1 files changed, 209 insertions, 130 deletions

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index ac70fa5a2e2..5678c3571e7 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -1,40 +1,25 @@
 /*
- * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
-#include "linux/kernel.h"
-#include "asm/errno.h"
-#include "linux/sched.h"
-#include "linux/mm.h"
-#include "linux/spinlock.h"
-#include "linux/config.h"
-#include "linux/init.h"
-#include "linux/ptrace.h"
-#include "asm/semaphore.h"
-#include "asm/pgtable.h"
-#include "asm/pgalloc.h"
-#include "asm/tlbflush.h"
-#include "asm/a.out.h"
-#include "asm/current.h"
-#include "asm/irq.h"
-#include "sysdep/sigcontext.h"
-#include "user_util.h"
-#include "kern_util.h"
-#include "kern.h"
-#include "chan_kern.h"
-#include "mconsole_kern.h"
-#include "mem.h"
-#include "mem_kern.h"
-#include "sysdep/sigcontext.h"
-#include "sysdep/ptrace.h"
-#include "os.h"
-#ifdef CONFIG_MODE_SKAS
-#include "skas.h"
-#endif
-#include "os.h"
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/hardirq.h>
+#include <linux/module.h>
+#include <asm/current.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <arch.h>
+#include <as-layout.h>
+#include <kern_util.h>
+#include <os.h>
+#include <skas.h>
 
-/* Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by segv(). */
+/*
+ * Note this is constrained to return 0, -EFAULT, -EACCESS, -ENOMEM by
+ * segv().
+ */
 int handle_page_fault(unsigned long address, unsigned long ip,
 		      int is_write, int is_user, int *code_out)
 {
@@ -45,61 +30,83 @@ int handle_page_fault(unsigned long address, unsigned long ip,
 	pmd_t *pmd;
 	pte_t *pte;
 	int err = -EFAULT;
+	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 
 	*code_out = SEGV_MAPERR;
 
-	/* If the fault was during atomic operation, don't take the fault, just
-	 * fail. */
+	/*
+	 * If the fault was during atomic operation, don't take the fault, just
+	 * fail.
+	 */
 	if (in_atomic())
 		goto out_nosemaphore;
 
+	if (is_user)
+		flags |= FAULT_FLAG_USER;
+retry:
 	down_read(&mm->mmap_sem);
 	vma = find_vma(mm, address);
-	if(!vma)
+	if (!vma)
 		goto out;
-	else if(vma->vm_start <= address)
+	else if (vma->vm_start <= address)
 		goto good_area;
-	else if(!(vma->vm_flags & VM_GROWSDOWN))
+	else if (!(vma->vm_flags & VM_GROWSDOWN))
 		goto out;
-	else if(is_user && !ARCH_IS_STACKGROW(address))
+	else if (is_user && !ARCH_IS_STACKGROW(address))
 		goto out;
-	else if(expand_stack(vma, address))
+	else if (expand_stack(vma, address))
 		goto out;
 
 good_area:
 	*code_out = SEGV_ACCERR;
-	if(is_write && !(vma->vm_flags & VM_WRITE))
-		goto out;
-
-	/* Don't require VM_READ|VM_EXEC for write faults! */
-        if(!is_write && !(vma->vm_flags & (VM_READ | VM_EXEC)))
-                goto out;
+	if (is_write) {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto out;
+		flags |= FAULT_FLAG_WRITE;
+	} else {
+		/* Don't require VM_READ|VM_EXEC for write faults! */
+		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+			goto out;
+	}
 
 	do {
-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:
-			err = -EACCES;
-			goto out;
-		case VM_FAULT_OOM:
-			err = -ENOMEM;
-			goto out_of_memory;
-		default:
+		int fault;
+
+		fault = handle_mm_fault(mm, vma, address, flags);
+
+		if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+			goto out_nosemaphore;
+
+		if (unlikely(fault & VM_FAULT_ERROR)) {
+			if (fault & VM_FAULT_OOM) {
+				goto out_of_memory;
+			} else if (fault & VM_FAULT_SIGBUS) {
+				err = -EACCES;
+				goto out;
+			}
 			BUG();
 		}
+		if (flags & FAULT_FLAG_ALLOW_RETRY) {
+			if (fault & VM_FAULT_MAJOR)
+				current->maj_flt++;
+			else
+				current->min_flt++;
+			if (fault & VM_FAULT_RETRY) {
+				flags &= ~FAULT_FLAG_ALLOW_RETRY;
+				flags |= FAULT_FLAG_TRIED;
+
+				goto retry;
+			}
+		}
+
 		pgd = pgd_offset(mm, address);
 		pud = pud_offset(pgd, address);
 		pmd = pmd_offset(pud, address);
 		pte = pte_offset_kernel(pmd, address);
-	} while(!pte_present(*pte));
+	} while (!pte_present(*pte));
 	err = 0;
-	/* The below warning was added in place of
+	/*
+	 * The below warning was added in place of
 	 *	pte_mkyoung(); if (is_write) pte_mkdirty();
 	 * If it's triggered, we'd see normally a hang here (a clean pte is
 	 * marked read-only to emulate the dirty bit).
@@ -113,135 +120,207 @@ survive:
 out:
 	up_read(&mm->mmap_sem);
 out_nosemaphore:
-	return(err);
+	return err;
 
