xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision 4da722ca)
1 /*
2  * c 2001 PPC 64 Team, IBM Corp
3  *
4  *      This program is free software; you can redistribute it and/or
5  *      modify it under the terms of the GNU General Public License
6  *      as published by the Free Software Foundation; either version
7  *      2 of the License, or (at your option) any later version.
8  */
9 
10 #include <linux/smp.h>
11 #include <linux/export.h>
12 #include <linux/memblock.h>
13 #include <linux/sched/task.h>
14 
15 #include <asm/lppaca.h>
16 #include <asm/paca.h>
17 #include <asm/sections.h>
18 #include <asm/pgtable.h>
19 #include <asm/kexec.h>
20 
21 #ifdef CONFIG_PPC_BOOK3S
22 
23 /*
24  * The structure which the hypervisor knows about - this structure
25  * should not cross a page boundary.  The vpa_init/register_vpa call
26  * is now known to fail if the lppaca structure crosses a page
27  * boundary.  The lppaca is also used on POWER5 pSeries boxes.
28  * The lppaca is 640 bytes long, and cannot readily
29  * change since the hypervisor knows its layout, so a 1kB alignment
30  * will suffice to ensure that it doesn't cross a page boundary.
31  */
32 struct lppaca lppaca[] = {
33 	[0 ... (NR_LPPACAS-1)] = {
34 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
35 		.size = cpu_to_be16(sizeof(struct lppaca)),
36 		.fpregs_in_use = 1,
37 		.slb_count = cpu_to_be16(64),
38 		.vmxregs_in_use = 0,
39 		.page_ins = 0,
40 	},
41 };
42 
43 static struct lppaca *extra_lppacas;
44 static long __initdata lppaca_size;
45 
46 static void __init allocate_lppacas(int nr_cpus, unsigned long limit)
47 {
48 	if (nr_cpus <= NR_LPPACAS)
49 		return;
50 
51 	lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
52 				 (nr_cpus - NR_LPPACAS));
53 	extra_lppacas = __va(memblock_alloc_base(lppaca_size,
54 						 PAGE_SIZE, limit));
55 }
56 
57 static struct lppaca * __init new_lppaca(int cpu)
58 {
59 	struct lppaca *lp;
60 
61 	if (cpu < NR_LPPACAS)
62 		return &lppaca[cpu];
63 
64 	lp = extra_lppacas + (cpu - NR_LPPACAS);
65 	*lp = lppaca[0];
66 
67 	return lp;
68 }
69 
70 static void __init free_lppacas(void)
71 {
72 	long new_size = 0, nr;
73 
74 	if (!lppaca_size)
75 		return;
76 	nr = num_possible_cpus() - NR_LPPACAS;
77 	if (nr > 0)
78 		new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
79 	if (new_size >= lppaca_size)
80 		return;
81 
82 	memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
83 	lppaca_size = new_size;
84 }
85 
86 #else
87 
88 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
89 static inline void free_lppacas(void) { }
90 
91 #endif /* CONFIG_PPC_BOOK3S */
92 
93 #ifdef CONFIG_PPC_STD_MMU_64
94 
95 /*
96  * 3 persistent SLBs are registered here.  The buffer will be zero
97  * initially, hence will all be invaild until we actually write them.
98  *
99  * If you make the number of persistent SLB entries dynamic, please also
100  * update PR KVM to flush and restore them accordingly.
101  */
102 static struct slb_shadow *slb_shadow;
103 
104 static void __init allocate_slb_shadows(int nr_cpus, int limit)
105 {
106 	int size = PAGE_ALIGN(sizeof(struct slb_shadow) * nr_cpus);
107 	slb_shadow = __va(memblock_alloc_base(size, PAGE_SIZE, limit));
108 	memset(slb_shadow, 0, size);
109 }
110 
111 static struct slb_shadow * __init init_slb_shadow(int cpu)
112 {
113 	struct slb_shadow *s = &slb_shadow[cpu];
114 
115 	/*
116 	 * When we come through here to initialise boot_paca, the slb_shadow
117 	 * buffers are not allocated yet. That's OK, we'll get one later in
118 	 * boot, but make sure we don't corrupt memory at 0.
119 	 */
120 	if (!slb_shadow)
121 		return NULL;
122 
123 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
124 	s->buffer_length = cpu_to_be32(sizeof(*s));
125 
126 	return s;
127 }
128 
129 #else /* CONFIG_PPC_STD_MMU_64 */
130 
131 static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
132 
133 #endif /* CONFIG_PPC_STD_MMU_64 */
134 
135 /* The Paca is an array with one entry per processor.  Each contains an
136  * lppaca, which contains the information shared between the
137  * hypervisor and Linux.
