/* Linux-dependent part of branch trace support for GDB, and GDBserver.
- Copyright (C) 2013-2018 Free Software Foundation, Inc.
+ Copyright (C) 2013-2019 Free Software Foundation, Inc.
Contributed by Intel Corp. <markus.t.metzger@intel.com>
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#include "common-defs.h"
+#include "gdbsupport/common-defs.h"
#include "linux-btrace.h"
-#include "common-regcache.h"
-#include "gdb_wait.h"
+#include "gdbsupport/common-regcache.h"
+#include "gdbsupport/gdb_wait.h"
#include "x86-cpuid.h"
-#include "filestuff.h"
+#include "gdbsupport/filestuff.h"
+#include "gdbsupport/scoped_fd.h"
+#include "gdbsupport/scoped_mmap.h"
#include <inttypes.h>
pev->last_head = data_head;
}
-/* Determine the event type.
- Returns zero on success and fills in TYPE; returns -1 otherwise. */
-
-static int
-perf_event_pt_event_type (int *type)
-{
- FILE *file;
- int found;
-
- file = fopen ("/sys/bus/event_source/devices/intel_pt/type", "r");
- if (file == NULL)
- return -1;
-
- found = fscanf (file, "%d", type);
-
- fclose (file);
-
- if (found == 1)
- return 0;
- return -1;
-}
-
/* Try to determine the start address of the Linux kernel. */
static uint64_t
In case the buffer overflows during sampling, one sample may have its lower
part at the end and its upper part at the beginning of the buffer. */
-static VEC (btrace_block_s) *
+static std::vector<btrace_block> *
perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
const uint8_t *end, const uint8_t *start, size_t size)
{
- VEC (btrace_block_s) *btrace = NULL;
+ std::vector<btrace_block> *btrace = new std::vector<btrace_block>;
struct perf_event_sample sample;
size_t read = 0;
struct btrace_block block = { 0, 0 };
/* We found a valid sample, so we can complete the current block. */
block.begin = psample->bts.to;
- VEC_safe_push (btrace_block_s, btrace, &block);
+ btrace->push_back (block);
/* Start the next block. */
block.end = psample->bts.from;
reading delta trace, we can fill in the start address later on.
Otherwise we will prune it. */
block.begin = 0;
- VEC_safe_push (btrace_block_s, btrace, &block);
+ btrace->push_back (block);
return btrace;
}
-/* Check whether the kernel supports BTS. */
-
-static int
-kernel_supports_bts (void)
-{
- struct perf_event_attr attr;
- pid_t child, pid;
- int status, file;
-
- errno = 0;
- child = fork ();
- switch (child)
- {
- case -1:
- warning (_("test bts: cannot fork: %s."), safe_strerror (errno));
- return 0;
-
- case 0:
- status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
- if (status != 0)
- {
- warning (_("test bts: cannot PTRACE_TRACEME: %s."),
- safe_strerror (errno));
- _exit (1);
- }
-
- status = raise (SIGTRAP);
- if (status != 0)
- {
- warning (_("test bts: cannot raise SIGTRAP: %s."),
- safe_strerror (errno));
- _exit (1);
- }
-
- _exit (1);
-
- default:
- pid = waitpid (child, &status, 0);
- if (pid != child)
- {
- warning (_("test bts: bad pid %ld, error: %s."),
- (long) pid, safe_strerror (errno));
- return 0;
- }
-
- if (!WIFSTOPPED (status))
- {
- warning (_("test bts: expected stop. status: %d."),
- status);
- return 0;
- }
-
- memset (&attr, 0, sizeof (attr));
-
- attr.type = PERF_TYPE_HARDWARE;
- attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
- attr.sample_period = 1;
- attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR;
- attr.exclude_kernel = 1;
- attr.exclude_hv = 1;
- attr.exclude_idle = 1;
-
- file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0);
- if (file >= 0)
- close (file);
-
- kill (child, SIGKILL);
