[PATCH] bpf/samples: Fix PT_REGS_IP on s390x and use it

[PATCH] bpf/samples: Fix PT_REGS_IP on s390x and use it

[Michael Holzheu]

The files "sampleip_kern.c" and "trace_event_kern.c" directly access
"ctx->regs.ip" which is not available on s390x. Fix this and use the
PT_REGS_IP() macro instead.

Besides of that also fix the macro for s390x and use psw.addr from pt_regs.

Reported-by: Zvonko Kosic <zvonko.kosic@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
---
 samples/bpf/bpf_helpers.h      | 2 +-
 samples/bpf/sampleip_kern.c    | 2 +-
 samples/bpf/trace_event_kern.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h
index 90f44bd..dadd516 100644
--- a/samples/bpf/bpf_helpers.h
+++ b/samples/bpf/bpf_helpers.h
@@ -113,7 +113,7 @@ static int (*bpf_skb_under_cgroup)(void *ctx, void *map, int index) =
 #define PT_REGS_FP(x) ((x)->gprs[11]) /* Works only with CONFIG_FRAME_POINTER */
 #define PT_REGS_RC(x) ((x)->gprs[2])
 #define PT_REGS_SP(x) ((x)->gprs[15])
-#define PT_REGS_IP(x) ((x)->ip)
+#define PT_REGS_IP(x) ((x)->psw.addr)
 
 #elif defined(__aarch64__)
 
diff --git a/samples/bpf/sampleip_kern.c b/samples/bpf/sampleip_kern.c
index 774a681..ceabf31 100644
--- a/samples/bpf/sampleip_kern.c
+++ b/samples/bpf/sampleip_kern.c
@@ -25,7 +25,7 @@ int do_sample(struct bpf_perf_event_data *ctx)
 	u64 ip;
 	u32 *value, init_val = 1;
 
-	ip = ctx->regs.ip;
+	ip = PT_REGS_IP(&ctx->regs);
 	value = bpf_map_lookup_elem(&ip_map, &ip);
 	if (value)
 		*value += 1;
diff --git a/samples/bpf/trace_event_kern.c b/samples/bpf/trace_event_kern.c
index 71a8ed3..41b6115 100644
--- a/samples/bpf/trace_event_kern.c
+++ b/samples/bpf/trace_event_kern.c
@@ -50,7 +50,7 @@ int bpf_prog1(struct bpf_perf_event_data *ctx)
 	key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS);
 	if ((int)key.kernstack < 0 && (int)key.userstack < 0) {
 		bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period,
-				 ctx->regs.ip);
+				 PT_REGS_IP(&ctx->regs));
 		return 0;
 	}
 
-- 
2.8.4

Re: [PATCH] bpf/samples: Fix PT_REGS_IP on s390x and use it

[Alexei Starovoitov]

On Wed, Nov 23, 2016 at 04:28:39PM +0100, Michael Holzheu wrote:
> The files "sampleip_kern.c" and "trace_event_kern.c" directly access
> "ctx->regs.ip" which is not available on s390x. Fix this and use the
> PT_REGS_IP() macro instead.
> 
> Besides of that also fix the macro for s390x and use psw.addr from pt_regs.
> 
> Reported-by: Zvonko Kosic <zvonko.kosic@de.ibm.com>
> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>

Looks good.
Acked-by: Alexei Starovoitov <ast@kernel.org>

Please resubmit it to net-next and cc Dave.

note that my @plumgrid email no longer vaid.