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-rw-r--r--arch/sh64/mm/tlbmiss.c280
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diff --git a/arch/sh64/mm/tlbmiss.c b/arch/sh64/mm/tlbmiss.c
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+/*
+ * 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;
+}
+