MIPS: Add FPU emulator counter for emulated delay slots.

Delay slot emulation in the FPU emulator is the only kernel user of an
executable stack, it is also very slow.  Add a counter so we can see
how many of these emulations are done.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8634/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 3 insertions, 1 deletions

diff --git a/arch/mips/include/asm/fpu_emulator.h b/arch/mips/include/asm/fpu_emulator.h
index 3ee347713307..6370c82eb5e1 100644
--- a/arch/mips/include/asm/fpu_emulator.h
+++ b/arch/mips/include/asm/fpu_emulator.h
@@ -44,6 +44,7 @@ struct mips_fpu_emulator_stats {
         unsigned long ieee754_overflow;
         unsigned long ieee754_zerodiv;
         unsigned long ieee754_invalidop;
+        unsigned long ds_emul;
 };
 
 DECLARE_PER_CPU(struct mips_fpu_emulator_stats, fpuemustats);
diff --git a/arch/mips/math-emu/dsemul.c b/arch/mips/math-emu/dsemul.c
index 4f514f3724cb..58f58185f1c4 100644
--- a/arch/mips/math-emu/dsemul.c
+++ b/arch/mips/math-emu/dsemul.c
@@ -158,6 +158,6 @@ int do_dsemulret(struct pt_regs *xcp)
 
         /* Set EPC to return to post-branch instruction */
         xcp->cp0_epc = epc;
-
+        MIPS_FPU_EMU_INC_STATS(ds_emul);
         return 1;
 }
diff --git a/arch/mips/math-emu/me-debugfs.c b/arch/mips/math-emu/me-debugfs.c
index becdd63e14a9..f308e0f05fc5 100644
--- a/arch/mips/math-emu/me-debugfs.c
+++ b/arch/mips/math-emu/me-debugfs.c
@@ -61,6 +61,7 @@ do {									\
         FPU_STAT_CREATE(ieee754_overflow);
         FPU_STAT_CREATE(ieee754_zerodiv);
         FPU_STAT_CREATE(ieee754_invalidop);
+        FPU_STAT_CREATE(ds_emul);
 
         return 0;
 }