xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision de6da33e)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * c 2001 PPC 64 Team, IBM Corp
4  */
5 
6 #include <linux/smp.h>
7 #include <linux/export.h>
8 #include <linux/memblock.h>
9 #include <linux/sched/task.h>
10 #include <linux/numa.h>
11 #include <linux/pgtable.h>
12 
13 #include <asm/lppaca.h>
14 #include <asm/paca.h>
15 #include <asm/sections.h>
16 #include <asm/kexec.h>
17 #include <asm/svm.h>
18 #include <asm/ultravisor.h>
19 #include <asm/rtas.h>
20 
21 #include "setup.h"
22 
23 #ifndef CONFIG_SMP
24 #define boot_cpuid 0
25 #endif
26 
27 static void *__init alloc_paca_data(unsigned long size, unsigned long align,
28 				unsigned long limit, int cpu)
29 {
30 	void *ptr;
31 	int nid;
32 
33 	/*
34 	 * boot_cpuid paca is allocated very early before cpu_to_node is up.
35 	 * Set bottom-up mode, because the boot CPU should be on node-0,
36 	 * which will put its paca in the right place.
37 	 */
38 	if (cpu == boot_cpuid) {
39 		nid = NUMA_NO_NODE;
40 		memblock_set_bottom_up(true);
41 	} else {
42 		nid = early_cpu_to_node(cpu);
43 	}
44 
45 	ptr = memblock_alloc_try_nid(size, align, MEMBLOCK_LOW_LIMIT,
46 				     limit, nid);
47 	if (!ptr)
48 		panic("cannot allocate paca data");
49 
50 	if (cpu == boot_cpuid)
51 		memblock_set_bottom_up(false);
52 
53 	return ptr;
54 }
55 
56 #ifdef CONFIG_PPC_PSERIES
57 
58 #define LPPACA_SIZE 0x400
59 
60 static void *__init alloc_shared_lppaca(unsigned long size, unsigned long limit,
61 					int cpu)
62 {
63 	size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
64 	static unsigned long shared_lppaca_size;
65 	static void *shared_lppaca;
66 	void *ptr;
67 
68 	if (!shared_lppaca) {
69 		memblock_set_bottom_up(true);
70 
71 		/*
72 		 * See Documentation/powerpc/ultravisor.rst for more details.
73 		 *
74 		 * UV/HV data sharing is in PAGE_SIZE granularity. In order to
75 		 * minimize the number of pages shared, align the allocation to
76 		 * PAGE_SIZE.
77 		 */
78 		shared_lppaca =
79 			memblock_alloc_try_nid(shared_lppaca_total_size,
80 					       PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
81 					       limit, NUMA_NO_NODE);
82 		if (!shared_lppaca)
83 			panic("cannot allocate shared data");
84 
85 		memblock_set_bottom_up(false);
86 		uv_share_page(PHYS_PFN(__pa(shared_lppaca)),
87 			      shared_lppaca_total_size >> PAGE_SHIFT);
88 	}
89 
90 	ptr = shared_lppaca + shared_lppaca_size;
91 	shared_lppaca_size += size;
92 
93 	/*
94 	 * This is very early in boot, so no harm done if the kernel crashes at
95 	 * this point.
96 	 */
97 	BUG_ON(shared_lppaca_size > shared_lppaca_total_size);
98 
99 	return ptr;
100 }
101 
102 /*
103  * See asm/lppaca.h for more detail.
104  *
105  * lppaca structures must must be 1kB in size, L1 cache line aligned,
106  * and not cross 4kB boundary. A 1kB size and 1kB alignment will satisfy
107  * these requirements.
