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1/*
2 * arch/sh/kernel/head_64.S
3 *
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003, 2004 Paul Mundt
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
9 * for more details.
10 */
11
12#include <linux/init.h>
13
14#include <asm/page.h>
15#include <asm/cache.h>
16#include <asm/tlb.h>
17#include <cpu/registers.h>
18#include <cpu/mmu_context.h>
19#include <asm/thread_info.h>
20
21/*
22 * MMU defines: TLB boundaries.
23 */
24
25#define MMUIR_FIRST ITLB_FIXED
26#define MMUIR_END ITLB_LAST_VAR_UNRESTRICTED+TLB_STEP
27#define MMUIR_STEP TLB_STEP
28
29#define MMUDR_FIRST DTLB_FIXED
30#define MMUDR_END DTLB_LAST_VAR_UNRESTRICTED+TLB_STEP
31#define MMUDR_STEP TLB_STEP
32
33/* Safety check : CONFIG_PAGE_OFFSET has to be a multiple of 512Mb */
34#if (CONFIG_PAGE_OFFSET & ((1UL<<29)-1))
35#error "CONFIG_PAGE_OFFSET must be a multiple of 512Mb"
36#endif
37
38/*
39 * MMU defines: Fixed TLBs.
40 */
41/* Deal safely with the case where the base of RAM is not 512Mb aligned */
42
43#define ALIGN_512M_MASK (0xffffffffe0000000)
44#define ALIGNED_EFFECTIVE ((CONFIG_PAGE_OFFSET + CONFIG_MEMORY_START) & ALIGN_512M_MASK)
45#define ALIGNED_PHYSICAL (CONFIG_MEMORY_START & ALIGN_512M_MASK)
46
47#define MMUIR_TEXT_H (0x0000000000000003 | ALIGNED_EFFECTIVE)
48 /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
49
50#define MMUIR_TEXT_L (0x000000000000009a | ALIGNED_PHYSICAL)
51 /* 512 Mb, Cacheable, Write-back, execute, Not User, Ph. Add. */
52
53#define MMUDR_CACHED_H 0x0000000000000003 | ALIGNED_EFFECTIVE
54 /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
55#define MMUDR_CACHED_L 0x000000000000015a | ALIGNED_PHYSICAL
56 /* 512 Mb, Cacheable, Write-back, read/write, Not User, Ph. Add. */
57
58#ifdef CONFIG_CACHE_OFF
59#define ICCR0_INIT_VAL ICCR0_OFF /* ICACHE off */
60#else
61#define ICCR0_INIT_VAL ICCR0_ON | ICCR0_ICI /* ICE + ICI */
62#endif
63#define ICCR1_INIT_VAL ICCR1_NOLOCK /* No locking */
64
65#if defined (CONFIG_CACHE_OFF)
66#define OCCR0_INIT_VAL OCCR0_OFF /* D-cache: off */
67#elif defined (CONFIG_CACHE_WRITETHROUGH)
68#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WT /* D-cache: on, */
69 /* WT, invalidate */
70#elif defined (CONFIG_CACHE_WRITEBACK)
71#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WB /* D-cache: on, */
72 /* WB, invalidate */
73#else
74#error preprocessor flag CONFIG_CACHE_... not recognized!
