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>

diff --git a/arch/m68knommu/platform/5307/entry.S b/arch/m68knommu/platform/5307/entry.S
index a8cd867..b333731 100644 (file)
--- 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