Merge with Linux 2.1.131 plus some more MIPS goodies.

3 files changed, 55 insertions, 12 deletions

diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c
index 358ff5033..5a1f363bd 100644
--- a/arch/i386/mm/fault.c
+++ b/arch/i386/mm/fault.c
@@ -103,8 +103,13 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
 
 	tsk = current;
 	mm = tsk->mm;
-	if (in_interrupt())
-		die("page fault from irq handler",regs,error_code);
+
+	/*
+	 * If we're in an interrupt or have no user
+	 * context, we must not take the fault..
+	 */
+	if (in_interrupt() || mm == &init_mm)
+		goto no_context;
 
 	down(&mm->mmap_sem);
 
@@ -119,7 +124,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
 		/*
 		 * accessing the stack below %esp is always a bug.
 		 * The "+ 32" is there due to some instructions (like
-		 * pusha) doing pre-decrement on the stack and that
+		 * pusha) doing post-decrement on the stack and that
 		 * doesn't show up until later..
 		 */
 		if (address + 32 < regs->esp)
@@ -151,7 +156,14 @@ good_area:
 			if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
 				goto bad_area;
 	}
-	handle_mm_fault(tsk, vma, address, write);
+
+	/*
+	 * If for any reason at all we couldn't handle the fault,
+	 * make sure we exit gracefully rather than endlessly redo
+	 * the fault.
+	 */
+	if (!handle_mm_fault(tsk, vma, address, write))
+		goto do_sigbus;
 
 	/*
 	 * Did it hit the DOS screen memory VA from vm86 mode?
@@ -194,6 +206,7 @@ bad_area:
 		}
 	}
 
+no_context:
 	/* Are we prepared to handle this kernel fault?  */
 	if ((fixup = search_exception_table(regs->eip)) != 0) {
 		regs->eip = fixup;
@@ -235,8 +248,26 @@ bad_area:
 		page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
 		printk(KERN_ALERT "*pte = %08lx\n", page);
 	}
-	lock_kernel();
 	die("Oops", regs, error_code);
 	do_exit(SIGKILL);
-	unlock_kernel();
+
+/*
+ * We ran out of memory, or some other thing happened to us that made
+ * us unable to handle the page fault gracefully.
+ */
+do_sigbus:
+	up(&mm->mmap_sem);
+
+	/*
+	 * Send a sigbus, regardless of whether we were in kernel
+	 * or user mode.
+	 */
+	tsk->tss.cr2 = address;
+	tsk->tss.error_code = error_code;
+	tsk->tss.trap_no = 14;
+	force_sig(SIGBUS, tsk);
+
+	/* Kernel mode? Handle exceptions or die */
+	if (!(error_code & 4))
+		goto no_context;
 }
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index aed7ecc55..693072b1a 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -293,11 +293,18 @@ __initfunc(unsigned long paging_init(unsigned long start_mem, unsigned long end_
 		 * extended bios data area. 
 		 *
 		 * there is a real-mode segmented pointer pointing to the
-		 * 4K EBDA area at 0x40E, calculate and scan it here:
+		 * 4K EBDA area at 0x40E, calculate and scan it here.
+		 *
+		 * NOTE! There are Linux loaders that will corrupt the EBDA
+		 * area, and as such this kind of SMP config may be less
+		 * trustworthy, simply because the SMP table may have been
+		 * stomped on during early boot.
 		 */
 		address = *(unsigned short *)phys_to_virt(0x40E);
 		address<<=4;
 		smp_scan_config(address, 0x1000);
+		if (smp_found_config)
+			printk(KERN_WARNING "WARNING: MP table in the EBDA can be UNSAFE, contact linux-smp@vger.rutgers.edu if you experience SMP problems!\n");
 	}
 #endif
 	start_mem = PAGE_ALIGN(start_mem);
diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
index 740f4551f..28250b0bd 100644
--- a/arch/i386/mm/ioremap.c
+++ b/arch/i386/mm/ioremap.c
@@ -84,11 +84,16 @@ static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  * Remap an arbitrary physical address space into the kernel virtual
  * address space. Needed when the kernel wants to access high addresses
  * directly.
+ *
+ * NOTE! We need to allow non-page-aligned mappings too: we will obviously
+ * have to convert them into an offset in a page-aligned mapping, but the
+ * caller shouldn't need to know that small detail.
  */
 void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 {
 	void * addr;
 	struct vm_struct * area;
+	unsigned long offset;
 
 	/*
 	 * Don't remap the low PCI/ISA area, it's always mapped..
@@ -105,9 +110,9 @@ void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flag
 	/*
 	 * Mappings have to be page-aligned
 	 */
-	if (phys_addr & ~PAGE_MASK)
-		return NULL;
-	size = PAGE_ALIGN(size);
+	offset = phys_addr & ~PAGE_MASK;
+	phys_addr &= PAGE_MASK;
+	size = PAGE_ALIGN(size + offset);
 
 	/*
 	 * Don't allow mappings that wrap..
@@ -126,11 +131,11 @@ void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flag
 		vfree(addr);
 		return NULL;
 	}
-	return addr;
+	return (void *) (offset + (char *)addr);
 }
 
 void iounmap(void *addr)
 {
 	if (addr > high_memory)
-		return vfree(addr);
+		return vfree((void *) (PAGE_MASK & (unsigned long) addr));
 }