-/*
- * 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:
-	if (current->pid == 1) {
-		up_read(&mm->mmap_sem);
-		yield();
-		down_read(&mm->mmap_sem);
-		goto survive;
-	}
-	goto out;
+	/*
+	 * We ran out of memory, call the OOM killer, and return the userspace
+	 * (which will retry the fault, or kill us if we got oom-killed).
+	 */
+	up_read(&mm->mmap_sem);
+	if (!is_user)
+		goto out_nosemaphore;
+	pagefault_out_of_memory();
+	return 0;
+}
+EXPORT_SYMBOL(handle_page_fault);
+
+static void show_segv_info(struct uml_pt_regs *regs)
+{
+	struct task_struct *tsk = current;
+	struct faultinfo *fi = UPT_FAULTINFO(regs);
+
+	if (!unhandled_signal(tsk, SIGSEGV))
+		return;
+
+	if (!printk_ratelimit())
+		return;
+
+	printk("%s%s[%d]: segfault at %lx ip %p sp %p error %x",
+		task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+		tsk->comm, task_pid_nr(tsk), FAULT_ADDRESS(*fi),
+		(void *)UPT_IP(regs), (void *)UPT_SP(regs),
+		fi->error_code);
+
+	print_vma_addr(KERN_CONT " in ", UPT_IP(regs));
+	printk(KERN_CONT "\n");
 }
 
-void segv_handler(int sig, union uml_pt_regs *regs)
+static void bad_segv(struct faultinfo fi, unsigned long ip)
+{
+	struct siginfo si;
+
+	si.si_signo = SIGSEGV;
+	si.si_code = SEGV_ACCERR;
+	si.si_addr = (void __user *) FAULT_ADDRESS(fi);
+	current->thread.arch.faultinfo = fi;
+	force_sig_info(SIGSEGV, &si, current);
+}
+
+void fatal_sigsegv(void)
+{
+	force_sigsegv(SIGSEGV, current);
+	do_signal();
+	/*
+	 * This is to tell gcc that we're not returning - do_signal
+	 * can, in general, return, but in this case, it's not, since
+	 * we just got a fatal SIGSEGV queued.
+	 */
+	os_dump_core();
+}
+
+void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	struct faultinfo * fi = UPT_FAULTINFO(regs);
 
-	if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){
+	if (UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)) {
+		show_segv_info(regs);
 		bad_segv(*fi, UPT_IP(regs));
 		return;
 	}
 	segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
 }
 
-struct kern_handlers handlinfo_kern = {
-	.relay_signal = relay_signal,
-	.winch = winch,
-	.bus_handler = relay_signal,
-	.page_fault = segv_handler,
-	.sigio_handler = sigio_handler,
-	.timer_handler = timer_handler
-};
 /*
  * We give a *copy* of the faultinfo in the regs to segv.
  * This must be done, since nesting SEGVs could overwrite
  * the info in the regs. A pointer to the info then would
  * give us bad data!
  */
-unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
+unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
+		   struct uml_pt_regs *regs)
 {
 	struct siginfo si;
-	void *catcher;
+	jmp_buf *catcher;
 	int err;
-        int is_write = FAULT_WRITE(fi);
-        unsigned long address = FAULT_ADDRESS(fi);
-
-        if(!is_user && (address >= start_vm) && (address < end_vm)){
-                flush_tlb_kernel_vm();
-                return(0);
-        }
-	else if(current->mm == NULL)
+	int is_write = FAULT_WRITE(fi);
+	unsigned long address = FAULT_ADDRESS(fi);
+
+	if (!is_user && regs)
+		current->thread.segv_regs = container_of(regs, struct pt_regs, regs);
+
+	if (!is_user && (address >= start_vm) && (address < end_vm)) {
+		flush_tlb_kernel_vm();
+		goto out;
+	}
+	else if (current->mm == NULL) {
+		show_regs(container_of(regs, struct pt_regs, regs));
 		panic("Segfault with no mm");
+	}
 