- ptrace (PTRACE_KILL, child, NULL, NULL);
-
- pid = waitpid (child, &status, 0);
- if (pid != child)
- {
- warning (_("test bts: bad pid %ld, error: %s."),
- (long) pid, safe_strerror (errno));
- if (!WIFSIGNALED (status))
- warning (_("test bts: expected killed. status: %d."),
- status);
- }
-
- return (file >= 0);
- }
-}
-
-/* Check whether the kernel supports Intel Processor Trace. */
-
-static int
-kernel_supports_pt (void)
-{
- struct perf_event_attr attr;
- pid_t child, pid;
- int status, file, type;
-
- errno = 0;
- child = fork ();
- switch (child)
- {
- case -1:
- warning (_("test pt: cannot fork: %s."), safe_strerror (errno));
- return 0;
-
- case 0:
- status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
- if (status != 0)
- {
- warning (_("test pt: cannot PTRACE_TRACEME: %s."),
- safe_strerror (errno));
- _exit (1);
- }
-
- status = raise (SIGTRAP);
- if (status != 0)
- {
- warning (_("test pt: cannot raise SIGTRAP: %s."),
- safe_strerror (errno));
- _exit (1);
- }
-
- _exit (1);
-
- default:
- pid = waitpid (child, &status, 0);
- if (pid != child)
- {
- warning (_("test pt: bad pid %ld, error: %s."),
- (long) pid, safe_strerror (errno));
- return 0;
- }
-
- if (!WIFSTOPPED (status))
- {
- warning (_("test pt: expected stop. status: %d."),
- status);
- return 0;
- }
-
- status = perf_event_pt_event_type (&type);
- if (status != 0)
- file = -1;
- else
- {
- memset (&attr, 0, sizeof (attr));
-
- attr.size = sizeof (attr);
- attr.type = type;
- attr.exclude_kernel = 1;
- attr.exclude_hv = 1;
- attr.exclude_idle = 1;
-
- file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0);
- if (file >= 0)
- close (file);
- }
-
- kill (child, SIGKILL);
- ptrace (PTRACE_KILL, child, NULL, NULL);
-
- pid = waitpid (child, &status, 0);
- if (pid != child)
- {
- warning (_("test pt: bad pid %ld, error: %s."),
- (long) pid, safe_strerror (errno));
- if (!WIFSIGNALED (status))
- warning (_("test pt: expected killed. status: %d."),
- status);
- }
-
- return (file >= 0);
- }
-}
-
/* Check whether an Intel cpu supports BTS. */
static int
}
}
-/* Check whether the linux target supports BTS. */
-
-static int
-linux_supports_bts (void)
-{
- static int cached;
-
- if (cached == 0)
- {
- if (!kernel_supports_bts ())
- cached = -1;
- else if (!cpu_supports_bts ())
- cached = -1;
- else
- cached = 1;
- }
-
- return cached > 0;
-}
-
-/* Check whether the linux target supports Intel Processor Trace. */
-
-static int
-linux_supports_pt (void)
-{
- static int cached;
-
- if (cached == 0)
- {
- if (!kernel_supports_pt ())
- cached = -1;
- else
- cached = 1;
- }
-
- return cached > 0;
-}
-
-/* See linux-btrace.h. */
+/* The perf_event_open syscall failed. Try to print a helpful error
+ message. */
-int
-linux_supports_btrace (struct target_ops *ops, enum btrace_format format)
+static void
+diagnose_perf_event_open_fail ()
{
- switch (format)
+ switch (errno)
{
- case BTRACE_FORMAT_NONE:
- return 0;
+ case EPERM:
+ case EACCES:
+ {
+ static const char filename[] = "/proc/sys/kernel/perf_event_paranoid";
+ gdb_file_up file = gdb_fopen_cloexec (filename, "r");
+ if (file.get () == nullptr)
+ break;
- case BTRACE_FORMAT_BTS:
- return linux_supports_bts ();
+ int level, found = fscanf (file.get (), "%d", &level);
+ if (found == 1 && level > 2)
+ error (_("You do not have permission to record the process. "
+ "Try setting %s to 2 or less."), filename);
+ }
- case BTRACE_FORMAT_PT:
- return linux_supports_pt ();
+ break;
}
- internal_error (__FILE__, __LINE__, _("Unknown branch trace format"));