138  * On systems with hardware multi-threading, there are two threads
139  * per processor.  The Paca array must contain an entry for each thread.
140  * The VPD Areas will give a max logical processors = 2 * max physical
141  * processors.  The processor VPD array needs one entry per physical
142  * processor (not thread).
143  */
144 struct paca_struct *paca;
145 EXPORT_SYMBOL(paca);
146 
147 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
148 {
149 #ifdef CONFIG_PPC_BOOK3S
150 	new_paca->lppaca_ptr = new_lppaca(cpu);
151 #else
152 	new_paca->kernel_pgd = swapper_pg_dir;
153 #endif
154 	new_paca->lock_token = 0x8000;
155 	new_paca->paca_index = cpu;
156 	new_paca->kernel_toc = kernel_toc_addr();
157 	new_paca->kernelbase = (unsigned long) _stext;
158 	/* Only set MSR:IR/DR when MMU is initialized */
159 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
160 	new_paca->hw_cpu_id = 0xffff;
161 	new_paca->kexec_state = KEXEC_STATE_NONE;
162 	new_paca->__current = &init_task;
163 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
164 #ifdef CONFIG_PPC_STD_MMU_64
165 	new_paca->slb_shadow_ptr = init_slb_shadow(cpu);
166 #endif /* CONFIG_PPC_STD_MMU_64 */
167 
168 #ifdef CONFIG_PPC_BOOK3E
169 	/* For now -- if we have threads this will be adjusted later */
170 	new_paca->tcd_ptr = &new_paca->tcd;
171 #endif
172 }
173 
174 /* Put the paca pointer into r13 and SPRG_PACA */
175 void setup_paca(struct paca_struct *new_paca)
176 {
177 	/* Setup r13 */
178 	local_paca = new_paca;
179 
180 #ifdef CONFIG_PPC_BOOK3E
181 	/* On Book3E, initialize the TLB miss exception frames */
182 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
183 #else
184 	/* In HV mode, we setup both HPACA and PACA to avoid problems
185 	 * if we do a GET_PACA() before the feature fixups have been
186 	 * applied
187 	 */
188 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
189 		mtspr(SPRN_SPRG_HPACA, local_paca);
190 #endif
191 	mtspr(SPRN_SPRG_PACA, local_paca);
192 
193 }
194 
195 static int __initdata paca_size;
196 
197 void __init allocate_pacas(void)
198 {
199 	u64 limit;
200 	int cpu;
201 
202 	limit = ppc64_rma_size;
203 
204 #ifdef CONFIG_PPC_BOOK3S_64
205 	/*
206 	 * We can't take SLB misses on the paca, and we want to access them
207 	 * in real mode, so allocate them within the RMA and also within
208 	 * the first segment.
209 	 */
210 	limit = min(0x10000000ULL, limit);
211 #endif
212 
213 	paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
214 
215 	paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
216 	memset(paca, 0, paca_size);
217 
218 	printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
219 		paca_size, nr_cpu_ids, paca);
220 
221 	allocate_lppacas(nr_cpu_ids, limit);
222 
223 	allocate_slb_shadows(nr_cpu_ids, limit);
224 
225 	/* Can't use for_each_*_cpu, as they aren't functional yet */
226 	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
227 		initialise_paca(&paca[cpu], cpu);
228 }
229 
230 void __init free_unused_pacas(void)
231 {
232 	int new_size;
233 
234 	new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
235 
236 	if (new_size >= paca_size)
237 		return;
238 
239 	memblock_free(__pa(paca) + new_size, paca_size - new_size);
240 
241 	printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
242 		paca_size - new_size);
243 
244 	paca_size = new_size;
245 
246 	free_lppacas();
247 }
248 
249 void copy_mm_to_paca(struct mm_struct *mm)
250 {
251 #ifdef CONFIG_PPC_BOOK3S
252 	mm_context_t *context = &mm->context;
253 
254 	get_paca()->mm_ctx_id = context->id;
255 #ifdef CONFIG_PPC_MM_SLICES
256 	VM_BUG_ON(!mm->context.addr_limit);
257 	get_paca()->addr_limit = mm->context.addr_limit;
258 	get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
259 	memcpy(&get_paca()->mm_ctx_high_slices_psize,
260 	       &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
261 #else /* CONFIG_PPC_MM_SLICES */
262 	get_paca()->mm_ctx_user_psize = context->user_psize;
263 	get_paca()->mm_ctx_sllp = context->sllp;
264 #endif
265 #else /* CONFIG_PPC_BOOK3S */
266 	return;
267 #endif
268 }
269