microblaze: Add TLS support to sys_clone

Formerly unused Args 4/5 now load parent tid / child tid so the brid to
do_fork can pick up TLS from r10. Arg 3 still unused

There is also necessary to fix old glibc which do not setup r9/r10 (arg 4/5).
Simple clearing them is fine.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: David Holsgrove <david.holsgrove@petalogix.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 66e34a3bfe1b..288678c5fea6 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -493,10 +493,11 @@ C_ENTRY(sys_clone):
         bnei    r6, 1f;                 /* See if child SP arg (arg 1) is 0. */
         lwi     r6, r1, PT_R1;  /* If so, use paret's stack ptr */
 1:      addik   r7, r1, 0;                      /* Arg 2: parent context */
-        add     r8, r0, r0;                     /* Arg 3: (unused) */
-        add     r9, r0, r0;                     /* Arg 4: (unused) */
+        lwi     r9, r1, PT_R8;          /* parent tid.  */
+        lwi     r10, r1, PT_R9;         /* child tid.  */
+        /* do_fork will pick up TLS from regs->r10.  */
         brid    do_fork         /* Do real work (tail-call) */
-        add     r10, r0, r0;                    /* Arg 5: (unused) */
+        add     r8, r0, r0;             /* Arg 3: (unused) */
 
 C_ENTRY(sys_execve):
         brid    microblaze_execve;      /* Do real work (tail-call).*/