+ error (_("Failed to start recording: %s"), safe_strerror (errno));
}
/* Enable branch tracing in BTS format. */
static struct btrace_target_info *
linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
{
- struct perf_event_mmap_page *header;
- struct btrace_target_info *tinfo;
struct btrace_tinfo_bts *bts;
size_t size, pages;
__u64 data_offset;
int pid, pg;
- tinfo = XCNEW (struct btrace_target_info);
+ if (!cpu_supports_bts ())
+ error (_("BTS support has been disabled for the target cpu."));
+
+ gdb::unique_xmalloc_ptr<btrace_target_info> tinfo
+ (XCNEW (btrace_target_info));
tinfo->ptid = ptid;
tinfo->conf.format = BTRACE_FORMAT_BTS;
bts->attr.exclude_hv = 1;
bts->attr.exclude_idle = 1;
- pid = ptid_get_lwp (ptid);
+ pid = ptid.lwp ();
if (pid == 0)
- pid = ptid_get_pid (ptid);
+ pid = ptid.pid ();
errno = 0;
- bts->file = syscall (SYS_perf_event_open, &bts->attr, pid, -1, -1, 0);
- if (bts->file < 0)
- goto err_out;
+ scoped_fd fd (syscall (SYS_perf_event_open, &bts->attr, pid, -1, -1, 0));
+ if (fd.get () < 0)
+ diagnose_perf_event_open_fail ();
/* Convert the requested size in bytes to pages (rounding up). */
pages = ((size_t) conf->size / PAGE_SIZE
/* We try to allocate the requested size.
If that fails, try to get as much as we can. */
+ scoped_mmap data;
for (; pages > 0; pages >>= 1)
{
size_t length;
if ((__u64) length != data_size + PAGE_SIZE)
continue;
+ errno = 0;
/* The number of pages we request needs to be a power of two. */
- header = ((struct perf_event_mmap_page *)
- mmap (NULL, length, PROT_READ, MAP_SHARED, bts->file, 0));
- if (header != MAP_FAILED)
+ data.reset (nullptr, length, PROT_READ, MAP_SHARED, fd.get (), 0);
+ if (data.get () != MAP_FAILED)
break;
}
if (pages == 0)
- goto err_file;
+ error (_("Failed to map trace buffer: %s."), safe_strerror (errno));
+ struct perf_event_mmap_page *header = (struct perf_event_mmap_page *)
+ data.get ();
data_offset = PAGE_SIZE;
#if defined (PERF_ATTR_SIZE_VER5)
/* Check for overflows. */
if ((__u64) size != data_size)
- {
- munmap ((void *) header, size + PAGE_SIZE);
- goto err_file;
- }
+ error (_("Failed to determine trace buffer size."));
}
#endif /* defined (PERF_ATTR_SIZE_VER5) */
- bts->header = header;
- bts->bts.mem = ((const uint8_t *) header) + data_offset;
bts->bts.size = size;
bts->bts.data_head = &header->data_head;
+ bts->bts.mem = (const uint8_t *) data.release () + data_offset;
bts->bts.last_head = 0ull;
+ bts->header = header;
+ bts->file = fd.release ();
tinfo->conf.bts.size = (unsigned int) size;
- return tinfo;
-
- err_file:
- /* We were not able to allocate any buffer. */
- close (bts->file);
-
- err_out:
- xfree (tinfo);
- return NULL;
+ return tinfo.release ();
}
#if defined (PERF_ATTR_SIZE_VER5)
+/* Determine the event type. */
+
+static int
+perf_event_pt_event_type ()
+{
+ 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)
+ error (_("Failed to open %s: %s."), filename, safe_strerror (errno));
+
+ 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. */
static struct btrace_target_info *
linux_enable_pt (ptid_t ptid, const struct btrace_config_pt *conf)
{
- struct perf_event_mmap_page *header;
- struct btrace_target_info *tinfo;
struct btrace_tinfo_pt *pt;
- size_t pages, size;
- int pid, pg, errcode, type;
-
- if (conf->size == 0)
- return NULL;
-
- errcode = perf_event_pt_event_type (&type);
- if (errcode != 0)
- return NULL;
+ size_t pages;
+ int pid, pg;
- pid = ptid_get_lwp (ptid);
+ pid = ptid.lwp ();
if (pid == 0)
- pid = ptid_get_pid (ptid);
+ pid = ptid.pid ();
- tinfo = XCNEW (struct btrace_target_info);