75#endif
76
77#define OCCR1_INIT_VAL OCCR1_NOLOCK /* No locking */
78
79 .section .empty_zero_page, "aw"
80 .global empty_zero_page
81
82empty_zero_page:
83 .long 1 /* MOUNT_ROOT_RDONLY */
84 .long 0 /* RAMDISK_FLAGS */
85 .long 0x0200 /* ORIG_ROOT_DEV */
86 .long 1 /* LOADER_TYPE */
87 .long 0x00800000 /* INITRD_START */
88 .long 0x00800000 /* INITRD_SIZE */
89 .long 0
90
91 .text
92 .balign 4096,0,4096
93
94 .section .data, "aw"
95 .balign PAGE_SIZE
96
97 .section .data, "aw"
98 .balign PAGE_SIZE
99
100 .global mmu_pdtp_cache
101mmu_pdtp_cache:
102 .space PAGE_SIZE, 0
103
104 .global empty_bad_page
105empty_bad_page:
106 .space PAGE_SIZE, 0
107
108 .global empty_bad_pte_table
109empty_bad_pte_table:
110 .space PAGE_SIZE, 0
111
112 .global fpu_in_use
113fpu_in_use: .quad 0
114
115
116 __HEAD
117 .balign L1_CACHE_BYTES
118/*
119 * Condition at the entry of __stext:
120 * . Reset state:
121 * . SR.FD = 1 (FPU disabled)
122 * . SR.BL = 1 (Exceptions disabled)
123 * . SR.MD = 1 (Privileged Mode)
124 * . SR.MMU = 0 (MMU Disabled)
125 * . SR.CD = 0 (CTC User Visible)
126 * . SR.IMASK = Undefined (Interrupt Mask)
127 *
128 * Operations supposed to be performed by __stext:
129 * . prevent speculative fetch onto device memory while MMU is off
130 * . reflect as much as possible SH5 ABI (r15, r26, r27, r18)
131 * . first, save CPU state and set it to something harmless
132 * . any CPU detection and/or endianness settings (?)
133 * . initialize EMI/LMI (but not TMU/RTC/INTC/SCIF): TBD
134 * . set initial TLB entries for cached and uncached regions
135 * (no fine granularity paging)
136 * . set initial cache state
137 * . enable MMU and caches
138 * . set CPU to a consistent state
139 * . registers (including stack pointer and current/KCR0)
140 * . NOT expecting to set Exception handling nor VBR/RESVEC/DCR
141 * at this stage. This is all to later Linux initialization steps.
142 * . initialize FPU
143 * . clear BSS
144 * . jump into start_kernel()
145 * . be prepared to hopeless start_kernel() returns.
146 *
147 */
148 .global _stext
149_stext:
150 /*
151 * Prevent speculative fetch on device memory due to
152 * uninitialized target registers.
153 */
154 ptabs/u ZERO, tr0
155 ptabs/u ZERO, tr1
156 ptabs/u ZERO, tr2
157 ptabs/u ZERO, tr3
158 ptabs/u ZERO, tr4
159 ptabs/u ZERO, tr5
160 ptabs/u ZERO, tr6
161 ptabs/u ZERO, tr7
162 synci
163
164 /*
165 * Read/Set CPU state. After this block:
166 * r29 = Initial SR
167 */
168 getcon SR, r29
169 movi SR_HARMLESS, r20
170 putcon r20, SR
171
172 /*
173 * Initialize EMI/LMI. To Be Done.
174 */
175
176 /*
177 * CPU detection and/or endianness settings (?). To Be Done.
178 * Pure PIC code here, please ! Just save state into r30.
179 * After this block:
180 * r30 = CPU type/Platform Endianness
181 */
182
183 /*
184 * Set initial TLB entries for cached and uncached regions.
185 * Note: PTA/BLINK is PIC code, PTABS/BLINK isn't !
