parisc: speed up flush_tlb_all_local with qemu

When started in qemu, we know that qemu will drop all local TLB entries
on any pxtlbe instruction. So, if we detect qemu, replace the whole
flush_tlb_all_local function by one pdtlbe instruction.

Signed-off-by: Helge Deller <deller@gmx.de>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index df46b0e5a915..fa092ed1e837 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -174,6 +174,15 @@ fdtdone:
 
 2:      bv              %r0(%r2)
         nop
+
+        /*
+         * When running in qemu, drop whole flush_tlb_all_local function and
+         * replace by one pdtlbe instruction, for which QEMU will drop all
+         * local TLB entries.
+         */
+3:      pdtlbe          %r0(%sr1,%r0)
+        bv,n            %r0(%r2)
+        ALTERNATIVE_CODE(flush_tlb_all_local, 2, ALT_COND_RUN_ON_QEMU, 3b)
 ENDPROC_CFI(flush_tlb_all_local)
 
         .import cache_info,data