Commit | Line | Data |
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9703d9d7 CM |
1 | /* |
2 | * Low-level CPU initialisation | |
3 | * Based on arch/arm/kernel/head.S | |
4 | * | |
5 | * Copyright (C) 1994-2002 Russell King | |
6 | * Copyright (C) 2003-2012 ARM Ltd. | |
7 | * Authors: Catalin Marinas <catalin.marinas@arm.com> | |
8 | * Will Deacon <will.deacon@arm.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
21 | */ | |
22 | ||
23 | #include <linux/linkage.h> | |
24 | #include <linux/init.h> | |
25 | ||
26 | #include <asm/assembler.h> | |
27 | #include <asm/ptrace.h> | |
28 | #include <asm/asm-offsets.h> | |
c218bca7 | 29 | #include <asm/cache.h> |
0359b0e2 | 30 | #include <asm/cputype.h> |
9703d9d7 CM |
31 | #include <asm/memory.h> |
32 | #include <asm/thread_info.h> | |
33 | #include <asm/pgtable-hwdef.h> | |
34 | #include <asm/pgtable.h> | |
35 | #include <asm/page.h> | |
f35a9205 | 36 | #include <asm/virt.h> |
9703d9d7 | 37 | |
9703d9d7 CM |
38 | #define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET) |
39 | ||
da57a369 MR |
40 | #if (TEXT_OFFSET & 0xf) != 0 |
41 | #error TEXT_OFFSET must be at least 16B aligned | |
42 | #elif (PAGE_OFFSET & 0xfffff) != 0 | |
43 | #error PAGE_OFFSET must be at least 2MB aligned | |
44 | #elif TEXT_OFFSET > 0xfffff | |
45 | #error TEXT_OFFSET must be less than 2MB | |
9703d9d7 CM |
46 | #endif |
47 | ||
bd00cd5f MR |
48 | .macro pgtbl, ttb0, ttb1, virt_to_phys |
49 | ldr \ttb1, =swapper_pg_dir | |
50 | ldr \ttb0, =idmap_pg_dir | |
51 | add \ttb1, \ttb1, \virt_to_phys | |
52 | add \ttb0, \ttb0, \virt_to_phys | |
9703d9d7 CM |
53 | .endm |
54 | ||
55 | #ifdef CONFIG_ARM64_64K_PAGES | |
56 | #define BLOCK_SHIFT PAGE_SHIFT | |
57 | #define BLOCK_SIZE PAGE_SIZE | |
58 | #else | |
59 | #define BLOCK_SHIFT SECTION_SHIFT | |
60 | #define BLOCK_SIZE SECTION_SIZE | |
61 | #endif | |
62 | ||
63 | #define KERNEL_START KERNEL_RAM_VADDR | |
64 | #define KERNEL_END _end | |
65 | ||
66 | /* | |
67 | * Initial memory map attributes. | |
68 | */ | |
69 | #ifndef CONFIG_SMP | |
70 | #define PTE_FLAGS PTE_TYPE_PAGE | PTE_AF | |
71 | #define PMD_FLAGS PMD_TYPE_SECT | PMD_SECT_AF | |
72 | #else | |
73 | #define PTE_FLAGS PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | |
74 | #define PMD_FLAGS PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | |
75 | #endif | |
76 | ||
77 | #ifdef CONFIG_ARM64_64K_PAGES | |
78 | #define MM_MMUFLAGS PTE_ATTRINDX(MT_NORMAL) | PTE_FLAGS | |
9703d9d7 CM |
79 | #else |
80 | #define MM_MMUFLAGS PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS | |
9703d9d7 CM |
81 | #endif |
82 | ||
83 | /* | |
84 | * Kernel startup entry point. | |
85 | * --------------------------- | |
86 | * | |
87 | * The requirements are: | |
88 | * MMU = off, D-cache = off, I-cache = on or off, | |
89 | * x0 = physical address to the FDT blob. | |
90 | * | |
91 | * This code is mostly position independent so you call this at | |
92 | * __pa(PAGE_OFFSET + TEXT_OFFSET). | |
93 | * | |
94 | * Note that the callee-saved registers are used for storing variables | |
95 | * that are useful before the MMU is enabled. The allocations are described | |
96 | * in the entry routines. | |
97 | */ | |
98 | __HEAD | |
99 | ||
100 | /* | |
101 | * DO NOT MODIFY. Image header expected by Linux boot-loaders. | |
