Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 280 insertions, 0 deletions

diff --git a/arch/sh64/mm/tlbmiss.c b/arch/sh64/mm/tlbmiss.c
new file mode 100644
index 000000000000..c8615954aaa9
--- /dev/null
+++ b/arch/sh64/mm/tlbmiss.c
@@ -0,0 +1,280 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * arch/sh64/mm/tlbmiss.c
+ *
+ * Original code from fault.c
+ * Copyright (C) 2000, 2001  Paolo Alberelli
+ *
+ * Fast PTE->TLB refill path
+ * Copyright (C) 2003 Richard.Curnow@superh.com
+ *
+ * IMPORTANT NOTES :
+ * The do_fast_page_fault function is called from a context in entry.S where very few registers
+ * have been saved.  In particular, the code in this file must be compiled not to use ANY
+ * caller-save regiseters that are not part of the restricted save set.  Also, it means that
+ * code in this file must not make calls to functions elsewhere in the kernel, or else the
+ * excepting context will see corruption in its caller-save registers.  Plus, the entry.S save
+ * area is non-reentrant, so this code has to run with SR.BL==1, i.e. no interrupts taken inside
+ * it and panic on any exception.
+ *
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+
+#include <asm/system.h>
+#include <asm/tlb.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+#include <asm/mmu_context.h>
+#include <asm/registers.h>              /* required by inline asm statements */
+
+/* Callable from fault.c, so not static */
+inline void __do_tlb_refill(unsigned long address,
+                            unsigned long long is_text_not_data, pte_t *pte)
+{
+        unsigned long long ptel;
+        unsigned long long pteh=0;
+        struct tlb_info *tlbp;
+        unsigned long long next;
+
+        /* Get PTEL first */
+        ptel = pte_val(*pte);
+
+        /*
+         * Set PTEH register
+         */
+        pteh = address & MMU_VPN_MASK;
+
+        /* Sign extend based on neff. */
+#if (NEFF == 32)
+        /* Faster sign extension */
+        pteh = (unsigned long long)(signed long long)(signed long)pteh;
+#else
+        /* General case */
+        pteh = (pteh & NEFF_SIGN) ? (pteh | NEFF_MASK) : pteh;
+#endif
+
+        /* Set the ASID. */
+        pteh |= get_asid() << PTEH_ASID_SHIFT;
+        pteh |= PTEH_VALID;
+
+        /* Set PTEL register, set_pte has performed the sign extension */
+        ptel &= _PAGE_FLAGS_HARDWARE_MASK; /* drop software flags */
+
+        tlbp = is_text_not_data ? &(cpu_data->itlb) : &(cpu_data->dtlb);
+        next = tlbp->next;
+        __flush_tlb_slot(next);
+        asm volatile ("putcfg %0,1,%2\n\n\t"
+                      "putcfg %0,0,%1\n"
+                      :  : "r" (next), "r" (pteh), "r" (ptel) );
+
+        next += TLB_STEP;
+        if (next > tlbp->last) next = tlbp->first;
+        tlbp->next = next;
+
+}
+
+static int handle_vmalloc_fault(struct mm_struct *mm, unsigned long protection_flags,
+                                unsigned long long textaccess,
+                                unsigned long address)
+{
+        pgd_t *dir;
+        pmd_t *pmd;
+        static pte_t *pte;
+        pte_t entry;
+
+        dir = pgd_offset_k(address);
+        pmd = pmd_offset(dir, address);
+
+        if (pmd_none(*pmd)) {
+                return 0;
+        }
+
+        if (pmd_bad(*pmd)) {
+                pmd_clear(pmd);
+                return 0;
+        }
+
+        pte = pte_offset_kernel(pmd, address);
+        entry = *pte;
+
+        if (pte_none(entry) || !pte_present(entry)) {
+                return 0;
+        }
+
+        if ((pte_val(entry) & protection_flags) != protection_flags) {
+                return 0;
+        }
+
+        __do_tlb_refill(address, textaccess, pte);
+
+        return 1;
+}
+
+static int handle_tlbmiss(struct mm_struct *mm, unsigned long long protection_flags,
+                        unsigned long long textaccess,
+                        unsigned long address)
+{
+        pgd_t *dir;
+        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 0;
+        }
+        dir = pgd_offset(mm, address);
+        if (pgd_none(*dir)) {
+                return 0;
+        }
+        if (!pgd_present(*dir)) {
+                return 0;
+        }
+
+        pmd = pmd_offset(dir, address);
+        if (pmd_none(*pmd)) {
+                return 0;
+        }
+        if (!pmd_present(*pmd)) {
+                return 0;
+        }
+        pte = pte_offset_kernel(pmd, address);
+        entry = *pte;
+        if (pte_none(entry)) {
+                return 0;
+        }
+        if (!pte_present(entry)) {
+                return 0;
+        }
+
+        /* If the page doesn't have sufficient protection bits set to service the
+           kind of fault being handled, there's not much point doing the TLB refill.
