xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision 2cf1c348)
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_64S_HASH_MMU
143 /*
144  * 3 persistent SLBs are allocated here.  The buffer will be zero
145  * initially, hence will all be invaild until we actually write them.
146  *
147  * If you make the number of persistent SLB entries dynamic, please also
148  * update PR KVM to flush and restore them accordingly.
149  */
150 static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
151 {
152 	struct slb_shadow *s;
153 
154 	if (cpu != boot_cpuid) {
155 		/*
156 		 * Boot CPU comes here before early_radix_enabled
157 		 * is parsed (e.g., for disable_radix). So allocate
158 		 * always and this will be fixed up in free_unused_pacas.
159 		 */
160 		if (early_radix_enabled())
161 			return NULL;
162 	}
163 
164 	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);
165 
166 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
167 	s->buffer_length = cpu_to_be32(sizeof(*s));
168 
169 	return s;
170 }
171 #endif /* CONFIG_PPC_64S_HASH_MMU */
172 
173 #ifdef CONFIG_PPC_PSERIES
174 /**
175  * new_rtas_args() - Allocates rtas args
176  * @cpu:	CPU number
177  * @limit:	Memory limit for this allocation
178  *
179  * Allocates a struct rtas_args and return it's pointer,
180  * if not in Hypervisor mode
181  *
182  * Return:	Pointer to allocated rtas_args
183  *		NULL if CPU in Hypervisor Mode
184  */
185 static struct rtas_args * __init new_rtas_args(int cpu, unsigned long limit)
186 {
187 	limit = min_t(unsigned long, limit, RTAS_INSTANTIATE_MAX);
188 
189 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
190 		return NULL;
191 
192 	return alloc_paca_data(sizeof(struct rtas_args), L1_CACHE_BYTES,
193 			       limit, cpu);
194 }
195 #endif /* CONFIG_PPC_PSERIES */
196 
197 /* The Paca is an array with one entry per processor.  Each contains an
198  * lppaca, which contains the information shared between the
199  * hypervisor and Linux.
200  * On systems with hardware multi-threading, there are two threads
201  * per processor.  The Paca array must contain an entry for each thread.
202  * The VPD Areas will give a max logical processors = 2 * max physical
203  * processors.  The processor VPD array needs one entry per physical
204  * processor (not thread).
205  */
206 struct paca_struct **paca_ptrs __read_mostly;
207 EXPORT_SYMBOL(paca_ptrs);
208 
209 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
210 {
211 #ifdef CONFIG_PPC_PSERIES
212 	new_paca->lppaca_ptr = NULL;
213 #endif
214 #ifdef CONFIG_PPC_BOOK3E
215 	new_paca->kernel_pgd = swapper_pg_dir;
216 #endif
217 	new_paca->lock_token = 0x8000;
218 	new_paca->paca_index = cpu;
219 	new_paca->kernel_toc = kernel_toc_addr();
220 	new_paca->kernelbase = (unsigned long) _stext;
221 	/* Only set MSR:IR/DR when MMU is initialized */
222 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
223 	new_paca->hw_cpu_id = 0xffff;
224 	new_paca->kexec_state = KEXEC_STATE_NONE;
225 	new_paca->__current = &init_task;
226 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
227 #ifdef CONFIG_PPC_64S_HASH_MMU
228 	new_paca->slb_shadow_ptr = NULL;
229 #endif
230 
231 #ifdef CONFIG_PPC_BOOK3E
232 	/* For now -- if we have threads this will be adjusted later */
233 	new_paca->tcd_ptr = &new_paca->tcd;
234 #endif
235 
236 #ifdef CONFIG_PPC_PSERIES
237 	new_paca->rtas_args_reentrant = NULL;
238 #endif
239 }
240 
241 /* Put the paca pointer into r13 and SPRG_PACA */
242 void setup_paca(struct paca_struct *new_paca)
243 {
244 	/* Setup r13 */
245 	local_paca = new_paca;
246 
247 #ifdef CONFIG_PPC_BOOK3E
248 	/* On Book3E, initialize the TLB miss exception frames */
249 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
250 #else
251 	/*
252 	 * In HV mode, we setup both HPACA and PACA to avoid problems
253 	 * if we do a GET_PACA() before the feature fixups have been
254 	 * applied.