102 | */ | |
3c7f2550 MS |
103 | #ifdef CONFIG_EFI |
104 | efi_head: | |
105 | /* | |
106 | * This add instruction has no meaningful effect except that | |
107 | * its opcode forms the magic "MZ" signature required by UEFI. | |
108 | */ | |
109 | add x13, x18, #0x16 | |
110 | b stext | |
111 | #else | |
9703d9d7 CM |
112 | b stext // branch to kernel start, magic |
113 | .long 0 // reserved | |
3c7f2550 | 114 | #endif |
a2c1d73b MR |
115 | .quad _kernel_offset_le // Image load offset from start of RAM, little-endian |
116 | .quad _kernel_size_le // Effective size of kernel image, little-endian | |
117 | .quad _kernel_flags_le // Informative flags, little-endian | |
4370eec0 RF |
118 | .quad 0 // reserved |
119 | .quad 0 // reserved | |
120 | .quad 0 // reserved | |
121 | .byte 0x41 // Magic number, "ARM\x64" | |
122 | .byte 0x52 | |
123 | .byte 0x4d | |
124 | .byte 0x64 | |
3c7f2550 MS |
125 | #ifdef CONFIG_EFI |
126 | .long pe_header - efi_head // Offset to the PE header. | |
127 | #else | |
4370eec0 | 128 | .word 0 // reserved |
3c7f2550 MS |
129 | #endif |
130 | ||
131 | #ifdef CONFIG_EFI | |
132 | .align 3 | |
133 | pe_header: | |
134 | .ascii "PE" | |
135 | .short 0 | |
136 | coff_header: | |
137 | .short 0xaa64 // AArch64 | |
138 | .short 2 // nr_sections | |
139 | .long 0 // TimeDateStamp | |
140 | .long 0 // PointerToSymbolTable | |
141 | .long 1 // NumberOfSymbols | |
142 | .short section_table - optional_header // SizeOfOptionalHeader | |
143 | .short 0x206 // Characteristics. | |
144 | // IMAGE_FILE_DEBUG_STRIPPED | | |
145 | // IMAGE_FILE_EXECUTABLE_IMAGE | | |
146 | // IMAGE_FILE_LINE_NUMS_STRIPPED | |
147 | optional_header: | |
148 | .short 0x20b // PE32+ format | |
149 | .byte 0x02 // MajorLinkerVersion | |
150 | .byte 0x14 // MinorLinkerVersion | |
151 | .long _edata - stext // SizeOfCode | |
152 | .long 0 // SizeOfInitializedData | |
153 | .long 0 // SizeOfUninitializedData | |
154 | .long efi_stub_entry - efi_head // AddressOfEntryPoint | |
155 | .long stext - efi_head // BaseOfCode | |
156 | ||
157 | extra_header_fields: | |
158 | .quad 0 // ImageBase | |
159 | .long 0x20 // SectionAlignment | |
160 | .long 0x8 // FileAlignment | |
161 | .short 0 // MajorOperatingSystemVersion | |
162 | .short 0 // MinorOperatingSystemVersion | |
163 | .short 0 // MajorImageVersion | |
164 | .short 0 // MinorImageVersion | |
165 | .short 0 // MajorSubsystemVersion | |
166 | .short 0 // MinorSubsystemVersion | |
167 | .long 0 // Win32VersionValue | |
168 | ||
169 | .long _edata - efi_head // SizeOfImage | |
170 | ||
171 | // Everything before the kernel image is considered part of the header | |
172 | .long stext - efi_head // SizeOfHeaders | |
173 | .long 0 // CheckSum | |
174 | .short 0xa // Subsystem (EFI application) | |
175 | .short 0 // DllCharacteristics | |
176 | .quad 0 // SizeOfStackReserve | |
177 | .quad 0 // SizeOfStackCommit | |
178 | .quad 0 // SizeOfHeapReserve | |
179 | .quad 0 // SizeOfHeapCommit | |
180 | .long 0 // LoaderFlags | |
181 | .long 0x6 // NumberOfRvaAndSizes | |
182 | ||
183 | .quad 0 // ExportTable | |
184 | .quad 0 // ImportTable | |
185 | .quad 0 // ResourceTable | |
186 | .quad 0 // ExceptionTable | |
187 | .quad 0 // CertificationTable | |
188 | .quad 0 // BaseRelocationTable | |
189 | ||
190 | // Section table | |
