xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision e0d68273)
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 
20 #include "setup.h"
21 
22 #ifndef CONFIG_SMP
23 #define boot_cpuid 0
24 #endif
25 
26 static void *__init alloc_paca_data(unsigned long size, unsigned long align,
27 				unsigned long limit, int cpu)
28 {
29 	void *ptr;
30 	int nid;
31 
32 	/*
33 	 * boot_cpuid paca is allocated very early before cpu_to_node is up.
34 	 * Set bottom-up mode, because the boot CPU should be on node-0,
35 	 * which will put its paca in the right place.
36 	 */
37 	if (cpu == boot_cpuid) {
38 		nid = NUMA_NO_NODE;
39 		memblock_set_bottom_up(true);
40 	} else {
41 		nid = early_cpu_to_node(cpu);
42 	}
43 
44 	ptr = memblock_alloc_try_nid(size, align, MEMBLOCK_LOW_LIMIT,
45 				     limit, nid);
46 	if (!ptr)
47 		panic("cannot allocate paca data");
48 
49 	if (cpu == boot_cpuid)
50 		memblock_set_bottom_up(false);
51 
52 	return ptr;
53 }
54 
55 #ifdef CONFIG_PPC_PSERIES
56 
57 #define LPPACA_SIZE 0x400
58 
59 static void *__init alloc_shared_lppaca(unsigned long size, unsigned long limit,
60 					int cpu)
61 {
62 	size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
63 	static unsigned long shared_lppaca_size;
64 	static void *shared_lppaca;
65 	void *ptr;
66 
67 	if (!shared_lppaca) {
68 		memblock_set_bottom_up(true);
69 
70 		/*
71 		 * See Documentation/powerpc/ultravisor.rst for more details.
72 		 *
73 		 * UV/HV data sharing is in PAGE_SIZE granularity. In order to
74 		 * minimize the number of pages shared, align the allocation to
75 		 * PAGE_SIZE.
76 		 */
77 		shared_lppaca =
78 			memblock_alloc_try_nid(shared_lppaca_total_size,
79 					       PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
80 					       limit, NUMA_NO_NODE);
81 		if (!shared_lppaca)
82 			panic("cannot allocate shared data");
83 
84 		memblock_set_bottom_up(false);
85 		uv_share_page(PHYS_PFN(__pa(shared_lppaca)),
86 			      shared_lppaca_total_size >> PAGE_SHIFT);
87 	}
88 
89 	ptr = shared_lppaca + shared_lppaca_size;
90 	shared_lppaca_size += size;
91 
92 	/*
93 	 * This is very early in boot, so no harm done if the kernel crashes at
94 	 * this point.
95 	 */
96 	BUG_ON(shared_lppaca_size > shared_lppaca_total_size);
97 
98 	return ptr;
99 }
100 
101 /*
102  * See asm/lppaca.h for more detail.
103  *
104  * lppaca structures must must be 1kB in size, L1 cache line aligned,
105  * and not cross 4kB boundary. A 1kB size and 1kB alignment will satisfy
106  * these requirements.
107  */
108 static inline void init_lppaca(struct lppaca *lppaca)
109 {
110 	BUILD_BUG_ON(sizeof(struct lppaca) != 640);
111 
112 	*lppaca = (struct lppaca) {
113 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
114 		.size = cpu_to_be16(LPPACA_SIZE),
115 		.fpregs_in_use = 1,
116 		.slb_count = cpu_to_be16(64),
117 		.vmxregs_in_use = 0,
118 		.page_ins = 0, };
119 };
120 
121 static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
122 {
123 	struct lppaca *lp;
124 
125 	BUILD_BUG_ON(sizeof(struct lppaca) > LPPACA_SIZE);
126 
127 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
128 		return NULL;
129 
130 	if (is_secure_guest())
131 		lp = alloc_shared_lppaca(LPPACA_SIZE, limit, cpu);
132 	else
133 		lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);
134 
135 	init_lppaca(lp);
136 
137 	return lp;
138 }
139 #endif /* CONFIG_PPC_PSERIES */
140 
141 #ifdef CONFIG_PPC_64S_HASH_MMU
142 /*
143  * 3 persistent SLBs are allocated here.  The buffer will be zero
144  * initially, hence will all be invaild until we actually write them.
145  *
146  * If you make the number of persistent SLB entries dynamic, please also
147  * update PR KVM to flush and restore them accordingly.
148  */
149 static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
150 {
151 	struct slb_shadow *s;
152 
153 	if (cpu != boot_cpuid) {
154 		/*
155 		 * Boot CPU comes here before early_radix_enabled
156 		 * is parsed (e.g., for disable_radix). So allocate
157 		 * always and this will be fixed up in free_unused_pacas.
158 		 */
159 		if (early_radix_enabled())
160 			return NULL;
161 	}
162 
163 	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);
164 
165 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
166 	s->buffer_length = cpu_to_be32(sizeof(*s));
167 
168 	return s;
169 }
170 #endif /* CONFIG_PPC_64S_HASH_MMU */
171 
172 /* The Paca is an array with one entry per processor.  Each contains an
173  * lppaca, which contains the information shared between the
174  * hypervisor and Linux.
