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xtensa: reimplement register spilling 

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  <jcmvbkbc@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.

From-SVN: r226962
This commit is contained in:
Max Filippov 2015-08-18 01:05:44 +00:00 committed by Max Filippov
parent 3b6e040122
commit b6ac5f6231
2 changed files with 30 additions and 7 deletions
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7
libgcc/ChangeLog
View File

@ -1,3 +1,10 @@
2015-08-18 Max Filippov <jcmvbkbc@gmail.com>
* 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.
2015-08-14 Yuri Rumyantsev <ysrumyan@gmail.com>
* config/i386/cpuinfo.c (enum processor_subtypes): Add skylake.

30
libgcc/config/xtensa/lib2funcs.S
View File

@ -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