191 | section_table: | |
192 | ||
193 | /* | |
194 | * The EFI application loader requires a relocation section | |
195 | * because EFI applications must be relocatable. This is a | |
196 | * dummy section as far as we are concerned. | |
197 | */ | |
198 | .ascii ".reloc" | |
199 | .byte 0 | |
200 | .byte 0 // end of 0 padding of section name | |
201 | .long 0 | |
202 | .long 0 | |
203 | .long 0 // SizeOfRawData | |
204 | .long 0 // PointerToRawData | |
205 | .long 0 // PointerToRelocations | |
206 | .long 0 // PointerToLineNumbers | |
207 | .short 0 // NumberOfRelocations | |
208 | .short 0 // NumberOfLineNumbers | |
209 | .long 0x42100040 // Characteristics (section flags) | |
210 | ||
211 | ||
212 | .ascii ".text" | |
213 | .byte 0 | |
214 | .byte 0 | |
215 | .byte 0 // end of 0 padding of section name | |
216 | .long _edata - stext // VirtualSize | |
217 | .long stext - efi_head // VirtualAddress | |
218 | .long _edata - stext // SizeOfRawData | |
219 | .long stext - efi_head // PointerToRawData | |
220 | ||
221 | .long 0 // PointerToRelocations (0 for executables) | |
222 | .long 0 // PointerToLineNumbers (0 for executables) | |
223 | .short 0 // NumberOfRelocations (0 for executables) | |
224 | .short 0 // NumberOfLineNumbers (0 for executables) | |
225 | .long 0xe0500020 // Characteristics (section flags) | |
226 | .align 5 | |
227 | #endif | |
9703d9d7 CM |
228 | |
229 | ENTRY(stext) | |
230 | mov x21, x0 // x21=FDT | |
828e9834 | 231 | bl el2_setup // Drop to EL1, w20=cpu_boot_mode |
f35a9205 | 232 | bl __calc_phys_offset // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET |
828e9834 | 233 | bl set_cpu_boot_mode_flag |
9703d9d7 CM |
234 | mrs x22, midr_el1 // x22=cpuid |
235 | mov x0, x22 | |
236 | bl lookup_processor_type | |
237 | mov x23, x0 // x23=current cpu_table | |
238 | cbz x23, __error_p // invalid processor (x23=0)? | |
9703d9d7 CM |
239 | bl __vet_fdt |
240 | bl __create_page_tables // x25=TTBR0, x26=TTBR1 | |
241 | /* | |
242 | * The following calls CPU specific code in a position independent | |
243 | * manner. See arch/arm64/mm/proc.S for details. x23 = base of | |
244 | * cpu_info structure selected by lookup_processor_type above. | |
245 | * On return, the CPU will be ready for the MMU to be turned on and | |
246 | * the TCR will have been set. | |
247 | */ | |
248 | ldr x27, __switch_data // address to jump to after | |
249 | // MMU has been enabled | |
250 | adr lr, __enable_mmu // return (PIC) address | |
251 | ldr x12, [x23, #CPU_INFO_SETUP] | |
252 | add x12, x12, x28 // __virt_to_phys | |
253 | br x12 // initialise processor | |
254 | ENDPROC(stext) | |
255 | ||
256 | /* | |
257 | * If we're fortunate enough to boot at EL2, ensure that the world is | |
258 | * sane before dropping to EL1. | |
828e9834 ML |
259 | * |
260 | * Returns either BOOT_CPU_MODE_EL1 or BOOT_CPU_MODE_EL2 in x20 if | |
261 | * booted in EL1 or EL2 respectively. | |
9703d9d7 CM |
262 | */ |
263 | ENTRY(el2_setup) | |
264 | mrs x0, CurrentEL | |
974c8e45 | 265 | cmp x0, #CurrentEL_EL2 |
9cf71728 ML |
266 | b.ne 1f |
267 | mrs x0, sctlr_el2 | |
268 | CPU_BE( orr x0, x0, #(1 << 25) ) // Set the EE bit for EL2 | |
269 | CPU_LE( bic x0, x0, #(1 << 25) ) // Clear the EE bit for EL2 | |
270 | msr sctlr_el2, x0 | |
271 | b 2f | |
272 | 1: mrs x0, sctlr_el1 | |