108  */
109 static inline void init_lppaca(struct lppaca *lppaca)
110 {
111 	BUILD_BUG_ON(sizeof(struct lppaca) != 640);
112 
113 	*lppaca = (struct lppaca) {
114 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
115 		.size = cpu_to_be16(LPPACA_SIZE),
116 		.fpregs_in_use = 1,
117 		.slb_count = cpu_to_be16(64),
118 		.vmxregs_in_use = 0,
119 		.page_ins = 0, };
120 };
121 
122 static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
123 {
124 	struct lppaca *lp;
125 
126 	BUILD_BUG_ON(sizeof(struct lppaca) > LPPACA_SIZE);
127 
128 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
129 		return NULL;
130 
131 	if (is_secure_guest())
132 		lp = alloc_shared_lppaca(LPPACA_SIZE, limit, cpu);
133 	else
134 		lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);
135 
136 	init_lppaca(lp);
137 
138 	return lp;
139 }
140 #endif /* CONFIG_PPC_PSERIES */
141 
142 #ifdef CONFIG_PPC_BOOK3S_64
143 
144 /*
145  * 3 persistent SLBs are allocated here.  The buffer will be zero
146  * initially, hence will all be invaild until we actually write them.
147  *
148  * If you make the number of persistent SLB entries dynamic, please also
149  * update PR KVM to flush and restore them accordingly.
150  */
151 static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
152 {
153 	struct slb_shadow *s;
154 
155 	if (cpu != boot_cpuid) {
156 		/*
157 		 * Boot CPU comes here before early_radix_enabled
158 		 * is parsed (e.g., for disable_radix). So allocate
159 		 * always and this will be fixed up in free_unused_pacas.
160 		 */
161 		if (early_radix_enabled())
162 			return NULL;
163 	}
164 
165 	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);
166 
167 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
168 	s->buffer_length = cpu_to_be32(sizeof(*s));
169 
170 	return s;
171 }
172 
173 #endif /* CONFIG_PPC_BOOK3S_64 */
174 
175 #ifdef CONFIG_PPC_PSERIES
176 /**
177  * new_rtas_args() - Allocates rtas args
178  * @cpu:	CPU number
179  * @limit:	Memory limit for this allocation
180  *
181  * Allocates a struct rtas_args and return it's pointer,
182  * if not in Hypervisor mode
183  *
184  * Return:	Pointer to allocated rtas_args
185  *		NULL if CPU in Hypervisor Mode
186  */
187 static struct rtas_args * __init new_rtas_args(int cpu, unsigned long limit)
188 {
189 	limit = min_t(unsigned long, limit, RTAS_INSTANTIATE_MAX);
190 
191 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
192 		return NULL;
193 
194 	return alloc_paca_data(sizeof(struct rtas_args), L1_CACHE_BYTES,
195 			       limit, cpu);
196 }
197 #endif /* CONFIG_PPC_PSERIES */
198 
199 /* The Paca is an array with one entry per processor.  Each contains an
200  * lppaca, which contains the information shared between the
201  * hypervisor and Linux.
202  * On systems with hardware multi-threading, there are two threads
203  * per processor.  The Paca array must contain an entry for each thread.
204  * The VPD Areas will give a max logical processors = 2 * max physical
205  * processors.  The processor VPD array needs one entry per physical
206  * processor (not thread).
207  */
208 struct paca_struct **paca_ptrs __read_mostly;
209 EXPORT_SYMBOL(paca_ptrs);
210 
211 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
212 {
213 #ifdef CONFIG_PPC_PSERIES
214 	new_paca->lppaca_ptr = NULL;
215 #endif
216 #ifdef CONFIG_PPC_BOOK3E
217 	new_paca->kernel_pgd = swapper_pg_dir;
218 #endif
219 	new_paca->lock_token = 0x8000;
220 	new_paca->paca_index = cpu;
221 	new_paca->kernel_toc = kernel_toc_addr();
222 	new_paca->kernelbase = (unsigned long) _stext;
223 	/* Only set MSR:IR/DR when MMU is initialized */
224 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
225 	new_paca->hw_cpu_id = 0xffff;
226 	new_paca->kexec_state = KEXEC_STATE_NONE;
227 	new_paca->__current = &init_task;
228 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
229 #ifdef CONFIG_PPC_BOOK3S_64
230 	new_paca->slb_shadow_ptr = NULL;
231 #endif
232 
233 #ifdef CONFIG_PPC_BOOK3E
234 	/* For now -- if we have threads this will be adjusted later */
235 	new_paca->tcd_ptr = &new_paca->tcd;
236 #endif
237 
238 #ifdef CONFIG_PPC_PSERIES
239 	new_paca->rtas_args_reentrant = NULL;
240 #endif
241 }
242 
243 /* Put the paca pointer into r13 and SPRG_PACA */
244 void setup_paca(struct paca_struct *new_paca)
245 {
246 	/* Setup r13 */
247 	local_paca = new_paca;
248 
249 #ifdef CONFIG_PPC_BOOK3E
250 	/* On Book3E, initialize the TLB miss exception frames */
251 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
252 #else
253 	/*
254 	 * In HV mode, we setup both HPACA and PACA to avoid problems
255 	 * if we do a GET_PACA() before the feature fixups have been
256 	 * applied.
