aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMarkus Metzger <markus.t.metzger@intel.com>2018-01-19 13:56:32 +0100
committerMarkus Metzger <markus.t.metzger@intel.com>2018-02-09 14:03:20 +0100
commit17ad2a4f466f22b7a75b5ebf8a68446bb328c40c (patch)
tree7b11b712b8dc20cd7ed532bd6a6abc58ae881241
parentde6242d3075700ec4b73bdee583dc216f3a0b046 (diff)
downloadgdb-17ad2a4f466f22b7a75b5ebf8a68446bb328c40c.zip
gdb-17ad2a4f466f22b7a75b5ebf8a68446bb328c40c.tar.gz
gdb-17ad2a4f466f22b7a75b5ebf8a68446bb328c40c.tar.bz2
btrace: improve enable error messages
Improve the error message when GDB fails to start recording branch trace. This patch also removes a zero buffer size check for PT to align with BTS. The buffer size can not be configured to be zero. gdb/ * nat/linux-btrace.c (perf_event_pt_event_type): Improve error message. Remove parameter and change return type. Update callers. Move it. (linux_enable_bts, linux_enable_pt): Improve error message. (linux_enable_pt): Remove zero buffer size check. (linux_enable_btrace): Improve error messages. Remove NULL return check.
-rw-r--r--gdb/ChangeLog9
-rw-r--r--gdb/nat/linux-btrace.c69
2 files changed, 38 insertions, 40 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index df0283a..769858b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,14 @@
2018-02-09 Markus Metzger <markus.t.metzger@intel.com>
+ * nat/linux-btrace.c (perf_event_pt_event_type): Improve error message.
+ Remove parameter and change return type. Update callers. Move it.
+ (linux_enable_bts, linux_enable_pt): Improve error message.
+ (linux_enable_pt): Remove zero buffer size check.
+ (linux_enable_btrace): Improve error messages. Remove NULL return
+ check.
+
+2018-02-09 Markus Metzger <markus.t.metzger@intel.com>
+
* btrace.c (btrace_enable): Remove target_supports_btrace call.
* nat/linux-btrace.c (perf_event_pt_event_type): Move.
(kernel_supports_bts, kernel_supports_pt, linux_supports_bts)
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index 42f56f9..301649b 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -448,7 +448,7 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
errno = 0;
scoped_fd fd (syscall (SYS_perf_event_open, &bts->attr, pid, -1, -1, 0));
if (fd.get () < 0)
- return nullptr;
+ error (_("Failed to start recording: %s"), safe_strerror (errno));
/* Convert the requested size in bytes to pages (rounding up). */
pages = ((size_t) conf->size / PAGE_SIZE
@@ -484,6 +484,7 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
if ((__u64) length != data_size + PAGE_SIZE)
continue;
+ errno = 0;
/* The number of pages we request needs to be a power of two. */
data.reset (nullptr, length, PROT_READ, MAP_SHARED, fd.get (), 0);
if (data.get () != MAP_FAILED)
@@ -491,7 +492,7 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
}
if (pages == 0)
- return nullptr;
+ error (_("Failed to map trace buffer: %s."), safe_strerror (errno));
struct perf_event_mmap_page *header = (struct perf_event_mmap_page *)
data.get ();
@@ -509,7 +510,7 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
/* Check for overflows. */
if ((__u64) size != data_size)
- return nullptr;
+ error (_("Failed to determine trace buffer size."));
}
#endif /* defined (PERF_ATTR_SIZE_VER5) */
@@ -528,21 +529,23 @@ linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
#if defined (PERF_ATTR_SIZE_VER5)
-/* Determine the event type.
- Returns zero on success and fills in TYPE; returns -1 otherwise. */
+/* Determine the event type. */
static int
-perf_event_pt_event_type (int *type)
+perf_event_pt_event_type ()
{
- gdb_file_up file =
- gdb_fopen_cloexec ("/sys/bus/event_source/devices/intel_pt/type", "r");
+ static const char filename[] = "/sys/bus/event_source/devices/intel_pt/type";
+
+ errno = 0;
+ gdb_file_up file = gdb_fopen_cloexec (filename, "r");
if (file.get () == nullptr)
- return -1;
+ error (_("Failed to open %s: %s."), filename, safe_strerror (errno));
- int found = fscanf (file.get (), "%d", type);
- if (found == 1)
- return 0;
- return -1;
+ int type, found = fscanf (file.get (), "%d", &type);
+ if (found != 1)
+ error (_("Failed to read the PT event type from %s."), filename);
+
+ return type;
}
/* Enable branch tracing in Intel Processor Trace format. */
@@ -552,14 +555,7 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
{
struct btrace_tinfo_pt *pt;
size_t pages;
- int pid, pg, errcode, type;
-
- if (conf->size == 0)
- return NULL;
-
- errcode = perf_event_pt_event_type (&type);
- if (errcode != 0)
- return NULL;
+ int pid, pg;
pid = ptid_get_lwp (ptid);
if (pid == 0)
@@ -573,7 +569,7 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
pt = &tinfo->variant.pt;
pt->attr.size = sizeof (pt->attr);
- pt->attr.type = type;
+ pt->attr.type = perf_event_pt_event_type ();
pt->attr.exclude_kernel = 1;
pt->attr.exclude_hv = 1;
@@ -582,13 +578,13 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
errno = 0;
scoped_fd fd (syscall (SYS_perf_event_open, &pt->attr, pid, -1, -1, 0));
if (fd.get () < 0)
- return nullptr;
+ error (_("Failed to start recording: %s"), safe_strerror (errno));
/* Allocate the configuration page. */
scoped_mmap data (nullptr, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
fd.get (), 0);
if (data.get () == MAP_FAILED)
- return nullptr;
+ error (_("Failed to map trace user page: %s."), safe_strerror (errno));
struct perf_event_mmap_page *header = (struct perf_event_mmap_page *)
data.get ();
@@ -630,6 +626,7 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
header->aux_size = data_size;
+ errno = 0;
aux.reset (nullptr, length, PROT_READ, MAP_SHARED, fd.get (),
header->aux_offset);
if (aux.get () != MAP_FAILED)
@@ -637,7 +634,7 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
}
if (pages == 0)
- return nullptr;
+ error (_("Failed to map trace buffer: %s."), safe_strerror (errno));
pt->pt.size = aux.size ();
pt->pt.mem = (const uint8_t *) aux.release ();
@@ -656,8 +653,7 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
static struct btrace_target_info *
linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
{
- errno = EOPNOTSUPP;
- return NULL;
+ error (_("Intel Processor Trace support was disabled at compile time."));
}
#endif /* !defined (PERF_ATTR_SIZE_VER5) */
@@ -667,27 +663,20 @@ linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
struct btrace_target_info *
linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
{
- struct btrace_target_info *tinfo;
-
- tinfo = NULL;
switch (conf->format)
{
case BTRACE_FORMAT_NONE:
- break;
+ error (_("Bad branch trace format."));
+
+ default:
+ error (_("Unknown branch trace format."));
case BTRACE_FORMAT_BTS:
- tinfo = linux_enable_bts (ptid, &conf->bts);
- break;
+ return linux_enable_bts (ptid, &conf->bts);
case BTRACE_FORMAT_PT:
- tinfo = linux_enable_pt (ptid, &conf->pt);
- break;
+ return linux_enable_pt (ptid, &conf->pt);
}
-
- if (tinfo == NULL)
- error (_("Unknown error."));
-
- return tinfo;
}
/* Disable BTS tracing. */