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 358