asm-generic/tlb: Provide generic tlb_flush() based on flush_tlb_mm()
When an architecture does not have (an efficient) flush_tlb_range(),
but instead always uses full TLB invalidates, the current generic
tlb_flush() is sub-optimal, for it will generate extra flushes in
order to keep the range small.
But if we cannot do range flushes, that is a moot concern. Optionally
provide this simplified default.
No change in behavior intended.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>