xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision 7e3a68be)
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 
alloc_paca_data(unsigned long size,unsigned long align,unsigned long limit,int cpu)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 
alloc_shared_lppaca(unsigned long size,unsigned long limit,int cpu)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  */
init_lppaca(struct lppaca * lppaca)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 
new_lppaca(int cpu,unsigned long limit)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  */
new_slb_shadow(int cpu,unsigned long limit)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 
initialise_paca(struct paca_struct * new_paca,int cpu)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 #ifndef CONFIG_PPC_KERNEL_PCREL
195 	new_paca->kernel_toc = kernel_toc_addr();
196 #endif
197 	new_paca->kernelbase = (unsigned long) _stext;
198 	/* Only set MSR:IR/DR when MMU is initialized */
199 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
200 	new_paca->hw_cpu_id = 0xffff;
201 	new_paca->kexec_state = KEXEC_STATE_NONE;
202 	new_paca->__current = &init_task;
203 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
204 #ifdef CONFIG_PPC_64S_HASH_MMU
205 	new_paca->slb_shadow_ptr = NULL;
206 #endif
207 
208 #ifdef CONFIG_PPC_BOOK3E_64
209 	/* For now -- if we have threads this will be adjusted later */
210 	new_paca->tcd_ptr = &new_paca->tcd;
211 #endif
212 }
213 
214 /* Put the paca pointer into r13 and SPRG_PACA */
setup_paca(struct paca_struct * new_paca)215 void setup_paca(struct paca_struct *new_paca)
216 {
217 	/* Setup r13 */
218 	local_paca = new_paca;
219 
220 #ifdef CONFIG_PPC_BOOK3E_64
221 	/* On Book3E, initialize the TLB miss exception frames */
222 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
223 #else
224 	/*
225 	 * In HV mode, we setup both HPACA and PACA to avoid problems
226 	 * if we do a GET_PACA() before the feature fixups have been
227 	 * applied.
228 	 *
229 	 * Normally you should test against CPU_FTR_HVMODE, but CPU features
230 	 * are not yet set up when we first reach here.
231 	 */
232 	if (mfmsr() & MSR_HV)
233 		mtspr(SPRN_SPRG_HPACA, local_paca);
234 #endif
235 	mtspr(SPRN_SPRG_PACA, local_paca);
236 
237 }
238 
239 static int __initdata paca_nr_cpu_ids;
240 static int __initdata paca_ptrs_size;
241 static int __initdata paca_struct_size;
242 
allocate_paca_ptrs(void)243 void __init allocate_paca_ptrs(void)
244 {
245 	paca_nr_cpu_ids = nr_cpu_ids;
246 
247 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
248 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
249 	if (!paca_ptrs)
250 		panic("Failed to allocate %d bytes for paca pointers\n",
251 		      paca_ptrs_size);
252 
253 	memset(paca_ptrs, 0x88, paca_ptrs_size);
254 }
255 
allocate_paca(int cpu)256 void __init allocate_paca(int cpu)
257 {
258 	u64 limit;
259 	struct paca_struct *paca;
260 
261 	BUG_ON(cpu >= paca_nr_cpu_ids);
262 
263 #ifdef CONFIG_PPC_BOOK3S_64
264 	/*
265 	 * We access pacas in real mode, and cannot take SLB faults
266 	 * on them when in virtual mode, so allocate them accordingly.
267 	 */
268 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
269 #else
270 	limit = ppc64_rma_size;
271 #endif
272 
273 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
274 				limit, cpu);
275 	paca_ptrs[cpu] = paca;
276 
277 	initialise_paca(paca, cpu);
278 #ifdef CONFIG_PPC_PSERIES
279 	paca->lppaca_ptr = new_lppaca(cpu, limit);
280 #endif
281 #ifdef CONFIG_PPC_64S_HASH_MMU
282 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
283 #endif
284 	paca_struct_size += sizeof(struct paca_struct);
285 }
286 
free_unused_pacas(void)287 void __init free_unused_pacas(void)
288 {
289 	int new_ptrs_size;
290 
291 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
292 	if (new_ptrs_size < paca_ptrs_size)
293 		memblock_phys_free(__pa(paca_ptrs) + new_ptrs_size,
294 				   paca_ptrs_size - new_ptrs_size);
295 
296 	paca_nr_cpu_ids = nr_cpu_ids;
297 	paca_ptrs_size = new_ptrs_size;
298 
299 #ifdef CONFIG_PPC_64S_HASH_MMU
300 	if (early_radix_enabled()) {
301 		/* Ugly fixup, see new_slb_shadow() */
302 		memblock_phys_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
303 				   sizeof(struct slb_shadow));
304 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
305 	}
306 #endif
307 
308 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
309 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
310 }
311 
312 #ifdef CONFIG_PPC_64S_HASH_MMU
copy_mm_to_paca(struct mm_struct * mm)313 void copy_mm_to_paca(struct mm_struct *mm)
314 {
315 	mm_context_t *context = &mm->context;
316 
317 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
318 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
319 	       LOW_SLICE_ARRAY_SZ);
320 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
321 	       TASK_SLICE_ARRAY_SZ(context));
322 }
323 #endif /* CONFIG_PPC_64S_HASH_MMU */
324