273 | CPU_BE( orr x0, x0, #(3 << 24) ) // Set the EE and E0E bits for EL1 | |
274 | CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1 | |
275 | msr sctlr_el1, x0 | |
828e9834 | 276 | mov w20, #BOOT_CPU_MODE_EL1 // This cpu booted in EL1 |
9cf71728 | 277 | isb |
9703d9d7 CM |
278 | ret |
279 | ||
280 | /* Hyp configuration. */ | |
9cf71728 | 281 | 2: mov x0, #(1 << 31) // 64-bit EL1 |
9703d9d7 CM |
282 | msr hcr_el2, x0 |
283 | ||
284 | /* Generic timers. */ | |
285 | mrs x0, cnthctl_el2 | |
286 | orr x0, x0, #3 // Enable EL1 physical timers | |
287 | msr cnthctl_el2, x0 | |
1f75ff0a | 288 | msr cntvoff_el2, xzr // Clear virtual offset |
9703d9d7 CM |
289 | |
290 | /* Populate ID registers. */ | |
291 | mrs x0, midr_el1 | |
292 | mrs x1, mpidr_el1 | |
293 | msr vpidr_el2, x0 | |
294 | msr vmpidr_el2, x1 | |
295 | ||
296 | /* sctlr_el1 */ | |
297 | mov x0, #0x0800 // Set/clear RES{1,0} bits | |
9cf71728 ML |
298 | CPU_BE( movk x0, #0x33d0, lsl #16 ) // Set EE and E0E on BE systems |
299 | CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems | |
9703d9d7 CM |
300 | msr sctlr_el1, x0 |
301 | ||
302 | /* Coprocessor traps. */ | |
303 | mov x0, #0x33ff | |
304 | msr cptr_el2, x0 // Disable copro. traps to EL2 | |
305 | ||
306 | #ifdef CONFIG_COMPAT | |
307 | msr hstr_el2, xzr // Disable CP15 traps to EL2 | |
308 | #endif | |
309 | ||
7dbfbe5b MZ |
310 | /* Stage-2 translation */ |
311 | msr vttbr_el2, xzr | |
312 | ||
712c6ff4 MZ |
313 | /* Hypervisor stub */ |
314 | adr x0, __hyp_stub_vectors | |
315 | msr vbar_el2, x0 | |
316 | ||
9703d9d7 CM |
317 | /* spsr */ |
318 | mov x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\ | |
319 | PSR_MODE_EL1h) | |
320 | msr spsr_el2, x0 | |
321 | msr elr_el2, lr | |
828e9834 | 322 | mov w20, #BOOT_CPU_MODE_EL2 // This CPU booted in EL2 |
9703d9d7 CM |
323 | eret |
324 | ENDPROC(el2_setup) | |
325 | ||
828e9834 ML |
326 | /* |
327 | * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed | |
328 | * in x20. See arch/arm64/include/asm/virt.h for more info. | |
329 | */ | |
330 | ENTRY(set_cpu_boot_mode_flag) | |
331 | ldr x1, =__boot_cpu_mode // Compute __boot_cpu_mode | |
332 | add x1, x1, x28 | |
333 | cmp w20, #BOOT_CPU_MODE_EL2 | |
334 | b.ne 1f | |
335 | add x1, x1, #4 | |
d0488597 WD |
336 | 1: str w20, [x1] // This CPU has booted in EL1 |
337 | dmb sy | |
338 | dc ivac, x1 // Invalidate potentially stale cache line | |
828e9834 ML |
339 | ret |
340 | ENDPROC(set_cpu_boot_mode_flag) | |
341 | ||
f35a9205 MZ |
342 | /* |
343 | * We need to find out the CPU boot mode long after boot, so we need to | |
344 | * store it in a writable variable. | |
345 | * | |
346 | * This is not in .bss, because we set it sufficiently early that the boot-time | |
347 | * zeroing of .bss would clobber it. | |
348 | */ | |
c218bca7 | 349 | .pushsection .data..cacheline_aligned |
f35a9205 | 350 | ENTRY(__boot_cpu_mode) |
c218bca7 | 351 | .align L1_CACHE_SHIFT |
f35a9205 MZ |
352 | .long BOOT_CPU_MODE_EL2 |
353 | .long 0 | |
354 | .popsection | |
355 | ||
9703d9d7 CM |
356 | .align 3 |
357 | 2: .quad . | |
358 | .quad PAGE_OFFSET | |
359 | ||
360 | #ifdef CONFIG_SMP | |
9703d9d7 CM |
361 | .align 3 |
362 | 1: .quad . | |
363 | .quad secondary_holding_pen_release | |
364 | ||
365 | /* | |
