Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-block.git] / arch / x86 / mm / fault.c

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 0cdf14cf3270c97010e0fd97b003f6a59e064abf..b836a7274e123af88edd7b4f261da88609778be9 100644 (file)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1258,10 +1258,6 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
- *
- * This function must have noinline because both callers
- * {,trace_}do_page_fault() have notrace on. Having this an actual function
- * guarantees there's a function trace entry.
  */
 static noinline void
 __do_page_fault(struct pt_regs *regs, unsigned long error_code,
@@ -1494,27 +1490,6 @@ good_area:
 }
 NOKPROBE_SYMBOL(__do_page_fault);
 
-dotraplinkage void notrace
-do_page_fault(struct pt_regs *regs, unsigned long error_code)
-{
-       unsigned long address = read_cr2(); /* Get the faulting address */
-       enum ctx_state prev_state;
-
-       /*
-        * We must have this function tagged with __kprobes, notrace and call
-        * read_cr2() before calling anything else. To avoid calling any kind
-        * of tracing machinery before we've observed the CR2 value.
-        *
-        * exception_{enter,exit}() contain all sorts of tracepoints.
-        */
-
-       prev_state = exception_enter();
-       __do_page_fault(regs, error_code, address);
-       exception_exit(prev_state);
-}
-NOKPROBE_SYMBOL(do_page_fault);
-
-#ifdef CONFIG_TRACING
 static nokprobe_inline void
 trace_page_fault_entries(unsigned long address, struct pt_regs *regs,
                         unsigned long error_code)
@@ -1525,22 +1500,24 @@ trace_page_fault_entries(unsigned long address, struct pt_regs *regs,
                trace_page_fault_kernel(address, regs, error_code);
 }
 
+/*
+ * We must have this function blacklisted from kprobes, tagged with notrace
+ * and call read_cr2() before calling anything else. To avoid calling any
+ * kind of tracing machinery before we've observed the CR2 value.
+ *
+ * exception_{enter,exit}() contains all sorts of tracepoints.
+ */
 dotraplinkage void notrace
-trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
+do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
-       /*
-        * The exception_enter and tracepoint processing could
-        * trigger another page faults (user space callchain
-        * reading) and destroy the original cr2 value, so read
-        * the faulting address now.
-        */
-       unsigned long address = read_cr2();
+       unsigned long address = read_cr2(); /* Get the faulting address */
        enum ctx_state prev_state;
 
        prev_state = exception_enter();
-       trace_page_fault_entries(address, regs, error_code);
+       if (trace_pagefault_enabled())
+               trace_page_fault_entries(address, regs, error_code);
+
        __do_page_fault(regs, error_code, address);
        exception_exit(prev_state);
 }
-NOKPROBE_SYMBOL(trace_do_page_fault);
-#endif /* CONFIG_TRACING */
+NOKPROBE_SYMBOL(do_page_fault);