diff options
author | Markus Metzger <markus.t.metzger@intel.com> | 2018-01-19 13:56:32 +0100 |
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committer | Markus Metzger <markus.t.metzger@intel.com> | 2018-02-09 14:03:20 +0100 |
commit | 17ad2a4f466f22b7a75b5ebf8a68446bb328c40c (patch) | |
tree | 7b11b712b8dc20cd7ed532bd6a6abc58ae881241 | |
parent | de6242d3075700ec4b73bdee583dc216f3a0b046 (diff) | |
download | gdb-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/ChangeLog | 9 | ||||
-rw-r--r-- | gdb/nat/linux-btrace.c | 69 |
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. */ |