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authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>2019-03-05 15:46:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 21:07:18 -0800
commit5b323367ef2567dff0d3daff477186002754f0bd (patch)
tree48198967c06de704b46750342fdce8ec4677461d /arch
parent04a8645304500be88b3345b65fef7efe58016166 (diff)
arch/powerpc/mm: Nest MMU workaround for mprotect RW upgrade
NestMMU requires us to mark the pte invalid and flush the tlb when we do a RW upgrade of pte. We fixed a variant of this in the fault path in bd5050e38aec ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang"). Do the same for mprotect upgrades. Hugetlb is handled in the next patch. Link: http://lkml.kernel.org/r/20190116085035.29729-4-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/book3s/64/pgtable.h18
-rw-r--r--arch/powerpc/include/asm/book3s/64/radix.h4
-rw-r--r--arch/powerpc/mm/pgtable-book3s64.c25
-rw-r--r--arch/powerpc/mm/pgtable-radix.c18
4 files changed, 65 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index d8c8d7c9df15..868fcaf56f6b 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1306,6 +1306,24 @@ static inline int pud_pfn(pud_t pud)
BUILD_BUG();
return 0;
}
+#define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
+pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, pte_t *);
+void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long,
+ pte_t *, pte_t, pte_t);
+
+/*
+ * Returns true for a R -> RW upgrade of pte
+ */
+static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_val)
+{
+ if (!(old_val & _PAGE_READ))
+ return false;
+
+ if ((!(old_val & _PAGE_WRITE)) && (new_val & _PAGE_WRITE))
+ return true;
+
+ return false;
+}
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 7d1a3d1543fc..5ab134eeed20 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -127,6 +127,10 @@ extern void radix__ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep
pte_t entry, unsigned long address,
int psize);
+extern void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep,
+ pte_t old_pte, pte_t pte);
+
static inline unsigned long __radix_pte_update(pte_t *ptep, unsigned long clr,
unsigned long set)
{
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index ecd31569a120..e7da590c7a78 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -401,6 +401,31 @@ void arch_report_meminfo(struct seq_file *m)
}
#endif /* CONFIG_PROC_FS */
+pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr,
+ pte_t *ptep)
+{
+ unsigned long pte_val;
+
+ /*
+ * Clear the _PAGE_PRESENT so that no hardware parallel update is
+ * possible. Also keep the pte_present true so that we don't take
+ * wrong fault.
+ */
+ pte_val = pte_update(vma->vm_mm, addr, ptep, _PAGE_PRESENT, _PAGE_INVALID, 0);
+
+ return __pte(pte_val);
+
+}
+
+void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
+ pte_t *ptep, pte_t old_pte, pte_t pte)
+{
+ if (radix_enabled())
+ return radix__ptep_modify_prot_commit(vma, addr,
+ ptep, old_pte, pte);
+ set_pte_at(vma->vm_mm, addr, ptep, pte);
+}
+
/*
* For hash translation mode, we use the deposited table to store hash slot
* information and they are stored at PTRS_PER_PMD offset from related pmd
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 931156069a81..dced3cd241c2 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -1063,3 +1063,21 @@ void radix__ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep,
}
/* See ptesync comment in radix__set_pte_at */
}
+
+void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep,
+ pte_t old_pte, pte_t pte)
+{
+ struct mm_struct *mm = vma->vm_mm;
+
+ /*
+ * To avoid NMMU hang while relaxing access we need to flush the tlb before
+ * we set the new value. We need to do this only for radix, because hash
+ * translation does flush when updating the linux pte.
+ */
+ if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) &&
+ (atomic_read(&mm->context.copros) > 0))
+ radix__flush_tlb_page(vma, addr);
+
+ set_pte_at(mm, addr, ptep, pte);
+}