[PATCH 01/11] perf intel-pt: Fix ip compression

Arnaldo Carvalho de Melo
2016-08-15T22:00:48Z

From: Adrian Hunter <adrian.hunter@intel.com>

The June 2015 Intel SDM introduced IP Compression types 4 and 6. Refer
to section 36.4.2.2 Target IP (TIP) Packet - IP Compression.

Existing Intel PT packet decoder did not support type 4, and got type 6
wrong. Because type 3 and type 4 have the same number of bytes, the
packet 'count' has been changed from being the number of ip bytes to
being the type code. That allows the Intel PT decoder to correctly
decide whether to sign-extend or use the last ip. However that also
meant the code had to be adjusted in a number of places.

Currently hardware is not using the new compression types, so this fix
has no effect on existing hardware.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1469005206-3049-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
.../perf/util/intel-pt-decoder/intel-pt-decoder.c | 44 +++++++++++-----------
.../util/intel-pt-decoder/intel-pt-pkt-decoder.c | 24 ++++++++----
2 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 9c8f15da86ce..8ff6c6a61291 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -123,8 +123,6 @@ struct intel_pt_decoder {
bool have_calc_cyc_to_tsc;
int exec_mode;
unsigned int insn_bytes;
- uint64_t sign_bit;
- uint64_t sign_bits;
uint64_t period;
enum intel_pt_period_type period_type;
uint64_t tot_insn_cnt;
@@ -191,9 +189,6 @@ struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
decoder->data = params->data;
decoder->return_compression = params->return_compression;

- decoder->sign_bit = (uint64_t)1 << 47;
- decoder->sign_bits = ~(((uint64_t)1 << 48) - 1);
-
decoder->period = params->period;
decoder->period_type = params->period_type;

@@ -362,21 +357,30 @@ int intel_pt__strerror(int code, char *buf, size_t buflen)
return 0;
}

-static uint64_t intel_pt_calc_ip(struct intel_pt_decoder *decoder,
- const struct intel_pt_pkt *packet,
+static uint64_t intel_pt_calc_ip(const struct intel_pt_pkt *packet,
uint64_t last_ip)
{
uint64_t ip;

switch (packet->count) {
- case 2:
+ case 1:
ip = (last_ip & (uint64_t)0xffffffffffff0000ULL) |
packet->payload;
break;
- case 4:
+ case 2:
ip = (last_ip & (uint64_t)0xffffffff00000000ULL) |
packet->payload;
break;
+ case 3:
+ ip = packet->payload;
+ /* Sign-extend 6-byte ip */
+ if (ip & (uint64_t)0x800000000000ULL)
+ ip |= (uint64_t)0xffff000000000000ULL;
+ break;
+ case 4:
+ ip = (last_ip & (uint64_t)0xffff000000000000ULL) |
+ packet->payload;
+ break;
case 6:
ip = packet->payload;
break;
@@ -384,16 +388,12 @@ static uint64_t intel_pt_calc_ip(struct intel_pt_decoder *decoder,
return 0;
}

- if (ip & decoder->sign_bit)
- return ip | decoder->sign_bits;
-
return ip;
}

static inline void intel_pt_set_last_ip(struct intel_pt_decoder *decoder)
{
- decoder->last_ip = intel_pt_calc_ip(decoder, &decoder->packet,
- decoder->last_ip);
+ decoder->last_ip = intel_pt_calc_ip(&decoder->packet, decoder->last_ip);
}

static inline void intel_pt_set_ip(struct intel_pt_decoder *decoder)
@@ -1657,6 +1657,12 @@ next:
}
}

+static inline bool intel_pt_have_ip(struct intel_pt_decoder *decoder)
+{
+ return decoder->last_ip || decoder->packet.count == 0 ||
+ decoder->packet.count == 3 || decoder->packet.count == 6;
+}
+
/* Walk PSB+ packets to get in sync. */
static int intel_pt_walk_psb(struct intel_pt_decoder *decoder)
{
@@ -1677,8 +1683,7 @@ static int intel_pt_walk_psb(struct intel_pt_decoder *decoder)

case INTEL_PT_FUP:
decoder->pge = true;
- if (decoder->last_ip || decoder->packet.count == 6 ||
- decoder->packet.count == 0) {
+ if (intel_pt_have_ip(decoder)) {
uint64_t current_ip = decoder->ip;

intel_pt_set_ip(decoder);
@@ -1767,8 +1772,7 @@ static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)
case INTEL_PT_TIP_PGE:
case INTEL_PT_TIP:
decoder->pge = decoder->packet.type != INTEL_PT_TIP_PGD;
- if (decoder->last_ip || decoder->packet.count == 6 ||
- decoder->packet.count == 0)
+ if (intel_pt_have_ip(decoder))
intel_pt_set_ip(decoder);
if (decoder->ip)
return 0;
@@ -1776,9 +1780,7 @@ static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)

case INTEL_PT_FUP:
if (decoder->overflow) {
- if (decoder->last_ip ||
- decoder->packet.count == 6 ||
- decoder->packet.count == 0)
+ if (intel_pt_have_ip(decoder))
intel_pt_set_ip(decoder);
if (decoder->ip)
return 0;
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.c
index b1257c816310..4f7b32020487 100644
--- a/tools/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.c
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.c
@@ -292,36 +292,46 @@ static int intel_pt_get_ip(enum intel_pt_pkt_type type, unsigned int byte,
const unsigned char *buf, size_t len,
struct intel_pt_pkt *packet)
{
- switch (byte >> 5) {
+ int ip_len;
+
+ packet->count = byte >> 5;
+
+ switch (packet->count) {
case 0:
- packet->count = 0;
+ ip_len = 0;
break;
case 1:
if (len < 3)
return INTEL_PT_NEED_MORE_BYTES;
- packet->count = 2;
+ ip_len = 2;
packet->payload = le16_to_cpu(*(uint16_t *)(buf + 1));
break;
case 2:
if (len < 5)
return INTEL_PT_NEED_MORE_BYTES;
- packet->count = 4;
+ ip_len = 4;
packet->payload = le32_to_cpu(*(uint32_t *)(buf + 1));
break;
case 3:
- case 6:
+ case 4:
if (len < 7)
return INTEL_PT_NEED_MORE_BYTES;
- packet->count = 6;
+ ip_len = 6;
memcpy_le64(&packet->payload, buf + 1, 6);
break;
+ case 6:
+ if (len < 9)
+ return INTEL_PT_NEED_MORE_BYTES;
+ ip_len = 8;
+ packet->payload = le64_to_cpu(*(uint64_t *)(buf + 1));
+ break;
default:
return INTEL_PT_BAD_PACKET;
}

packet->type = type;

- return packet->count + 1;
+ return ip_len + 1;
}

static int intel_pt_get_mode(const unsigned char *buf, size_t len,
--
2.7.4