xref: /openbmc/linux/arch/powerpc/kernel/paca.c (revision bc5aa3a0)
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 
14 #include <asm/lppaca.h>
15 #include <asm/paca.h>
16 #include <asm/sections.h>
17 #include <asm/pgtable.h>
18 #include <asm/kexec.h>
19 
20 #ifdef CONFIG_PPC_BOOK3S
21 
22 /*
23  * The structure which the hypervisor knows about - this structure
24  * should not cross a page boundary.  The vpa_init/register_vpa call
25  * is now known to fail if the lppaca structure crosses a page
26  * boundary.  The lppaca is also used on POWER5 pSeries boxes.
27  * The lppaca is 640 bytes long, and cannot readily
28  * change since the hypervisor knows its layout, so a 1kB alignment
29  * will suffice to ensure that it doesn't cross a page boundary.
30  */
31 struct lppaca lppaca[] = {
32 	[0 ... (NR_LPPACAS-1)] = {
33 		.desc = cpu_to_be32(0xd397d781),	/* "LpPa" */
34 		.size = cpu_to_be16(sizeof(struct lppaca)),
35 		.fpregs_in_use = 1,
36 		.slb_count = cpu_to_be16(64),
37 		.vmxregs_in_use = 0,
38 		.page_ins = 0,
39 	},
40 };
41 
42 static struct lppaca *extra_lppacas;
43 static long __initdata lppaca_size;
44 
45 static void __init allocate_lppacas(int nr_cpus, unsigned long limit)
46 {
47 	if (nr_cpus <= NR_LPPACAS)
48 		return;
49 
50 	lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
51 				 (nr_cpus - NR_LPPACAS));
52 	extra_lppacas = __va(memblock_alloc_base(lppaca_size,
53 						 PAGE_SIZE, limit));
54 }
55 
56 static struct lppaca * __init new_lppaca(int cpu)
57 {
58 	struct lppaca *lp;
59 
60 	if (cpu < NR_LPPACAS)
61 		return &lppaca[cpu];
62 
63 	lp = extra_lppacas + (cpu - NR_LPPACAS);
64 	*lp = lppaca[0];
65 
66 	return lp;
67 }
68 
69 static void __init free_lppacas(void)
70 {
71 	long new_size = 0, nr;
72 
73 	if (!lppaca_size)
74 		return;
75 	nr = num_possible_cpus() - NR_LPPACAS;
76 	if (nr > 0)
77 		new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
78 	if (new_size >= lppaca_size)
79 		return;
80 
81 	memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
82 	lppaca_size = new_size;
83 }
84 
85 #else
86 
87 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
88 static inline void free_lppacas(void) { }
89 
90 #endif /* CONFIG_PPC_BOOK3S */
91 
92 #ifdef CONFIG_PPC_STD_MMU_64
93 
94 /*
95  * 3 persistent SLBs are registered 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 *slb_shadow;
102 
103 static void __init allocate_slb_shadows(int nr_cpus, int limit)
104 {
105 	int size = PAGE_ALIGN(sizeof(struct slb_shadow) * nr_cpus);
106 	slb_shadow = __va(memblock_alloc_base(size, PAGE_SIZE, limit));
107 	memset(slb_shadow, 0, size);
108 }
109 
110 static struct slb_shadow * __init init_slb_shadow(int cpu)
111 {
112 	struct slb_shadow *s = &slb_shadow[cpu];
113 
114 	/*
115 	 * When we come through here to initialise boot_paca, the slb_shadow
116 	 * buffers are not allocated yet. That's OK, we'll get one later in
117 	 * boot, but make sure we don't corrupt memory at 0.
118 	 */
119 	if (!slb_shadow)
120 		return NULL;
121 
122 	s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
123 	s->buffer_length = cpu_to_be32(sizeof(*s));
124 
125 	return s;
126 }
127 
128 #else /* CONFIG_PPC_STD_MMU_64 */
129 
130 static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
131 
132 #endif /* CONFIG_PPC_STD_MMU_64 */
133 
134 /* The Paca is an array with one entry per processor.  Each contains an
135  * lppaca, which contains the information shared between the
136  * hypervisor and Linux.
