sh64: Tidy up and consolidate the TLB miss fast path.

This unifies the fast-path TLB miss handler, allowing for further cleanup
and eventual utilization of a shared _32/_64 handler.

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

1 files changed, 15 insertions, 92 deletions

diff --git a/arch/sh/mm/tlbex_64.c b/arch/sh/mm/tlbex_64.c
index 59cb058217a0..24dd4ab33dec 100644
--- a/arch/sh/mm/tlbex_64.c
+++ b/arch/sh/mm/tlbex_64.c
@@ -33,76 +33,32 @@
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/interrupt.h>
+#include <linux/kprobes.h>
 #include <asm/tlb.h>
 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/pgalloc.h>
 #include <asm/mmu_context.h>
 
-static int handle_vmalloc_fault(struct mm_struct *mm,
-                                unsigned long protection_flags,
-                                unsigned long address)
-{
-        pgd_t *dir;
-        pud_t *pud;
-        pmd_t *pmd;
-        pte_t *pte;
-        pte_t entry;
-
-        dir = pgd_offset_k(address);
-
-        pud = pud_offset(dir, address);
-        if (pud_none_or_clear_bad(pud))
-                return 1;
-
-        pmd = pmd_offset(pud, address);
-        if (pmd_none_or_clear_bad(pmd))
-                return 1;
-
-        pte = pte_offset_kernel(pmd, address);
-        entry = *pte;
-
-        if (pte_none(entry) || !pte_present(entry))
-                return 1;
-        if ((pte_val(entry) & protection_flags) != protection_flags)
-                return 1;
-
-        update_mmu_cache(NULL, address, pte);
-
-        return 0;
-}
-
-static int handle_tlbmiss(struct mm_struct *mm,
-                          unsigned long long protection_flags,
+static int handle_tlbmiss(unsigned long long protection_flags,
                           unsigned long address)
 {
-        pgd_t *dir;
+        pgd_t *pgd;
         pud_t *pud;
         pmd_t *pmd;
         pte_t *pte;
         pte_t entry;
 
-        /* NB. The PGD currently only contains a single entry - there is no
-           page table tree stored for the top half of the address space since
-           virtual pages in that region should never be mapped in user mode.
-           (In kernel mode, the only things in that region are the 512Mb super
-           page (locked in), and vmalloc (modules) +  I/O device pages (handled
-           by handle_vmalloc_fault), so no PGD for the upper half is required
-           by kernel mode either).
-
-           See how mm->pgd is allocated and initialised in pgd_alloc to see why
-           the next test is necessary.  - RPC */
-        if (address >= (unsigned long) TASK_SIZE)
-                /* upper half - never has page table entries. */
-                return 1;
+        if (is_vmalloc_addr((void *)address)) {
+                pgd = pgd_offset_k(address);
+        } else {
+                if (unlikely(address >= TASK_SIZE || !current->mm))
+                        return 1;
 
-        dir = pgd_offset(mm, address);
-        if (pgd_none(*dir) || !pgd_present(*dir))
-                return 1;
-        if (!pgd_present(*dir))
-                return 1;
+                pgd = pgd_offset(current->mm, address);
+        }
 
-        pud = pud_offset(dir, address);
+        pud = pud_offset(pgd, address);
         if (pud_none(*pud) || !pud_present(*pud))
                 return 1;
 
@@ -112,7 +68,6 @@ static int handle_tlbmiss(struct mm_struct *mm,
 
         pte = pte_offset_kernel(pmd, address);
         entry = *pte;
-
         if (pte_none(entry) || !pte_present(entry))
                 return 1;
 
@@ -146,9 +101,6 @@ struct expevt_lookup {
 #define PRX (1<<7)
 #define PRR (1<<6)
 
-#define DIRTY (_PAGE_DIRTY | _PAGE_ACCESSED)
-#define YOUNG (_PAGE_ACCESSED)
-
 /* Sized as 8 rather than 4 to allow checking the PTE's PRU bit against whether
    the fault happened in user mode or privileged mode. */
 static struct expevt_lookup expevt_lookup_table = {
@@ -164,12 +116,10 @@ static struct expevt_lookup expevt_lookup_table = {
    general fault handling in fault.c which deals with mapping file-backed
    pages, stack growth, segmentation faults, swapping etc etc)
  */
-asmlinkage int do_fast_page_fault(unsigned long long ssr_md,
-                                  unsigned long long expevt,
-                                  unsigned long address)
+asmlinkage int __kprobes
+do_fast_page_fault(unsigned long long ssr_md, unsigned long long expevt,
+                   unsigned long address)
 {
-        struct task_struct *tsk;
-        struct mm_struct *mm;
         unsigned long long protection_flags;
         unsigned long long index;
         unsigned long long expevt4;
@@ -194,32 +144,5 @@ asmlinkage int do_fast_page_fault(unsigned long long ssr_md,
         if (expevt_lookup_table.is_text_access[index])
                 set_thread_fault_code(FAULT_CODE_ITLB);
 
-        /* SIM
-         * Note this is now called with interrupts still disabled
-         * This is to cope with being called for a missing IO port
-         * address with interrupts disabled. This should be fixed as
-         * soon as we have a better 'fast path' miss handler.
-         *
-         * Plus take care how you try and debug this stuff.
-         * For example, writing debug data to a port which you
-         * have just faulted on is not going to work.
-         */
-
-        tsk = current;
-        mm = tsk->mm;
-
-        if (is_vmalloc_addr((void *)address)) {
-                if (ssr_md)
-                        /*
-                         * Process-contexts can never have this address
-                         * range mapped
-                         */
-                        if (handle_vmalloc_fault(mm, protection_flags, address) == 0)
-                                return 0;
-        } else if (!in_interrupt() && mm) {
-                if (handle_tlbmiss(mm, protection_flags, address) == 0)
-                        return 0;
-        }
-
-        return 1;
+        return handle_tlbmiss(protection_flags, address);
 }