patch-2.3.39 linux/arch/ppc/mm/4xx_tlb.c

• Lines: 398
• Date: Mon Jan 10 18:25:32 2000
• Orig file: v2.3.38/linux/arch/ppc/mm/4xx_tlb.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.38/linux/arch/ppc/mm/4xx_tlb.c linux/arch/ppc/mm/4xx_tlb.c
@@ -0,0 +1,397 @@
+/*
+ *
+ *    Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
+ *
+ *    Module name: 4xx_tlb.c
+ *
+ *    Description:
+ *      Routines for manipulating the TLB on PowerPC 400-class processors.
+ *
+ */
+
+#include <asm/processor.h>
+#include <asm/mmu.h>
+#include <asm/pgtable.h>
+#include <asm/system.h>
+
+
+/* Preprocessor Defines */
+
+#if !defined(TRUE) || TRUE != 1
+#define TRUE    1
+#endif
+
+#if !defined(FALSE) || FALSE != 0
+#define FALSE   0
+#endif
+
+
+/* Function Macros */
+
+
+/* Type Definitios */
+
+typedef struct pin_entry_s {
+	unsigned int	e_pinned: 1,	/* This TLB entry is pinned down. */
+			e_used: 23;	/* Number of users for this mapping. */
+} pin_entry_t;
+
+
+/* Global Variables */
+
+static pin_entry_t pin_table[PPC4XX_TLB_SIZE];
+
+
+/* Function Prototypes */
+
+
+void
+PPC4xx_tlb_pin(unsigned long va, unsigned long pa, int pagesz, int cache)
+{
+	int i, found = FALSE;
+	unsigned long tag, data;
+	unsigned long opid;
+
+	opid = mfspr(SPRN_PID);
+	mtspr(SPRN_PID, 0);
+
+	data = (pa & TLB_RPN_MASK) | TLB_WR;
+
+	if (cache)
+		data |= (TLB_EX | TLB_I);
+	else
+		data |= (TLB_G | TLB_I);
+
+	tag = (va & TLB_EPN_MASK) | TLB_VALID | pagesz;
+
+	for (i = 0; i < PPC4XX_TLB_SIZE; i++) {
+		if (pin_table[i].e_pinned == FALSE) {
+			found = TRUE;
+			break;
+		}
+	}
+
+	if (found) {
+		/* printk("Pinning %#x -> %#x in entry %d...\n", va, pa, i); */
+		asm("tlbwe %0,%1,1" : : "r" (data), "r" (i));
+		asm("tlbwe %0,%1,0" : : "r" (tag), "r" (i));
+		asm("isync");
+		pin_table[i].e_pinned = found;
+	}
+
+	mtspr(SPRN_PID, opid);
+	return;
+}
+
+void
+PPC4xx_tlb_unpin(unsigned long va, unsigned long pa, int size)
+{
+	/* XXX - To beimplemented. */
+}
+
+void
+PPC4xx_tlb_flush_all(void)
+{
+	int i;
+	unsigned long flags, opid;
+
+	save_flags(flags);
+	cli();
+
+	opid = mfspr(SPRN_PID);
+	mtspr(SPRN_PID, 0);
+
+	for (i = 0; i < PPC4XX_TLB_SIZE; i++) {
+		unsigned long ov = 0;
+
+		if (pin_table[i].e_pinned)
+			continue;
+
+		asm("tlbwe %0,%1,0" : : "r" (ov), "r" (i));
+		asm("tlbwe %0,%1,1" : : "r" (ov), "r" (i));
+	}
+
+	asm("sync;isync");
+
+	mtspr(SPRN_PID, opid);
+	restore_flags(flags);
+}
+
+void
+PPC4xx_tlb_flush(unsigned long va, int pid)
+{
+	unsigned long i, tag, flags, found = 1, opid;
+
+	save_flags(flags);
+	cli();
+
+	opid = mfspr(SPRN_PID);
+	mtspr(SPRN_PID, pid);
+
+	asm("tlbsx. %0,0,%2;beq 1f;li %1,0;1:" : "=r" (i), "=r" (found) : "r" (va));
+
+	if (found && pin_table[i].e_pinned == 0) {
+		asm("tlbre %0,%1,0" : "=r" (tag) : "r" (i));
+		tag &= ~ TLB_VALID;
+		asm("tlbwe %0,%1,0" : : "r" (tag), "r" (i));
+	}
+
+	mtspr(SPRN_PID, opid);
+
+	restore_flags(flags);
+}
+
+#if 0
+/*
+ * TLB miss handling code.
+ */
+
+/*
+ * Handle TLB faults. We should push this back to assembly code eventually.
+ * Caller is responsible for turning off interrupts ...
+ */
+static inline void
+tlbDropin(unsigned long tlbhi, unsigned long tlblo) {
+	/*
+	 * Avoid the divide at the slight cost of a little too
+	 * much emphasis on the last few entries.
+	 */
+	unsigned long rand = mfspr(SPRN_TBLO);
+	rand &= 0x3f;
+        rand += NTLB_WIRED;
+        if (rand >= NTLB)
+		rand -= NTLB_WIRED;
+
+	asm("tlbwe %0,%1,1" : : "r" (tlblo), "r" (rand));
+	asm("tlbwe %0,%1,0" : : "r" (tlbhi), "r" (rand));
+	asm("isync;sync");
+}
+
+static inline void
+mkTlbEntry(unsigned long addr, pte_t *pte) {
+	unsigned long tlbhi;
+	unsigned long tlblo;
+	int found = 1;
+	int idx;
+
+	/*
+	 * Construct the TLB entry.
+	 */
+	tlbhi = addr & ~(PAGE_SIZE-1);
+	tlblo = virt_to_phys(pte_page(*pte)) & TLBLO_RPN;
+	if (pte_val(*pte) & _PAGE_HWWRITE)
+		tlblo |= TLBLO_WR;
+	if (pte_val(*pte) & _PAGE_NO_CACHE)
+		tlblo |= TLBLO_I;
+	tlblo |= TLBLO_EX;
+	if (addr < KERNELBASE)
+		tlblo |= TLBLO_Z_USER;
+	tlbhi |= TLBHI_PGSZ_4K;
+	tlbhi |= TLBHI_VALID;
+
+	/*
+	 * See if a match already exists in the TLB.
+	 */
+	asm("tlbsx. %0,0,%2;beq 1f;li %1,0;1:" : "=r" (idx), "=r" (found) : "r" (tlbhi));
+	if (found) {
+		/*
+		 * Found an existing entry. Just reuse the index.
+		 */
+		asm("tlbwe %0,%1,0" : : "r" (tlbhi), "r" (idx));
+		asm("tlbwe %0,%1,1" : : "r" (tlblo), "r" (idx));
+	}
+	else {
+		/*
+		 * Do the more expensive operation
+		 */
+		tlbDropin(tlbhi, tlblo);
+	}
+}
+
+/*
+ * Mainline of the TLB miss handler. The above inline routines should fold into
+ * this one, eliminating most function call overhead.
+ */
+#ifdef TLBMISS_DEBUG
+volatile unsigned long miss_start;
+volatile unsigned long miss_end;
+#endif
+
+static inline int tlbMiss(struct pt_regs *regs, unsigned long badaddr, int wasWrite)
+{
+	int spid, ospid;
+	struct mm_struct *mm;
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	if (!user_mode(regs) && (badaddr >= KERNELBASE)) {
+		mm = task[0]->mm;
+		spid = 0;
+#ifdef TLBMISS_DEBUG
+                miss_start = 0;
+#endif
+	}
+	else {
+		mm = current->mm;
+		spid = mfspr(SPRN_PID);
+#ifdef TLBMISS_DEBUG
+                miss_start = 1;
+#endif
+	}
+#ifdef TLBMISS_DEBUG
+        store_cache_range((unsigned long)&miss_start, sizeof(miss_start));
+#endif
+
+	pgd = pgd_offset(mm, badaddr);
+	if (pgd_none(*pgd))
+		goto NOGOOD;
+
+	pmd = pmd_offset(pgd, badaddr);
+	if (pmd_none(*pmd))
+		goto NOGOOD;
+
+	pte = pte_offset(pmd, badaddr);
+	if (pte_none(*pte))
+		goto NOGOOD;
+	if (!pte_present(*pte))
+		goto NOGOOD;
+#if 1
+        prohibit_if_guarded(badaddr, sizeof(int));
+#endif
+	if (wasWrite) {
+		if (!pte_write(*pte)) {
+			goto NOGOOD;
+		}
+		set_pte(pte, pte_mkdirty(*pte));
+	}
+	set_pte(pte, pte_mkyoung(*pte));
+
+	ospid = mfspr(SPRN_PID);
+	mtspr(SPRN_PID, spid);
+	mkTlbEntry(badaddr, pte);
+	mtspr(SPRN_PID, ospid);
+
+#ifdef TLBMISS_DEBUG
+        miss_end = 0;
+        store_cache_range((unsigned long)&miss_end, sizeof(miss_end));
+#endif
+	return 0;
+
+NOGOOD:
+#ifdef TLBMISS_DEBUG
+        miss_end = 1;
+        store_cache_range((unsigned long)&miss_end, sizeof(miss_end));
+#endif
+        return 1;
+}
+
+/*
+ * End TLB miss handling code.
