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, 440 insertions, 0 deletions

diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c
new file mode 100644
index 00000000000..57d9930843a
--- /dev/null
+++ b/arch/ppc/mm/fault.c
@@ -0,0 +1,440 @@
+/*
+ *  arch/ppc/mm/fault.c
+ *
+ *  PowerPC version
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Derived from "arch/i386/mm/fault.c"
+ *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *
+ *  Modified by Cort Dougan and Paul Mackerras.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#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/interrupt.h>
+#include <linux/highmem.h>
+#include <linux/module.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/mmu_context.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/tlbflush.h>
+
+#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
+extern void (*debugger)(struct pt_regs *);
+extern void (*debugger_fault_handler)(struct pt_regs *);
+extern int (*debugger_dabr_match)(struct pt_regs *);
+int debugger_kernel_faults = 1;
+#endif
+
+unsigned long htab_reloads;	/* updated by hashtable.S:hash_page() */
+unsigned long htab_evicts; 	/* updated by hashtable.S:hash_page() */
+unsigned long htab_preloads;	/* updated by hashtable.S:add_hash_page() */
+unsigned long pte_misses;	/* updated by do_page_fault() */
+unsigned long pte_errors;	/* updated by do_page_fault() */
+unsigned int probingmem;
+
+/*
+ * Check whether the instruction at regs->nip is a store using
+ * an update addressing form which will update r1.
+ */
+static int store_updates_sp(struct pt_regs *regs)
+{
+	unsigned int inst;
+
+	if (get_user(inst, (unsigned int __user *)regs->nip))
+		return 0;
+	/* check for 1 in the rA field */
+	if (((inst >> 16) & 0x1f) != 1)
+		return 0;
+	/* check major opcode */
+	switch (inst >> 26) {
+	case 37:	/* stwu */
+	case 39:	/* stbu */
+	case 45:	/* sthu */
+	case 53:	/* stfsu */
+	case 55:	/* stfdu */
+		return 1;
+	case 31:
+		/* check minor opcode */
+		switch ((inst >> 1) & 0x3ff) {
+		case 183:	/* stwux */
+		case 247:	/* stbux */
+		case 439:	/* sthux */
+		case 695:	/* stfsux */
+		case 759:	/* stfdux */
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * For 600- and 800-family processors, the error_code parameter is DSISR
+ * for a data fault, SRR1 for an instruction fault. For 400-family processors
+ * the error_code parameter is ESR for a data fault, 0 for an instruction
+ * fault.
+ */
+int do_page_fault(struct pt_regs *regs, unsigned long address,
+		  unsigned long error_code)
+{
+	struct vm_area_struct * vma;
+	struct mm_struct *mm = current->mm;
+	siginfo_t info;
+	int code = SEGV_MAPERR;
+#if defined(CONFIG_4xx) || defined (CONFIG_BOOKE)
+	int is_write = error_code & ESR_DST;
+#else
+	int is_write = 0;
+
+	/*
+	 * Fortunately the bit assignments in SRR1 for an instruction
+	 * fault and DSISR for a data fault are mostly the same for the
+	 * bits we are interested in.  But there are some bits which
+	 * indicate errors in DSISR but can validly be set in SRR1.
+	 */
+	if (TRAP(regs) == 0x400)
+		error_code &= 0x48200000;
+	else
+		is_write = error_code & 0x02000000;
+#endif /* CONFIG_4xx || CONFIG_BOOKE */
+
+#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
+	if (debugger_fault_handler && TRAP(regs) == 0x300) {
+		debugger_fault_handler(regs);
+		return 0;
+	}
+#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
+	if (error_code & 0x00400000) {
+		/* DABR match */
+		if (debugger_dabr_match(regs))
+			return 0;
+	}
+#endif /* !(CONFIG_4xx || CONFIG_BOOKE)*/
+#endif /* CONFIG_XMON || CONFIG_KGDB */
+
+	if (in_atomic() || mm == NULL)
+		return SIGSEGV;
+
+	down_read(&mm->mmap_sem);
+	vma = find_vma(mm, address);
+	if (!vma)
+		goto bad_area;
+	if (vma->vm_start <= address)
+		goto good_area;
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		goto bad_area;
+	if (!is_write)
+                goto bad_area;
+
+	/*
+	 * N.B. The rs6000/xcoff ABI allows programs to access up to
+	 * a few hundred bytes below the stack pointer.
+	 * The kernel signal delivery code writes up to about 1.5kB
+	 * below the stack pointer (r1) before decrementing it.