186 */
187 /* Clear ITLBs */
188 pta clear_ITLB, tr1
189 movi MMUIR_FIRST, r21
190 movi MMUIR_END, r22
191clear_ITLB:
192 putcfg r21, 0, ZERO /* Clear MMUIR[n].PTEH.V */
193 addi r21, MMUIR_STEP, r21
194 bne r21, r22, tr1
195
196 /* Clear DTLBs */
197 pta clear_DTLB, tr1
198 movi MMUDR_FIRST, r21
199 movi MMUDR_END, r22
200clear_DTLB:
201 putcfg r21, 0, ZERO /* Clear MMUDR[n].PTEH.V */
202 addi r21, MMUDR_STEP, r21
203 bne r21, r22, tr1
204
205 /* Map one big (512Mb) page for ITLB */
206 movi MMUIR_FIRST, r21
207 movi MMUIR_TEXT_L, r22 /* PTEL first */
208 add.l r22, r63, r22 /* Sign extend */
209 putcfg r21, 1, r22 /* Set MMUIR[0].PTEL */
210 movi MMUIR_TEXT_H, r22 /* PTEH last */
211 add.l r22, r63, r22 /* Sign extend */
212 putcfg r21, 0, r22 /* Set MMUIR[0].PTEH */
213
214 /* Map one big CACHED (512Mb) page for DTLB */
215 movi MMUDR_FIRST, r21
216 movi MMUDR_CACHED_L, r22 /* PTEL first */
217 add.l r22, r63, r22 /* Sign extend */
218 putcfg r21, 1, r22 /* Set MMUDR[0].PTEL */
219 movi MMUDR_CACHED_H, r22 /* PTEH last */
220 add.l r22, r63, r22 /* Sign extend */
221 putcfg r21, 0, r22 /* Set MMUDR[0].PTEH */
222
223 /*
224 * Setup a DTLB translation for SCIF phys.
225 */
226 addi r21, MMUDR_STEP, r21
227 movi 0x0a03, r22 /* SCIF phys */
228 shori 0x0148, r22
229 putcfg r21, 1, r22 /* PTEL first */
230 movi 0xfa03, r22 /* 0xfa030000, fixed SCIF virt */
231 shori 0x0003, r22
232 putcfg r21, 0, r22 /* PTEH last */
233
234 /*
235 * Set cache behaviours.
236 */
237 /* ICache */
238 movi ICCR_BASE, r21
239 movi ICCR0_INIT_VAL, r22
240 movi ICCR1_INIT_VAL, r23
241 putcfg r21, ICCR_REG0, r22
242 putcfg r21, ICCR_REG1, r23
243
244 /* OCache */
245 movi OCCR_BASE, r21
246 movi OCCR0_INIT_VAL, r22
247 movi OCCR1_INIT_VAL, r23
248 putcfg r21, OCCR_REG0, r22
249 putcfg r21, OCCR_REG1, r23
250
251
252 /*
253 * Enable Caches and MMU. Do the first non-PIC jump.
254 * Now head.S global variables, constants and externs
255 * can be used.
256 */
257 getcon SR, r21
258 movi SR_ENABLE_MMU, r22
259 or r21, r22, r21
260 putcon r21, SSR
261 movi hyperspace, r22
262 ori r22, 1, r22 /* Make it SHmedia, not required but..*/
263 putcon r22, SPC
264 synco
265 rte /* And now go into the hyperspace ... */
266hyperspace: /* ... that's the next instruction ! */
267
268 /*
269 * Set CPU to a consistent state.
270 * r31 = FPU support flag
271 * tr0/tr7 in use. Others give a chance to loop somewhere safe
272 */
273 movi start_kernel, r32
274 ori r32, 1, r32
275
276 ptabs r32, tr0 /* r32 = _start_kernel address */
277 pta/u hopeless, tr1
278 pta/u hopeless, tr2
279 pta/u hopeless, tr3
280 pta/u hopeless, tr4
281 pta/u hopeless, tr5
282 pta/u hopeless, tr6
283 pta/u hopeless, tr7
284 gettr tr1, r28 /* r28 = hopeless address */
285
286 /* Set initial stack pointer */
287 movi init_thread_union, SP
288 putcon SP, KCR0 /* Set current to init_task */
289 movi THREAD_SIZE, r22 /* Point to the end */
290 add SP, r22, SP
291
292 /*
293 * Initialize FPU.