366 | * This provides a "holding pen" for platforms to hold all secondary | |
367 | * cores are held until we're ready for them to initialise. | |
368 | */ | |
369 | ENTRY(secondary_holding_pen) | |
828e9834 ML |
370 | bl el2_setup // Drop to EL1, w20=cpu_boot_mode |
371 | bl __calc_phys_offset // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET | |
372 | bl set_cpu_boot_mode_flag | |
9703d9d7 | 373 | mrs x0, mpidr_el1 |
0359b0e2 JM |
374 | ldr x1, =MPIDR_HWID_BITMASK |
375 | and x0, x0, x1 | |
9703d9d7 CM |
376 | adr x1, 1b |
377 | ldp x2, x3, [x1] | |
378 | sub x1, x1, x2 | |
379 | add x3, x3, x1 | |
380 | pen: ldr x4, [x3] | |
381 | cmp x4, x0 | |
382 | b.eq secondary_startup | |
383 | wfe | |
384 | b pen | |
385 | ENDPROC(secondary_holding_pen) | |
652af899 MR |
386 | |
387 | /* | |
388 | * Secondary entry point that jumps straight into the kernel. Only to | |
389 | * be used where CPUs are brought online dynamically by the kernel. | |
390 | */ | |
391 | ENTRY(secondary_entry) | |
652af899 | 392 | bl el2_setup // Drop to EL1 |
85cc00ea LP |
393 | bl __calc_phys_offset // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET |
394 | bl set_cpu_boot_mode_flag | |
652af899 MR |
395 | b secondary_startup |
396 | ENDPROC(secondary_entry) | |
9703d9d7 CM |
397 | |
398 | ENTRY(secondary_startup) | |
399 | /* | |
400 | * Common entry point for secondary CPUs. | |
401 | */ | |
402 | mrs x22, midr_el1 // x22=cpuid | |
403 | mov x0, x22 | |
404 | bl lookup_processor_type | |
405 | mov x23, x0 // x23=current cpu_table | |
406 | cbz x23, __error_p // invalid processor (x23=0)? | |
407 | ||
bd00cd5f | 408 | pgtbl x25, x26, x28 // x25=TTBR0, x26=TTBR1 |
9703d9d7 CM |
409 | ldr x12, [x23, #CPU_INFO_SETUP] |
410 | add x12, x12, x28 // __virt_to_phys | |
411 | blr x12 // initialise processor | |
412 | ||
413 | ldr x21, =secondary_data | |
414 | ldr x27, =__secondary_switched // address to jump to after enabling the MMU | |
415 | b __enable_mmu | |
416 | ENDPROC(secondary_startup) | |
417 | ||
418 | ENTRY(__secondary_switched) | |
419 | ldr x0, [x21] // get secondary_data.stack | |
420 | mov sp, x0 | |
421 | mov x29, #0 | |
422 | b secondary_start_kernel | |
423 | ENDPROC(__secondary_switched) | |
424 | #endif /* CONFIG_SMP */ | |
425 | ||
426 | /* | |
427 | * Setup common bits before finally enabling the MMU. Essentially this is just | |
428 | * loading the page table pointer and vector base registers. | |
429 | * | |
430 | * On entry to this code, x0 must contain the SCTLR_EL1 value for turning on | |
431 | * the MMU. | |
432 | */ | |
433 | __enable_mmu: | |
434 | ldr x5, =vectors | |
435 | msr vbar_el1, x5 | |
436 | msr ttbr0_el1, x25 // load TTBR0 | |
437 | msr ttbr1_el1, x26 // load TTBR1 | |
438 | isb | |
439 | b __turn_mmu_on | |
440 | ENDPROC(__enable_mmu) | |
441 | ||
442 | /* | |
443 | * Enable the MMU. This completely changes the structure of the visible memory | |
444 | * space. You will not be able to trace execution through this. | |
445 | * | |
446 | * x0 = system control register | |
447 | * x27 = *virtual* address to jump to upon completion | |
448 | * | |
449 | * other registers depend on the function called upon completion | |
909a4069 MR |
450 | * |
451 | * We align the entire function to the smallest power of two larger than it to | |
