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#ifndef RND_H
#define RND_H

#define HIG_ENTROPY_SOURCE	"/dev/random"
#define LOW_ENTROPY_SOURCE	"/dev/urandom"

/* secrand is not really secure, but the name only suggests it's better to use
 * than rand(3) when transferring bytes over the network in non-security
 * critical structure members. secrand() is only used to fill up salts actually.
 */
extern int secrand(void);
extern void gen_key_bytes(unsigned char *area, size_t len);

#endif /* RND_H */
Bangoria <ravi.bangoria@linux.vnet.ibm.com>2016-08-09 01:23:25 -0500 committerArnaldo Carvalho de Melo <acme@redhat.com>2016-08-09 12:14:29 -0300 commit99e608b5954c9e1ebadbf9660b74697d9dfd9f20 (patch) treed3e90cf32de461417ca4a962094bff0daa717b43 parentd820456dc70b231d62171ba46b43db0045e9bd57 (diff)
perf probe ppc64le: Fix probe location when using DWARF
Powerpc has Global Entry Point and Local Entry Point for functions. LEP catches call from both the GEP and the LEP. Symbol table of ELF contains GEP and Offset from which we can calculate LEP, but debuginfo does not have LEP info. Currently, perf prioritize symbol table over dwarf to probe on LEP for ppc64le. But when user tries to probe with function parameter, we fall back to using dwarf(i.e. GEP) and when function called via LEP, probe will never hit. For example: $ objdump -d vmlinux ... do_sys_open(): c0000000002eb4a0: e8 00 4c 3c addis r2,r12,232 c0000000002eb4a4: 60 00 42 38 addi r2,r2,96 c0000000002eb4a8: a6 02 08 7c mflr r0 c0000000002eb4ac: d0 ff 41 fb std r26,-48(r1) $ sudo ./perf probe do_sys_open $ sudo cat /sys/kernel/debug/tracing/kprobe_events p:probe/do_sys_open _text+3060904 $ sudo ./perf probe 'do_sys_open filename:string' $ sudo cat /sys/kernel/debug/tracing/kprobe_events p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string For second case, perf probed on GEP. So when function will be called via LEP, probe won't hit. $ sudo ./perf record -a -e probe:do_sys_open ls [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.195 MB perf.data ] To resolve this issue, let's not prioritize symbol table, let perf decide what it wants to use. Perf is already converting GEP to LEP when it uses symbol table. When perf uses debuginfo, let it find LEP offset form symbol table. This way we fall back to probe on LEP for all cases. After patch: $ sudo ./perf probe 'do_sys_open filename:string' $ sudo cat /sys/kernel/debug/tracing/kprobe_events p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string $ sudo ./perf record -a -e probe:do_sys_open ls [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.197 MB perf.data (11 samples) ] Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/r/1470723805-5081-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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