257 	 *
258 	 * Normally you should test against CPU_FTR_HVMODE, but CPU features
259 	 * are not yet set up when we first reach here.
260 	 */
261 	if (mfmsr() & MSR_HV)
262 		mtspr(SPRN_SPRG_HPACA, local_paca);
263 #endif
264 	mtspr(SPRN_SPRG_PACA, local_paca);
265 
266 }
267 
268 static int __initdata paca_nr_cpu_ids;
269 static int __initdata paca_ptrs_size;
270 static int __initdata paca_struct_size;
271 
272 void __init allocate_paca_ptrs(void)
273 {
274 	paca_nr_cpu_ids = nr_cpu_ids;
275 
276 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
277 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
278 	if (!paca_ptrs)
279 		panic("Failed to allocate %d bytes for paca pointers\n",
280 		      paca_ptrs_size);
281 
282 	memset(paca_ptrs, 0x88, paca_ptrs_size);
283 }
284 
285 void __init allocate_paca(int cpu)
286 {
287 	u64 limit;
288 	struct paca_struct *paca;
289 
290 	BUG_ON(cpu >= paca_nr_cpu_ids);
291 
292 #ifdef CONFIG_PPC_BOOK3S_64
293 	/*
294 	 * We access pacas in real mode, and cannot take SLB faults
295 	 * on them when in virtual mode, so allocate them accordingly.
296 	 */
297 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
298 #else
299 	limit = ppc64_rma_size;
300 #endif
301 
302 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
303 				limit, cpu);
304 	paca_ptrs[cpu] = paca;
305 
306 	initialise_paca(paca, cpu);
307 #ifdef CONFIG_PPC_PSERIES
308 	paca->lppaca_ptr = new_lppaca(cpu, limit);
309 #endif
310 #ifdef CONFIG_PPC_BOOK3S_64
311 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
312 #endif
313 #ifdef CONFIG_PPC_PSERIES
314 	paca->rtas_args_reentrant = new_rtas_args(cpu, limit);
315 #endif
316 	paca_struct_size += sizeof(struct paca_struct);
317 }
318 
319 void __init free_unused_pacas(void)
320 {
321 	int new_ptrs_size;
322 
323 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
324 	if (new_ptrs_size < paca_ptrs_size)
325 		memblock_phys_free(__pa(paca_ptrs) + new_ptrs_size,
326 				   paca_ptrs_size - new_ptrs_size);
327 
328 	paca_nr_cpu_ids = nr_cpu_ids;
329 	paca_ptrs_size = new_ptrs_size;
330 
331 #ifdef CONFIG_PPC_BOOK3S_64
332 	if (early_radix_enabled()) {
333 		/* Ugly fixup, see new_slb_shadow() */
334 		memblock_phys_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
335 				   sizeof(struct slb_shadow));
336 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
337 	}
338 #endif
339 
340 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
341 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
342 }
343 
344 void copy_mm_to_paca(struct mm_struct *mm)
345 {
346 #ifdef CONFIG_PPC_BOOK3S
347 	mm_context_t *context = &mm->context;
348 
349 #ifdef CONFIG_PPC_MM_SLICES
350 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
351 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
352 	       LOW_SLICE_ARRAY_SZ);
353 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
354 	       TASK_SLICE_ARRAY_SZ(context));
355 #else /* CONFIG_PPC_MM_SLICES */
356 	get_paca()->mm_ctx_user_psize = context->user_psize;
357 	get_paca()->mm_ctx_sllp = context->sllp;
358 #endif
359 #else /* !CONFIG_PPC_BOOK3S */
360 	return;
361 #endif
362 }
363