+	 * The exec code can write slightly over 640kB to the stack
+	 * before setting the user r1.  Thus we allow the stack to
+	 * expand to 1MB without further checks.
+	 */
+	if (address + 0x100000 < vma->vm_end) {
+		/* get user regs even if this fault is in kernel mode */
+		struct pt_regs *uregs = current->thread.regs;
+		if (uregs == NULL)
+			goto bad_area;
+
+		/*
+		 * A user-mode access to an address a long way below
+		 * the stack pointer is only valid if the instruction
+		 * is one which would update the stack pointer to the
+		 * address accessed if the instruction completed,
+		 * i.e. either stwu rs,n(r1) or stwux rs,r1,rb
+		 * (or the byte, halfword, float or double forms).
+		 *
+		 * If we don't check this then any write to the area
+		 * between the last mapped region and the stack will
+		 * expand the stack rather than segfaulting.
+		 */
+		if (address + 2048 < uregs->gpr[1]
+		    && (!user_mode(regs) || !store_updates_sp(regs)))
+			goto bad_area;
+	}
+	if (expand_stack(vma, address))
+		goto bad_area;
+
+good_area:
+	code = SEGV_ACCERR;
+#if defined(CONFIG_6xx)
+	if (error_code & 0x95700000)
+		/* an error such as lwarx to I/O controller space,
+		   address matching DABR, eciwx, etc. */
+		goto bad_area;
+#endif /* CONFIG_6xx */
+#if defined(CONFIG_8xx)
+        /* The MPC8xx seems to always set 0x80000000, which is
+         * "undefined".  Of those that can be set, this is the only
+         * one which seems bad.
+         */
+	if (error_code & 0x10000000)
+                /* Guarded storage error. */
+		goto bad_area;
+#endif /* CONFIG_8xx */
+
+	/* a write */
+	if (is_write) {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+	/* an exec  - 4xx/Book-E allows for per-page execute permission */
+	} else if (TRAP(regs) == 0x400) {
+		pte_t *ptep;
+
+#if 0
+		/* It would be nice to actually enforce the VM execute
+		   permission on CPUs which can do so, but far too
+		   much stuff in userspace doesn't get the permissions
+		   right, so we let any page be executed for now. */
+		if (! (vma->vm_flags & VM_EXEC))
+			goto bad_area;
+#endif
+
+		/* Since 4xx/Book-E supports per-page execute permission,
+		 * we lazily flush dcache to icache. */
+		ptep = NULL;
+		if (get_pteptr(mm, address, &ptep) && pte_present(*ptep)) {
+			struct page *page = pte_page(*ptep);
+
+			if (! test_bit(PG_arch_1, &page->flags)) {
+				flush_dcache_icache_page(page);
+				set_bit(PG_arch_1, &page->flags);
+			}
+			pte_update(ptep, 0, _PAGE_HWEXEC);
+			_tlbie(address);
+			pte_unmap(ptep);
+			up_read(&mm->mmap_sem);
+			return 0;
+		}
+		if (ptep != NULL)
+			pte_unmap(ptep);
+#endif
+	/* a read */
+	} else {
+		/* protection fault */
+		if (error_code & 0x08000000)
+			goto bad_area;
+		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+			goto bad_area;
+	}
+
+	/*
+	 * If for any reason at all we couldn't handle the fault,
+	 * make sure we exit gracefully rather than endlessly redo
+	 * the fault.
+	 */
+ survive:
+        switch (handle_mm_fault(mm, vma, address, is_write)) {
+        case VM_FAULT_MINOR:
+                current->min_flt++;
+                break;
+        case VM_FAULT_MAJOR:
+                current->maj_flt++;
+                break;
+        case VM_FAULT_SIGBUS:
+                goto do_sigbus;
+        case VM_FAULT_OOM:
+                goto out_of_memory;
+	default:
+		BUG();
+	}
+
+	up_read(&mm->mmap_sem);
+	/*
+	 * keep track of tlb+htab misses that are good addrs but
+	 * just need pte's created via handle_mm_fault()
+	 * -- Cort
+	 */
+	pte_misses++;
+	return 0;
+
+bad_area:
+	up_read(&mm->mmap_sem);
+	pte_errors++;
+
+	/* User mode accesses cause a SIGSEGV */
+	if (user_mode(regs)) {
+		info.si_signo = SIGSEGV;
+		info.si_errno = 0;
+		info.si_code = code;
+		info.si_addr = (void __user *) address;
+		force_sig_info(SIGSEGV, &info, current);
+		return 0;
+	}
+
+	return SIGSEGV;
+
+/*
+ * We ran out of memory, or some other thing happened to us that made
+ * us unable to handle the page fault gracefully.
