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1da177e4
LT
1/*
2 * PowerPC64 SLB support.
3 *
4 * Copyright (C) 2004 David Gibson <dwg@au.ibm.com>, IBM
5 * Based on earlier code writteh by:
6 * Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com
7 * Copyright (c) 2001 Dave Engebretsen
8 * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
9 *
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 */
16
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17#undef DEBUG
18
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19#include <asm/pgtable.h>
20#include <asm/mmu.h>
21#include <asm/mmu_context.h>
22#include <asm/paca.h>
23#include <asm/cputable.h>
3c726f8d 24#include <asm/cacheflush.h>
2f6093c8 25#include <asm/smp.h>
56291e19 26#include <asm/firmware.h>
2f6093c8 27#include <linux/compiler.h>
aa39be09 28#include <asm/udbg.h>
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29
30#ifdef DEBUG
31#define DBG(fmt...) udbg_printf(fmt)
32#else
33#define DBG(fmt...)
34#endif
1da177e4 35
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36extern void slb_allocate_realmode(unsigned long ea);
37extern void slb_allocate_user(unsigned long ea);
38
39static void slb_allocate(unsigned long ea)
40{
41 /* Currently, we do real mode for all SLBs including user, but
42 * that will change if we bring back dynamic VSIDs
43 */
44 slb_allocate_realmode(ea);
45}
1da177e4 46
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47static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
48 unsigned long slot)
1da177e4 49{
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50 unsigned long mask;
51
52 mask = (ssize == MMU_SEGSIZE_256M)? ESID_MASK: ESID_MASK_1T;
53 return (ea & mask) | SLB_ESID_V | slot;
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54}
55
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56#define slb_vsid_shift(ssize) \
57 ((ssize) == MMU_SEGSIZE_256M? SLB_VSID_SHIFT: SLB_VSID_SHIFT_1T)
58
59static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
60 unsigned long flags)
1da177e4 61{
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62 return (get_kernel_vsid(ea, ssize) << slb_vsid_shift(ssize)) | flags |
63 ((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
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64}
65
1189be65 66static inline void slb_shadow_update(unsigned long ea, int ssize,
67439b76 67 unsigned long flags,
2f6093c8 68 unsigned long entry)
1da177e4 69{
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MN
70 /*
71 * Clear the ESID first so the entry is not valid while we are
00efee7d
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72 * updating it. No write barriers are needed here, provided
73 * we only update the current CPU's SLB shadow buffer.
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74 */
75 get_slb_shadow()->save_area[entry].esid = 0;
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76 get_slb_shadow()->save_area[entry].vsid = mk_vsid_data(ea, ssize, flags);
77 get_slb_shadow()->save_area[entry].esid = mk_esid_data(ea, ssize, entry);
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MN
78}
79
edd0622b 80static inline void slb_shadow_clear(unsigned long entry)
2f6093c8 81{
edd0622b 82 get_slb_shadow()->save_area[entry].esid = 0;
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83}
84
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85static inline void create_shadowed_slbe(unsigned long ea, int ssize,
86 unsigned long flags,
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87 unsigned long entry)
88{
89 /*
90 * Updating the shadow buffer before writing the SLB ensures
91 * we don't get a stale entry here if we get preempted by PHYP
92 * between these two statements.
93 */
1189be65 94 slb_shadow_update(ea, ssize, flags, entry);
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95
96 asm volatile("slbmte %0,%1" :
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97 : "r" (mk_vsid_data(ea, ssize, flags)),
98 "r" (mk_esid_data(ea, ssize, entry))
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99 : "memory" );
100}
101
bf72aeba 102void slb_flush_and_rebolt(void)
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103{
104 /* If you change this make sure you change SLB_NUM_BOLTED
105 * appropriately too. */
bf72aeba 106 unsigned long linear_llp, vmalloc_llp, lflags, vflags;
1189be65 107 unsigned long ksp_esid_data, ksp_vsid_data;
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108
109 WARN_ON(!irqs_disabled());
110
3c726f8d 111 linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
bf72aeba 112 vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp;
3c726f8d 113 lflags = SLB_VSID_KERNEL | linear_llp;
bf72aeba 114 vflags = SLB_VSID_KERNEL | vmalloc_llp;
1da177e4 115
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116 ksp_esid_data = mk_esid_data(get_paca()->kstack, mmu_kernel_ssize, 2);
117 if ((ksp_esid_data & ~0xfffffffUL) <= PAGE_OFFSET) {
1da177e4 118 ksp_esid_data &= ~SLB_ESID_V;
1189be65 119 ksp_vsid_data = 0;
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120 slb_shadow_clear(2);
121 } else {
122 /* Update stack entry; others don't change */
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123 slb_shadow_update(get_paca()->kstack, mmu_kernel_ssize, lflags, 2);
124 ksp_vsid_data = get_slb_shadow()->save_area[2].vsid;
edd0622b 125 }
2f6093c8 126
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AB
127 /*
128 * We can't take a PMU exception in the following code, so hard
129 * disable interrupts.