175  * On systems with hardware multi-threading, there are two threads
176  * per processor.  The Paca array must contain an entry for each thread.
177  * The VPD Areas will give a max logical processors = 2 * max physical
178  * processors.  The processor VPD array needs one entry per physical
179  * processor (not thread).
180  */
181 struct paca_struct **paca_ptrs __read_mostly;
182 EXPORT_SYMBOL(paca_ptrs);
183 
184 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
185 {
186 #ifdef CONFIG_PPC_PSERIES
187 	new_paca->lppaca_ptr = NULL;
188 #endif
189 #ifdef CONFIG_PPC_BOOK3E_64
190 	new_paca->kernel_pgd = swapper_pg_dir;
191 #endif
192 	new_paca->lock_token = 0x8000;
193 	new_paca->paca_index = cpu;
194 	new_paca->kernel_toc = kernel_toc_addr();
195 	new_paca->kernelbase = (unsigned long) _stext;
196 	/* Only set MSR:IR/DR when MMU is initialized */
197 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
198 	new_paca->hw_cpu_id = 0xffff;
199 	new_paca->kexec_state = KEXEC_STATE_NONE;
200 	new_paca->__current = &init_task;
201 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
202 #ifdef CONFIG_PPC_64S_HASH_MMU
203 	new_paca->slb_shadow_ptr = NULL;
204 #endif
205 
206 #ifdef CONFIG_PPC_BOOK3E_64
207 	/* For now -- if we have threads this will be adjusted later */
208 	new_paca->tcd_ptr = &new_paca->tcd;
209 #endif
210 }
211 
212 /* Put the paca pointer into r13 and SPRG_PACA */
213 void setup_paca(struct paca_struct *new_paca)
214 {
215 	/* Setup r13 */
216 	local_paca = new_paca;
217 
218 #ifdef CONFIG_PPC_BOOK3E_64
219 	/* On Book3E, initialize the TLB miss exception frames */
220 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
221 #else
222 	/*
223 	 * In HV mode, we setup both HPACA and PACA to avoid problems
224 	 * if we do a GET_PACA() before the feature fixups have been
225 	 * applied.
226 	 *
227 	 * Normally you should test against CPU_FTR_HVMODE, but CPU features
228 	 * are not yet set up when we first reach here.
229 	 */
230 	if (mfmsr() & MSR_HV)
231 		mtspr(SPRN_SPRG_HPACA, local_paca);
232 #endif
233 	mtspr(SPRN_SPRG_PACA, local_paca);
234 
235 }
236 
237 static int __initdata paca_nr_cpu_ids;
238 static int __initdata paca_ptrs_size;
239 static int __initdata paca_struct_size;
240 
241 void __init allocate_paca_ptrs(void)
242 {
243 	paca_nr_cpu_ids = nr_cpu_ids;
244 
245 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
246 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
247 	if (!paca_ptrs)
248 		panic("Failed to allocate %d bytes for paca pointers\n",
249 		      paca_ptrs_size);
250 
251 	memset(paca_ptrs, 0x88, paca_ptrs_size);
252 }
253 
254 void __init allocate_paca(int cpu)
255 {
256 	u64 limit;
257 	struct paca_struct *paca;
258 
259 	BUG_ON(cpu >= paca_nr_cpu_ids);
260 
261 #ifdef CONFIG_PPC_BOOK3S_64
262 	/*
263 	 * We access pacas in real mode, and cannot take SLB faults
264 	 * on them when in virtual mode, so allocate them accordingly.
265 	 */
266 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
267 #else
268 	limit = ppc64_rma_size;
269 #endif
270 
271 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
272 				limit, cpu);
273 	paca_ptrs[cpu] = paca;
274 
275 	initialise_paca(paca, cpu);
276 #ifdef CONFIG_PPC_PSERIES
277 	paca->lppaca_ptr = new_lppaca(cpu, limit);
278 #endif
279 #ifdef CONFIG_PPC_64S_HASH_MMU
280 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
281 #endif
282 	paca_struct_size += sizeof(struct paca_struct);
283 }
284 
285 void __init free_unused_pacas(void)
286 {
287 	int new_ptrs_size;
288 
289 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
290 	if (new_ptrs_size < paca_ptrs_size)
291 		memblock_phys_free(__pa(paca_ptrs) + new_ptrs_size,
292 				   paca_ptrs_size - new_ptrs_size);
293 
294 	paca_nr_cpu_ids = nr_cpu_ids;
295 	paca_ptrs_size = new_ptrs_size;
296 
297 #ifdef CONFIG_PPC_64S_HASH_MMU
298 	if (early_radix_enabled()) {
299 		/* Ugly fixup, see new_slb_shadow() */
300 		memblock_phys_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
301 				   sizeof(struct slb_shadow));
302 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
303 	}
304 #endif
305 
306 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
307 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
308 }
309 
310 #ifdef CONFIG_PPC_64S_HASH_MMU
311 void copy_mm_to_paca(struct mm_struct *mm)
312 {
313 	mm_context_t *context = &mm->context;
314 
315 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
316 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
317 	       LOW_SLICE_ARRAY_SZ);
318 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
319 	       TASK_SLICE_ARRAY_SZ(context));
320 }
321 #endif /* CONFIG_PPC_64S_HASH_MMU */
322