294 * Keep FPU flag in r31. After this block:
295 * r31 = FPU flag
296 */
297 movi fpu_in_use, r31 /* Temporary */
298
299#ifdef CONFIG_SH_FPU
300 getcon SR, r21
301 movi SR_ENABLE_FPU, r22
302 and r21, r22, r22
303 putcon r22, SR /* Try to enable */
304 getcon SR, r22
305 xor r21, r22, r21
306 shlri r21, 15, r21 /* Supposedly 0/1 */
307 st.q r31, 0 , r21 /* Set fpu_in_use */
308#else
309 movi 0, r21
310 st.q r31, 0 , r21 /* Set fpu_in_use */
311#endif
312 or r21, ZERO, r31 /* Set FPU flag at last */
313
314#ifndef CONFIG_SH_NO_BSS_INIT
315/* Don't clear BSS if running on slow platforms such as an RTL simulation,
316 remote memory via SHdebug link, etc. For these the memory can be guaranteed
317 to be all zero on boot anyway. */
318 /*
319 * Clear bss
320 */
321 pta clear_quad, tr1
322 movi __bss_start, r22
323 movi _end, r23
324clear_quad:
325 st.q r22, 0, ZERO
326 addi r22, 8, r22
327 bne r22, r23, tr1 /* Both quad aligned, see vmlinux.lds.S */
328#endif
329 pta/u hopeless, tr1
330
331 /* Say bye to head.S but be prepared to wrongly get back ... */
332 blink tr0, LINK
333
334 /* If we ever get back here through LINK/tr1-tr7 */
335 pta/u hopeless, tr7
336
337hopeless:
338 /*
339 * Something's badly wrong here. Loop endlessly,
340 * there's nothing more we can do about it.
341 *
342 * Note on hopeless: it can be jumped into invariably
343 * before or after jumping into hyperspace. The only
344 * requirement is to be PIC called (PTA) before and
345 * any way (PTA/PTABS) after. According to Virtual
346 * to Physical mapping a simulator/emulator can easily
347 * tell where we came here from just looking at hopeless
348 * (PC) address.
349 *
350 * For debugging purposes:
351 * (r28) hopeless/loop address
352 * (r29) Original SR
353 * (r30) CPU type/Platform endianness
354 * (r31) FPU Support
355 * (r32) _start_kernel address
356 */
357 blink tr7, ZERO
1/*
2 * arch/sh/kernel/head_64.S
3 *
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003, 2004 Paul Mundt
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
9 * for more details.
10 */
11
12#include <linux/init.h>
13
14#include <asm/page.h>
15#include <asm/cache.h>
16#include <asm/tlb.h>
17#include <cpu/registers.h>
18#include <cpu/mmu_context.h>
19#include <asm/thread_info.h>
20
21/*
22 * MMU defines: TLB boundaries.
23 */
24
25#define MMUIR_FIRST ITLB_FIXED
26#define MMUIR_END ITLB_LAST_VAR_UNRESTRICTED+TLB_STEP
27#define MMUIR_STEP TLB_STEP
28
29#define MMUDR_FIRST DTLB_FIXED
30#define MMUDR_END DTLB_LAST_VAR_UNRESTRICTED+TLB_STEP
31#define MMUDR_STEP TLB_STEP
32
33/* Safety check : CONFIG_PAGE_OFFSET has to be a multiple of 512Mb */
34#if (CONFIG_PAGE_OFFSET & ((1UL<<29)-1))
35#error "CONFIG_PAGE_OFFSET must be a multiple of 512Mb"
36#endif
37
38/*
39 * MMU defines: Fixed TLBs.