452 | * ensure it fits within a single block map entry. Otherwise were PHYS_OFFSET | |
453 | * close to the end of a 512MB or 1GB block we might require an additional | |
454 | * table to map the entire function. | |
9703d9d7 | 455 | */ |
909a4069 | 456 | .align 4 |
9703d9d7 CM |
457 | __turn_mmu_on: |
458 | msr sctlr_el1, x0 | |
459 | isb | |
460 | br x27 | |
461 | ENDPROC(__turn_mmu_on) | |
462 | ||
463 | /* | |
464 | * Calculate the start of physical memory. | |
465 | */ | |
466 | __calc_phys_offset: | |
467 | adr x0, 1f | |
468 | ldp x1, x2, [x0] | |
469 | sub x28, x0, x1 // x28 = PHYS_OFFSET - PAGE_OFFSET | |
470 | add x24, x2, x28 // x24 = PHYS_OFFSET | |
471 | ret | |
472 | ENDPROC(__calc_phys_offset) | |
473 | ||
474 | .align 3 | |
475 | 1: .quad . | |
476 | .quad PAGE_OFFSET | |
477 | ||
478 | /* | |
c79b954b JL |
479 | * Macro to populate the PUD for the corresponding block entry in the next |
480 | * level (tbl) for the given virtual address in case of 4 levels. | |
9703d9d7 | 481 | * |
c79b954b JL |
482 | * Preserves: pgd, virt |
483 | * Corrupts: tbl, tmp1, tmp2 | |
484 | * Returns: pud | |
9703d9d7 | 485 | */ |
c79b954b JL |
486 | .macro create_pud_entry, pgd, tbl, virt, pud, tmp1, tmp2 |
487 | #ifdef CONFIG_ARM64_4_LEVELS | |
488 | add \tbl, \tbl, #PAGE_SIZE // bump tbl 1 page up. | |
489 | // to make room for pud | |
490 | add \pud, \pgd, #PAGE_SIZE // pgd points to pud which | |
491 | // follows pgd | |
492 | lsr \tmp1, \virt, #PUD_SHIFT | |
493 | and \tmp1, \tmp1, #PTRS_PER_PUD - 1 // PUD index | |
494 | orr \tmp2, \tbl, #3 // PUD entry table type | |
495 | str \tmp2, [\pud, \tmp1, lsl #3] | |
496 | #else | |
497 | mov \pud, \tbl | |
498 | #endif | |
499 | .endm | |
500 | ||
501 | /* | |
502 | * Macro to populate the PGD (and possibily PUD) for the corresponding | |
503 | * block entry in the next level (tbl) for the given virtual address. | |
504 | * | |
505 | * Preserves: pgd, virt | |
506 | * Corrupts: tmp1, tmp2, tmp3 | |
507 | * Returns: tbl -> page where block mappings can be placed | |
508 | * (changed to make room for pud with 4 levels, preserved otherwise) | |
509 | */ | |
510 | .macro create_pgd_entry, pgd, tbl, virt, tmp1, tmp2, tmp3 | |
511 | create_pud_entry \pgd, \tbl, \virt, \tmp3, \tmp1, \tmp2 | |
9703d9d7 CM |
512 | lsr \tmp1, \virt, #PGDIR_SHIFT |
513 | and \tmp1, \tmp1, #PTRS_PER_PGD - 1 // PGD index | |
c79b954b | 514 | orr \tmp2, \tmp3, #3 // PGD entry table type |
9703d9d7 CM |
515 | str \tmp2, [\pgd, \tmp1, lsl #3] |
516 | .endm | |
517 | ||
518 | /* | |
519 | * Macro to populate block entries in the page table for the start..end | |
520 | * virtual range (inclusive). | |
521 | * | |
522 | * Preserves: tbl, flags | |
523 | * Corrupts: phys, start, end, pstate | |
524 | */ | |
ea8c2e11 | 525 | .macro create_block_map, tbl, flags, phys, start, end |
9703d9d7 | 526 | lsr \phys, \phys, #BLOCK_SHIFT |
9703d9d7 CM |
527 | lsr \start, \start, #BLOCK_SHIFT |
528 | and \start, \start, #PTRS_PER_PTE - 1 // table index | |
9703d9d7 | 529 | orr \phys, \flags, \phys, lsl #BLOCK_SHIFT // table entry |
9703d9d7 CM |
530 | lsr \end, \end, #BLOCK_SHIFT |
531 | and \end, \end, #PTRS_PER_PTE - 1 // table end index | |
9703d9d7 | 532 | 9999: str \phys, [\tbl, \start, lsl #3] // store the entry |
9703d9d7 CM |
533 | add \start, \start, #1 // next entry |
