highmem, -rt: Implement pfn and prot kmaps

iomap_32 uses kmap_atomic_prot_pfn() for its maps, but on -rt we have
to use kmap() for such mappings, so teach kmap about pfn and prot
thingies.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 25 insertions, 43 deletions

diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
index 433ae1f02e95..827965748b96 100644
--- a/arch/x86/include/asm/highmem.h
+++ b/arch/x86/include/asm/highmem.h
@@ -55,14 +55,17 @@ extern unsigned long highstart_pfn, highend_pfn;
 #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
 
 extern void *kmap_high(struct page *page);
+extern void *kmap_pfn_prot(unsigned long pfn, pgprot_t prot);
 extern void kunmap_high(struct page *page);
 
 void *kmap(struct page *page);
+void *kmap_page_prot(struct page *page, pgprot_t prot);
 extern void kunmap_virt(void *ptr);
 extern struct page *kmap_to_page(void *ptr);
 void kunmap(struct page *page);
 
 void *__kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot);
+void *__kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
 void *__kmap_atomic(struct page *page, enum km_type type);
 void *__kmap_atomic_direct(struct page *page, enum km_type type);
 void __kunmap_atomic(void *kvaddr, enum km_type type);
@@ -85,15 +88,17 @@ extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
  * on PREEMPT_RT kmap_atomic() is a wrapper that uses kmap():
  */
 #ifdef CONFIG_PREEMPT_RT
-# define kmap_atomic_prot(page, type, prot)	({ pagefault_disable(); kmap(page); })
+# define kmap_atomic_prot(page, type, prot)	({ pagefault_disable(); kmap_pfn_prot(page_to_pfn(page), prot); })
+# define kmap_atomic_prot_pfn(pfn, type, prot)	({ pagefault_disable(); kmap_pfn_prot(pfn, prot); })
 # define kmap_atomic(page, type)	({ pagefault_disable(); kmap(page); })
 # define kmap_atomic_pfn(pfn, type)	kmap(pfn_to_page(pfn))
-# define kunmap_atomic(kvaddr, type)	do { pagefault_enable(); kunmap_virt(kvaddr); } while(0)
+# define kunmap_atomic(kvaddr, type)	do { kunmap_virt(kvaddr); pagefault_enable(); } while(0)
 # define kmap_atomic_to_page(kvaddr)	kmap_to_page(kvaddr)
 # define kmap_atomic_direct(page, type)	__kmap_atomic_direct(page, type)
 # define kunmap_atomic_direct(kvaddr, type)	__kunmap_atomic(kvaddr, type)
 #else
 # define kmap_atomic_prot(page, type, prot)	__kmap_atomic_prot(page, type, prot)
+# define kmap_atomic_prot_pfn(pfn, type, prot)  __kmap_atomic_prot_pfn(pfn, type, prot)
 # define kmap_atomic(page, type)	__kmap_atomic(page, type)
 # define kmap_atomic_pfn(pfn, type)	__kmap_atomic_pfn(pfn, type)
 # define kunmap_atomic(kvaddr, type)	__kunmap_atomic(kvaddr, type)
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index dcb1899bcff7..b4eb59a59ef4 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -19,16 +19,6 @@ void kunmap(struct page *page)
 	kunmap_high(page);
 }
 
-void kunmap_virt(void *ptr)
-{
-	struct page *page;
-
-	if ((unsigned long)ptr < PKMAP_ADDR(0))
-		return;
-	page = pte_page(pkmap_page_table[PKMAP_NR((unsigned long)ptr)]);
-	kunmap(page);
-}
-
 struct page *kmap_to_page(void *ptr)
 {
 	struct page *page;
@@ -70,6 +60,23 @@ void *__kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
 	return (void *)vaddr;
 }
 
+void *__kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
+{
+	enum fixed_addresses idx;
+	unsigned long vaddr;
+
+	preempt_disable();
+	pagefault_disable();
+
+	debug_kmap_atomic(type);
+	idx = type + KM_TYPE_NR * smp_processor_id();
+	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
+	arch_flush_lazy_mmu_mode();
+
+	return (void *)vaddr;
+}
+
 void *__kmap_atomic_direct(struct page *page, enum km_type type)
 {
 	return __kmap_atomic_prot(page, type, kmap_prot);
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index 715d822334b4..38a1a6845a73 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -55,23 +55,6 @@ iomap_free(resource_size_t base, unsigned long size)
 }
 EXPORT_SYMBOL_GPL(iomap_free);
 
-void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
-{
-	enum fixed_addresses idx;
-	unsigned long vaddr;
-
-	preempt_disable();
-	pagefault_disable();
-
-	debug_kmap_atomic(type);
-	idx = type + KM_TYPE_NR * smp_processor_id();
-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
-	arch_flush_lazy_mmu_mode();
-
-	return (void *)vaddr;
-}
-
 /*
  * Map 'pfn' using fixed map 'type' and protections 'prot'
  */
@@ -94,19 +77,6 @@ EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
 void
 iounmap_atomic(void *kvaddr, enum km_type type)
 {
-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
-
-	/*
-	 * Force other mappings to Oops if they'll try to access this pte
-	 * without first remap it.  Keeping stale mappings around is a bad idea
-	 * also, in case the page changes cacheability attributes or becomes
-	 * a protected page in a hypervisor.
-	 */
-	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
-		kpte_clear_flush(kmap_pte-idx, vaddr);
-
-	pagefault_enable();
-	preempt_enable();
+	kunmap_atomic(kvaddr, type);
 }
 EXPORT_SYMBOL_GPL(iounmap_atomic);