arch/powerpc/mm/pgtable.c | 2 +-
arch/powerpc/mm/tlb-radix.c | 40 +++++++++++++++++++---
5 files changed, 57 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h b/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h
index af06c6fe8a9f..f1851eb64026 100644
--- a/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush-radix.h
@@ -16,6 +16,8 @@ extern void radix__flush_tlb_range_psize(struct mm_struct *mm, unsigned long sta
unsigned long end, int psize);
extern void radix__flush_pmd_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
+extern void radix__local_flush_pmd_tlb_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end);
extern void radix__flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
extern void radix__flush_tlb_kernel_range(unsigned long start, unsigned long end);
@@ -25,6 +27,9 @@ extern void radix__local_flush_all_mm(struct mm_struct *mm);
extern void radix__local_flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr);
extern void radix__local_flush_tlb_page_psize(struct mm_struct *mm, unsigned long vmaddr,
int psize);
+extern void radix__local_flush_tlb_range_psize(struct mm_struct *mm,
+ unsigned long start, unsigned long end,
+ int psize);
extern void radix__tlb_flush(struct mmu_gather *tlb);
#ifdef CONFIG_SMP
extern void radix__flush_tlb_mm(struct mm_struct *mm);
diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush.h b/arch/powerpc/include/asm/book3s/64/tlbflush.h
index 70760d018bcd..accfb49247a4 100644
--- a/arch/powerpc/include/asm/book3s/64/tlbflush.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush.h
@@ -98,6 +98,17 @@ static inline void flush_all_mm(struct mm_struct *mm)
#define flush_tlb_page(vma, addr) local_flush_tlb_page(vma, addr)
#define flush_all_mm(mm) local_flush_all_mm(mm)
#endif /* CONFIG_SMP */
+
+#define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault
+static inline void flush_tlb_fix_spurious_fault(struct vm_area_struct *vma,
+ unsigned long address)
+{
+ if (radix_enabled())
+ radix__local_flush_tlb_page(vma, address);
+ else
+ flush_tlb_page(vma, address);
+}
+
/*
* flush the page walk cache for the address
*/
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 3b65917785a5..e46f346388d6 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -40,7 +40,10 @@ int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
if (changed) {
__ptep_set_access_flags(vma->vm_mm, pmdp_ptep(pmdp),
pmd_pte(entry), address);
- flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+ if (radix_enabled())
+ radix__local_flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+ else
+ flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
return changed;
}
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index a03ff3d99e0c..acd6ae8062ce 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -223,7 +223,7 @@ int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
if (!is_vm_hugetlb_page(vma))
assert_pte_locked(vma->vm_mm, address);
__ptep_set_access_flags(vma->vm_mm, ptep, entry, address);
- flush_tlb_page(vma, address);
+ flush_tlb_fix_spurious_fault(vma, address);
}
return changed;
}
diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index db7e696e4faf..2aca596e3853 100644
--- a/arch/powerpc/mm/tlb-radix.c
+++ b/arch/powerpc/mm/tlb-radix.c
@@ -410,16 +410,18 @@ void radix__flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
asm volatile("ptesync": : :"memory");
if (local) {
- __tlbiel_va_range(start, end, pid, page_size, mmu_virtual_psize);
+ __tlbiel_va_range(start, end, pid, page_size,
+ mmu_virtual_psize);
if (hflush)
__tlbiel_va_range(hstart, hend, pid,
- HPAGE_PMD_SIZE, MMU_PAGE_2M);
+ HPAGE_PMD_SIZE, MMU_PAGE_2M);
asm volatile("ptesync": : :"memory");
} else {
- __tlbie_va_range(start, end, pid, page_size, mmu_virtual_psize);
+ __tlbie_va_range(start, end, pid, page_size,
+ mmu_virtual_psize);
if (hflush)
__tlbie_va_range(hstart, hend, pid,
- HPAGE_PMD_SIZE, MMU_PAGE_2M);
+ HPAGE_PMD_SIZE, MMU_PAGE_2M);
asm volatile("eieio; tlbsync; ptesync": : :"memory");
}
}
@@ -477,6 +479,30 @@ void radix__tlb_flush(struct mmu_gather *tlb)
tlb->need_flush_all = 0;
}
+void radix__local_flush_tlb_range_psize(struct mm_struct *mm,
+ unsigned long start, unsigned long end,
+ int psize)
+{
+ unsigned long pid;
+ unsigned int page_shift = mmu_psize_defs[psize].shift;
+ unsigned long page_size = 1UL << page_shift;
+ unsigned long nr_pages = (end - start) >> page_shift;
+ bool full;
+
+ pid = mm->context.id;
+ if (unlikely(pid == MMU_NO_CONTEXT))
+ return;
+
+ preempt_disable();
+ full = (end == TLB_FLUSH_ALL ||
+ nr_pages > tlb_local_single_page_flush_ceiling);
+ if (full)
+ _tlbiel_pid(pid, RIC_FLUSH_TLB);
+ else
+ _tlbiel_va_range(start, end, pid, page_size, psize, false);
+ preempt_enable();
+}
+
static inline void __radix__flush_tlb_range_psize(struct mm_struct *mm,
unsigned long start, unsigned long end,
int psize, bool also_pwc)
@@ -604,6 +630,12 @@ void radix__flush_tlb_lpid(unsigned long lpid)
}
EXPORT_SYMBOL(radix__flush_tlb_lpid);
+void radix__local_flush_pmd_tlb_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ radix__local_flush_tlb_range_psize(vma->vm_mm, start, end, MMU_PAGE_2M);
+}
+
void radix__flush_pmd_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
--
2.15.0.rc2
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