Spilling windowed registers in userspace is much easier, more portable,
less error-prone and equally effective as in kernel. Now that register
spilling syscall is considered obsolete in the xtensa linux kernel
replace it with CALL12 followed by series of ENTRY in libgcc.
2015-08-18 Max Filippov <jcmvb...@gmail.com>
libgcc/
* config/xtensa/lib2funcs.S (__xtensa_libgcc_window_spill): Use
CALL12 followed by series of ENTRY to spill windowed registers.
(__xtensa_nonlocal_goto): Call __xtensa_libgcc_window_spill
instead of making linux spill syscall.
---
libgcc/config/xtensa/lib2funcs.S | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)
diff --git a/libgcc/config/xtensa/lib2funcs.S b/libgcc/config/xtensa/lib2funcs.S
index 4d451c8..ef0703f 100644
--- a/libgcc/config/xtensa/lib2funcs.S
+++ b/libgcc/config/xtensa/lib2funcs.S
@@ -34,10 +34,29 @@ see the files COPYING3 and COPYING.RUNTIME respectively.
If not, see
.global __xtensa_libgcc_window_spill
.type __xtensa_libgcc_window_spill,@function
__xtensa_libgcc_window_spill:
- entry sp, 32
- movi a2, 0
- syscall
+ entry sp, 48
+#if XCHAL_NUM_AREGS > 16
+ call12 1f
+ retw
+ .align 4
+1:
+ .rept (XCHAL_NUM_AREGS - 24) / 12
+ _entry sp, 48
+ mov a12, a0
+ .endr
+ _entry sp, 16
+#if XCHAL_NUM_AREGS % 12 == 0
+ mov a4, a4
+#elif XCHAL_NUM_AREGS % 12 == 4
+ mov a8, a8
+#elif XCHAL_NUM_AREGS % 12 == 8
+ mov a12, a12
+#endif
retw
+#else
+ mov a8, a8
+ retw
+#endif
.size __xtensa_libgcc_window_spill, .-__xtensa_libgcc_window_spill
#endif
@@ -61,10 +80,7 @@ __xtensa_nonlocal_goto:
entry sp, 32
/* Flush registers. */
- mov a5, a2
- movi a2, 0
- syscall
- mov a2, a5
+ call8 __xtensa_libgcc_window_spill
/* Because the save area for a0-a3 is stored one frame below
the one identified by a2, the only way to restore those
--
1.8.1.4
