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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-13 01:32:17 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-13 14:23:33 -0300
commit0a2bb03fe20f81dc4cac96d7fe0e4194ae6efffd (patch)
treef643c68f37c9aa9e2e0b1623b363777c125350df /arch/parisc/include/asm/tlbflush.h
parentc49e505b3486503302e30c4237821bece90b4c2d (diff)
Linux-libre 4.1.5-gnupck-4.1.5-gnu
Diffstat (limited to 'arch/parisc/include/asm/tlbflush.h')
-rw-r--r--arch/parisc/include/asm/tlbflush.h53
1 files changed, 29 insertions, 24 deletions
diff --git a/arch/parisc/include/asm/tlbflush.h b/arch/parisc/include/asm/tlbflush.h
index 9d086a599..e84b96478 100644
--- a/arch/parisc/include/asm/tlbflush.h
+++ b/arch/parisc/include/asm/tlbflush.h
@@ -13,6 +13,9 @@
* active at any one time on the Merced bus. This tlb purge
* synchronisation is fairly lightweight and harmless so we activate
* it on all systems not just the N class.
+
+ * It is also used to ensure PTE updates are atomic and consistent
+ * with the TLB.
*/
extern spinlock_t pa_tlb_lock;
@@ -24,20 +27,24 @@ extern void flush_tlb_all_local(void *);
#define smp_flush_tlb_all() flush_tlb_all()
+int __flush_tlb_range(unsigned long sid,
+ unsigned long start, unsigned long end);
+
+#define flush_tlb_range(vma, start, end) \
+ __flush_tlb_range((vma)->vm_mm->context, start, end)
+
+#define flush_tlb_kernel_range(start, end) \
+ __flush_tlb_range(0, start, end)
+
/*
* flush_tlb_mm()
*
- * XXX This code is NOT valid for HP-UX compatibility processes,
- * (although it will probably work 99% of the time). HP-UX
- * processes are free to play with the space id's and save them
- * over long periods of time, etc. so we have to preserve the
- * space and just flush the entire tlb. We need to check the
- * personality in order to do that, but the personality is not
- * currently being set correctly.
- *
- * Of course, Linux processes could do the same thing, but
- * we don't support that (and the compilers, dynamic linker,
- * etc. do not do that).
+ * The code to switch to a new context is NOT valid for processes
+ * which play with the space id's. Thus, we have to preserve the
+ * space and just flush the entire tlb. However, the compilers,
+ * dynamic linker, etc, do not manipulate space id's, so there
+ * could be a significant performance benefit in switching contexts
+ * and not flushing the whole tlb.
*/
static inline void flush_tlb_mm(struct mm_struct *mm)
@@ -45,10 +52,18 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
BUG_ON(mm == &init_mm); /* Should never happen */
#if 1 || defined(CONFIG_SMP)
+ /* Except for very small threads, flushing the whole TLB is
+ * faster than using __flush_tlb_range. The pdtlb and pitlb
+ * instructions are very slow because of the TLB broadcast.
+ * It might be faster to do local range flushes on all CPUs
+ * on PA 2.0 systems.
+ */
flush_tlb_all();
#else
/* FIXME: currently broken, causing space id and protection ids
- * to go out of sync, resulting in faults on userspace accesses.
+ * to go out of sync, resulting in faults on userspace accesses.
+ * This approach needs further investigation since running many
+ * small applications (e.g., GCC testsuite) is faster on HP-UX.
*/
if (mm) {
if (mm->context != 0)
@@ -65,22 +80,12 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
{
unsigned long flags, sid;
- /* For one page, it's not worth testing the split_tlb variable */
-
- mb();
sid = vma->vm_mm->context;
purge_tlb_start(flags);
mtsp(sid, 1);
pdtlb(addr);
- pitlb(addr);
+ if (unlikely(split_tlb))
+ pitlb(addr);
purge_tlb_end(flags);
}
-
-void __flush_tlb_range(unsigned long sid,
- unsigned long start, unsigned long end);
-
-#define flush_tlb_range(vma,start,end) __flush_tlb_range((vma)->vm_mm->context,start,end)
-
-#define flush_tlb_kernel_range(start, end) __flush_tlb_range(0,start,end)
-
#endif