Merge branch 'parisc-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fixes from Helge Deller:
 "This patchset includes a bugfix to prevent a kernel crash when memory
  in page zero is accessed by the kernel itself, e.g.  via
  probe_kernel_read().

  Furthermore we now export flush_cache_page() which is needed
  (indirectly) by the lustre filesystem.  The other patches remove
  unused functions and optimizes the page fault handler to only evaluate
  variables if needed, which again protects against possible kernel
  crashes"

* 'parisc-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: let probe_kernel_read() capture access to page zero
  parisc: optimize variable initialization in do_page_fault
  parisc: fix interruption handler to respect pagefault_disable()
  parisc: mark parisc_terminate() noreturn and cold.
  parisc: remove unused syscall_ipi() function.
  parisc: kill SMP single function call interrupt
  parisc: Export flush_cache_page() (needed by lustre)

6 files changed, 30 insertions, 22 deletions

diff --git a/arch/parisc/include/asm/traps.h b/arch/parisc/include/asm/traps.h
index 1945f99..4736020 100644
--- a/arch/parisc/include/asm/traps.h
+++ b/arch/parisc/include/asm/traps.h
@@ -6,7 +6,7 @@ struct pt_regs;
 
 /* traps.c */
 void parisc_terminate(char *msg, struct pt_regs *regs,
-		int code, unsigned long offset);
+		int code, unsigned long offset) __noreturn __cold;
 
 /* mm/fault.c */
 void do_page_fault(struct pt_regs *regs, unsigned long code,
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index c035673..b521c0a 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -602,6 +602,7 @@ flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long
 		__flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
 	}
 }
+EXPORT_SYMBOL_GPL(flush_cache_page);
 
 #ifdef CONFIG_PARISC_TMPALIAS
 
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 8a252f2..2b96602 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -72,7 +72,6 @@ enum ipi_message_type {
 	IPI_NOP=0,
 	IPI_RESCHEDULE=1,
 	IPI_CALL_FUNC,
-	IPI_CALL_FUNC_SINGLE,
 	IPI_CPU_START,
 	IPI_CPU_STOP,
 	IPI_CPU_TEST
@@ -164,11 +163,6 @@ ipi_interrupt(int irq, void *dev_id)
 				generic_smp_call_function_interrupt();
 				break;
 
-			case IPI_CALL_FUNC_SINGLE:
-				smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu);
-				generic_smp_call_function_single_interrupt();
-				break;
-
 			case IPI_CPU_START:
 				smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
 				break;
@@ -260,7 +254,7 @@ void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 
 void arch_send_call_function_single_ipi(int cpu)
 {
-	send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
+	send_IPI_single(cpu, IPI_CALL_FUNC);
 }
 
 /*
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 04e47c6..1cd1d0c 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -291,11 +291,6 @@ void die_if_kernel(char *str, struct pt_regs *regs, long err)
 	do_exit(SIGSEGV);
 }
 
-int syscall_ipi(int (*syscall) (struct pt_regs *), struct pt_regs *regs)
-{
-	return syscall(regs);
-}
-
 /* gdb uses break 4,8 */
 #define GDB_BREAK_INSN 0x10004
 static void handle_gdb_break(struct pt_regs *regs, int wot)
@@ -805,14 +800,14 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
 	else {
 
 	    /*
-	     * The kernel should never fault on its own address space.
+	     * The kernel should never fault on its own address space,
+	     * unless pagefault_disable() was called before.
 	     */
 
-	    if (fault_space == 0) 
+	    if (fault_space == 0 && !in_atomic())
 	    {
 		pdc_chassis_send_status(PDC_CHASSIS_DIRECT_PANIC);
 		parisc_terminate("Kernel Fault", regs, code, fault_address);
-	
 	    }
 	}
 
diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c
index ac4370b..b5507ec 100644
--- a/arch/parisc/lib/memcpy.c
+++ b/arch/parisc/lib/memcpy.c
@@ -56,7 +56,7 @@
 #ifdef __KERNEL__
 #include <linux/module.h>
 #include <linux/compiler.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #define s_space "%%sr1"
 #define d_space "%%sr2"
 #else
@@ -524,4 +524,17 @@ EXPORT_SYMBOL(copy_to_user);
 EXPORT_SYMBOL(copy_from_user);
 EXPORT_SYMBOL(copy_in_user);
 EXPORT_SYMBOL(memcpy);
+
+long probe_kernel_read(void *dst, const void *src, size_t size)
+{
+	unsigned long addr = (unsigned long)src;
+
+	if (size < 0 || addr < PAGE_SIZE)
+		return -EFAULT;
+
+	/* check for I/O space F_EXTEND(0xfff00000) access as well? */
+
+	return __probe_kernel_read(dst, src, size);
+}
+
 #endif
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 00c0ed3..0293588 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -171,20 +171,25 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
 			      unsigned long address)
 {
 	struct vm_area_struct *vma, *prev_vma;
-	struct task_struct *tsk = current;
-	struct mm_struct *mm = tsk->mm;
+	struct task_struct *tsk;
+	struct mm_struct *mm;
 	unsigned long acc_type;
 	int fault;
-	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+	unsigned int flags;
 
-	if (in_atomic() || !mm)
+	if (in_atomic())
 		goto no_context;
 
+	tsk = current;
+	mm = tsk->mm;
+	if (!mm)
+		goto no_context;
+
+	flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 	if (user_mode(regs))
 		flags |= FAULT_FLAG_USER;
 
 	acc_type = parisc_acctyp(code, regs->iir);
-
 	if (acc_type & VM_WRITE)
 		flags |= FAULT_FLAG_WRITE;
 retry: