xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision 4419617e)
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 
12 #include <asm/lppaca.h>
13 #include <asm/paca.h>
14 #include <asm/sections.h>
15 #include <asm/pgtable.h>
16 #include <asm/kexec.h>
17 
18 #include "setup.h"
19 
20 #ifndef CONFIG_SMP
21 #define boot_cpuid 0
22 #endif
23 
24 static void *__init alloc_paca_data(unsigned long size, unsigned long align,
25 				unsigned long limit, int cpu)
26 {
27 	void *ptr;
28 	int nid;
29 
30 	/*
31 	 * boot_cpuid paca is allocated very early before cpu_to_node is up.
32 	 * Set bottom-up mode, because the boot CPU should be on node-0,
33 	 * which will put its paca in the right place.
34 	 */
35 	if (cpu == boot_cpuid) {
36 		nid = NUMA_NO_NODE;
37 		memblock_set_bottom_up(true);
38 	} else {
39 		nid = early_cpu_to_node(cpu);
40 	}
41 
42 	ptr = memblock_alloc_try_nid(size, align, MEMBLOCK_LOW_LIMIT,
43 				     limit, nid);
44 	if (!ptr)
45 		panic("cannot allocate paca data");
46 
47 	if (cpu == boot_cpuid)
48 		memblock_set_bottom_up(false);
49 
50 	return ptr;
51 }
52 
53 #ifdef CONFIG_PPC_PSERIES
54 
55 /*
56  * See asm/lppaca.h for more detail.
57  *
58  * lppaca structures must must be 1kB in size, L1 cache line aligned,
59  * and not cross 4kB boundary. A 1kB size and 1kB alignment will satisfy
60  * these requirements.
61  */
62 static inline void init_lppaca(struct lppaca *lppaca)
63 {
64 	BUILD_BUG_ON(sizeof(struct lppaca) != 640);
65 
66 	*lppaca = (struct lppaca) {
67 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
68 		.size = cpu_to_be16(0x400),
69 		.fpregs_in_use = 1,
70 		.slb_count = cpu_to_be16(64),
71 		.vmxregs_in_use = 0,
72 		.page_ins = 0, };
73 };
74 
75 static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
76 {
77 	struct lppaca *lp;
78 	size_t size = 0x400;
79 
80 	BUILD_BUG_ON(size < sizeof(struct lppaca));
81 
82 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
83 		return NULL;
84 
85 	lp = alloc_paca_data(size, 0x400, limit, cpu);
86 	init_lppaca(lp);
87 
88 	return lp;
89 }
90 #endif /* CONFIG_PPC_BOOK3S */
91 
92 #ifdef CONFIG_PPC_BOOK3S_64
93 
94 /*
95  * 3 persistent SLBs are allocated here.  The buffer will be zero
96  * initially, hence will all be invaild until we actually write them.
97  *
98  * If you make the number of persistent SLB entries dynamic, please also
99  * update PR KVM to flush and restore them accordingly.
100  */
101 static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
102 {
103 	struct slb_shadow *s;
104 
105 	if (cpu != boot_cpuid) {
106 		/*
107 		 * Boot CPU comes here before early_radix_enabled
108 		 * is parsed (e.g., for disable_radix). So allocate
109 		 * always and this will be fixed up in free_unused_pacas.
110 		 */
111 		if (early_radix_enabled())
112 			return NULL;
113 	}
114 
115 	s = alloc_paca_data(sizeof(*s), L1_CACHE_BYTES, limit, cpu);
116 
117 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
118 	s->buffer_length = cpu_to_be32(sizeof(*s));
119 
120 	return s;
121 }
122 
123 #endif /* CONFIG_PPC_BOOK3S_64 */
124 
125 /* The Paca is an array with one entry per processor.  Each contains an
126  * lppaca, which contains the information shared between the
127  * hypervisor and Linux.
128  * On systems with hardware multi-threading, there are two threads
129  * per processor.  The Paca array must contain an entry for each thread.
130  * The VPD Areas will give a max logical processors = 2 * max physical
131  * processors.  The processor VPD array needs one entry per physical
132  * processor (not thread).
