xtensa: userspace: simplify syscall trampoline a bit
There is no need to do a call4 and jx. Simply do a callx4
is enough.
Also amended the now incorrect comment about how syscall
trampoline is set up. It is now a straight call4 instead of
the old 2x call4.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
diff --git a/arch/xtensa/core/userspace.S b/arch/xtensa/core/userspace.S
index c798e12..cd446c4 100644
--- a/arch/xtensa/core/userspace.S
+++ b/arch/xtensa/core/userspace.S
@@ -122,9 +122,14 @@
wur.THREADPTR a0
#endif
- /* Set syscall parameters. We have an initial call4 to set up the
- * the stack and then a new call4 for the syscall function itself.
- * So parameters should be put as if it was a call8.
+ /* Set syscall parameters by moving them into place before we do
+ * a call4 for the syscall function itself.
+ * arg1 = a6
+ * arg2 = a3 (clobbered above, so we need to reload it)
+ * arg3 = a4
+ * arg4 = a5
+ * arg5 = a8
+ * arg6 = a9
*/
mov a10, a8
mov a11, a9
@@ -141,7 +146,7 @@
wsr.ps a0
rsync
- call4 _syscall_call0
+ callx4 a2
/* copy return value. Lets put it in the top of stack
* because registers will be clobbered in
@@ -152,12 +157,6 @@
j _syscall_returned
-.align 4
-_syscall_call0:
- /* We want an ENTRY to set a bit in windowstart */
- jx a2
-
-
_syscall_returned:
call0 xtensa_restore_high_regs