130 */
131 hard_irq_disable();
132
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133 /* We need to do this all in asm, so we're sure we don't touch
134 * the stack between the slbia and rebolting it. */
135 asm volatile("isync\n"
136 "slbia\n"
137 /* Slot 1 - first VMALLOC segment */
138 "slbmte %0,%1\n"
139 /* Slot 2 - kernel stack */
140 "slbmte %2,%3\n"
141 "isync"
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142 :: "r"(mk_vsid_data(VMALLOC_START, mmu_kernel_ssize, vflags)),
143 "r"(mk_esid_data(VMALLOC_START, mmu_kernel_ssize, 1)),
144 "r"(ksp_vsid_data),
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145 "r"(ksp_esid_data)
146 : "memory");
147}
148
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MN
149void slb_vmalloc_update(void)
150{
151 unsigned long vflags;
152
153 vflags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmalloc_psize].sllp;
1189be65 154 slb_shadow_update(VMALLOC_START, mmu_kernel_ssize, vflags, 1);
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MN
155 slb_flush_and_rebolt();
156}
157
465ccab9 158/* Helper function to compare esids. There are four cases to handle.
159 * 1. The system is not 1T segment size capable. Use the GET_ESID compare.
160 * 2. The system is 1T capable, both addresses are < 1T, use the GET_ESID compare.
161 * 3. The system is 1T capable, only one of the two addresses is > 1T. This is not a match.
162 * 4. The system is 1T capable, both addresses are > 1T, use the GET_ESID_1T macro to compare.
163 */
164static inline int esids_match(unsigned long addr1, unsigned long addr2)
165{
166 int esid_1t_count;
167
168 /* System is not 1T segment size capable. */
169 if (!cpu_has_feature(CPU_FTR_1T_SEGMENT))
170 return (GET_ESID(addr1) == GET_ESID(addr2));
171
172 esid_1t_count = (((addr1 >> SID_SHIFT_1T) != 0) +
173 ((addr2 >> SID_SHIFT_1T) != 0));
174
175 /* both addresses are < 1T */
176 if (esid_1t_count == 0)
177 return (GET_ESID(addr1) == GET_ESID(addr2));
178
179 /* One address < 1T, the other > 1T. Not a match */
180 if (esid_1t_count == 1)
181 return 0;
182
183 /* Both addresses are > 1T. */
184 return (GET_ESID_1T(addr1) == GET_ESID_1T(addr2));
185}
186
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187/* Flush all user entries from the segment table of the current processor. */
188void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
189{
190 unsigned long offset = get_paca()->slb_cache_ptr;
1189be65 191 unsigned long slbie_data = 0;
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192 unsigned long pc = KSTK_EIP(tsk);
193 unsigned long stack = KSTK_ESP(tsk);
194 unsigned long unmapped_base;
195
f66bce5e
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196 if (!cpu_has_feature(CPU_FTR_NO_SLBIE_B) &&
197 offset <= SLB_CACHE_ENTRIES) {
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198 int i;
199 asm volatile("isync" : : : "memory");
200 for (i = 0; i < offset; i++) {
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201 slbie_data = (unsigned long)get_paca()->slb_cache[i]
202 << SID_SHIFT; /* EA */
203 slbie_data |= user_segment_size(slbie_data)
204 << SLBIE_SSIZE_SHIFT;
205 slbie_data |= SLBIE_C; /* C set for user addresses */
206 asm volatile("slbie %0" : : "r" (slbie_data));
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207 }
208 asm volatile("isync" : : : "memory");
209 } else {
210 slb_flush_and_rebolt();
211 }
212
213 /* Workaround POWER5 < DD2.1 issue */
214 if (offset == 1 || offset > SLB_CACHE_ENTRIES)
1189be65 215 asm volatile("slbie %0" : : "r" (slbie_data));
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216
217 get_paca()->slb_cache_ptr = 0;
218 get_paca()->context = mm->context;
219
220 /*
221 * preload some userspace segments into the SLB.