40 */
41/* Deal safely with the case where the base of RAM is not 512Mb aligned */
42
43#define ALIGN_512M_MASK (0xffffffffe0000000)
44#define ALIGNED_EFFECTIVE ((CONFIG_PAGE_OFFSET + CONFIG_MEMORY_START) & ALIGN_512M_MASK)
45#define ALIGNED_PHYSICAL (CONFIG_MEMORY_START & ALIGN_512M_MASK)
46
47#define MMUIR_TEXT_H (0x0000000000000003 | ALIGNED_EFFECTIVE)
48 /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
49
50#define MMUIR_TEXT_L (0x000000000000009a | ALIGNED_PHYSICAL)
51 /* 512 Mb, Cacheable, Write-back, execute, Not User, Ph. Add. */
52
53#define MMUDR_CACHED_H 0x0000000000000003 | ALIGNED_EFFECTIVE
54 /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
55#define MMUDR_CACHED_L 0x000000000000015a | ALIGNED_PHYSICAL
56 /* 512 Mb, Cacheable, Write-back, read/write, Not User, Ph. Add. */
57
58#ifdef CONFIG_CACHE_OFF
59#define ICCR0_INIT_VAL ICCR0_OFF /* ICACHE off */
60#else
61#define ICCR0_INIT_VAL ICCR0_ON | ICCR0_ICI /* ICE + ICI */
62#endif
63#define ICCR1_INIT_VAL ICCR1_NOLOCK /* No locking */
64
65#if defined (CONFIG_CACHE_OFF)
66#define OCCR0_INIT_VAL OCCR0_OFF /* D-cache: off */
67#elif defined (CONFIG_CACHE_WRITETHROUGH)
68#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WT /* D-cache: on, */
69 /* WT, invalidate */
70#elif defined (CONFIG_CACHE_WRITEBACK)
71#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WB /* D-cache: on, */
72 /* WB, invalidate */
73#else
74#error preprocessor flag CONFIG_CACHE_... not recognized!
75#endif
76
77#define OCCR1_INIT_VAL OCCR1_NOLOCK /* No locking */
78
79 .section .empty_zero_page, "aw"
80 .global empty_zero_page
81
82empty_zero_page:
83 .long 1 /* MOUNT_ROOT_RDONLY */
84 .long 0 /* RAMDISK_FLAGS */
85 .long 0x0200 /* ORIG_ROOT_DEV */
86 .long 1 /* LOADER_TYPE */
87 .long 0x00800000 /* INITRD_START */
88 .long 0x00800000 /* INITRD_SIZE */
89 .long 0
90
91 .text
92 .balign 4096,0,4096
93
94 .section .data, "aw"
95 .balign PAGE_SIZE
96
97 .section .data, "aw"
98 .balign PAGE_SIZE
99
100 .global mmu_pdtp_cache
101mmu_pdtp_cache:
102 .space PAGE_SIZE, 0
103
104 .global fpu_in_use
105fpu_in_use: .quad 0
106
107
108 __HEAD
109 .balign L1_CACHE_BYTES
110/*
111 * Condition at the entry of __stext:
112 * . Reset state:
113 * . SR.FD = 1 (FPU disabled)
114 * . SR.BL = 1 (Exceptions disabled)
115 * . SR.MD = 1 (Privileged Mode)
116 * . SR.MMU = 0 (MMU Disabled)
117 * . SR.CD = 0 (CTC User Visible)
118 * . SR.IMASK = Undefined (Interrupt Mask)
119 *
120 * Operations supposed to be performed by __stext:
121 * . prevent speculative fetch onto device memory while MMU is off
122 * . reflect as much as possible SH5 ABI (r15, r26, r27, r18)
123 * . first, save CPU state and set it to something harmless
124 * . any CPU detection and/or endianness settings (?)
125 * . initialize EMI/LMI (but not TMU/RTC/INTC/SCIF): TBD
126 * . set initial TLB entries for cached and uncached regions
127 * (no fine granularity paging)
128 * . set initial cache state
129 * . enable MMU and caches
130 * . set CPU to a consistent state
131 * . registers (including stack pointer and current/KCR0)
132 * . NOT expecting to set Exception handling nor VBR/RESVEC/DCR
133 * at this stage. This is all to later Linux initialization steps.
134 * . initialize FPU
135 * . clear BSS
136 * . jump into start_kernel()
137 * . be prepared to hopeless start_kernel() returns.
138 *
139 */
140 .global _stext
141_stext:
142 /*
143 * Prevent speculative fetch on device memory due to
144 * uninitialized target registers.