133  */
134 struct paca_struct **paca_ptrs __read_mostly;
135 EXPORT_SYMBOL(paca_ptrs);
136 
137 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
138 {
139 #ifdef CONFIG_PPC_PSERIES
140 	new_paca->lppaca_ptr = NULL;
141 #endif
142 #ifdef CONFIG_PPC_BOOK3E
143 	new_paca->kernel_pgd = swapper_pg_dir;
144 #endif
145 	new_paca->lock_token = 0x8000;
146 	new_paca->paca_index = cpu;
147 	new_paca->kernel_toc = kernel_toc_addr();
148 	new_paca->kernelbase = (unsigned long) _stext;
149 	/* Only set MSR:IR/DR when MMU is initialized */
150 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
151 	new_paca->hw_cpu_id = 0xffff;
152 	new_paca->kexec_state = KEXEC_STATE_NONE;
153 	new_paca->__current = &init_task;
154 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
155 #ifdef CONFIG_PPC_BOOK3S_64
156 	new_paca->slb_shadow_ptr = NULL;
157 #endif
158 
159 #ifdef CONFIG_PPC_BOOK3E
160 	/* For now -- if we have threads this will be adjusted later */
161 	new_paca->tcd_ptr = &new_paca->tcd;
162 #endif
163 }
164 
165 /* Put the paca pointer into r13 and SPRG_PACA */
166 void setup_paca(struct paca_struct *new_paca)
167 {
168 	/* Setup r13 */
169 	local_paca = new_paca;
170 
171 #ifdef CONFIG_PPC_BOOK3E
172 	/* On Book3E, initialize the TLB miss exception frames */
173 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
174 #else
175 	/* In HV mode, we setup both HPACA and PACA to avoid problems
176 	 * if we do a GET_PACA() before the feature fixups have been
177 	 * applied
178 	 */
179 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
180 		mtspr(SPRN_SPRG_HPACA, local_paca);
181 #endif
182 	mtspr(SPRN_SPRG_PACA, local_paca);
183 
184 }
185 
186 static int __initdata paca_nr_cpu_ids;
187 static int __initdata paca_ptrs_size;
188 static int __initdata paca_struct_size;
189 
190 void __init allocate_paca_ptrs(void)
191 {
192 	paca_nr_cpu_ids = nr_cpu_ids;
193 
194 	paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
195 	paca_ptrs = memblock_alloc_raw(paca_ptrs_size, SMP_CACHE_BYTES);
196 	if (!paca_ptrs)
197 		panic("Failed to allocate %d bytes for paca pointers\n",
198 		      paca_ptrs_size);
199 
200 	memset(paca_ptrs, 0x88, paca_ptrs_size);
201 }
202 
203 void __init allocate_paca(int cpu)
204 {
205 	u64 limit;
206 	struct paca_struct *paca;
207 
208 	BUG_ON(cpu >= paca_nr_cpu_ids);
209 
210 #ifdef CONFIG_PPC_BOOK3S_64
211 	/*
212 	 * We access pacas in real mode, and cannot take SLB faults
213 	 * on them when in virtual mode, so allocate them accordingly.
214 	 */
215 	limit = min(ppc64_bolted_size(), ppc64_rma_size);
216 #else
217 	limit = ppc64_rma_size;
218 #endif
219 
220 	paca = alloc_paca_data(sizeof(struct paca_struct), L1_CACHE_BYTES,
221 				limit, cpu);
222 	paca_ptrs[cpu] = paca;
223 
224 	initialise_paca(paca, cpu);
225 #ifdef CONFIG_PPC_PSERIES
226 	paca->lppaca_ptr = new_lppaca(cpu, limit);
227 #endif
228 #ifdef CONFIG_PPC_BOOK3S_64
229 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
230 #endif
231 	paca_struct_size += sizeof(struct paca_struct);
232 }
233 
234 void __init free_unused_pacas(void)
235 {
236 	int new_ptrs_size;
237 
238 	new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
239 	if (new_ptrs_size < paca_ptrs_size)
240 		memblock_free(__pa(paca_ptrs) + new_ptrs_size,
241 					paca_ptrs_size - new_ptrs_size);
242 
243 	paca_nr_cpu_ids = nr_cpu_ids;
244 	paca_ptrs_size = new_ptrs_size;
245 
246 #ifdef CONFIG_PPC_BOOK3S_64
247 	if (early_radix_enabled()) {
248 		/* Ugly fixup, see new_slb_shadow() */
249 		memblock_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
250 				sizeof(struct slb_shadow));
251 		paca_ptrs[boot_cpuid]->slb_shadow_ptr = NULL;
252 	}
253 #endif
254 
255 	printk(KERN_DEBUG "Allocated %u bytes for %u pacas\n",
256 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
257 }
258 
259 void copy_mm_to_paca(struct mm_struct *mm)
260 {
261 #ifdef CONFIG_PPC_BOOK3S
262 	mm_context_t *context = &mm->context;
263 
264 	get_paca()->mm_ctx_id = context->id;
265 #ifdef CONFIG_PPC_MM_SLICES
266 	VM_BUG_ON(!mm_ctx_slb_addr_limit(context));
267 	get_paca()->mm_ctx_slb_addr_limit = mm_ctx_slb_addr_limit(context);
268 	memcpy(&get_paca()->mm_ctx_low_slices_psize, mm_ctx_low_slices(context),
269 	       LOW_SLICE_ARRAY_SZ);
270 	memcpy(&get_paca()->mm_ctx_high_slices_psize, mm_ctx_high_slices(context),
271 	       TASK_SLICE_ARRAY_SZ(context));
272 #else /* CONFIG_PPC_MM_SLICES */
273 	get_paca()->mm_ctx_user_psize = context->user_psize;
274 	get_paca()->mm_ctx_sllp = context->sllp;
275 #endif
276 #else /* !CONFIG_PPC_BOOK3S */
277 	return;
278 #endif
279 }
280