spu_restore_crt0.S

  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