ARM: pgtable: consolidate set_pte_ext(TOP_PTE,...) + tlb flush

A number of places establish a PTE in our top page table and
immediately flush the TLB.  Rather than having this at every callsite,
provide an inline function for this purpose.

This changes some global tlb flushes to be local; each time we setup
one of these mappings, we always do it with preemption disabled which
would prevent us migrating to another CPU.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/copypage-v4mc.c

@@ -74,8 +74,7 @@ void v4_mc_copy_user_highpage(struct page *to, struct page *from,
 
 	raw_spin_lock(&minicache_lock);
 
-	set_pte_ext(TOP_PTE(COPYPAGE_MINICACHE), mk_pte(from, minicache_pgprot), 0);
-	flush_tlb_kernel_page(COPYPAGE_MINICACHE);
+	set_top_pte(COPYPAGE_MINICACHE, mk_pte(from, minicache_pgprot));
 
 	mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto);
 

arch/arm/mm/copypage-v6.c

@@ -90,11 +90,8 @@ static void v6_copy_user_highpage_aliasing(struct page *to,
 	kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
 	kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
 
-	set_pte_ext(TOP_PTE(kfrom), mk_pte(from, PAGE_KERNEL), 0);
-	set_pte_ext(TOP_PTE(kto), mk_pte(to, PAGE_KERNEL), 0);
-
-	flush_tlb_kernel_page(kfrom);
-	flush_tlb_kernel_page(kto);
+	set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
+	set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
 
 	copy_page((void *)kto, (void *)kfrom);
 
@@ -119,8 +116,7 @@ static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vad
 	 */
 	raw_spin_lock(&v6_lock);
 
-	set_pte_ext(TOP_PTE(to), mk_pte(page, PAGE_KERNEL), 0);
-	flush_tlb_kernel_page(to);
+	set_top_pte(to, mk_pte(page, PAGE_KERNEL));
 	clear_page((void *)to);
 
 	raw_spin_unlock(&v6_lock);

arch/arm/mm/copypage-xscale.c

@@ -94,8 +94,7 @@ void xscale_mc_copy_user_highpage(struct page *to, struct page *from,
 
 	raw_spin_lock(&minicache_lock);
 
-	set_pte_ext(TOP_PTE(COPYPAGE_MINICACHE), mk_pte(from, minicache_pgprot), 0);
-	flush_tlb_kernel_page(COPYPAGE_MINICACHE);
+	set_top_pte(COPYPAGE_MINICACHE, mk_pte(from, minicache_pgprot));
 
 	mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto);
 

arch/arm/mm/flush.c

@@ -28,8 +28,7 @@ static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
 	unsigned long to = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
 	const int zero = 0;
 
-	set_pte_ext(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL), 0);
-	flush_tlb_kernel_page(to);
+	set_top_pte(to, pfn_pte(pfn, PAGE_KERNEL));
 
 	asm(	"mcrr	p15, 0, %1, %0, c14\n"
 	"	mcr	p15, 0, %2, c7, c10, 4"
@@ -40,13 +39,12 @@ static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
 
 static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
 {
-	unsigned long colour = CACHE_COLOUR(vaddr);
+	unsigned long va = FLUSH_ALIAS_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
 	unsigned long offset = vaddr & (PAGE_SIZE - 1);
 	unsigned long to;
 
-	set_pte_ext(TOP_PTE(FLUSH_ALIAS_START) + colour, pfn_pte(pfn, PAGE_KERNEL), 0);
-	to = FLUSH_ALIAS_START + (colour << PAGE_SHIFT) + offset;
-	flush_tlb_kernel_page(to);
+	set_top_pte(va, pfn_pte(pfn, PAGE_KERNEL));
+	to = va + offset;
 	flush_icache_range(to, to + len);
 }
 

arch/arm/mm/highmem.c

@@ -71,13 +71,12 @@ void *__kmap_atomic(struct page *page)
 	 */
 	BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
 #endif
-	set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
 	/*
 	 * When debugging is off, kunmap_atomic leaves the previous mapping
-	 * in place, so this TLB flush ensures the TLB is updated with the
-	 * new mapping.
+	 * in place, so the contained TLB flush ensures the TLB is updated
+	 * with the new mapping.
 	 */
-	local_flush_tlb_kernel_page(vaddr);
+	set_top_pte(vaddr, mk_pte(page, kmap_prot));
 
 	return (void *)vaddr;
 }
@@ -96,8 +95,7 @@ void __kunmap_atomic(void *kvaddr)
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
 #ifdef CONFIG_DEBUG_HIGHMEM
 		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
-		set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
-		local_flush_tlb_kernel_page(vaddr);
+		set_top_pte(vaddr, __pte(0));
 #else
 		(void) idx;  /* to kill a warning */
 #endif
@@ -123,8 +121,7 @@ void *kmap_atomic_pfn(unsigned long pfn)
 #ifdef CONFIG_DEBUG_HIGHMEM
 	BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
 #endif
-	set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
-	local_flush_tlb_kernel_page(vaddr);
+	set_top_pte(vaddr, pfn_pte(pfn, kmap_prot));
 
 	return (void *)vaddr;
 }

arch/arm/mm/mm.h

@@ -18,6 +18,12 @@ extern pmd_t *top_pmd;
 /* PFN alias flushing, for VIPT caches */
 #define FLUSH_ALIAS_START	0xffff4000
 
+static inline void set_top_pte(unsigned long va, pte_t pte)
+{
+	set_pte_ext(TOP_PTE(va), pte, 0);
+	local_flush_tlb_kernel_page(va);
+}
+
 static inline pmd_t *pmd_off_k(unsigned long virt)
 {
 	return pmd_offset(pud_offset(pgd_offset_k(virt), virt), virt);