+           Punt the fault to the general handler. */
+        if ((pte_val(entry) & protection_flags) != protection_flags) {
+                return 0;
+        }
+
+        __do_tlb_refill(address, textaccess, pte);
+
+        return 1;
+}
+
+/* Put all this information into one structure so that everything is just arithmetic
+   relative to a single base address.  This reduces the number of movi/shori pairs needed
+   just to load addresses of static data. */
+struct expevt_lookup {
+        unsigned short protection_flags[8];
+        unsigned char  is_text_access[8];
+        unsigned char  is_write_access[8];
+};
+
+#define PRU (1<<9)
+#define PRW (1<<8)
+#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 = {
+        .protection_flags = {PRX, PRX, 0, 0, PRR, PRR, PRW, PRW},
+        .is_text_access   = {1,   1,   0, 0, 0,   0,   0,   0}
+};
+
+/*
+   This routine handles page faults that can be serviced just by refilling a
+   TLB entry from an existing page table entry.  (This case represents a very
+   large majority of page faults.) Return 1 if the fault was successfully
+   handled.  Return 0 if the fault could not be handled.  (This leads into the
+   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)
+{
+        struct task_struct *tsk;
+        struct mm_struct *mm;
+        unsigned long long textaccess;
+        unsigned long long protection_flags;
+        unsigned long long index;
+        unsigned long long expevt4;
+
+        /* The next few lines implement a way of hashing EXPEVT into a small array index
+           which can be used to lookup parameters specific to the type of TLBMISS being
+           handled.  Note:
+           ITLBMISS has EXPEVT==0xa40
+           RTLBMISS has EXPEVT==0x040
+           WTLBMISS has EXPEVT==0x060
+        */
+
+        expevt4 = (expevt >> 4);
+        /* TODO : xor ssr_md into this expression too.  Then we can check that PRU is set
+           when it needs to be. */
+        index = expevt4 ^ (expevt4 >> 5);
+        index &= 7;
+        protection_flags = expevt_lookup_table.protection_flags[index];
+        textaccess       = expevt_lookup_table.is_text_access[index];
+
+#ifdef CONFIG_SH64_PROC_TLB
+        ++calls_to_do_fast_page_fault;
+#endif
+
+        /* SIM
+         * Note this is now called with interrupts still disabled
+         * This is to cope with being called for a missing IO port
+         * address with interupts 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 ((address >= VMALLOC_START && address < VMALLOC_END) ||
+            (address >= IOBASE_VADDR  && address < IOBASE_END)) {
+                if (ssr_md) {
+                        /* Process-contexts can never have this address range mapped */
+                        if (handle_vmalloc_fault(mm, protection_flags, textaccess, address)) {
+                                return 1;
+                        }
+                }
+        } else if (!in_interrupt() && mm) {
+                if (handle_tlbmiss(mm, protection_flags, textaccess, address)) {
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+