145 */
146 ptabs/u ZERO, tr0
147 ptabs/u ZERO, tr1
148 ptabs/u ZERO, tr2
149 ptabs/u ZERO, tr3
150 ptabs/u ZERO, tr4
151 ptabs/u ZERO, tr5
152 ptabs/u ZERO, tr6
153 ptabs/u ZERO, tr7
154 synci
155
156 /*
157 * Read/Set CPU state. After this block:
158 * r29 = Initial SR
159 */
160 getcon SR, r29
161 movi SR_HARMLESS, r20
162 putcon r20, SR
163
164 /*
165 * Initialize EMI/LMI. To Be Done.
166 */
167
168 /*
169 * CPU detection and/or endianness settings (?). To Be Done.
170 * Pure PIC code here, please ! Just save state into r30.
171 * After this block:
172 * r30 = CPU type/Platform Endianness
173 */
174
175 /*
176 * Set initial TLB entries for cached and uncached regions.
177 * Note: PTA/BLINK is PIC code, PTABS/BLINK isn't !
178 */
179 /* Clear ITLBs */
180 pta clear_ITLB, tr1
181 movi MMUIR_FIRST, r21
182 movi MMUIR_END, r22
183clear_ITLB:
184 putcfg r21, 0, ZERO /* Clear MMUIR[n].PTEH.V */
185 addi r21, MMUIR_STEP, r21
186 bne r21, r22, tr1
187
188 /* Clear DTLBs */
189 pta clear_DTLB, tr1
190 movi MMUDR_FIRST, r21
191 movi MMUDR_END, r22
192clear_DTLB:
193 putcfg r21, 0, ZERO /* Clear MMUDR[n].PTEH.V */
194 addi r21, MMUDR_STEP, r21
195 bne r21, r22, tr1
196
197 /* Map one big (512Mb) page for ITLB */
198 movi MMUIR_FIRST, r21
199 movi MMUIR_TEXT_L, r22 /* PTEL first */
200 add.l r22, r63, r22 /* Sign extend */
201 putcfg r21, 1, r22 /* Set MMUIR[0].PTEL */
202 movi MMUIR_TEXT_H, r22 /* PTEH last */
203 add.l r22, r63, r22 /* Sign extend */
204 putcfg r21, 0, r22 /* Set MMUIR[0].PTEH */
205
206 /* Map one big CACHED (512Mb) page for DTLB */
207 movi MMUDR_FIRST, r21
208 movi MMUDR_CACHED_L, r22 /* PTEL first */
209 add.l r22, r63, r22 /* Sign extend */
210 putcfg r21, 1, r22 /* Set MMUDR[0].PTEL */
211 movi MMUDR_CACHED_H, r22 /* PTEH last */
212 add.l r22, r63, r22 /* Sign extend */
213 putcfg r21, 0, r22 /* Set MMUDR[0].PTEH */
214
215 /*
216 * Setup a DTLB translation for SCIF phys.
217 */
218 addi r21, MMUDR_STEP, r21
219 movi 0x0a03, r22 /* SCIF phys */
220 shori 0x0148, r22
221 putcfg r21, 1, r22 /* PTEL first */
222 movi 0xfa03, r22 /* 0xfa030000, fixed SCIF virt */
223 shori 0x0003, r22
224 putcfg r21, 0, r22 /* PTEH last */
225
226 /*
227 * Set cache behaviours.
228 */
229 /* ICache */
230 movi ICCR_BASE, r21
231 movi ICCR0_INIT_VAL, r22
232 movi ICCR1_INIT_VAL, r23
233 putcfg r21, ICCR_REG0, r22
234 putcfg r21, ICCR_REG1, r23
235
236 /* OCache */
237 movi OCCR_BASE, r21
238 movi OCCR0_INIT_VAL, r22
239 movi OCCR1_INIT_VAL, r23
240 putcfg r21, OCCR_REG0, r22
241 putcfg r21, OCCR_REG1, r23
242
243
244 /*
245 * Enable Caches and MMU. Do the first non-PIC jump.