137  * On systems with hardware multi-threading, there are two threads
138  * per processor.  The Paca array must contain an entry for each thread.
139  * The VPD Areas will give a max logical processors = 2 * max physical
140  * processors.  The processor VPD array needs one entry per physical
141  * processor (not thread).
142  */
143 struct paca_struct *paca;
144 EXPORT_SYMBOL(paca);
145 
146 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
147 {
148 #ifdef CONFIG_PPC_BOOK3S
149 	new_paca->lppaca_ptr = new_lppaca(cpu);
150 #else
151 	new_paca->kernel_pgd = swapper_pg_dir;
152 #endif
153 	new_paca->lock_token = 0x8000;
154 	new_paca->paca_index = cpu;
155 	new_paca->kernel_toc = kernel_toc_addr();
156 	new_paca->kernelbase = (unsigned long) _stext;
157 	/* Only set MSR:IR/DR when MMU is initialized */
158 	new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
159 	new_paca->hw_cpu_id = 0xffff;
160 	new_paca->kexec_state = KEXEC_STATE_NONE;
161 	new_paca->__current = &init_task;
162 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
163 #ifdef CONFIG_PPC_STD_MMU_64
164 	new_paca->slb_shadow_ptr = init_slb_shadow(cpu);
165 #endif /* CONFIG_PPC_STD_MMU_64 */
166 
167 #ifdef CONFIG_PPC_BOOK3E
168 	/* For now -- if we have threads this will be adjusted later */
169 	new_paca->tcd_ptr = &new_paca->tcd;
170 #endif
171 }
172 
173 /* Put the paca pointer into r13 and SPRG_PACA */
174 void setup_paca(struct paca_struct *new_paca)
175 {
176 	/* Setup r13 */
177 	local_paca = new_paca;
178 
179 #ifdef CONFIG_PPC_BOOK3E
180 	/* On Book3E, initialize the TLB miss exception frames */
181 	mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
182 #else
183 	/* In HV mode, we setup both HPACA and PACA to avoid problems
184 	 * if we do a GET_PACA() before the feature fixups have been
185 	 * applied
186 	 */
187 	if (early_cpu_has_feature(CPU_FTR_HVMODE))
188 		mtspr(SPRN_SPRG_HPACA, local_paca);
189 #endif
190 	mtspr(SPRN_SPRG_PACA, local_paca);
191 
192 }
193 
194 static int __initdata paca_size;
195 
196 void __init allocate_pacas(void)
197 {
198 	u64 limit;
199 	int cpu;
200 
201 	limit = ppc64_rma_size;
202 
203 #ifdef CONFIG_PPC_BOOK3S_64
204 	/*
205 	 * We can't take SLB misses on the paca, and we want to access them
206 	 * in real mode, so allocate them within the RMA and also within
207 	 * the first segment.
208 	 */
209 	limit = min(0x10000000ULL, limit);
210 #endif
211 
212 	paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
213 
214 	paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
215 	memset(paca, 0, paca_size);
216 
217 	printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
218 		paca_size, nr_cpu_ids, paca);
219 
220 	allocate_lppacas(nr_cpu_ids, limit);
221 
222 	allocate_slb_shadows(nr_cpu_ids, limit);
223 
224 	/* Can't use for_each_*_cpu, as they aren't functional yet */
225 	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
226 		initialise_paca(&paca[cpu], cpu);
227 }
228 
229 void __init free_unused_pacas(void)
230 {
231 	int new_size;
232 
233 	new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
234 
235 	if (new_size >= paca_size)
236 		return;
237 
238 	memblock_free(__pa(paca) + new_size, paca_size - new_size);
239 
240 	printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
241 		paca_size - new_size);
242 
243 	paca_size = new_size;
244 
245 	free_lppacas();
246 }
247