xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision 74be2d3b)
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 align,
61 					unsigned long limit, 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 		shared_lppaca =
72 			memblock_alloc_try_nid(shared_lppaca_total_size,
73 					       PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
74 					       limit, NUMA_NO_NODE);
75 		if (!shared_lppaca)
76 			panic("cannot allocate shared data");
77 
78 		memblock_set_bottom_up(false);
79 		uv_share_page(PHYS_PFN(__pa(shared_lppaca)),
80 			      shared_lppaca_total_size >> PAGE_SHIFT);
81 	}
82 
83 	ptr = shared_lppaca + shared_lppaca_size;
84 	shared_lppaca_size += size;
85 
86 	/*
87 	 * This is very early in boot, so no harm done if the kernel crashes at
88 	 * this point.
89 	 */
90 	BUG_ON(shared_lppaca_size >= shared_lppaca_total_size);
91 
92 	return ptr;
93 }
94 
95 /*
96  * See asm/lppaca.h for more detail.
97  *
98  * lppaca structures must must be 1kB in size, L1 cache line aligned,
99  * and not cross 4kB boundary. A 1kB size and 1kB alignment will satisfy
100  * these requirements.
101  */
102 static inline void init_lppaca(struct lppaca *lppaca)
103 {
104 	BUILD_BUG_ON(sizeof(struct lppaca) != 640);
105 
106 	*lppaca = (struct lppaca) {
107 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
108 		.size = cpu_to_be16(LPPACA_SIZE),
109 		.fpregs_in_use = 1,
110 		.slb_count = cpu_to_be16(64),
111 		.vmxregs_in_use = 0,
112 		.page_ins = 0, };
113 };
114 
115 static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
116 {
117 	struct lppaca *lp;
118 
119 	BUILD_BUG_ON(sizeof(struct lppaca) > LPPACA_SIZE);
120 
121 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
122 		return NULL;
123 
124 	if (is_secure_guest())
125 		lp = alloc_shared_lppaca(LPPACA_SIZE, 0x400, limit, cpu);
126 	else
127 		lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);
128 
129 	init_lppaca(lp);
130 
131 	return lp;
132 }
133 #endif /* CONFIG_PPC_PSERIES */
134 
135 #ifdef CONFIG_PPC_BOOK3S_64
136 
137 /*
138  * 3 persistent SLBs are allocated here.  The buffer will be zero
139  * initially, hence will all be invaild until we actually write them.
140  *
141  * If you make the number of persistent SLB entries dynamic, please also
142  * update PR KVM to flush and restore them accordingly.
143  */
144 static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
145 {
146 	struct slb_shadow *s;
147 
148 	if (cpu != boot_cpuid) {
149 		/*
150 		 * Boot CPU comes here before early_radix_enabled
151 		 * is parsed (e.g., for disable_radix). So allocate
152 		 * always and this will be fixed up in free_unused_pacas.
153 		 */
154 		if (early_radix_enabled())
155 			return NULL;
156 	}
157 
158 	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);
159 
160 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
161 	s->buffer_length = cpu_to_be32(sizeof(*s));
162 
163 	return s;
164 }
165 
166 #endif /* CONFIG_PPC_BOOK3S_64 */
167 
168 #ifdef CONFIG_PPC_PSERIES
169 /**
170  * new_rtas_args() - Allocates rtas args
171  * @cpu:	CPU number
172  * @limit:	Memory limit for this allocation
173  *
174  * Allocates a struct rtas_args and return it's pointer,
175  * if not in Hypervisor mode
176  *
177  * Return:	Pointer to allocated rtas_args
178  *		NULL if CPU in Hypervisor Mode
179  */
180 static struct rtas_args * __init new_rtas_args(int cpu, unsigned long limit)
181 {
182 	limit = min_t(unsigned long, limit, RTAS_INSTANTIATE_MAX);
183 
184 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
185 		return NULL;
186 
187 	return alloc_paca_data(sizeof(struct rtas_args), L1_CACHE_BYTES,
188 			       limit, cpu);
189 }
190 #endif /* CONFIG_PPC_PSERIES */
191 
192 /* The Paca is an array with one entry per processor.  Each contains an
193  * lppaca, which contains the information shared between the
194  * hypervisor and Linux.
195  * On systems with hardware multi-threading, there are two threads
196  * per processor.  The Paca array must contain an entry for each thread.
197  * The VPD Areas will give a max logical processors = 2 * max physical
198  * processors.  The processor VPD array needs one entry per physical
199  * processor (not thread).
