nios2: update_mmu_cache preload the TLB with the new PTE

Rather than flush the TLB entry when installing a new PTE to allow
the fast TLB reload to re-fill the TLB, just refill the TLB entry
when removing the old one.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>

3 files changed, 36 insertions, 9 deletions

diff --git a/arch/nios2/include/asm/tlbflush.h b/arch/nios2/include/asm/tlbflush.h
index 982a7ecf221f..b4bf487b9832 100644
--- a/arch/nios2/include/asm/tlbflush.h
+++ b/arch/nios2/include/asm/tlbflush.h
@@ -30,6 +30,9 @@ struct mm_struct;
  *  - flush_tlb_page(vma, address) flushes a page
  *  - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
  *  - flush_tlb_kernel_page(address) flushes a kernel page
+ *
+ *  - reload_tlb_page(vma, address, pte) flushes the TLB for address like
+ *    flush_tlb_page, then replaces it with a TLB for pte.
  */
 extern void flush_tlb_all(void);
 extern void flush_tlb_mm(struct mm_struct *mm);
@@ -48,4 +51,7 @@ static inline void flush_tlb_kernel_page(unsigned long address)
 	flush_tlb_kernel_range(address, address + PAGE_SIZE);
 }
 
+extern void reload_tlb_page(struct vm_area_struct *vma, unsigned long addr,
+			    pte_t pte);
+
 #endif /* _ASM_NIOS2_TLBFLUSH_H */
diff --git a/arch/nios2/mm/cacheflush.c b/arch/nios2/mm/cacheflush.c
index d58e7e80dc0d..65de1bd6a760 100644
--- a/arch/nios2/mm/cacheflush.c
+++ b/arch/nios2/mm/cacheflush.c
@@ -198,13 +198,14 @@ void flush_dcache_page(struct page *page)
 EXPORT_SYMBOL(flush_dcache_page);
 
 void update_mmu_cache(struct vm_area_struct *vma,
-		      unsigned long address, pte_t *pte)
+		      unsigned long address, pte_t *ptep)
 {
-	unsigned long pfn = pte_pfn(*pte);
+	pte_t pte = *ptep;
+	unsigned long pfn = pte_pfn(pte);
 	struct page *page;
 	struct address_space *mapping;
 
-	flush_tlb_page(vma, address);
+	reload_tlb_page(vma, address, pte);
 
 	if (!pfn_valid(pfn))
 		return;
diff --git a/arch/nios2/mm/tlb.c b/arch/nios2/mm/tlb.c
index 2e49993d29ef..af8711885569 100644
--- a/arch/nios2/mm/tlb.c
+++ b/arch/nios2/mm/tlb.c
@@ -43,13 +43,11 @@ static unsigned long pteaddr_invalid(unsigned long addr)
  * This one is only used for pages with the global bit set so we don't care
  * much about the ASID.
  */
-void flush_tlb_one_pid(unsigned long addr, unsigned long mmu_pid)
+static void replace_tlb_one_pid(unsigned long addr, unsigned long mmu_pid, unsigned long tlbacc)
 {
 	unsigned int way;
 	unsigned long org_misc, pid_misc;
 
-	pr_debug("Flush tlb-entry for vaddr=%#lx\n", addr);
-
 	/* remember pid/way until we return. */
 	get_misc_and_pid(&org_misc, &pid_misc);
 
@@ -72,10 +70,11 @@ void flush_tlb_one_pid(unsigned long addr, unsigned long mmu_pid)
 		if (pid != mmu_pid)
 			continue;
 
-		tlbmisc = TLBMISC_WE | (way << TLBMISC_WAY_SHIFT);
+		tlbmisc = mmu_pid | TLBMISC_WE | (way << TLBMISC_WAY_SHIFT);
 		WRCTL(CTL_TLBMISC, tlbmisc);
-		WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
-		WRCTL(CTL_TLBACC, 0);
+		if (tlbacc == 0)
+			WRCTL(CTL_PTEADDR, pteaddr_invalid(addr));
+		WRCTL(CTL_TLBACC, tlbacc);
 		/*
 		 * There should be only a single entry that maps a
 		 * particular {address,pid} so break after a match.
@@ -86,6 +85,20 @@ void flush_tlb_one_pid(unsigned long addr, unsigned long mmu_pid)
 	WRCTL(CTL_TLBMISC, org_misc);
 }
 
+static void flush_tlb_one_pid(unsigned long addr, unsigned long mmu_pid)
+{
+	pr_debug("Flush tlb-entry for vaddr=%#lx\n", addr);
+
+	replace_tlb_one_pid(addr, mmu_pid, 0);
+}
+
+static void reload_tlb_one_pid(unsigned long addr, unsigned long mmu_pid, pte_t pte)
+{
+	pr_debug("Reload tlb-entry for vaddr=%#lx\n", addr);
+
+	replace_tlb_one_pid(addr, mmu_pid, pte_val(pte));
+}
+
 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 			unsigned long end)
 {
@@ -97,6 +110,13 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 	}
 }
 
+void reload_tlb_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+{
+	unsigned long mmu_pid = get_pid_from_context(&vma->vm_mm->context);
+
+	reload_tlb_one_pid(addr, mmu_pid, pte);
+}
+
 /*
  * This one is only used for pages with the global bit set so we don't care
  * much about the ASID.