powerpc: Keep track of emulated instructions

If CONFIG_PPC_EMULATED_STATS is enabled, make available counters for the
various classes of emulated instructions under
/sys/kernel/debug/powerpc/emulated_instructions/ (assumed debugfs is mounted on
/sys/kernel/debug).  Optionally (controlled by
/sys/kernel/debug/powerpc/emulated_instructions/do_warn), rate-limited warnings
can be printed to the console when instructions are emulated.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index a1098e23221f..d79a902d155a 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -41,6 +41,19 @@ config HCALL_STATS
           This option will add a small amount of overhead to all hypervisor
           calls.
 
+config PPC_EMULATED_STATS
+        bool "Emulated instructions tracking"
+        depends on DEBUG_FS
+        help
+          Adds code to keep track of the number of instructions that are
+          emulated by the in-kernel emulator. Counters for the various classes
+          of emulated instructions are available under
+          powerpc/emulated_instructions/ in the root of the debugfs file
+          system. Optionally (controlled by
+          powerpc/emulated_instructions/do_warn in debugfs), rate-limited
+          warnings can be printed to the console when instructions are
+          emulated.
+
 config CODE_PATCHING_SELFTEST
         bool "Run self-tests of the code-patching code."
         depends on DEBUG_KERNEL