arch/tile: enable single-step support for TILE-Gx

This is not quite the complete support, since we're not yet shipping
intvec_64.S, but it is the support relevant to the set of files we are
currently shipping, and makes it easier to track changes between
our internal sources and our public GIT repository.

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

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S
index 206dc7e1fe36..f5821626247f 100644
--- a/arch/tile/kernel/intvec_32.S
+++ b/arch/tile/kernel/intvec_32.S
@@ -1472,7 +1472,12 @@ handle_ill:
         lw      r26, r24
         sw      r28, r26
 
-        /* Clear TIF_SINGLESTEP */
+        /*
+         * Clear TIF_SINGLESTEP to prevent recursion if we execute an ill.
+         * The normal non-arch flow redundantly clears TIF_SINGLESTEP, but we
+         * need to clear it here and can't really impose on all other arches.
+         * So what's another write between friends?
+         */
         GET_THREAD_INFO(r0)
 
         addi    r1, r0, THREAD_INFO_FLAGS_OFFSET