2 files changed, 43 insertions, 6 deletions

diff --git a/init/Kconfig b/init/Kconfig
index f068071fcc5d..5a3ad5c20e2b 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -869,6 +869,36 @@ config AIO
           by some high performance threaded applications. Disabling
           this option saves about 7k.
 
+config HAVE_PERF_COUNTERS
+        bool
+
+menu "Performance Counters"
+
+config PERF_COUNTERS
+        bool "Kernel Performance Counters"
+        depends on HAVE_PERF_COUNTERS
+        default y
+        select ANON_INODES
+        help
+          Enable kernel support for performance counter hardware.
+
+          Performance counters are special hardware registers available
+          on most modern CPUs. These registers count the number of certain
+          types of hw events: such as instructions executed, cachemisses
+          suffered, or branches mis-predicted - without slowing down the
+          kernel or applications. These registers can also trigger interrupts
+          when a threshold number of events have passed - and can thus be
+          used to profile the code that runs on that CPU.
+
+          The Linux Performance Counter subsystem provides an abstraction of
+          these hardware capabilities, available via a system call. It
+          provides per task and per CPU counters, and it provides event
+          capabilities on top of those.
+
+          Say Y if unsure.
+
+endmenu
+
 config VM_EVENT_COUNTERS
         default y
         bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
diff --git a/init/main.c b/init/main.c
index 83697e160b3a..6bf83afd654d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -14,6 +14,7 @@
 #include <linux/proc_fs.h>
 #include <linux/kernel.h>
 #include <linux/syscalls.h>
+#include <linux/stackprotector.h>
 #include <linux/string.h>
 #include <linux/ctype.h>
 #include <linux/delay.h>
@@ -135,14 +136,14 @@ unsigned int __initdata setup_max_cpus = NR_CPUS;
  * greater than 0, limits the maximum number of CPUs activated in
  * SMP mode to <NUM>.
  */
-#ifndef CONFIG_X86_IO_APIC
-static inline void disable_ioapic_setup(void) {};
-#endif
+
+void __weak arch_disable_smp_support(void) { }
 
 static int __init nosmp(char *str)
 {
         setup_max_cpus = 0;
-        disable_ioapic_setup();
+        arch_disable_smp_support();
+
         return 0;
 }
 
@@ -152,14 +153,14 @@ static int __init maxcpus(char *str)
 {
         get_option(&str, &setup_max_cpus);
         if (setup_max_cpus == 0)
-                disable_ioapic_setup();
+                arch_disable_smp_support();
 
         return 0;
 }
 
 early_param("maxcpus", maxcpus);
 #else
-#define setup_max_cpus NR_CPUS
+const unsigned int setup_max_cpus = NR_CPUS;
 #endif
 
 /*
@@ -540,6 +541,12 @@ asmlinkage void __init start_kernel(void)
          */
         lockdep_init();
         debug_objects_early_init();
+
+        /*
+         * Set up the the initial canary ASAP:
+         */
+        boot_init_stack_canary();
+
         cgroup_init_early();
 
         local_irq_disable();