Merge branch 'copy_user' of git://git.marvell.com/orion into devel

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c857111ab96..3473f8b8ede 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1091,6 +1091,22 @@ config ALIGNMENT_TRAP
           correct operation of some network protocols. With an IP-only
           configuration it is safe to say N, otherwise say Y.
 
+config UACCESS_WITH_MEMCPY
+        bool "Use kernel mem{cpy,set}() for {copy_to,clear}_user() (EXPERIMENTAL)"
+        depends on MMU && EXPERIMENTAL
+        default y if CPU_FEROCEON
+        help
+          Implement faster copy_to_user and clear_user methods for CPU
+          cores where a 8-word STM instruction give significantly higher
+          memory write throughput than a sequence of individual 32bit stores.
+
+          A possible side effect is a slight increase in scheduling latency
+          between threads sharing the same address space if they invoke
+          such copy operations with large buffers.
+
+          However, if the CPU data cache is using a write-allocate mode,
+          this option is unlikely to provide any performance gain.
+
 endmenu
 
 menu "Boot options"