Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/stand/powerpc/ofw/trampolineLE.S
34860 views
1
/*-

2
 * SPDX-License-Identifier: BSD-2-Clause

3
 *

4
 * Copyright (c) 2020 Brandon Bergren <[email protected]>

5
 *

6
 * Redistribution and use in source and binary forms, with or without

7
 * modification, are permitted provided that the following conditions

8
 * are met:

9
 * 1. Redistributions of source code must retain the above copyright

10
 *    notice, this list of conditions and the following disclaimer.

11
 * 2. Redistributions in binary form must reproduce the above copyright

12
 *    notice, this list of conditions and the following disclaimer in the

13
 *    documentation and/or other materials provided with the distribution.

14
 *

15
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

16
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

17
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

18
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

19
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

20
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

21
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

22
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

23
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

24
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

25
 * SUCH DAMAGE.

26
 */

27


28
#include <machine/asm.h>

29


30
/**

31
 * int openfirmware_trampoline(void *buf, int (*cb)(void *));

32
 */

33
ASENTRY_NOPROF(openfirmware_trampoline)

34
	mflr	%r0

35
	stw	%r0, 4(%r1)

36
	stwu	%r1, -16(%r1)

37
	stw	%r30, 8(%r1)

38
	/* Save current MSR for restoration post-call. */

39
	mfmsr	%r30

40
	mr	%r5, %r30

41
	/* Remove LE bit from MSR. */

42
	clrrwi	%r5, %r5, 1

43
	mtsrr0	%r4

44
	mtsrr1	%r5

45
	LOAD_LR_NIA

46
1:

47
	mflr	%r4

48
	addi	%r4, %r4, (2f - 1b)

49
	mtlr	%r4

50
	/* Switch to BE and transfer control to OF entry */

51
	rfid

52
2:

53
	/* Control is returned here, but in BE. */

54
	.long	0x05009f42	/* LOAD_LR_NIA				*/

55
				/* 0:					*/

56
	.long	0xa603db7f	/* mtsrr1 	%r30			*/

57
	.long	0xa602c87f	/* mflr		%r30			*/

58
	.long	0x1400de3b	/* addi		%r30, %r30, (1f - 0b)	*/

59
	.long	0xa603da7f	/* mtsrr0	%r30			*/

60
	.long	0x2400004c	/* rfid					*/

61
				/* 1:					*/

62
1:

63
	/* Back to normal. Tidy up for return. */

64
	lwz	%r30, 8(%r1)

65
	lwz	%r0, 20(%r1)

66
	addi	%r1, %r1, 16

67
	mtlr	%r0

68
	blr

69
ASEND(openfirmware_trampoline)

70


71