+ */
+out_of_memory:
+	up_read(&mm->mmap_sem);
+	if (current->pid == 1) {
+		yield();
+		down_read(&mm->mmap_sem);
+		goto survive;
+	}
+	printk("VM: killing process %s\n", current->comm);
+	if (user_mode(regs))
+		do_exit(SIGKILL);
+	return SIGKILL;
+
+do_sigbus:
+	up_read(&mm->mmap_sem);
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = BUS_ADRERR;
+	info.si_addr = (void __user *)address;
+	force_sig_info (SIGBUS, &info, current);
+	if (!user_mode(regs))
+		return SIGBUS;
+	return 0;
+}
+
+/*
+ * bad_page_fault is called when we have a bad access from the kernel.
+ * It is called from the DSI and ISI handlers in head.S and from some
+ * of the procedures in traps.c.
+ */
+void
+bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
+{
+	const struct exception_table_entry *entry;
+
+	/* Are we prepared to handle this fault?  */
+	if ((entry = search_exception_tables(regs->nip)) != NULL) {
+		regs->nip = entry->fixup;
+		return;
+	}
+
+	/* kernel has accessed a bad area */
+#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
+	if (debugger_kernel_faults)
+		debugger(regs);
+#endif
+	die("kernel access of bad area", regs, sig);
+}
+
+#ifdef CONFIG_8xx
+
+/* The pgtable.h claims some functions generically exist, but I
+ * can't find them......
+ */
+pte_t *va_to_pte(unsigned long address)
+{
+	pgd_t *dir;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	if (address < TASK_SIZE)
+		return NULL;
+
+	dir = pgd_offset(&init_mm, address);
+	if (dir) {
+		pmd = pmd_offset(dir, address & PAGE_MASK);
+		if (pmd && pmd_present(*pmd)) {
+			pte = pte_offset_kernel(pmd, address & PAGE_MASK);
+			if (pte && pte_present(*pte))
+				return(pte);
+		}
+	}
+	return NULL;
+}
+
+unsigned long va_to_phys(unsigned long address)
+{
+	pte_t *pte;
+
+	pte = va_to_pte(address);
+	if (pte)
+		return(((unsigned long)(pte_val(*pte)) & PAGE_MASK) | (address & ~(PAGE_MASK)));
+	return (0);
+}
+
+void
+print_8xx_pte(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t * pgd;
+        pmd_t * pmd;
+        pte_t * pte;
+
+        printk(" pte @ 0x%8lx: ", addr);
+        pgd = pgd_offset(mm, addr & PAGE_MASK);
+        if (pgd) {
+                pmd = pmd_offset(pgd, addr & PAGE_MASK);
+                if (pmd && pmd_present(*pmd)) {
+                        pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
+                        if (pte) {
+                                printk(" (0x%08lx)->(0x%08lx)->0x%08lx\n",
+                                        (long)pgd, (long)pte, (long)pte_val(*pte));
+#define pp ((long)pte_val(*pte))			
+				printk(" RPN: %05lx PP: %lx SPS: %lx SH: %lx "
+				       "CI: %lx v: %lx\n",
+				       pp>>12,    /* rpn */
+				       (pp>>10)&3, /* pp */
+				       (pp>>3)&1, /* small */
+				       (pp>>2)&1, /* shared */
+				       (pp>>1)&1, /* cache inhibit */
+				       pp&1       /* valid */
+				       );
+#undef pp			
+                        }
+                        else {
+                                printk("no pte\n");
+                        }
+                }
+                else {
+                        printk("no pmd\n");
+                }
+        }
+        else {
+                printk("no pgd\n");
+        }
+}
+
+int
+get_8xx_pte(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t * pgd;
+        pmd_t * pmd;
+        pte_t * pte;
+        int     retval = 0;
+
+        pgd = pgd_offset(mm, addr & PAGE_MASK);
+        if (pgd) {
+                pmd = pmd_offset(pgd, addr & PAGE_MASK);
+                if (pmd && pmd_present(*pmd)) {
+                        pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
+                        if (pte) {
+				retval = (int)pte_val(*pte);
+                        }
+                }
+        }
+        return(retval);
+}
+#endif /* CONFIG_8xx */