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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
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2#ifndef _ASM_X86_TLBFLUSH_H
3#define _ASM_X86_TLBFLUSH_H
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4
5#include <linux/mm.h>
6#include <linux/sched.h>
7
8#include <asm/processor.h>
cd4d09ec 9#include <asm/cpufeature.h>
f05e798a 10#include <asm/special_insns.h>
ce4a4e56 11#include <asm/smp.h>
d291cf83 12
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13static inline void __invpcid(unsigned long pcid, unsigned long addr,
14 unsigned long type)
15{
e2c7698c 16 struct { u64 d[2]; } desc = { { pcid, addr } };
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17
18 /*
19 * The memory clobber is because the whole point is to invalidate
20 * stale TLB entries and, especially if we're flushing global
21 * mappings, we don't want the compiler to reorder any subsequent
22 * memory accesses before the TLB flush.
23 *
24 * The hex opcode is invpcid (%ecx), %eax in 32-bit mode and
25 * invpcid (%rcx), %rax in long mode.
26 */
27 asm volatile (".byte 0x66, 0x0f, 0x38, 0x82, 0x01"
e2c7698c 28 : : "m" (desc), "a" (type), "c" (&desc) : "memory");
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29}
30
31#define INVPCID_TYPE_INDIV_ADDR 0
32#define INVPCID_TYPE_SINGLE_CTXT 1
33#define INVPCID_TYPE_ALL_INCL_GLOBAL 2
34#define INVPCID_TYPE_ALL_NON_GLOBAL 3
35
36/* Flush all mappings for a given pcid and addr, not including globals. */
37static inline void invpcid_flush_one(unsigned long pcid,
38 unsigned long addr)
39{
40 __invpcid(pcid, addr, INVPCID_TYPE_INDIV_ADDR);
41}
42
43/* Flush all mappings for a given PCID, not including globals. */
44static inline void invpcid_flush_single_context(unsigned long pcid)
45{
46 __invpcid(pcid, 0, INVPCID_TYPE_SINGLE_CTXT);
47}
48
49/* Flush all mappings, including globals, for all PCIDs. */
50static inline void invpcid_flush_all(void)
51{
52 __invpcid(0, 0, INVPCID_TYPE_ALL_INCL_GLOBAL);
53}
54
55/* Flush all mappings for all PCIDs except globals. */
56static inline void invpcid_flush_all_nonglobals(void)
57{
58 __invpcid(0, 0, INVPCID_TYPE_ALL_NON_GLOBAL);
59}
60
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61static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
62{
63 u64 new_tlb_gen;
64
65 /*
66 * Bump the generation count. This also serves as a full barrier
67 * that synchronizes with switch_mm(): callers are required to order
68 * their read of mm_cpumask after their writes to the paging
69 * structures.
70 */
71 smp_mb__before_atomic();
72 new_tlb_gen = atomic64_inc_return(&mm->context.tlb_gen);
73 smp_mb__after_atomic();
74
75 return new_tlb_gen;
76}
77
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78#ifdef CONFIG_PARAVIRT
79#include <asm/paravirt.h>
80#else
81#define __flush_tlb() __native_flush_tlb()
82#define __flush_tlb_global() __native_flush_tlb_global()
83#define __flush_tlb_single(addr) __native_flush_tlb_single(addr)
84#endif
85
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86static inline bool tlb_defer_switch_to_init_mm(void)
87{
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88 /*
89 * If we have PCID, then switching to init_mm is reasonably
90 * fast. If we don't have PCID, then switching to init_mm is
91 * quite slow, so we try to defer it in the hopes that we can
92 * avoid it entirely. The latter approach runs the risk of
93 * receiving otherwise unnecessary IPIs.
94 *
95 * This choice is just a heuristic. The tlb code can handle this
96 * function returning true or false regardless of whether we have
97 * PCID.
98 */
99 return !static_cpu_has(X86_FEATURE_PCID);
4e57b946 100}
b956575b 101
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102/*
103 * 6 because 6 should be plenty and struct tlb_state will fit in
104 * two cache lines.
105 */
106#define TLB_NR_DYN_ASIDS 6
107
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108struct tlb_context {
109 u64 ctx_id;
110 u64 tlb_gen;
111};
112
1e02ce4c 113struct tlb_state {
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114 /*
115 * cpu_tlbstate.loaded_mm should match CR3 whenever interrupts
116 * are on. This means that it may not match current->active_mm,
117 * which will contain the previous user mm when we're in lazy TLB
118 * mode even if we've already switched back to swapper_pg_dir.
