m68knommu: fix syscall tracing

Fix the system call code for handling syscall tracing, so strace
and gdbserver work properly.

This fix originally developed by Philippe De Muyter and Stuart Hughes.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/m68knommu/platform/5307/entry.S b/arch/m68knommu/platform/5307/entry.S
index a8cd867805c..b333731b875 100644
--- a/arch/m68knommu/platform/5307/entry.S
+++ b/arch/m68knommu/platform/5307/entry.S
@@ -74,7 +74,8 @@ ENTRY(system_call)
         movel   %sp,%d2                 /* get thread_info pointer */
         andl    #-THREAD_SIZE,%d2       /* at start of kernel stack */
         movel   %d2,%a0
-        movel   %sp,%a0@(THREAD_ESP0)   /* save top of frame */
+        movel   %a0@,%a1                /* save top of frame */
+        movel   %sp,%a1@(TASK_THREAD+THREAD_ESP0)
         btst    #(TIF_SYSCALL_TRACE%8),%a0@(TI_FLAGS+(31-TIF_SYSCALL_TRACE)/8)
         bnes    1f
 
@@ -83,6 +84,8 @@ ENTRY(system_call)
         movel   %d0,%sp@(PT_D0)         /* save the return value */
         jra     ret_from_exception
 1:
+        movel   #-ENOSYS,%d2            /* strace needs -ENOSYS in PT_D0 */
+        movel   %d2,PT_D0(%sp)          /* on syscall entry */
         subql   #4,%sp
         SAVE_SWITCH_STACK
         jbsr    syscall_trace