1 files changed, 32 insertions, 3 deletions

diff --git a/arch/sparc/lib/memmove.S b/arch/sparc/lib/memmove.S
index b7f6334e159f..857ad4f8905f 100644
--- a/arch/sparc/lib/memmove.S
+++ b/arch/sparc/lib/memmove.S
@@ -8,9 +8,11 @@
 
         .text
 ENTRY(memmove) /* o0=dst o1=src o2=len */
-        mov             %o0, %g1
+        brz,pn          %o2, 99f
+         mov            %o0, %g1
+
         cmp             %o0, %o1
-        bleu,pt         %xcc, memcpy
+        bleu,pt         %xcc, 2f
          add            %o1, %o2, %g7
         cmp             %g7, %o0
         bleu,pt         %xcc, memcpy
@@ -24,7 +26,34 @@ ENTRY(memmove) /* o0=dst o1=src o2=len */
         stb             %g7, [%o0]
         bne,pt          %icc, 1b
          sub            %o0, 1, %o0
-
+99:
         retl
          mov            %g1, %o0
+
+        /* We can't just call memcpy for these memmove cases.  On some
+         * chips the memcpy uses cache initializing stores and when dst
+         * and src are close enough, those can clobber the source data
+         * before we've loaded it in.
+         */
+2:      or              %o0, %o1, %g7
+        or              %o2, %g7, %g7
+        andcc           %g7, 0x7, %g0
+        bne,pn          %xcc, 4f
+         nop
+
+3:      ldx             [%o1], %g7
+        add             %o1, 8, %o1
+        subcc           %o2, 8, %o2
+        add             %o0, 8, %o0
+        bne,pt          %icc, 3b
+         stx            %g7, [%o0 - 0x8]
+        ba,a,pt         %xcc, 99b
+
+4:      ldub            [%o1], %g7
+        add             %o1, 1, %o1
+        subcc           %o2, 1, %o2
+        add             %o0, 1, %o0
+        bne,pt          %icc, 4b
+         stb            %g7, [%o0 - 0x1]
+        ba,a,pt         %xcc, 99b
 ENDPROC(memmove)