1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SPARC64_MMU_CONTEXT_H
#define __SPARC64_MMU_CONTEXT_H
/* Derived heavily from Linus's Alpha/AXP ASN code... */
#ifndef __ASSEMBLY__
#include <linux/spinlock.h>
#include <linux/mm_types.h>
#include <asm/spitfire.h>
#include <asm-generic/mm_hooks.h>
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
extern spinlock_t ctx_alloc_lock;
extern unsigned long tlb_context_cache;
extern unsigned long mmu_context_bmap[];
DECLARE_PER_CPU(struct mm_struct *, per_cpu_secondary_mm);
void get_new_mmu_context(struct mm_struct *mm);
int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
void destroy_context(struct mm_struct *mm);
void __tsb_context_switch(unsigned long pgd_pa,
struct tsb_config *tsb_base,
struct tsb_config *tsb_huge,
unsigned long tsb_descr_pa,
unsigned long secondary_ctx);
static inline void tsb_context_switch_ctx(struct mm_struct *mm,
unsigned long ctx)
{
__tsb_context_switch(__pa(mm->pgd),
&mm->context.tsb_block[MM_TSB_BASE],
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
(mm->context.tsb_block[MM_TSB_HUGE].tsb ?
&mm->context.tsb_block[MM_TSB_HUGE] :
NULL)
#else
NULL
#endif
, __pa(&mm->context.tsb_descr[MM_TSB_BASE]),
ctx);
}
#define tsb_context_switch(X) tsb_context_switch_ctx(X, 0)
void tsb_grow(struct mm_struct *mm,
unsigned long tsb_index,
unsigned long mm_rss);
#ifdef CONFIG_SMP
void smp_tsb_sync(struct mm_struct *mm);
#else
#define smp_tsb_sync(__mm) do { } while (0)
#endif
/* Set MMU context in the actual hardware. */
#define load_secondary_context(__mm) \
__asm__ __volatile__( \
"\n661: stxa %0, [%1] %2\n" \
" .section .sun4v_1insn_patch, \"ax\"\n" \
" .word 661b\n" \
" stxa %0, [%1] %3\n" \
" .previous\n" \
" flush %%g6\n" \
: /* No outputs */ \
: "r" (CTX_HWBITS((__mm)->context)), \
"r" (SECONDARY_CONTEXT), "i" (ASI_DMMU), "i" (ASI_MMU))
void __flush_tlb_mm(unsigned long, unsigned long);
/* Switch the current MM context. */
static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
{
unsigned long ctx_valid, flags;
int cpu = smp_processor_id();
per_cpu(per_cpu_secondary_mm, cpu) = mm;
if (unlikely(mm == &init_mm))
return;
spin_lock_irqsave(&mm->context.lock, flags);
ctx_valid = CTX_VALID(mm->context);
if (!ctx_valid)
get_new_mmu_context(mm);
/* We have to be extremely careful here or else we will miss
* a TSB grow if we switch back and forth between a kernel
* thread and an address space which has it's TSB size increased
* on another processor.
*
* It is possible to play some games in order to optimize the
* switch, but the safest thing to do is to unconditionally
* perform the secondary context load and the TSB context switch.
*
* For reference the bad case is, for address space "A":
*
* CPU 0 CPU 1
* run address space A
* set cpu0's bits in cpu_vm_mask
* switch to kernel thread, borrow
* address space A via entry_lazy_tlb
* run address space A
* set cpu1's bit in cpu_vm_mask
* flush_tlb_pending()
* reset cpu_vm_mask to just cpu1
* TSB grow
* run address space A
* context was valid, so skip
* TSB context switch
*
* At that point cpu0 continues to use a stale TSB, the one from
* before the TSB grow performed on cpu1. cpu1 did not cross-call
* cpu0 to update it's TSB because at that point the cpu_vm_mask
* only had cpu1 set in it.
*/
tsb_context_switch_ctx(mm, CTX_HWBITS(mm->context));
/* Any time a processor runs a context on an address space
* for the first time, we must flush that context out of the
* local TLB.
*/
if (!ctx_valid || !cpumask_test_cpu(cpu, mm_cpumask(mm))) {
cpumask_set_cpu(cpu, mm_cpumask(mm));
__flush_tlb_mm(CTX_HWBITS(mm->context),
SECONDARY_CONTEXT);
}
spin_unlock_irqrestore(&mm->context.lock, flags);
}
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(active_mm, mm) switch_mm(active_mm, mm, NULL)
#endif /* !(__ASSEMBLY__) */
#endif /* !(__SPARC64_MMU_CONTEXT_H) */
|