246 * Now head.S global variables, constants and externs
247 * can be used.
248 */
249 getcon SR, r21
250 movi SR_ENABLE_MMU, r22
251 or r21, r22, r21
252 putcon r21, SSR
253 movi hyperspace, r22
254 ori r22, 1, r22 /* Make it SHmedia, not required but..*/
255 putcon r22, SPC
256 synco
257 rte /* And now go into the hyperspace ... */
258hyperspace: /* ... that's the next instruction ! */
259
260 /*
261 * Set CPU to a consistent state.
262 * r31 = FPU support flag
263 * tr0/tr7 in use. Others give a chance to loop somewhere safe
264 */
265 movi start_kernel, r32
266 ori r32, 1, r32
267
268 ptabs r32, tr0 /* r32 = _start_kernel address */
269 pta/u hopeless, tr1
270 pta/u hopeless, tr2
271 pta/u hopeless, tr3
272 pta/u hopeless, tr4
273 pta/u hopeless, tr5
274 pta/u hopeless, tr6
275 pta/u hopeless, tr7
276 gettr tr1, r28 /* r28 = hopeless address */
277
278 /* Set initial stack pointer */
279 movi init_thread_union, SP
280 putcon SP, KCR0 /* Set current to init_task */
281 movi THREAD_SIZE, r22 /* Point to the end */
282 add SP, r22, SP
283
284 /*
285 * Initialize FPU.
286 * Keep FPU flag in r31. After this block:
287 * r31 = FPU flag
288 */
289 movi fpu_in_use, r31 /* Temporary */
290
291#ifdef CONFIG_SH_FPU
292 getcon SR, r21
293 movi SR_ENABLE_FPU, r22
294 and r21, r22, r22
295 putcon r22, SR /* Try to enable */
296 getcon SR, r22
297 xor r21, r22, r21
298 shlri r21, 15, r21 /* Supposedly 0/1 */
299 st.q r31, 0 , r21 /* Set fpu_in_use */
300#else
301 movi 0, r21
302 st.q r31, 0 , r21 /* Set fpu_in_use */
303#endif
304 or r21, ZERO, r31 /* Set FPU flag at last */
305
306#ifndef CONFIG_SH_NO_BSS_INIT
307/* Don't clear BSS if running on slow platforms such as an RTL simulation,
308 remote memory via SHdebug link, etc. For these the memory can be guaranteed
309 to be all zero on boot anyway. */
310 /*
311 * Clear bss
312 */
313 pta clear_quad, tr1
314 movi __bss_start, r22
315 movi _end, r23
316clear_quad:
317 st.q r22, 0, ZERO
318 addi r22, 8, r22
319 bne r22, r23, tr1 /* Both quad aligned, see vmlinux.lds.S */
320#endif
321 pta/u hopeless, tr1
322
323 /* Say bye to head.S but be prepared to wrongly get back ... */
324 blink tr0, LINK
325
326 /* If we ever get back here through LINK/tr1-tr7 */
327 pta/u hopeless, tr7
328
329hopeless:
330 /*
331 * Something's badly wrong here. Loop endlessly,
332 * there's nothing more we can do about it.
333 *
334 * Note on hopeless: it can be jumped into invariably
335 * before or after jumping into hyperspace. The only
336 * requirement is to be PIC called (PTA) before and
337 * any way (PTA/PTABS) after. According to Virtual
338 * to Physical mapping a simulator/emulator can easily
339 * tell where we came here from just looking at hopeless
340 * (PC) address.
341 *
342 * For debugging purposes:
343 * (r28) hopeless/loop address
344 * (r29) Original SR
345 * (r30) CPU type/Platform endianness
346 * (r31) FPU Support
347 * (r32) _start_kernel address
348 */
349 blink tr7, ZERO