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 <matt@console-pimps.org>
diff --git a/arch/sh/include/asm/pgtable_32.h b/arch/sh/include/asm/pgtable_32.h
index 5003ee8..c573d45 100644
--- a/arch/sh/include/asm/pgtable_32.h
+++ b/arch/sh/include/asm/pgtable_32.h
@@ -71,6 +71,8 @@
#define _PAGE_EXT_KERN_WRITE 0x1000 /* EPR4-bit: Kernel space writable */
#define _PAGE_EXT_KERN_READ 0x2000 /* EPR5-bit: Kernel space readable */
+#define _PAGE_EXT_WIRED 0x4000 /* software: Wire TLB entry */
+
/* Wrapper for extended mode pgprot twiddling */
#define _PAGE_EXT(x) ((unsigned long long)(x) << 32)
@@ -164,6 +166,8 @@
(PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | \
_PAGE_DIRTY | _PAGE_SPECIAL)
+#define _PAGE_WIRED (_PAGE_EXT(_PAGE_EXT_WIRED))
+
#ifndef __ASSEMBLY__
#if defined(CONFIG_X2TLB) /* SH-X2 TLB */
diff --git a/arch/sh/include/asm/tlb.h b/arch/sh/include/asm/tlb.h
index da8fe7a..3ed2f7a 100644
--- a/arch/sh/include/asm/tlb.h
+++ b/arch/sh/include/asm/tlb.h
@@ -97,6 +97,22 @@
#define tlb_migrate_finish(mm) do { } while (0)
+#ifdef CONFIG_CPU_SH4
+extern void tlb_wire_entry(struct vm_area_struct *, unsigned long, pte_t);
+extern void tlb_unwire_entry(void);
+#else
+static inline void tlb_wire_entry(struct vm_area_struct *vma ,
+ unsigned long addr, pte_t pte)
+{
+ BUG();
+}
+
+static inline void tlb_unwire_entry(void)
+{
+ BUG();
+}
+#endif /* CONFIG_CPU_SH4 */
+
#else /* CONFIG_MMU */
#define tlb_start_vma(tlb, vma) do { } while (0)
diff --git a/arch/sh/include/cpu-sh4/cpu/mmu_context.h b/arch/sh/include/cpu-sh4/cpu/mmu_context.h
index 3ce7ef6..03ea75c 100644
--- a/arch/sh/include/cpu-sh4/cpu/mmu_context.h
+++ b/arch/sh/include/cpu-sh4/cpu/mmu_context.h
@@ -25,6 +25,10 @@
#define MMUCR_TI (1<<2)
+#define MMUCR_URB 0x00FC0000
+#define MMUCR_URB_SHIFT 18
+#define MMUCR_URB_NENTRIES 64
+
#if defined(CONFIG_32BIT) && defined(CONFIG_CPU_SUBTYPE_ST40)
#define MMUCR_SE (1 << 4)
#else
diff --git a/arch/sh/mm/tlb-pteaex.c b/arch/sh/mm/tlb-pteaex.c
index 409b7c2..88c8bb0 100644
--- a/arch/sh/mm/tlb-pteaex.c
+++ b/arch/sh/mm/tlb-pteaex.c
@@ -76,3 +76,69 @@
__raw_writel(asid, MMU_UTLB_ADDRESS_ARRAY2 | MMU_PAGE_ASSOC_BIT);
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);
+}
diff --git a/arch/sh/mm/tlb-sh4.c b/arch/sh/mm/tlb-sh4.c
index 8cf550e..4c62347 100644
--- a/arch/sh/mm/tlb-sh4.c
+++ b/arch/sh/mm/tlb-sh4.c
@@ -81,3 +81,69 @@
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);
+}