Which is the case in S/390, where symbols were not being resolved
because machine__get_kernel_start was only setting machine->kernel_start
when the just successfully loaded kernel symtab had its map->start set
to !0, when it was left at (1ULL << 63) assuming a partitioning of the
address space for user/kernel, which is not the case in S/390 nor in
Sparc.
So just check if map__load() was successfull and set
machine->kernel_start to zero, fixing kernel symbol resolution on S/390.
Test performed by Thomas:
----
I like this patch. I have done a new build and removed all my debug output to start
from scratch. Without your patch I get this:
# Samples: 4 of event 'cpu-clock'
# Event count (approx.): 1000000
#
# Children Self Command Shared Object Symbol
# ........ ........ ....... ................ ........................
75.00% 0.00% true [unknown] [k] 0x00000000004bedda
|
---0x4bedda
|
|--50.00%--0x42693a
| |
| --25.00%--0x2a72e0
| 0x2af0ca
| 0x3d1003fe4c0
|
--25.00%--0x4272bc
0x26fa84
and with your patch (I just rebuilt the perf tool, nothing else and used the same
perf.data file as input):
# Samples: 4 of event 'cpu-clock'
# Event count (approx.): 1000000
#
# Children Self Command Shared Object Symbol
# ........ ........ ....... .......................... ..................................
75.00% 0.00% true [kernel.vmlinux] [k] pgm_check_handler
|
---pgm_check_handler
do_dat_exception
handle_mm_fault
__handle_mm_fault
filemap_map_pages
|
|--25.00%--rcu_read_lock_held
| rcu_lockdep_current_cpu_online
| 0x3d1003ff4c0
|
--25.00%--lock_release
Looks good to me....
----
Reported-and-Tested-by: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zvonko Kosic <zvonko.kosic@de.ibm.com>
Link: http://lkml.kernel.org/n/tip-dk0n1uzmbe0tbthrpfqlx6bz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
4b1303d0b0