arch/tile: update some comments to clarify register usage.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 42ff73d5f637..221f12bd27fa 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -214,9 +214,10 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
         /*
          * Copy the callee-saved registers from the passed pt_regs struct
          * into the context-switch callee-saved registers area.
-         * We have to restore the callee-saved registers since we may
-         * be cloning a userspace task with userspace register state,
-         * and we won't be unwinding the same kernel frames to restore them.
+         * This way when we start the interrupt-return sequence, the
+         * callee-save registers will be correctly in registers, which
+         * is how we assume the compiler leaves them as we start doing
+         * the normal return-from-interrupt path after calling C code.
          * Zero out the C ABI save area to mark the top of the stack.
          */
         ksp = (unsigned long) childregs;