FAILED: patch "[PATCH] perf intel-pt: Fix last_ip usage" failed to apply to 4.4-stable tree

From ee14ac0ef6827cd6f9a572cc83dd0191ea17812c Mon Sep 17 00:00:00 2001

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

Quoted 1 line

From ee14ac0ef6827cd6f9a572cc83dd0191ea17812c Mon Sep 17 00:00:00 2001

From: Adrian Hunter <[email protected]>
Date: Fri, 26 May 2017 11:17:06 +0300
Subject: [PATCH] perf intel-pt: Fix last_ip usage

Intel PT uses IP compression based on the last IP. For decoding purposes, 'last IP' is considered to be reset to zero whenever there is a synchronization packet (PSB). The decoder wasn't doing that, and was treating the zero value to mean that there was no last IP, whereas compression can be done against the zero value. Fix by setting last_ip to zero when a PSB is received and keep track of have_last_ip.

Signed-off-by Adrian Hunter <[email protected]>

Cc Andi Kleen <[email protected]>

Cc [email protected]

Link http://lkml.kernel.org/r/[email protected] open here

Signed-off-by Arnaldo Carvalho de Melo <[email protected]>

tools/perf/util/intel-pt-decoder/intel-pt-decoder.c +11 -2

index f9cd3aaef488..62e2c2ad3f1d 100644
@@ -111,6 +111,7 @@ struct intel_pt_decoder {
 	bool have_tma;
 	bool have_cyc;
 	bool fixup_last_mtc;
+	bool have_last_ip;
 	uint64_t pos;
 	uint64_t last_ip;
 	uint64_t ip;

@@ -419,6 +420,7 @@ static uint64_t intel_pt_calc_ip(const struct intel_pt_pkt *packet,
 static inline void intel_pt_set_last_ip(struct intel_pt_decoder *decoder)
 {
 	decoder->last_ip = intel_pt_calc_ip(&decoder->packet, decoder->last_ip);
+	decoder->have_last_ip = true;
 }
 
 static inline void intel_pt_set_ip(struct intel_pt_decoder *decoder)

@@ -1672,6 +1674,8 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
 			break;
 
 		case INTEL_PT_PSB:
+			decoder->last_ip = 0;
+			decoder->have_last_ip = true;
 			intel_pt_clear_stack(&decoder->stack);
 			err = intel_pt_walk_psbend(decoder);
 			if (err == -EAGAIN)

@@ -1752,7 +1756,7 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
 
 static inline bool intel_pt_have_ip(struct intel_pt_decoder *decoder)
 {
-	return decoder->last_ip || decoder->packet.count == 0 ||
+	return decoder->have_last_ip || decoder->packet.count == 0 ||
 	       decoder->packet.count == 3 || decoder->packet.count == 6;
 }
 

@@ -1882,7 +1886,7 @@ static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)
 				if (decoder->ip)
 					return 0;
 			}
-			if (decoder->packet.count)
+			if (decoder->packet.count && decoder->have_last_ip)
 				intel_pt_set_last_ip(decoder);
 			break;
 

@@ -1932,6 +1936,8 @@ static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)
 			break;
 
 		case INTEL_PT_PSB:
+			decoder->last_ip = 0;
+			decoder->have_last_ip = true;
 			intel_pt_clear_stack(&decoder->stack);
 			err = intel_pt_walk_psb(decoder);
 			if (err)

@@ -2066,6 +2072,7 @@ static int intel_pt_sync(struct intel_pt_decoder *decoder)
 
 	decoder->pge = false;
 	decoder->continuous_period = false;
+	decoder->have_last_ip = false;
 	decoder->last_ip = 0;
 	decoder->ip = 0;
 	intel_pt_clear_stack(&decoder->stack);

@@ -2074,6 +2081,7 @@ static int intel_pt_sync(struct intel_pt_decoder *decoder)
 	if (err)
 		return err;
 
+	decoder->have_last_ip = true;
 	decoder->pkt_state = INTEL_PT_STATE_NO_IP;
 
 	err = intel_pt_walk_psb(decoder);

@@ -2116,6 +2124,7 @@ const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
 			err = intel_pt_sync(decoder);
 			break;
 		case INTEL_PT_STATE_NO_IP:
+			decoder->have_last_ip = false;
 			decoder->last_ip = 0;
 			decoder->ip = 0;
 			/* Fall through */

It seems to be dependent on:

	commit e1717e0485af4f47fc4da1e979ac817f9ad61b0f
	Author: Adrian Hunter <[email protected]>
	Date:   Wed Jul 20 12:00:06 2016 +0300

	    perf intel-pt: Fix ip compression

Please take that and then this and the other 2 failures:
perf intel-pt: Use FUP always when scanning for an IP perf intel-pt: Ensure never to set 'last_ip' when packet
should also apply.