[PATCH 4/6] MIPS: mm: Use the TLBINVF instruction to flush the VTLB

[Markos Chandras <markos.chandras@xxxxxxxxxx>]

From: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>

The TLBINVF instruction can be used to flush the entire VTLB.
This eliminates the need for the TLBWI loop and improves performance.

Reviewed-by: Paul Burton <paul.burton@xxxxxxxxxx>
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
---
 arch/mips/include/asm/mipsregs.h | 13 +++++++++++++
 arch/mips/mm/tlb-r4k.c           | 18 ++++++++++++------
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 412fe99..9cd0e13 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -685,6 +685,19 @@ static inline int mm_insn_16bit(u16 insn)
 }
 
 /*
+ * TLB Invalidate Flush
+ */
+static inline void tlbinvf(void)
+{
+	__asm__ __volatile__(
+		".set push\n\t"
+		".set noreorder\n\t"
+		".word 0x42000004\n\t" /* tlbinvf */
+		".set pop");
+}
+
+
+/*
  * Functions to access the R10000 performance counters.	 These are basically
  * mfc0 and mtc0 instructions from and to coprocessor register with a 5-bit
  * performance counter number encoded into bits 1 ... 5 of the instruction.
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index 363aa03..427dcac 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -83,13 +83,19 @@ void local_flush_tlb_all(void)
 	entry = read_c0_wired();
 
 	/* Blast 'em all away. */
-	while (entry < current_cpu_data.tlbsize) {
-		/* Make sure all entries differ. */
-		write_c0_entryhi(UNIQUE_ENTRYHI(entry));
-		write_c0_index(entry);
+	if (cpu_has_tlbinv && current_cpu_data.tlbsize) {
+		write_c0_index(0);
 		mtc0_tlbw_hazard();
-		tlb_write_indexed();
-		entry++;
+		tlbinvf();  /* invalidate VTLB */
+	} else {
+		while (entry < current_cpu_data.tlbsize) {
+			/* Make sure all entries differ. */
+			write_c0_entryhi(UNIQUE_ENTRYHI(entry));
+			write_c0_index(entry);
+			mtc0_tlbw_hazard();
+			tlb_write_indexed();
+			entry++;
+		}
 	}
 	tlbw_use_hazard();
 	write_c0_entryhi(old_ctx);
-- 
1.8.4