arch/tlb: Clean up simple architectures

For the architectures that do not implement their own tlb_flush() but
do already use the generic mmu_gather, there are two options:

 1) the platform has an efficient flush_tlb_range() and
    asm-generic/tlb.h doesn't need any overrides at all.

 2) the platform lacks an efficient flush_tlb_range() and
    we select MMU_GATHER_NO_RANGE to minimize full invalidates.

Convert all 'simple' architectures to one of these two forms.

alpha:	    has no range invalidate -> 2
arc:	    already used flush_tlb_range() -> 1
c6x:	    has no range invalidate -> 2
hexagon:    has an efficient flush_tlb_range() -> 1
            (flush_tlb_mm() is in fact a full range invalidate,
	     so no need to shoot down everything)
m68k:	    has inefficient flush_tlb_range() -> 2
microblaze: has no flush_tlb_range() -> 2
mips:	    has efficient flush_tlb_range() -> 1
	    (even though it currently seems to use flush_tlb_mm())
nds32:	    already uses flush_tlb_range() -> 1
nios2:	    has inefficient flush_tlb_range() -> 2
	    (no limit on range iteration)
openrisc:   has inefficient flush_tlb_range() -> 2
	    (no limit on range iteration)
parisc:	    already uses flush_tlb_range() -> 1
sparc32:    already uses flush_tlb_range() -> 1
unicore32:  has inefficient flush_tlb_range() -> 2
	    (no limit on range iteration)
xtensa:	    has efficient flush_tlb_range() -> 1

Note this also fixes a bug in the existing code for a number
platforms. Those platforms that did:

  tlb_end_vma() -> if (!full_mm) flush_tlb_*()
  tlb_flush -> if (full_mm) flush_tlb_mm()

missed the case of shift_arg_pages(), which doesn't have @fullmm set,
nor calls into tlb_*vma(), but still frees page-tables and thus needs
an invalidate. The new code handles this by detecting a non-empty
range, and either issuing the matching range invalidate or a full
invalidate, depending on the capabilities.

No change in behavior intended.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Greentime Hu <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Ley Foon Tan <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Richard Kuo <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

arch/nios2/Kconfig

@@ -24,6 +24,7 @@ config NIOS2
 	select USB_ARCH_HAS_HCD if USB_SUPPORT
 	select CPU_NO_EFFICIENT_FFS
 	select ARCH_DISCARD_MEMBLOCK
+	select MMU_GATHER_NO_RANGE if MMU
 
 config GENERIC_CSUM
 	def_bool y

arch/nios2/include/asm/tlb.h

@@ -11,12 +11,12 @@
 #ifndef _ASM_NIOS2_TLB_H
 #define _ASM_NIOS2_TLB_H
 
-#define tlb_flush(tlb)	flush_tlb_mm((tlb)->mm)
-
 extern void set_mmu_pid(unsigned long pid);
 
-#define tlb_end_vma(tlb, vma)	do { } while (0)
-#define __tlb_remove_tlb_entry(tlb, ptep, address)	do { } while (0)
+/*
+ * NIOS32 does have flush_tlb_range(), but it lacks a limit and fallback to
+ * full mm invalidation. So use flush_tlb_mm() for everything.
+ */
 
 #include <linux/pagemap.h>
 #include <asm-generic/tlb.h>