[PATCH] PowerPC: rearrange/add trap markers in do_page_fault()

Rearrange existing trap markers in PowerPC do_page_fault() to avoid duplicate
trap reporting in a certain case, and add the markers to some code paths that
were missed...
 
Signed-off-by: Sergei Shtylyov <[email protected]>

---
MIPS needs something along these lines as well.  Removing the trap tracepoints
from do_page_fault() was a bad move in the first place...

 arch/powerpc/mm/fault.c |   17 +++++++++++------
 1 files changed, 11 insertions(+), 6 deletions(-)

Index: linux-2.6-lttng/arch/powerpc/mm/fault.c
===================================================================
--- linux-2.6-lttng.orig/arch/powerpc/mm/fault.c
+++ linux-2.6-lttng/arch/powerpc/mm/fault.c
@@ -199,12 +199,15 @@ int __kprobes do_page_fault(struct pt_re
 	if (in_atomic() || mm == NULL) {
 		if (!user_mode(regs))
 			return SIGSEGV;
+		MARK(kernel_trap_entry, "%ld struct pt_regs %p",
+		     regs->trap, regs);
 		/* in_atomic() in user mode is really bad,
 		   as is current->mm == NULL. */
 		printk(KERN_EMERG "Page fault in user mode with"
 		       "in_atomic() = %d mm = %p\n", in_atomic(), mm);
 		printk(KERN_EMERG "NIP = %lx  MSR = %lx\n",
 		       regs->nip, regs->msr);
+		MARK(kernel_trap_exit, MARK_NOARGS);
 		die("Weird page fault", regs, SIGSEGV);
 	}
 
@@ -311,6 +314,8 @@ good_area:
 			if (pte_present(*ptep)) {
 				struct page *page = pte_page(*ptep);
 
+				MARK(kernel_trap_entry, "%ld struct pt_regs %p",
+				     regs->trap, regs);
 				if (!test_bit(PG_arch_1, &page->flags)) {
 					flush_dcache_icache_page(page);
 					set_bit(PG_arch_1, &page->flags);
@@ -319,6 +324,7 @@ good_area:
 				_tlbie(address);
 				pte_unmap_unlock(ptep, ptl);
 				up_read(&mm->mmap_sem);
+				MARK(kernel_trap_exit, MARK_NOARGS);
 				return 0;
 			}
 			pte_unmap_unlock(ptep, ptl);
@@ -342,30 +348,26 @@ good_area:
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
+	MARK(kernel_trap_entry, "%ld struct pt_regs %p", regs->trap, regs);
  survive:
- 	MARK(kernel_trap_entry, "%ld struct pt_regs %p",
-		regs->trap, regs);
 	switch (handle_mm_fault(mm, vma, address, is_write)) {
 
 	case VM_FAULT_MINOR:
-		MARK(kernel_trap_exit, MARK_NOARGS);
 		current->min_flt++;
 		break;
 	case VM_FAULT_MAJOR:
-		MARK(kernel_trap_exit, MARK_NOARGS);
 		current->maj_flt++;
 		break;
 	case VM_FAULT_SIGBUS:
-		MARK(kernel_trap_exit, MARK_NOARGS);
 		goto do_sigbus;
 	case VM_FAULT_OOM:
-		MARK(kernel_trap_exit, MARK_NOARGS);
 		goto out_of_memory;
 	default:
 		BUG();
 	}
 
 	up_read(&mm->mmap_sem);
+	MARK(kernel_trap_exit, MARK_NOARGS);
 	return 0;
 
 bad_area:
@@ -398,6 +400,7 @@ out_of_memory:
 		goto survive;
 	}
 	printk("VM: killing process %s\n", current->comm);
+	MARK(kernel_trap_exit, MARK_NOARGS);
 	if (user_mode(regs))
 		do_exit(SIGKILL);
 	return SIGKILL;
@@ -410,8 +413,10 @@ do_sigbus:
 		info.si_code = BUS_ADRERR;
 		info.si_addr = (void __user *)address;
 		force_sig_info(SIGBUS, &info, current);
+		MARK(kernel_trap_exit, MARK_NOARGS);
 		return 0;
 	}
+	MARK(kernel_trap_exit, MARK_NOARGS);
 	return SIGBUS;
 }