 	if (SEGV_IS_FIXABLE(&fi) || SEGV_MAYBE_FIXABLE(&fi))
-		err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);
+		err = handle_page_fault(address, ip, is_write, is_user,
+					&si.si_code);
 	else {
 		err = -EFAULT;
-		/* A thread accessed NULL, we get a fault, but CR2 is invalid.
-		 * This code is used in __do_copy_from_user() of TT mode. */
+		/*
+		 * A thread accessed NULL, we get a fault, but CR2 is invalid.
+		 * This code is used in __do_copy_from_user() of TT mode.
+		 * XXX tt mode is gone, so maybe this isn't needed any more
+		 */
 		address = 0;
 	}
 
 	catcher = current->thread.fault_catcher;
-	if(!err)
-		return(0);
-	else if(catcher != NULL){
+	if (!err)
+		goto out;
+	else if (catcher != NULL) {
 		current->thread.fault_addr = (void *) address;
-		do_longjmp(catcher, 1);
+		UML_LONGJMP(catcher, 1);
 	}
-	else if(current->thread.fault_addr != NULL)
+	else if (current->thread.fault_addr != NULL)
 		panic("fault_addr set but no fault catcher");
-        else if(!is_user && arch_fixup(ip, sc))
-		return(0);
+	else if (!is_user && arch_fixup(ip, regs))
+		goto out;
 
- 	if(!is_user)
+	if (!is_user) {
+		show_regs(container_of(regs, struct pt_regs, regs));
 		panic("Kernel mode fault at addr 0x%lx, ip 0x%lx",
 		      address, ip);
+	}
+
+	show_segv_info(regs);
 
 	if (err == -EACCES) {
 		si.si_signo = SIGBUS;
 		si.si_errno = 0;
 		si.si_code = BUS_ADRERR;
 		si.si_addr = (void __user *)address;
-                current->thread.arch.faultinfo = fi;
+		current->thread.arch.faultinfo = fi;
 		force_sig_info(SIGBUS, &si, current);
-	} else if (err == -ENOMEM) {
-		printk("VM: killing process %s\n", current->comm);
-		do_exit(SIGKILL);
 	} else {
 		BUG_ON(err != -EFAULT);
 		si.si_signo = SIGSEGV;
 		si.si_addr = (void __user *) address;
-                current->thread.arch.faultinfo = fi;
+		current->thread.arch.faultinfo = fi;
 		force_sig_info(SIGSEGV, &si, current);
 	}
-	return(0);
-}
 
-void bad_segv(struct faultinfo fi, unsigned long ip)
-{
-	struct siginfo si;
+out:
+	if (regs)
+		current->thread.segv_regs = NULL;
 
-	si.si_signo = SIGSEGV;
-	si.si_code = SEGV_ACCERR;
-	si.si_addr = (void __user *) FAULT_ADDRESS(fi);
-	current->thread.arch.faultinfo = fi;
-	force_sig_info(SIGSEGV, &si, current);
+	return 0;
 }
 
-void relay_signal(int sig, union uml_pt_regs *regs)
+void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
 {
-	if(arch_handle_signal(sig, regs)) return;
-	if(!UPT_IS_USER(regs))
+	struct faultinfo *fi;
+	struct siginfo clean_si;
+
+	if (!UPT_IS_USER(regs)) {
+		if (sig == SIGBUS)
+			printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
+			       "mount likely just ran out of space\n");
 		panic("Kernel mode signal %d", sig);
-        current->thread.arch.faultinfo = *UPT_FAULTINFO(regs);
-	force_sig(sig, current);
+	}
+
+	arch_examine_signal(sig, regs);
+
+	memset(&clean_si, 0, sizeof(clean_si));
+	clean_si.si_signo = si->si_signo;
+	clean_si.si_errno = si->si_errno;
+	clean_si.si_code = si->si_code;
+	switch (sig) {
+	case SIGILL:
+	case SIGFPE:
+	case SIGSEGV:
+	case SIGBUS:
+	case SIGTRAP:
+		fi = UPT_FAULTINFO(regs);
+		clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi);
+		current->thread.arch.faultinfo = *fi;
+#ifdef __ARCH_SI_TRAPNO
+		clean_si.si_trapno = si->si_trapno;
+#endif
+		break;
+	default:
+		printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
+			sig, si->si_code);
+	}
+
+	force_sig_info(sig, &clean_si, current);
 }
 
-void bus_handler(int sig, union uml_pt_regs *regs)
+void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs)
 {
-	if(current->thread.fault_catcher != NULL)
-		do_longjmp(current->thread.fault_catcher, 1);
-	else relay_signal(sig, regs);
+	if (current->thread.fault_catcher != NULL)
+		UML_LONGJMP(current->thread.fault_catcher, 1);
+	else
+		relay_signal(sig, si, regs);
 }
 
-void winch(int sig, union uml_pt_regs *regs)
+void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 {
 	do_IRQ(WINCH_IRQ, regs);
 }