534 | add \phys, \phys, #BLOCK_SIZE // next block | |
535 | cmp \start, \end | |
536 | b.ls 9999b | |
9703d9d7 CM |
537 | .endm |
538 | ||
539 | /* | |
540 | * Setup the initial page tables. We only setup the barest amount which is | |
541 | * required to get the kernel running. The following sections are required: | |
542 | * - identity mapping to enable the MMU (low address, TTBR0) | |
543 | * - first few MB of the kernel linear mapping to jump to once the MMU has | |
544 | * been enabled, including the FDT blob (TTBR1) | |
bf4b558e | 545 | * - pgd entry for fixed mappings (TTBR1) |
9703d9d7 CM |
546 | */ |
547 | __create_page_tables: | |
bd00cd5f | 548 | pgtbl x25, x26, x28 // idmap_pg_dir and swapper_pg_dir addresses |
c218bca7 CM |
549 | mov x27, lr |
550 | ||
551 | /* | |
552 | * Invalidate the idmap and swapper page tables to avoid potential | |
553 | * dirty cache lines being evicted. | |
554 | */ | |
555 | mov x0, x25 | |
556 | add x1, x26, #SWAPPER_DIR_SIZE | |
557 | bl __inval_cache_range | |
9703d9d7 CM |
558 | |
559 | /* | |
560 | * Clear the idmap and swapper page tables. | |
561 | */ | |
562 | mov x0, x25 | |
563 | add x6, x26, #SWAPPER_DIR_SIZE | |
564 | 1: stp xzr, xzr, [x0], #16 | |
565 | stp xzr, xzr, [x0], #16 | |
566 | stp xzr, xzr, [x0], #16 | |
567 | stp xzr, xzr, [x0], #16 | |
568 | cmp x0, x6 | |
569 | b.lo 1b | |
570 | ||
571 | ldr x7, =MM_MMUFLAGS | |
572 | ||
573 | /* | |
574 | * Create the identity mapping. | |
575 | */ | |
576 | add x0, x25, #PAGE_SIZE // section table address | |
ea8c2e11 CM |
577 | ldr x3, =KERNEL_START |
578 | add x3, x3, x28 // __pa(KERNEL_START) | |
c79b954b | 579 | create_pgd_entry x25, x0, x3, x1, x5, x6 |
ea8c2e11 CM |
580 | ldr x6, =KERNEL_END |
581 | mov x5, x3 // __pa(KERNEL_START) | |
582 | add x6, x6, x28 // __pa(KERNEL_END) | |
583 | create_block_map x0, x7, x3, x5, x6 | |
9703d9d7 CM |
584 | |
585 | /* | |
586 | * Map the kernel image (starting with PHYS_OFFSET). | |
587 | */ | |
588 | add x0, x26, #PAGE_SIZE // section table address | |
589 | mov x5, #PAGE_OFFSET | |
c79b954b | 590 | create_pgd_entry x26, x0, x5, x1, x3, x6 |
ea8c2e11 | 591 | ldr x6, =KERNEL_END |
9703d9d7 CM |
592 | mov x3, x24 // phys offset |
593 | create_block_map x0, x7, x3, x5, x6 | |
594 | ||
595 | /* | |
596 | * Map the FDT blob (maximum 2MB; must be within 512MB of | |
597 | * PHYS_OFFSET). | |
598 | */ | |
599 | mov x3, x21 // FDT phys address | |
600 | and x3, x3, #~((1 << 21) - 1) // 2MB aligned | |
601 | mov x6, #PAGE_OFFSET | |
602 | sub x5, x3, x24 // subtract PHYS_OFFSET | |
603 | tst x5, #~((1 << 29) - 1) // within 512MB? | |
604 | csel x21, xzr, x21, ne // zero the FDT pointer | |
605 | b.ne 1f | |
606 | add x5, x5, x6 // __va(FDT blob) | |
607 | add x6, x5, #1 << 21 // 2MB for the FDT blob | |
608 | sub x6, x6, #1 // inclusive range | |
609 | create_block_map x0, x7, x3, x5, x6 | |
610 | 1: | |
c218bca7 CM |
611 | /* |
612 | * Since the page tables have been populated with non-cacheable | |
613 | * accesses (MMU disabled), invalidate the idmap and swapper page | |
614 | * tables again to remove any speculatively loaded cache lines. | |
615 | */ | |
616 | mov x0, x25 | |
617 | add x1, x26, #SWAPPER_DIR_SIZE | |
618 | bl __inval_cache_range | |
619 | ||
620 | mov lr, x27 | |
9703d9d7 CM |
621 | ret |
622 | ENDPROC(__create_page_tables) | |
