From 8eda55142080f0373b1f0268fe6d6807f193e713 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Tue, 17 Nov 2009 21:05:31 +0000 Subject: sh: New extended page flag to wire/unwire TLB entries Provide a new extended page flag, _PAGE_WIRED and an SH4 implementation for wiring TLB entries and use it in the fixmap code path so that we can wire the fixmap TLB entry. Signed-off-by: Matt Fleming --- arch/sh/mm/tlb-sh4.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) (limited to 'arch/sh/mm/tlb-sh4.c') diff --git a/arch/sh/mm/tlb-sh4.c b/arch/sh/mm/tlb-sh4.c index 8cf550e2570..4c623474331 100644 --- a/arch/sh/mm/tlb-sh4.c +++ b/arch/sh/mm/tlb-sh4.c @@ -81,3 +81,69 @@ void __uses_jump_to_uncached local_flush_tlb_one(unsigned long asid, ctrl_outl(data, addr); back_to_cached(); } + +/* + * Load the entry for 'addr' into the TLB and wire the entry. + */ +void tlb_wire_entry(struct vm_area_struct *vma, unsigned long addr, pte_t pte) +{ + unsigned long status, flags; + int urb; + + local_irq_save(flags); + + /* Load the entry into the TLB */ + __update_tlb(vma, addr, pte); + + /* ... and wire it up. */ + status = ctrl_inl(MMUCR); + urb = (status & MMUCR_URB) >> MMUCR_URB_SHIFT; + status &= ~MMUCR_URB; + + /* + * Make sure we're not trying to wire the last TLB entry slot. + */ + BUG_ON(!--urb); + + urb = urb % MMUCR_URB_NENTRIES; + + status |= (urb << MMUCR_URB_SHIFT); + ctrl_outl(status, MMUCR); + ctrl_barrier(); + + local_irq_restore(flags); +} + +/* + * Unwire the last wired TLB entry. + * + * It should also be noted that it is not possible to wire and unwire + * TLB entries in an arbitrary order. If you wire TLB entry N, followed + * by entry N+1, you must unwire entry N+1 first, then entry N. In this + * respect, it works like a stack or LIFO queue. + */ +void tlb_unwire_entry(void) +{ + unsigned long status, flags; + int urb; + + local_irq_save(flags); + + status = ctrl_inl(MMUCR); + urb = (status & MMUCR_URB) >> MMUCR_URB_SHIFT; + status &= ~MMUCR_URB; + + /* + * Make sure we're not trying to unwire a TLB entry when none + * have been wired. + */ + BUG_ON(urb++ == MMUCR_URB_NENTRIES); + + urb = urb % MMUCR_URB_NENTRIES; + + status |= (urb << MMUCR_URB_SHIFT); + ctrl_outl(status, MMUCR); + ctrl_barrier(); + + local_irq_restore(flags); +} -- cgit v1.2.3