119 */
120 struct mm_struct *loaded_mm;
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121 u16 loaded_mm_asid;
122 u16 next_asid;
1e02ce4c 123
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124 /*
125 * We can be in one of several states:
126 *
127 * - Actively using an mm. Our CPU's bit will be set in
128 * mm_cpumask(loaded_mm) and is_lazy == false;
129 *
130 * - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit
131 * will not be set in mm_cpumask(&init_mm) and is_lazy == false.
132 *
133 * - Lazily using a real mm. loaded_mm != &init_mm, our bit
134 * is set in mm_cpumask(loaded_mm), but is_lazy == true.
135 * We're heuristically guessing that the CR3 load we
136 * skipped more than makes up for the overhead added by
137 * lazy mode.
138 */
139 bool is_lazy;
140
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141 /*
142 * Access to this CR4 shadow and to H/W CR4 is protected by
143 * disabling interrupts when modifying either one.
144 */
145 unsigned long cr4;
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146
147 /*
148 * This is a list of all contexts that might exist in the TLB.
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149 * There is one per ASID that we use, and the ASID (what the
150 * CPU calls PCID) is the index into ctxts.
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151 *
152 * For each context, ctx_id indicates which mm the TLB's user
153 * entries came from. As an invariant, the TLB will never
154 * contain entries that are out-of-date as when that mm reached
155 * the tlb_gen in the list.
156 *
157 * To be clear, this means that it's legal for the TLB code to
158 * flush the TLB without updating tlb_gen. This can happen
159 * (for now, at least) due to paravirt remote flushes.
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160 *
161 * NB: context 0 is a bit special, since it's also used by
162 * various bits of init code. This is fine -- code that
163 * isn't aware of PCID will end up harmlessly flushing
164 * context 0.
b0579ade 165 */
10af6235 166 struct tlb_context ctxs[TLB_NR_DYN_ASIDS];
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167};
168DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate);
169
170/* Initialize cr4 shadow for this CPU. */
171static inline void cr4_init_shadow(void)
172{
1ef55be1 173 this_cpu_write(cpu_tlbstate.cr4, __read_cr4());
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174}
175
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176/* Set in this cpu's CR4. */
177static inline void cr4_set_bits(unsigned long mask)
178{
179 unsigned long cr4;
180
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181 cr4 = this_cpu_read(cpu_tlbstate.cr4);
182 if ((cr4 | mask) != cr4) {
183 cr4 |= mask;
184 this_cpu_write(cpu_tlbstate.cr4, cr4);
185 __write_cr4(cr4);
186 }
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187}
188
189/* Clear in this cpu's CR4. */
190static inline void cr4_clear_bits(unsigned long mask)
191{
192 unsigned long cr4;
193
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194 cr4 = this_cpu_read(cpu_tlbstate.cr4);
195 if ((cr4 & ~mask) != cr4) {
196 cr4 &= ~mask;
197 this_cpu_write(cpu_tlbstate.cr4, cr4);
198 __write_cr4(cr4);
199 }
200}
201
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202static inline void cr4_toggle_bits(unsigned long mask)
203{
204 unsigned long cr4;
205
206 cr4 = this_cpu_read(cpu_tlbstate.cr4);
207 cr4 ^= mask;
208 this_cpu_write(cpu_tlbstate.cr4, cr4);
209 __write_cr4(cr4);
210}
211
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212/* Read the CR4 shadow. */
213static inline unsigned long cr4_read_shadow(void)
214{
215 return this_cpu_read(cpu_tlbstate.cr4);
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216}
217
218/*
219 * Save some of cr4 feature set we're using (e.g. Pentium 4MB
220 * enable and PPro Global page enable), so that any CPU's that boot
221 * up after us can get the correct flags. This should only be used
222 * during boot on the boot cpu.
223 */
224extern unsigned long mmu_cr4_features;
225extern u32 *trampoline_cr4_features;
226
227static inline void cr4_set_bits_and_update_boot(unsigned long mask)
228{
229 mmu_cr4_features |= mask;
230 if (trampoline_cr4_features)
231 *trampoline_cr4_features = mmu_cr4_features;
232 cr4_set_bits(mask);
233}
234
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235extern void initialize_tlbstate_and_flush(void);
236
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237static inline void __native_flush_tlb(void)
238{
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239 /*
240 * If current->mm == NULL then we borrow a mm which may change during a
241 * task switch and therefore we must not be preempted while we write CR3
242 * back:
243 */
244 preempt_disable();
6c690ee1 245 native_write_cr3(__native_read_cr3());
5cf0791d 246 preempt_enable();
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247}
248
249static inline void __native_flush_tlb_global(void)
250{
23cb7d46 251 unsigned long cr4, flags;
d291cf83 252
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253 if (static_cpu_has(X86_FEATURE_INVPCID)) {
254 /*
255 * Using INVPCID is considerably faster than a pair of writes
256 * to CR4 sandwiched inside an IRQ flag save/restore.