+ gdb::unique_xmalloc_ptr<btrace_target_info> tinfo
+ (XCNEW (btrace_target_info));
tinfo->ptid = ptid;
tinfo->conf.format = BTRACE_FORMAT_PT;
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;
pt->attr.exclude_idle = 1;
errno = 0;
- pt->file = syscall (SYS_perf_event_open, &pt->attr, pid, -1, -1, 0);
- if (pt->file < 0)
- goto err;
+ scoped_fd fd (syscall (SYS_perf_event_open, &pt->attr, pid, -1, -1, 0));
+ if (fd.get () < 0)
+ diagnose_perf_event_open_fail ();
/* Allocate the configuration page. */
- header = ((struct perf_event_mmap_page *)
- mmap (NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
- pt->file, 0));
- if (header == MAP_FAILED)
- goto err_file;
+ scoped_mmap data (nullptr, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
+ fd.get (), 0);
+ if (data.get () == MAP_FAILED)
+ error (_("Failed to map trace user page: %s."), safe_strerror (errno));
+
+ struct perf_event_mmap_page *header = (struct perf_event_mmap_page *)
+ data.get ();
header->aux_offset = header->data_offset + header->data_size;
/* We try to allocate the requested size.
If that fails, try to get as much as we can. */
+ scoped_mmap aux;
for (; pages > 0; pages >>= 1)
{
size_t length;
if ((__u64) UINT_MAX < data_size)
continue;
- size = (size_t) data_size;
+ length = (size_t) data_size;
/* Check for overflows. */
- if ((__u64) size != data_size)
+ if ((__u64) length != data_size)
continue;
header->aux_size = data_size;
- length = size;
- pt->pt.mem = ((const uint8_t *)
- mmap (NULL, length, PROT_READ, MAP_SHARED, pt->file,
- header->aux_offset));
- if (pt->pt.mem != MAP_FAILED)
+ errno = 0;
+ aux.reset (nullptr, length, PROT_READ, MAP_SHARED, fd.get (),
+ header->aux_offset);
+ if (aux.get () != MAP_FAILED)
break;
}
if (pages == 0)
- goto err_conf;
+ error (_("Failed to map trace buffer: %s."), safe_strerror (errno));
- pt->header = header;
- pt->pt.size = size;
+ pt->pt.size = aux.size ();
+ pt->pt.mem = (const uint8_t *) aux.release ();
pt->pt.data_head = &header->aux_head;
+ pt->header = (struct perf_event_mmap_page *) data.release ();
+ gdb_assert (pt->header == header);
+ pt->file = fd.release ();
- tinfo->conf.pt.size = (unsigned int) size;
- return tinfo;
-
- err_conf:
- munmap((void *) header, PAGE_SIZE);
-
- err_file:
- close (pt->file);
-
- err:
- xfree (tinfo);
- return NULL;
+ tinfo->conf.pt.size = (unsigned int) pt->pt.size;
+ return tinfo.release ();
}
#else /* !defined (PERF_ATTR_SIZE_VER5) */
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) */
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);
}
-
- return tinfo;
}
/* Disable BTS tracing. */
data_head = *pevent->data_head;
/* Delete any leftover trace from the previous iteration. */
- VEC_free (btrace_block_s, btrace->blocks);
+ delete btrace->blocks;
+ btrace->blocks = nullptr;
if (type == BTRACE_READ_DELTA)
{
/* Prune the incomplete last block (i.e. the first one of inferior execution)
if we're not doing a delta read. There is no way of filling in its zeroed
BEGIN element. */
- if (!VEC_empty (btrace_block_s, btrace->blocks)
- && type != BTRACE_READ_DELTA)
- VEC_pop (btrace_block_s, btrace->blocks);
+ if (!btrace->blocks->empty () && type != BTRACE_READ_DELTA)
+ btrace->blocks->pop_back ();
return BTRACE_ERR_NONE;
}
/* See linux-btrace.h. */
-int
-linux_supports_btrace (struct target_ops *ops, enum btrace_format format)
-{
- return 0;
-}
-
-/* See linux-btrace.h. */
-
struct btrace_target_info *
linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
{
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