623 | .ltorg | |
624 | ||
625 | .align 3 | |
626 | .type __switch_data, %object | |
627 | __switch_data: | |
628 | .quad __mmap_switched | |
9703d9d7 | 629 | .quad __bss_start // x6 |
bd00cd5f | 630 | .quad __bss_stop // x7 |
9703d9d7 CM |
631 | .quad processor_id // x4 |
632 | .quad __fdt_pointer // x5 | |
633 | .quad memstart_addr // x6 | |
634 | .quad init_thread_union + THREAD_START_SP // sp | |
635 | ||
636 | /* | |
637 | * The following fragment of code is executed with the MMU on in MMU mode, and | |
638 | * uses absolute addresses; this is not position independent. | |
639 | */ | |
640 | __mmap_switched: | |
641 | adr x3, __switch_data + 8 | |
642 | ||
9703d9d7 | 643 | ldp x6, x7, [x3], #16 |
9703d9d7 CM |
644 | 1: cmp x6, x7 |
645 | b.hs 2f | |
646 | str xzr, [x6], #8 // Clear BSS | |
647 | b 1b | |
648 | 2: | |
649 | ldp x4, x5, [x3], #16 | |
650 | ldr x6, [x3], #8 | |
651 | ldr x16, [x3] | |
652 | mov sp, x16 | |
653 | str x22, [x4] // Save processor ID | |
654 | str x21, [x5] // Save FDT pointer | |
655 | str x24, [x6] // Save PHYS_OFFSET | |
656 | mov x29, #0 | |
657 | b start_kernel | |
658 | ENDPROC(__mmap_switched) | |
659 | ||
660 | /* | |
661 | * Exception handling. Something went wrong and we can't proceed. We ought to | |
662 | * tell the user, but since we don't have any guarantee that we're even | |
663 | * running on the right architecture, we do virtually nothing. | |
664 | */ | |
665 | __error_p: | |
666 | ENDPROC(__error_p) | |
667 | ||
668 | __error: | |
669 | 1: nop | |
670 | b 1b | |
671 | ENDPROC(__error) | |
672 | ||
673 | /* | |
674 | * This function gets the processor ID in w0 and searches the cpu_table[] for | |
675 | * a match. It returns a pointer to the struct cpu_info it found. The | |
676 | * cpu_table[] must end with an empty (all zeros) structure. | |
677 | * | |
678 | * This routine can be called via C code and it needs to work with the MMU | |
679 | * both disabled and enabled (the offset is calculated automatically). | |
680 | */ | |
681 | ENTRY(lookup_processor_type) | |
682 | adr x1, __lookup_processor_type_data | |
683 | ldp x2, x3, [x1] | |
684 | sub x1, x1, x2 // get offset between VA and PA | |
685 | add x3, x3, x1 // convert VA to PA | |
686 | 1: | |
687 | ldp w5, w6, [x3] // load cpu_id_val and cpu_id_mask | |
688 | cbz w5, 2f // end of list? | |
689 | and w6, w6, w0 | |
690 | cmp w5, w6 | |
691 | b.eq 3f | |
692 | add x3, x3, #CPU_INFO_SZ | |
693 | b 1b | |
694 | 2: | |
695 | mov x3, #0 // unknown processor | |
696 | 3: | |
697 | mov x0, x3 | |
698 | ret | |
699 | ENDPROC(lookup_processor_type) | |
700 | ||
701 | .align 3 | |
702 | .type __lookup_processor_type_data, %object | |
703 | __lookup_processor_type_data: | |
704 | .quad . | |
705 | .quad cpu_table | |
706 | .size __lookup_processor_type_data, . - __lookup_processor_type_data | |
707 | ||
708 | /* | |
709 | * Determine validity of the x21 FDT pointer. | |
710 | * The dtb must be 8-byte aligned and live in the first 512M of memory. | |
711 | */ | |
712 | __vet_fdt: | |
713 | tst x21, #0x7 | |
714 | b.ne 1f | |
715 | cmp x21, x24 | |
716 | b.lt 1f | |
717 | mov x0, #(1 << 29) | |
718 | add x0, x0, x24 | |
719 | cmp x21, x0 | |
720 | b.ge 1f | |
721 | ret | |
722 | 1: | |
723 | mov x21, #0 | |
724 | ret | |
725 | ENDPROC(__vet_fdt) |