222 */
223 if (test_tsk_thread_flag(tsk, TIF_32BIT))
224 unmapped_base = TASK_UNMAPPED_BASE_USER32;
225 else
226 unmapped_base = TASK_UNMAPPED_BASE_USER64;
227
51fae6de 228 if (is_kernel_addr(pc))
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229 return;
230 slb_allocate(pc);
231
465ccab9 232 if (esids_match(pc,stack))
1da177e4
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233 return;
234
51fae6de 235 if (is_kernel_addr(stack))
1da177e4
LT
236 return;
237 slb_allocate(stack);
238
465ccab9 239 if (esids_match(pc,unmapped_base) || esids_match(stack,unmapped_base))
1da177e4
LT
240 return;
241
51fae6de 242 if (is_kernel_addr(unmapped_base))
1da177e4
LT
243 return;
244 slb_allocate(unmapped_base);
245}
246
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247static inline void patch_slb_encoding(unsigned int *insn_addr,
248 unsigned int immed)
249{
250 /* Assume the instruction had a "0" immediate value, just
251 * "or" in the new value
252 */
253 *insn_addr |= immed;
254 flush_icache_range((unsigned long)insn_addr, 4+
255 (unsigned long)insn_addr);
256}
257
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258void slb_initialize(void)
259{
bf72aeba 260 unsigned long linear_llp, vmalloc_llp, io_llp;
56291e19 261 unsigned long lflags, vflags;
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262 static int slb_encoding_inited;
263 extern unsigned int *slb_miss_kernel_load_linear;
bf72aeba 264 extern unsigned int *slb_miss_kernel_load_io;
584f8b71 265 extern unsigned int *slb_compare_rr_to_size;
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266
267 /* Prepare our SLB miss handler based on our page size */
268 linear_llp = mmu_psize_defs[mmu_linear_psize].sllp;
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269 io_llp = mmu_psize_defs[mmu_io_psize].sllp;
270 vmalloc_llp = mmu_psize_defs[mmu_vmalloc_psize].sllp;
271 get_paca()->vmalloc_sllp = SLB_VSID_KERNEL | vmalloc_llp;
272
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273 if (!slb_encoding_inited) {
274 slb_encoding_inited = 1;
275 patch_slb_encoding(slb_miss_kernel_load_linear,
276 SLB_VSID_KERNEL | linear_llp);
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277 patch_slb_encoding(slb_miss_kernel_load_io,
278 SLB_VSID_KERNEL | io_llp);
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279 patch_slb_encoding(slb_compare_rr_to_size,
280 mmu_slb_size);
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281
282 DBG("SLB: linear LLP = %04x\n", linear_llp);
bf72aeba 283 DBG("SLB: io LLP = %04x\n", io_llp);
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284 }
285
56291e19
SR
286 get_paca()->stab_rr = SLB_NUM_BOLTED;
287
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288 /* On iSeries the bolted entries have already been set up by
289 * the hypervisor from the lparMap data in head.S */
56291e19
SR
290 if (firmware_has_feature(FW_FEATURE_ISERIES))
291 return;
1da177e4 292
3c726f8d 293 lflags = SLB_VSID_KERNEL | linear_llp;
bf72aeba 294 vflags = SLB_VSID_KERNEL | vmalloc_llp;
1da177e4 295
3c726f8d 296 /* Invalidate the entire SLB (even slot 0) & all the ERATS */
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297 asm volatile("isync":::"memory");
298 asm volatile("slbmte %0,%0"::"r" (0) : "memory");
299 asm volatile("isync; slbia; isync":::"memory");
1189be65 300 create_shadowed_slbe(PAGE_OFFSET, mmu_kernel_ssize, lflags, 0);
175587cc 301
1189be65 302 create_shadowed_slbe(VMALLOC_START, mmu_kernel_ssize, vflags, 1);
175587cc 303
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PM
304 slb_shadow_clear(2);
305
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306 /* We don't bolt the stack for the time being - we're in boot,
307 * so the stack is in the bolted segment. By the time it goes
308 * elsewhere, we'll call _switch() which will bolt in the new
309 * one. */
310 asm volatile("isync":::"memory");
1da177e4 311}