257 */
258 invpcid_flush_all();
259 return;
260 }
261
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262 /*
263 * Read-modify-write to CR4 - protect it from preemption and
264 * from interrupts. (Use the raw variant because this code can
265 * be called from deep inside debugging code.)
266 */
267 raw_local_irq_save(flags);
268
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269 cr4 = this_cpu_read(cpu_tlbstate.cr4);
270 /* toggle PGE */
271 native_write_cr4(cr4 ^ X86_CR4_PGE);
272 /* write old PGE again and flush TLBs */
273 native_write_cr4(cr4);
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274
275 raw_local_irq_restore(flags);
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276}
277
278static inline void __native_flush_tlb_single(unsigned long addr)
279{
94cf8de0 280 asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
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281}
282
283static inline void __flush_tlb_all(void)
284{
2c4ea6e2 285 if (boot_cpu_has(X86_FEATURE_PGE))
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286 __flush_tlb_global();
287 else
288 __flush_tlb();
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289
290 /*
291 * Note: if we somehow had PCID but not PGE, then this wouldn't work --
292 * we'd end up flushing kernel translations for the current ASID but
293 * we might fail to flush kernel translations for other cached ASIDs.
294 *
295 * To avoid this issue, we force PCID off if PGE is off.
296 */
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297}
298
299static inline void __flush_tlb_one(unsigned long addr)
300{
ec659934 301 count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
e8747f10 302 __flush_tlb_single(addr);
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303}
304
3e7f3db0 305#define TLB_FLUSH_ALL -1UL
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306
307/*
308 * TLB flushing:
309 *
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310 * - flush_tlb_all() flushes all processes TLBs
311 * - flush_tlb_mm(mm) flushes the specified mm context TLB's
312 * - flush_tlb_page(vma, vmaddr) flushes one page
313 * - flush_tlb_range(vma, start, end) flushes a range of pages
314 * - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
a2055abe 315 * - flush_tlb_others(cpumask, info) flushes TLBs on other cpus
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316 *
317 * ..but the i386 has somewhat limited tlb flushing capabilities,
318 * and page-granular flushes are available only on i486 and up.
d291cf83 319 */
a2055abe 320struct flush_tlb_info {
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321 /*
322 * We support several kinds of flushes.
323 *
324 * - Fully flush a single mm. .mm will be set, .end will be
325 * TLB_FLUSH_ALL, and .new_tlb_gen will be the tlb_gen to
326 * which the IPI sender is trying to catch us up.
327 *
328 * - Partially flush a single mm. .mm will be set, .start and
329 * .end will indicate the range, and .new_tlb_gen will be set
330 * such that the changes between generation .new_tlb_gen-1 and
331 * .new_tlb_gen are entirely contained in the indicated range.
332 *
333 * - Fully flush all mms whose tlb_gens have been updated. .mm
334 * will be NULL, .end will be TLB_FLUSH_ALL, and .new_tlb_gen
335 * will be zero.
336 */
337 struct mm_struct *mm;
338 unsigned long start;
339 unsigned long end;
340 u64 new_tlb_gen;
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341};
342
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343#define local_flush_tlb() __flush_tlb()
344
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345#define flush_tlb_mm(mm) flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL)
346
347#define flush_tlb_range(vma, start, end) \
348 flush_tlb_mm_range(vma->vm_mm, start, end, vma->vm_flags)
349
d291cf83 350extern void flush_tlb_all(void);
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351extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
352 unsigned long end, unsigned long vmflag);
effee4b9 353extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
d291cf83 354
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355static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a)
356{
357 flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, VM_NONE);
358}
359
4595f962 360void native_flush_tlb_others(const struct cpumask *cpumask,
a2055abe 361 const struct flush_tlb_info *info);
d291cf83 362
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363static inline void arch_tlbbatch_add_mm(struct arch_tlbflush_unmap_batch *batch,
364 struct mm_struct *mm)
365{
f39681ed 366 inc_mm_tlb_gen(mm);
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367 cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm));
368}
369
370extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
371
d291cf83 372#ifndef CONFIG_PARAVIRT
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373#define flush_tlb_others(mask, info) \
374 native_flush_tlb_others(mask, info)
96a388de 375#endif
d291cf83 376
1965aae3 377#endif /* _ASM_X86_TLBFLUSH_H */