255 	 *
256 	 * Normally you should test against CPU_FTR_HVMODE, but CPU features
257 	 * are not yet set up when we first reach here.
258 	 */
259 	if (mfmsr() & MSR_HV)
260 		mtspr(SPRN_SPRG_HPACA, local_paca);
261 #endif
262 	mtspr(SPRN_SPRG_PACA, local_paca);
263 
264 }
265 
266 static int __initdata paca_nr_cpu_ids;
267 static int __initdata paca_ptrs_size;
268 static int __initdata paca_struct_size;
269 
270 void __init allocate_paca_ptrs(void)
271 {
272 	paca_nr_cpu_ids = nr_cpu_ids;
273 
274 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
275 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
276 	if (!paca_ptrs)
277 		panic("Failed to allocate %d bytes for paca pointers\n",
278 		      paca_ptrs_size);
279 
280 	memset(paca_ptrs, 0x88, paca_ptrs_size);
281 }
282 
283 void __init allocate_paca(int cpu)
284 {
285 	u64 limit;
286 	struct paca_struct *paca;
287 
288 	BUG_ON(cpu >= paca_nr_cpu_ids);
289 
290 #ifdef CONFIG_PPC_BOOK3S_64
291 	/*
292 	 * We access pacas in real mode, and cannot take SLB faults
293 	 * on them when in virtual mode, so allocate them accordingly.
294 	 */
295 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
296 #else
297 	limit = ppc64_rma_size;
298 #endif
299 
300 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
301 				limit, cpu);
302 	paca_ptrs[cpu] = paca;
303 
304 	initialise_paca(paca, cpu);
305 #ifdef CONFIG_PPC_PSERIES
306 	paca->lppaca_ptr = new_lppaca(cpu, limit);
307 #endif
308 #ifdef CONFIG_PPC_64S_HASH_MMU
309 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
310 #endif
311 #ifdef CONFIG_PPC_PSERIES
312 	paca->rtas_args_reentrant = new_rtas_args(cpu, limit);
313 #endif
314 	paca_struct_size += sizeof(struct paca_struct);
315 }
316 
317 void __init free_unused_pacas(void)
318 {
319 	int new_ptrs_size;
320 
321 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
322 	if (new_ptrs_size < paca_ptrs_size)
323 		memblock_phys_free(__pa(paca_ptrs) + new_ptrs_size,
324 				   paca_ptrs_size - new_ptrs_size);
325 
326 	paca_nr_cpu_ids = nr_cpu_ids;
327 	paca_ptrs_size = new_ptrs_size;
328 
329 #ifdef CONFIG_PPC_64S_HASH_MMU
330 	if (early_radix_enabled()) {
331 		/* Ugly fixup, see new_slb_shadow() */
332 		memblock_phys_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
333 				   sizeof(struct slb_shadow));
334 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
335 	}
336 #endif
337 
338 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
339 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
340 }
341 
342 #ifdef CONFIG_PPC_64S_HASH_MMU
343 void copy_mm_to_paca(struct mm_struct *mm)
344 {
345 	mm_context_t *context = &mm->context;
346 
347 #ifdef CONFIG_PPC_MM_SLICES
348 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
349 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
350 	       LOW_SLICE_ARRAY_SZ);
351 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
352 	       TASK_SLICE_ARRAY_SZ(context));
353 #else /* CONFIG_PPC_MM_SLICES */
354 	get_paca()->mm_ctx_user_psize = context->user_psize;
355 	get_paca()->mm_ctx_sllp = context->sllp;
356 #endif
357 }
358 #endif /* CONFIG_PPC_64S_HASH_MMU */
359