xref: /openbmc/linux/arch/parisc/include/asm/tlbflush.h (revision 293d5b43)
1 #ifndef _PARISC_TLBFLUSH_H
2 #define _PARISC_TLBFLUSH_H
3 
4 /* TLB flushing routines.... */
5 
6 #include <linux/mm.h>
7 #include <linux/sched.h>
8 #include <asm/mmu_context.h>
9 
10 
11 /* This is for the serialisation of PxTLB broadcasts.  At least on the
12  * N class systems, only one PxTLB inter processor broadcast can be
13  * active at any one time on the Merced bus.  This tlb purge
14  * synchronisation is fairly lightweight and harmless so we activate
15  * it on all systems not just the N class.
16 
17  * It is also used to ensure PTE updates are atomic and consistent
18  * with the TLB.
19  */
20 extern spinlock_t pa_tlb_lock;
21 
22 #define purge_tlb_start(flags)	spin_lock_irqsave(&pa_tlb_lock, flags)
23 #define purge_tlb_end(flags)	spin_unlock_irqrestore(&pa_tlb_lock, flags)
24 
25 extern void flush_tlb_all(void);
26 extern void flush_tlb_all_local(void *);
27 
28 #define smp_flush_tlb_all()	flush_tlb_all()
29 
30 int __flush_tlb_range(unsigned long sid,
31 	unsigned long start, unsigned long end);
32 
33 #define flush_tlb_range(vma, start, end) \
34 	__flush_tlb_range((vma)->vm_mm->context, start, end)
35 
36 #define flush_tlb_kernel_range(start, end) \
37 	__flush_tlb_range(0, start, end)
38 
39 /*
40  * flush_tlb_mm()
41  *
42  * The code to switch to a new context is NOT valid for processes
43  * which play with the space id's.  Thus, we have to preserve the
44  * space and just flush the entire tlb.  However, the compilers,
45  * dynamic linker, etc, do not manipulate space id's, so there
46  * could be a significant performance benefit in switching contexts
47  * and not flushing the whole tlb.
48  */
49 
50 static inline void flush_tlb_mm(struct mm_struct *mm)
51 {
52 	BUG_ON(mm == &init_mm); /* Should never happen */
53 
54 #if 1 || defined(CONFIG_SMP)
55 	/* Except for very small threads, flushing the whole TLB is
56 	 * faster than using __flush_tlb_range.  The pdtlb and pitlb
57 	 * instructions are very slow because of the TLB broadcast.
58 	 * It might be faster to do local range flushes on all CPUs
59 	 * on PA 2.0 systems.
60 	 */
61 	flush_tlb_all();
62 #else
63 	/* FIXME: currently broken, causing space id and protection ids
64 	 * to go out of sync, resulting in faults on userspace accesses.
65 	 * This approach needs further investigation since running many
66 	 * small applications (e.g., GCC testsuite) is faster on HP-UX.
67 	 */
68 	if (mm) {
69 		if (mm->context != 0)
70 			free_sid(mm->context);
71 		mm->context = alloc_sid();
72 		if (mm == current->active_mm)
73 			load_context(mm->context);
74 	}
75 #endif
76 }
77 
78 static inline void flush_tlb_page(struct vm_area_struct *vma,
79 	unsigned long addr)
80 {
81 	unsigned long flags, sid;
82 
83 	sid = vma->vm_mm->context;
84 	purge_tlb_start(flags);
85 	mtsp(sid, 1);
86 	pdtlb(addr);
87 	if (unlikely(split_tlb))
88 		pitlb(addr);
89 	purge_tlb_end(flags);
90 }
91 #endif
92