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From: Alexandre Ghiti <alexghiti@rivosinc.com>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Subject: [PATCH] riscv: Call secondary mmu notifier when flushing the tlb
Date: Wed, 24 Jan 2024 09:03:25 +0100
Message-Id: <20240124080325.2324462-1-alexghiti@rivosinc.com>
Precedence: bulk
MIME-Version: 1.0
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This is required to allow the IOMMU driver to correctly flush its own
TLB.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/mm/tlbflush.c | 39 +++++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index 8d12b26f5ac3..ad7c4205524d 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -4,6 +4,7 @@
 #include <linux/smp.h>
 #include <linux/sched.h>
 #include <linux/hugetlb.h>
+#include <linux/mmu_notifier.h>
 #include <asm/sbi.h>
 #include <asm/mmu_context.h>
 
@@ -98,11 +99,19 @@ static void __ipi_flush_tlb_range_asid(void *info)
 	local_flush_tlb_range_asid(d->start, d->size, d->stride, d->asid);
 }
 
-static void __flush_tlb_range(struct cpumask *cmask, unsigned long asid,
+static inline unsigned long get_mm_asid(struct mm_struct *mm)
+{
+	return (mm && static_branch_unlikely(&use_asid_allocator)) ?
+			atomic_long_read(&mm->context.id) & asid_mask : FLUSH_TLB_NO_ASID;
+}
+
+static void __flush_tlb_range(struct mm_struct *mm,
+			      struct cpumask *cmask,
 			      unsigned long start, unsigned long size,
 			      unsigned long stride)
 {
 	struct flush_tlb_range_data ftd;
+	unsigned long asid = get_mm_asid(mm);
 	bool broadcast;
 
 	if (cpumask_empty(cmask))
@@ -136,31 +145,26 @@ static void __flush_tlb_range(struct cpumask *cmask, unsigned long asid,
 
 	if (cmask != cpu_online_mask)
 		put_cpu();
-}
 
-static inline unsigned long get_mm_asid(struct mm_struct *mm)
-{
-	return static_branch_unlikely(&use_asid_allocator) ?
-			atomic_long_read(&mm->context.id) & asid_mask : FLUSH_TLB_NO_ASID;
+	if (mm)
+		mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, start + size);
 }
 
 void flush_tlb_mm(struct mm_struct *mm)
 {
-	__flush_tlb_range(mm_cpumask(mm), get_mm_asid(mm),
-			  0, FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
+	__flush_tlb_range(mm, mm_cpumask(mm), 0, FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
 }
 
 void flush_tlb_mm_range(struct mm_struct *mm,
 			unsigned long start, unsigned long end,
 			unsigned int page_size)
 {
-	__flush_tlb_range(mm_cpumask(mm), get_mm_asid(mm),
-			  start, end - start, page_size);
+	__flush_tlb_range(mm, mm_cpumask(mm), start, end - start, page_size);
 }
 
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 {
-	__flush_tlb_range(mm_cpumask(vma->vm_mm), get_mm_asid(vma->vm_mm),
+	__flush_tlb_range(vma->vm_mm, mm_cpumask(vma->vm_mm),
 			  addr, PAGE_SIZE, PAGE_SIZE);
 }
 
@@ -193,13 +197,13 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 		}
 	}
 
-	__flush_tlb_range(mm_cpumask(vma->vm_mm), get_mm_asid(vma->vm_mm),
+	__flush_tlb_range(vma->vm_mm, mm_cpumask(vma->vm_mm),
 			  start, end - start, stride_size);
 }
 
 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 {
-	__flush_tlb_range((struct cpumask *)cpu_online_mask, FLUSH_TLB_NO_ASID,
+	__flush_tlb_range(NULL, (struct cpumask *)cpu_online_mask,
 			  start, end - start, PAGE_SIZE);
 }
 
@@ -207,7 +211,7 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
 			unsigned long end)
 {
-	__flush_tlb_range(mm_cpumask(vma->vm_mm), get_mm_asid(vma->vm_mm),
+	__flush_tlb_range(vma->vm_mm, mm_cpumask(vma->vm_mm),
 			  start, end - start, PMD_SIZE);
 }
 #endif
@@ -221,7 +225,10 @@ void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
 			       struct mm_struct *mm,
 			       unsigned long uaddr)
 {
+	unsigned long start = uaddr & PAGE_MASK;
+
 	cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm));
+	mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, start + PAGE_SIZE);
 }
 
 void arch_flush_tlb_batched_pending(struct mm_struct *mm)
@@ -231,6 +238,6 @@ void arch_flush_tlb_batched_pending(struct mm_struct *mm)
 
 void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
 {
-	__flush_tlb_range(&batch->cpumask, FLUSH_TLB_NO_ASID, 0,
-			  FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
+	__flush_tlb_range(NULL, &batch->cpumask,
+			  0, FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
 }
-- 
2.39.2