From: "David S. Miller" davem@davemloft.net

When processing using 'perf report -g caller', which is the default, we ended up reverting the callchain entries received from the kernel, but simply reverting throws away the information that tells that from a point onwards the addresses are for userspace, kernel, guest kernel, guest user, hypervisor.

The idea is that if we are walking backwards, for each cluster of non-cpumode entries we have to first scan backwards for the next one and use that for the cluster.

This seems silly and more expensive than it needs to be but it is enough for a initial fix.

The code here is really complicated because it is intimately intertwined with the lbr and branch handling, as well as this callchain order, further fixes will be needed to properly take into account the cpumode in those cases.

Another problem with ORDER_CALLER is that the NULL "0" IP that is at the end of most callchains shows up at the top of the histogram because every callchain contains it and with ORDER_CALLER it is the first entry.

Signed-off-by: David S. Miller davem@davemloft.net Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Adrian Hunter adrian.hunter@intel.com Cc: David Ahern dsahern@gmail.com Cc: Jiri Olsa jolsa@kernel.org Cc: Namhyung Kim namhyung@kernel.org Cc: Souvik Banerjee souvik1997@gmail.com Cc: Wang Nan wangnan0@huawei.com Cc: stable@vger.kernel.org # 4.19 Link: https://lkml.kernel.org/n/tip-2wt3ayp6j2y2f2xowixa8y6y@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com --- tools/perf/util/machine.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 111ae858cbcb..8ee8ab39d8ac 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -2140,6 +2140,27 @@ static int resolve_lbr_callchain_sample(struct thread *thread, return 0; }

+static int find_prev_cpumode(struct ip_callchain *chain, struct thread *thread, + struct callchain_cursor *cursor, + struct symbol **parent, + struct addr_location *root_al, + u8 *cpumode, int ent) +{ + int err = 0; + + while (--ent >= 0) { + u64 ip = chain->ips[ent]; + + if (ip >= PERF_CONTEXT_MAX) { + err = add_callchain_ip(thread, cursor, parent, + root_al, cpumode, ip, + false, NULL, NULL, 0); + break; + } + } + return err; +} + static int thread__resolve_callchain_sample(struct thread *thread, struct callchain_cursor *cursor, struct perf_evsel *evsel, @@ -2246,6 +2267,12 @@ static int thread__resolve_callchain_sample(struct thread *thread, }

check_calls: + if (callchain_param.order != ORDER_CALLEE) { + err = find_prev_cpumode(chain, thread, cursor, parent, root_al, + &cpumode, chain->nr - first_call); + if (err) + return (err < 0) ? err : 0; + } for (i = first_call, nr_entries = 0; i < chain_nr && nr_entries < max_stack; i++) { u64 ip; @@ -2260,9 +2287,15 @@ static int thread__resolve_callchain_sample(struct thread *thread, continue; #endif ip = chain->ips[j]; - if (ip < PERF_CONTEXT_MAX) ++nr_entries; + else if (callchain_param.order != ORDER_CALLEE) { + err = find_prev_cpumode(chain, thread, cursor, parent, + root_al, &cpumode, j); + if (err) + return (err < 0) ? err : 0; + continue; + }

err = add_callchain_ip(thread, cursor, parent, root_al, &cpumode, ip,