+ */
+/* ---------- */
+
+/*
+ * Used to flush the TLB if the page fault handler decides to change
+ * something.
+ */
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte) {
+	int spid;
+	unsigned long flags;
+
+	save_flags(flags);
+	cli();
+
+	if (addr >= KERNELBASE)
+		spid = 0;
+	else
+		spid = vma->vm_mm->context;
+	tlbFlush1(addr, spid);
+
+	restore_flags(flags);
+}
+
+/*
+ * Given a virtual address in the current address space, make
+ * sure the associated physical page is present in memory,
+ * and if the data is to be modified, that any copy-on-write
+ * actions have taken place.
+ */
+unsigned long make_page_present(unsigned long p, int rw) {
+        pte_t *pte;
+        char c;
+
+        get_user(c, (char *) p);
+
+        pte = findPTE(current->mm, p);
+        if (pte_none(*pte) || !pte_present(*pte))
+            debug("make_page_present didn't load page", 0);
+
+        if (rw) {
+            /*
+            * You have to write-touch the page, so that
+            * zero-filled pages are forced to be copied
+            * rather than still pointing at the zero
+            * page.
+            */
+            extern void tlbFlush1(unsigned long, int);
+            tlbFlush1(p, get_context());
+            put_user(c, (char *) p);
+            if (!pte_write(*pte))
+                debug("make_page_present didn't make page writable", 0);
+
+            tlbFlush1(p, get_context());
+        }
+        return pte_page(*pte);
+}
+
+void DataTLBMissException(struct pt_regs *regs)
+{
+	unsigned long badaddr = mfspr(SPRN_DEAR);
+	int wasWrite = mfspr(SPRN_ESR) & 0x800000;
+	if (tlbMiss(regs, badaddr, wasWrite)) {
+		sti();
+		do_page_fault(regs, badaddr, wasWrite);
+		cli();
+    	}
+}
+
+void InstructionTLBMissException(struct pt_regs *regs)
+{
+	if (!current) {
+		debug("ITLB Miss with no current task", regs);
+		sti();
+		bad_page_fault(regs, regs->nip);
+		cli();
+		return;
+	}
+	if (tlbMiss(regs, regs->nip, 0)) {
+		sti();
+		do_page_fault(regs, regs->nip, 0);
+		cli();
+    	}
+}
+
+void DataPageFault(struct pt_regs *regs)
+{
+	unsigned long badaddr = mfspr(SPRN_DEAR);
+	int wasWrite = mfspr(SPRN_ESR) & 0x800000;
+	sti();
+	do_page_fault(regs, badaddr, wasWrite);
+	cli();
+}
+
+void InstructionPageFault(struct pt_regs *regs)
+{
+	if (!current) {
+		debug("ITLB fault with no current task", regs);
+		sti();
+		bad_page_fault(regs, regs->nip);
+		cli();
+		return;
+	}
+	sti();
+	do_page_fault(regs, regs->nip, 0);
+	cli();
+}
+#endif