From 849c498766060a16aad5b0e0d03206726e7d2fa4 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 25 Oct 2016 19:43:17 -0700 Subject: [PATCH] sparc64: Handle extremely large kernel TSB range flushes sanely. If the number of pages we are flushing is more than twice the number of entries in the TSB, just scan the TSB table for matches rather than probing each and every page in the range. Based upon a patch and report by James Clarke. Signed-off-by: David S. Miller --- arch/sparc/mm/tsb.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c index f2b77112e9d8..e20fbbafb0b0 100644 --- a/arch/sparc/mm/tsb.c +++ b/arch/sparc/mm/tsb.c @@ -27,6 +27,20 @@ static inline int tag_compare(unsigned long tag, unsigned long vaddr) return (tag == (vaddr >> 22)); } +static void flush_tsb_kernel_range_scan(unsigned long start, unsigned long end) +{ + unsigned long idx; + + for (idx = 0; idx < KERNEL_TSB_NENTRIES; idx++) { + struct tsb *ent = &swapper_tsb[idx]; + unsigned long match = idx << 13; + + match |= (ent->tag << 22); + if (match >= start && match < end) + ent->tag = (1UL << TSB_TAG_INVALID_BIT); + } +} + /* TSB flushes need only occur on the processor initiating the address * space modification, not on each cpu the address space has run on. * Only the TLB flush needs that treatment. @@ -36,6 +50,9 @@ void flush_tsb_kernel_range(unsigned long start, unsigned long end) { unsigned long v; + if ((end - start) >> PAGE_SHIFT >= 2 * KERNEL_TSB_NENTRIES) + return flush_tsb_kernel_range_scan(start, end); + for (v = start; v < end; v += PAGE_SIZE) { unsigned long hash = tsb_hash(v, PAGE_SHIFT, KERNEL_TSB_NENTRIES); -- 2.20.1