1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * crt0_r.S: Entry function for SPU-side context restore.
4 *
5 * Copyright (C) 2005 IBM
6 *
7 * Entry and exit function for SPU-side of the context restore
8 * sequence.  Sets up an initial stack frame, then branches to
9 * 'main'.  On return, restores all 128 registers from the LSCSA
10 * and exits.
11 */
12
13#include <asm/spu_csa.h>
14
15.data
16.align 7
17.globl regs_spill
18regs_spill:
19.space SIZEOF_SPU_SPILL_REGS, 0x0
20
21.text
22.global _start
23_start:
24	/* Initialize the stack pointer to point to 16368
25	 * (16kb-16). The back chain pointer is initialized
26	 * to NULL.
27	 */
28	il      $0, 0
29	il      $SP, 16368
30	stqd    $0, 0($SP)
31
32	/* Allocate a minimum stack frame for the called main.
33	 * This is needed so that main has a place to save the
34	 * link register when it calls another function.
35	 */
36	stqd    $SP, -160($SP)
37	ai      $SP, $SP, -160
38
39	/* Call the program's main function. */
40	brsl    $0, main
41
42.global exit
43.global	_exit
44exit:
45_exit:
46	/* SPU Context Restore, Step 5: Restore the remaining 112 GPRs. */
47	ila     $3, regs_spill + 256
48restore_regs:
49	lqr     $4, restore_reg_insts
50restore_reg_loop:
51	ai      $4, $4, 4
52	.balignl 16, 0x40200000
53restore_reg_insts:       /* must be quad-word aligned. */
54	lqd     $16, 0($3)
55	lqd     $17, 16($3)
56	lqd     $18, 32($3)
57	lqd     $19, 48($3)
58	andi    $5, $4, 0x7F
59	stqr    $4, restore_reg_insts
60	ai      $3, $3, 64
61	brnz    $5, restore_reg_loop
62
63	/* SPU Context Restore Step 17: Restore the first 16 GPRs. */
64	lqa $0, regs_spill + 0
65	lqa $1, regs_spill + 16
66	lqa $2, regs_spill + 32
67	lqa $3, regs_spill + 48
68	lqa $4, regs_spill + 64
69	lqa $5, regs_spill + 80
70	lqa $6, regs_spill + 96
71	lqa $7, regs_spill + 112
72	lqa $8, regs_spill + 128
73	lqa $9, regs_spill + 144
74	lqa $10, regs_spill + 160
75	lqa $11, regs_spill + 176
76	lqa $12, regs_spill + 192
77	lqa $13, regs_spill + 208
78	lqa $14, regs_spill + 224
79	lqa $15, regs_spill + 240
80
81	/* Under normal circumstances, the 'exit' function
82	 * terminates with 'stop SPU_RESTORE_COMPLETE',
83	 * indicating that the SPU-side restore code has
84	 * completed.
85	 *
86	 * However it is possible that instructions immediately
87	 * following the 'stop 0x3ffc' have been modified at run
88	 * time so as to recreate the exact SPU_Status settings
89	 * from the application, e.g. illegal instruciton, halt,
90	 * etc.
91	 */
92.global exit_fini
93.global	_exit_fini
94exit_fini:
95_exit_fini:
96	stop	SPU_RESTORE_COMPLETE
97	stop	0
98	stop	0
99	stop	0
100
101	/* Pad the size of this crt0.o to be multiple of 16 bytes. */
102.balignl 16, 0x0
103