[patch RFC 04/15] arc/mm/highmem: Use generic kmap atomic implementation

[Thomas Gleixner]

Adopt the map ordering to match the other architectures and the generic
code.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
---
Note: Completely untested
---
 arch/arc/Kconfig               |    1 
 arch/arc/include/asm/highmem.h |    8 ++++++-
 arch/arc/mm/highmem.c          |   44 -----------------------------------------
 3 files changed, 9 insertions(+), 44 deletions(-)

--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -508,6 +508,7 @@ config LINUX_RAM_BASE
 config HIGHMEM
 	bool "High Memory Support"
 	select ARCH_DISCONTIGMEM_ENABLE
+	select KMAP_ATOMIC_GENERIC
 	help
 	  With ARC 2G:2G address split, only upper 2G is directly addressable by
 	  kernel. Enable this to potentially allow access to rest of 2G and PAE
--- a/arch/arc/include/asm/highmem.h
+++ b/arch/arc/include/asm/highmem.h
@@ -15,7 +15,10 @@
 #define FIXMAP_BASE		(PAGE_OFFSET - FIXMAP_SIZE - PKMAP_SIZE)
 #define FIXMAP_SIZE		PGDIR_SIZE	/* only 1 PGD worth */
 #define KM_TYPE_NR		((FIXMAP_SIZE >> PAGE_SHIFT)/NR_CPUS)
-#define FIXMAP_ADDR(nr)		(FIXMAP_BASE + ((nr) << PAGE_SHIFT))
+
+#define FIX_KMAP_BEGIN		(0)
+#define FIX_KMAP_END		((FIXMAP_SIZE >> PAGE_SHIFT) - 1)
+#define FIXADDR_TOP		(FIXMAP_BASE + FIXMAP_SIZE - PAGE_SIZE)
 
 /* start after fixmap area */
 #define PKMAP_BASE		(FIXMAP_BASE + FIXMAP_SIZE)
@@ -29,6 +32,9 @@
 
 extern void kmap_init(void);
 
+#define arch_kmap_temp_post_unmap(vaddr)			\
+	local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE)
+
 static inline void flush_cache_kmaps(void)
 {
 	flush_cache_all();
--- a/arch/arc/mm/highmem.c
+++ b/arch/arc/mm/highmem.c
@@ -47,48 +47,6 @@
  */
 
 extern pte_t * pkmap_page_table;
-static pte_t * fixmap_page_table;
-
-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
-{
-	int idx, cpu_idx;
-	unsigned long vaddr;
-
-	cpu_idx = kmap_atomic_idx_push();
-	idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
-	vaddr = FIXMAP_ADDR(idx);
-
-	set_pte_at(&init_mm, vaddr, fixmap_page_table + idx,
-		   mk_pte(page, prot));
-
-	return (void *)vaddr;
-}
-EXPORT_SYMBOL(kmap_atomic_high_prot);
-
-void kunmap_atomic_high(void *kv)
-{
-	unsigned long kvaddr = (unsigned long)kv;
-
-	if (kvaddr >= FIXMAP_BASE && kvaddr < (FIXMAP_BASE + FIXMAP_SIZE)) {
-
-		/*
-		 * Because preemption is disabled, this vaddr can be associated
-		 * with the current allocated index.
-		 * But in case of multiple live kmap_atomic(), it still relies on
-		 * callers to unmap in right order.
-		 */
-		int cpu_idx = kmap_atomic_idx();
-		int idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
-
-		WARN_ON(kvaddr != FIXMAP_ADDR(idx));
-
-		pte_clear(&init_mm, kvaddr, fixmap_page_table + idx);
-		local_flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE);
-
-		kmap_atomic_idx_pop();
-	}
-}
-EXPORT_SYMBOL(kunmap_atomic_high);
 
 static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
 {
@@ -113,5 +71,5 @@ void __init kmap_init(void)
 	pkmap_page_table = alloc_kmap_pgtable(PKMAP_BASE);
 
 	BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE);
-	fixmap_page_table = alloc_kmap_pgtable(FIXMAP_BASE);
+	alloc_kmap_pgtable(FIXMAP_BASE);
 }