200  */
201 struct paca_struct **paca_ptrs __read_mostly;
202 EXPORT_SYMBOL(paca_ptrs);
203 
204 void __init __nostackprotector initialise_paca(struct paca_struct *new_paca, int cpu)
205 {
206 #ifdef CONFIG_PPC_PSERIES
207 	new_paca->lppaca_ptr = NULL;
208 #endif
209 #ifdef CONFIG_PPC_BOOK3E
210 	new_paca->kernel_pgd = swapper_pg_dir;
211 #endif
212 	new_paca->lock_token = 0x8000;
213 	new_paca->paca_index = cpu;
214 	new_paca->kernel_toc = kernel_toc_addr();
215 	new_paca->kernelbase = (unsigned long) _stext;
216 	/* Only set MSR:IR/DR when MMU is initialized */
217 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
218 	new_paca->hw_cpu_id = 0xffff;
219 	new_paca->kexec_state = KEXEC_STATE_NONE;
220 	new_paca->__current = &init_task;
221 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
222 #ifdef CONFIG_PPC_BOOK3S_64
223 	new_paca->slb_shadow_ptr = NULL;
224 #endif
225 
226 #ifdef CONFIG_PPC_BOOK3E
227 	/* For now -- if we have threads this will be adjusted later */
228 	new_paca->tcd_ptr = &new_paca->tcd;
229 #endif
230 
231 #ifdef CONFIG_PPC_PSERIES
232 	new_paca->rtas_args_reentrant = NULL;
233 #endif
234 }
235 
236 /* Put the paca pointer into r13 and SPRG_PACA */
237 void __nostackprotector setup_paca(struct paca_struct *new_paca)
238 {
239 	/* Setup r13 */
240 	local_paca = new_paca;
241 
242 #ifdef CONFIG_PPC_BOOK3E
243 	/* On Book3E, initialize the TLB miss exception frames */
244 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
245 #else
246 	/*
247 	 * In HV mode, we setup both HPACA and PACA to avoid problems
248 	 * if we do a GET_PACA() before the feature fixups have been
249 	 * applied.
250 	 *
251 	 * Normally you should test against CPU_FTR_HVMODE, but CPU features
252 	 * are not yet set up when we first reach here.
253 	 */
254 	if (mfmsr() & MSR_HV)
255 		mtspr(SPRN_SPRG_HPACA, local_paca);
256 #endif
257 	mtspr(SPRN_SPRG_PACA, local_paca);
258 
259 }
260 
261 static int __initdata paca_nr_cpu_ids;
262 static int __initdata paca_ptrs_size;
263 static int __initdata paca_struct_size;
264 
265 void __init allocate_paca_ptrs(void)
266 {
267 	paca_nr_cpu_ids = nr_cpu_ids;
268 
269 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
270 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
271 	if (!paca_ptrs)
272 		panic("Failed to allocate %d bytes for paca pointers\n",
273 		      paca_ptrs_size);
274 
275 	memset(paca_ptrs, 0x88, paca_ptrs_size);
276 }
277 
278 void __init allocate_paca(int cpu)
279 {
280 	u64 limit;
281 	struct paca_struct *paca;
282 
283 	BUG_ON(cpu >= paca_nr_cpu_ids);
284 
285 #ifdef CONFIG_PPC_BOOK3S_64
286 	/*
287 	 * We access pacas in real mode, and cannot take SLB faults
288 	 * on them when in virtual mode, so allocate them accordingly.
289 	 */
290 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
291 #else
292 	limit = ppc64_rma_size;
293 #endif
294 
295 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
296 				limit, cpu);
297 	paca_ptrs[cpu] = paca;
298 
299 	initialise_paca(paca, cpu);
300 #ifdef CONFIG_PPC_PSERIES
301 	paca->lppaca_ptr = new_lppaca(cpu, limit);
302 #endif
303 #ifdef CONFIG_PPC_BOOK3S_64
304 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
305 #endif
306 #ifdef CONFIG_PPC_PSERIES
307 	paca->rtas_args_reentrant = new_rtas_args(cpu, limit);
308 #endif
309 	paca_struct_size += sizeof(struct paca_struct);
310 }
311 
312 void __init free_unused_pacas(void)
313 {
314 	int new_ptrs_size;
315 
316 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
317 	if (new_ptrs_size < paca_ptrs_size)
318 		memblock_free(__pa(paca_ptrs) + new_ptrs_size,
319 					paca_ptrs_size - new_ptrs_size);
320 
321 	paca_nr_cpu_ids = nr_cpu_ids;
322 	paca_ptrs_size = new_ptrs_size;
323 
324 #ifdef CONFIG_PPC_BOOK3S_64
325 	if (early_radix_enabled()) {
326 		/* Ugly fixup, see new_slb_shadow() */
327 		memblock_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
328 				sizeof(struct slb_shadow));
329 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
330 	}
331 #endif
332 
333 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
334 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
335 }
336 
337 void copy_mm_to_paca(struct mm_struct *mm)
338 {
339 #ifdef CONFIG_PPC_BOOK3S
340 	mm_context_t *context = &mm->context;
341 
342 	get_paca()->mm_ctx_id = context->id;
343 #ifdef CONFIG_PPC_MM_SLICES
344 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
345 	get_paca()->mm_ctx_slb_addr_limit = mm_ctx_slb_addr_limit(context);
346 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
347 	       LOW_SLICE_ARRAY_SZ);
348 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
349 	       TASK_SLICE_ARRAY_SZ(context));
350 #else /* CONFIG_PPC_MM_SLICES */
351 	get_paca()->mm_ctx_user_psize = context->user_psize;
352 	get_paca()->mm_ctx_sllp = context->sllp;
353 #endif
354 #else /* !CONFIG_PPC_BOOK3S */
355 	return;
356 #endif
357 }
358