David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 1 | ############################################################################### |
| 2 | # |
| 3 | # MN10300 Context switch operation |
| 4 | # |
| 5 | # Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| 6 | # Written by David Howells (dhowells@redhat.com) |
| 7 | # |
| 8 | # This program is free software; you can redistribute it and/or |
| 9 | # modify it under the terms of the GNU General Public Licence |
| 10 | # as published by the Free Software Foundation; either version |
| 11 | # 2 of the Licence, or (at your option) any later version. |
| 12 | # |
| 13 | ############################################################################### |
| 14 | #include <linux/sys.h> |
| 15 | #include <linux/linkage.h> |
| 16 | #include <asm/thread_info.h> |
| 17 | #include <asm/cpu-regs.h> |
Akira Takeuchi | 368dd5a | 2010-10-27 17:28:55 +0100 | [diff] [blame] | 18 | #ifdef CONFIG_SMP |
| 19 | #include <proc/smp-regs.h> |
| 20 | #endif /* CONFIG_SMP */ |
David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 21 | |
| 22 | .text |
| 23 | |
| 24 | ############################################################################### |
| 25 | # |
| 26 | # struct task_struct *__switch_to(struct thread_struct *prev, |
| 27 | # struct thread_struct *next, |
| 28 | # struct task_struct *prev_task) |
| 29 | # |
| 30 | ############################################################################### |
| 31 | ENTRY(__switch_to) |
| 32 | movm [d2,d3,a2,a3,exreg1],(sp) |
| 33 | or EPSW_NMID,epsw |
| 34 | |
| 35 | mov (44,sp),d2 |
| 36 | |
| 37 | mov d0,a0 |
| 38 | mov d1,a1 |
| 39 | |
| 40 | # save prev context |
David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 41 | mov __switch_back,d0 |
David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 42 | mov sp,a2 |
| 43 | mov a2,(THREAD_SP,a0) |
| 44 | mov a3,(THREAD_A3,a0) |
| 45 | |
David Howells | 5141c46 | 2011-03-18 16:54:32 +0000 | [diff] [blame] | 46 | #ifdef CONFIG_KGDB |
| 47 | btst 0xff,(kgdb_single_step) |
| 48 | bne __switch_to__lift_sstep_bp |
| 49 | __switch_to__continue: |
| 50 | #endif |
| 51 | mov d0,(THREAD_PC,a0) |
| 52 | |
David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 53 | mov (THREAD_A3,a1),a3 |
| 54 | mov (THREAD_SP,a1),a2 |
| 55 | |
| 56 | # switch |
| 57 | mov a2,sp |
| 58 | |
| 59 | # load next context |
| 60 | GET_THREAD_INFO a2 |
| 61 | mov a2,(__current_ti) |
| 62 | mov (TI_task,a2),a2 |
| 63 | mov a2,(__current) |
| 64 | #ifdef CONFIG_MN10300_CURRENT_IN_E2 |
| 65 | mov a2,e2 |
| 66 | #endif |
| 67 | |
David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 68 | mov (THREAD_PC,a1),a2 |
| 69 | mov d2,d0 # for ret_from_fork |
| 70 | mov d0,a0 # for __switch_to |
| 71 | |
| 72 | jmp (a2) |
| 73 | |
| 74 | __switch_back: |
| 75 | and ~EPSW_NMID,epsw |
| 76 | ret [d2,d3,a2,a3,exreg1],32 |
David Howells | 5141c46 | 2011-03-18 16:54:32 +0000 | [diff] [blame] | 77 | |
| 78 | #ifdef CONFIG_KGDB |
| 79 | ############################################################################### |
| 80 | # |
| 81 | # Lift the single-step breakpoints when the task being traced is switched out |
| 82 | # A0 = prev |
| 83 | # A1 = next |
| 84 | # |
| 85 | ############################################################################### |
| 86 | __switch_to__lift_sstep_bp: |
| 87 | add -12,sp |
| 88 | mov a0,e4 |
| 89 | mov a1,e5 |
| 90 | |
| 91 | # Clear the single-step flag to prevent us coming this way until we get |
| 92 | # switched back in |
| 93 | bclr 0xff,(kgdb_single_step) |
| 94 | |
| 95 | # Remove first breakpoint |
| 96 | mov (kgdb_sstep_bp_addr),a2 |
| 97 | cmp 0,a2 |
| 98 | beq 1f |
| 99 | movbu (kgdb_sstep_bp),d0 |
| 100 | movbu d0,(a2) |
| 101 | #if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) |
| 102 | mov a2,d0 |
| 103 | mov a2,d1 |
| 104 | add 1,d1 |
| 105 | calls flush_icache_range |
| 106 | #endif |
| 107 | 1: |
| 108 | |
| 109 | # Remove second breakpoint |
| 110 | mov (kgdb_sstep_bp_addr+4),a2 |
| 111 | cmp 0,a2 |
| 112 | beq 2f |
| 113 | movbu (kgdb_sstep_bp+1),d0 |
| 114 | movbu d0,(a2) |
| 115 | #if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) |
| 116 | mov a2,d0 |
| 117 | mov a2,d1 |
| 118 | add 1,d1 |
| 119 | calls flush_icache_range |
| 120 | #endif |
| 121 | 2: |
| 122 | |
| 123 | # Change the resumption address and return |
| 124 | mov __switch_back__reinstall_sstep_bp,d0 |
| 125 | mov e4,a0 |
| 126 | mov e5,a1 |
| 127 | add 12,sp |
| 128 | bra __switch_to__continue |
| 129 | |
| 130 | ############################################################################### |
| 131 | # |
| 132 | # Reinstall the single-step breakpoints when the task being traced is switched |
| 133 | # back in (A1 points to the new thread_struct). |
| 134 | # |
| 135 | ############################################################################### |
| 136 | __switch_back__reinstall_sstep_bp: |
| 137 | add -12,sp |
| 138 | mov a0,e4 # save the return value |
| 139 | mov 0xff,d3 |
| 140 | |
| 141 | # Reinstall first breakpoint |
| 142 | mov (kgdb_sstep_bp_addr),a2 |
| 143 | cmp 0,a2 |
| 144 | beq 1f |
| 145 | movbu (a2),d0 |
| 146 | movbu d0,(kgdb_sstep_bp) |
| 147 | movbu d3,(a2) |
| 148 | #if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) |
| 149 | mov a2,d0 |
| 150 | mov a2,d1 |
| 151 | add 1,d1 |
| 152 | calls flush_icache_range |
| 153 | #endif |
| 154 | 1: |
| 155 | |
| 156 | # Reinstall second breakpoint |
| 157 | mov (kgdb_sstep_bp_addr+4),a2 |
| 158 | cmp 0,a2 |
| 159 | beq 2f |
| 160 | movbu (a2),d0 |
| 161 | movbu d0,(kgdb_sstep_bp+1) |
| 162 | movbu d3,(a2) |
| 163 | #if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE) |
| 164 | mov a2,d0 |
| 165 | mov a2,d1 |
| 166 | add 1,d1 |
| 167 | calls flush_icache_range |
| 168 | #endif |
| 169 | 2: |
| 170 | |
| 171 | mov d3,(kgdb_single_step) |
| 172 | |
| 173 | # Restore the return value (the previous thread_struct pointer) |
| 174 | mov e4,a0 |
| 175 | mov a0,d0 |
| 176 | add 12,sp |
| 177 | bra __switch_back |
| 178 | |
| 179 | #endif /* CONFIG_KGDB */ |