sh: Revert TLB miss fast-path changes that broke PTEA parts.

This ended up causing problems for older parts (particularly ones
using PTEA). Revert this for now, it can be added back in once it's
had some more testing.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 87 insertions, 0 deletions

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 716ebf568af2..fa5d7f0b9f18 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -17,6 +17,7 @@
 #include <linux/kprobes.h>
 #include <asm/system.h>
 #include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
 #include <asm/kgdb.h>
 
 extern void die(const char *,struct pt_regs *,long);
@@ -224,3 +225,89 @@ do_sigbus:
         if (!user_mode(regs))
                 goto no_context;
 }
+
+#ifdef CONFIG_SH_STORE_QUEUES
+/*
+ * This is a special case for the SH-4 store queues, as pages for this
+ * space still need to be faulted in before it's possible to flush the
+ * store queue cache for writeout to the remapped region.
+ */
+#define P3_ADDR_MAX             (P4SEG_STORE_QUE + 0x04000000)
+#else
+#define P3_ADDR_MAX             P4SEG
+#endif
+
+/*
+ * Called with interrupts disabled.
+ */
+asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
+                                         unsigned long writeaccess,
+                                         unsigned long address)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *pte;
+        pte_t entry;
+        struct mm_struct *mm = current->mm;
+        spinlock_t *ptl;
+        int ret = 1;
+
+#ifdef CONFIG_SH_KGDB
+        if (kgdb_nofault && kgdb_bus_err_hook)
+                kgdb_bus_err_hook();
+#endif
+
+        /*
+         * We don't take page faults for P1, P2, and parts of P4, these
+         * are always mapped, whether it be due to legacy behaviour in
+         * 29-bit mode, or due to PMB configuration in 32-bit mode.
+         */
+        if (address >= P3SEG && address < P3_ADDR_MAX) {
+                pgd = pgd_offset_k(address);
+                mm = NULL;
+        } else {
+                if (unlikely(address >= TASK_SIZE || !mm))
+                        return 1;
+
+                pgd = pgd_offset(mm, address);
+        }
+
+        pud = pud_offset(pgd, address);
+        if (pud_none_or_clear_bad(pud))
+                return 1;
+        pmd = pmd_offset(pud, address);
+        if (pmd_none_or_clear_bad(pmd))
+                return 1;
+
+        if (mm)
+                pte = pte_offset_map_lock(mm, pmd, address, &ptl);
+        else
+                pte = pte_offset_kernel(pmd, address);
+
+        entry = *pte;
+        if (unlikely(pte_none(entry) || pte_not_present(entry)))
+                goto unlock;
+        if (unlikely(writeaccess && !pte_write(entry)))
+                goto unlock;
+
+        if (writeaccess)
+                entry = pte_mkdirty(entry);
+        entry = pte_mkyoung(entry);
+
+#ifdef CONFIG_CPU_SH4
+        /*
+         * ITLB is not affected by "ldtlb" instruction.
+         * So, we need to flush the entry by ourselves.
+         */
+        local_flush_tlb_one(get_asid(), address & PAGE_MASK);
+#endif
+
+        set_pte(pte, entry);
+        update_mmu_cache(NULL, address, entry);
+        ret = 0;
+unlock:
+        if (mm)
+                pte_unmap_unlock(pte, ptl);
+        return ret;
+}