Eric Lee / linux-smarc-t335x-v3.2

Download as
Browse Code ยป

Commit 1ccd15497869f3ed83b5225d410df53a96e52757

Authored by Peter Zijlstra
Committed by Ingo Molnar
1 parent 9ee318a782
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

perf_counter: sysctl for system wide perf counters 

Impact: add sysctl for paranoid/relaxed perfcounters policy

Allow the use of system wide perf counters to everybody, but provide
a sysctl to disable it for the paranoid security minded.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090409085524.514046352@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 3 changed files with 16 additions and 1 deletions Side-by-side Diff

include/linux/perf_counter.h
Diff comments   View file @ 1ccd154
... ... @@ -568,6 +568,8 @@
568 568  
569 569 extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
570 570  
  571 +extern int sysctl_perf_counter_priv;
  572 +
571 573 #else
572 574 static inline void
573 575 perf_counter_task_sched_in(struct task_struct *task, int cpu) { }
kernel/perf_counter.c
Diff comments   View file @ 1ccd154
... ... @@ -42,6 +42,8 @@
42 42 static atomic_t nr_munmap_tracking __read_mostly;
43 43 static atomic_t nr_comm_tracking __read_mostly;
44 44  
  45 +int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
  46 +
45 47 /*
46 48 * Mutex for (sysadmin-configurable) counter reservations:
47 49 */
... ... @@ -1132,7 +1134,7 @@
1132 1134 */
1133 1135 if (cpu != -1) {
1134 1136 /* Must be root to operate on a CPU counter: */
1135   - if (!capable(CAP_SYS_ADMIN))
  1137 + if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))
1136 1138 return ERR_PTR(-EACCES);
1137 1139  
1138 1140 if (cpu < 0 || cpu > num_possible_cpus())
... ... @@ -49,6 +49,7 @@
49 49 #include <linux/reboot.h>
50 50 #include <linux/ftrace.h>
51 51 #include <linux/slow-work.h>
  52 +#include <linux/perf_counter.h>
52 53  
53 54 #include <asm/uaccess.h>
54 55 #include <asm/processor.h>
... ... @@ -918,6 +919,16 @@
918 919 .procname = "slow-work",
919 920 .mode = 0555,
920 921 .child = slow_work_sysctls,
  922 + },
  923 +#endif
  924 +#ifdef CONFIG_PERF_COUNTERS
  925 + {
  926 + .ctl_name = CTL_UNNUMBERED,
  927 + .procname = "perf_counter_privileged",
  928 + .data = &sysctl_perf_counter_priv,
  929 + .maxlen = sizeof(sysctl_perf_counter_priv),
  930 + .mode = 0644,
  931 + .proc_handler = &proc_dointvec,
921 932 },
922 933 #endif
923 934 /*