/* Linux-dependent part of branch trace support for GDB, and GDBserver.
- Copyright (C) 2013-2015 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 "gdbsupport/filestuff.h"
+#include "gdbsupport/scoped_fd.h"
+#include "gdbsupport/scoped_mmap.h"
+
+#include <inttypes.h>
-#ifdef HAVE_SYS_SYSCALL_H
#include <sys/syscall.h>
-#endif
#if HAVE_LINUX_PERF_EVENT_H && defined(SYS_perf_event_open)
-
-#include <stdint.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/user.h>
-#include <sys/ptrace.h>
+#include "nat/gdb_ptrace.h"
#include <sys/types.h>
#include <signal.h>
struct perf_event_bts bts;
};
-/* Get the perf_event header. */
-
-static inline volatile struct perf_event_mmap_page *
-perf_event_header (struct btrace_target_info* tinfo)
+/* Identify the cpu we're running on. */
+static struct btrace_cpu
+btrace_this_cpu (void)
{
- return tinfo->buffer;
+ struct btrace_cpu cpu;
+ unsigned int eax, ebx, ecx, edx;
+ int ok;
+
+ memset (&cpu, 0, sizeof (cpu));
+
+ ok = x86_cpuid (0, &eax, &ebx, &ecx, &edx);
+ if (ok != 0)
+ {
+ if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
+ && edx == signature_INTEL_edx)
+ {
+ unsigned int cpuid, ignore;
+
+ ok = x86_cpuid (1, &cpuid, &ignore, &ignore, &ignore);
+ if (ok != 0)
+ {
+ cpu.vendor = CV_INTEL;
+
+ cpu.family = (cpuid >> 8) & 0xf;
+ cpu.model = (cpuid >> 4) & 0xf;
+
+ if (cpu.family == 0x6)
+ cpu.model += (cpuid >> 12) & 0xf0;
+ }
+ }
+ }
+
+ return cpu;
}
-/* Get the size of the perf_event mmap buffer. */
+/* Return non-zero if there is new data in PEVENT; zero otherwise. */
-static inline size_t
-perf_event_mmap_size (const struct btrace_target_info *tinfo)
+static int
+perf_event_new_data (const struct perf_event_buffer *pev)
{
- /* The branch trace buffer is preceded by a configuration page. */
- return (tinfo->size + 1) * PAGE_SIZE;
+ return *pev->data_head != pev->last_head;
}
-/* Get the size of the perf_event buffer. */
+/* Copy the last SIZE bytes from PEV ending at DATA_HEAD and return a pointer
+ to the memory holding the copy.
+ The caller is responsible for freeing the memory. */
-static inline size_t
-perf_event_buffer_size (struct btrace_target_info* tinfo)
+static gdb_byte *
+perf_event_read (const struct perf_event_buffer *pev, __u64 data_head,
+ size_t size)
{
- return tinfo->size * PAGE_SIZE;
+ const gdb_byte *begin, *end, *start, *stop;
+ gdb_byte *buffer;
+ size_t buffer_size;
+ __u64 data_tail;
+
+ if (size == 0)
+ return NULL;
+
+ /* We should never ask for more data than the buffer can hold. */
+ buffer_size = pev->size;
+ gdb_assert (size <= buffer_size);
+
+ /* If we ask for more data than we seem to have, we wrap around and read
+ data from the end of the buffer. This is already handled by the %
+ BUFFER_SIZE operation, below. Here, we just need to make sure that we
+ don't underflow.
+
+ Note that this is perfectly OK for perf event buffers where data_head
+ doesn'grow indefinitely and instead wraps around to remain within the
+ buffer's boundaries. */
+ if (data_head < size)
+ data_head += buffer_size;
+
+ gdb_assert (size <= data_head);
+ data_tail = data_head - size;
+
+ begin = pev->mem;
+ start = begin + data_tail % buffer_size;
+ stop = begin + data_head % buffer_size;
+
+ buffer = (gdb_byte *) xmalloc (size);
+
+ if (start < stop)
+ memcpy (buffer, start, stop - start);
+ else
+ {
+ end = begin + buffer_size;
+
+ memcpy (buffer, start, end - start);
+ memcpy (buffer + (end - start), begin, stop - begin);
+ }
+
+ return buffer;
}
-/* Get the start address of the perf_event buffer. */
+/* Copy the perf event buffer data from PEV.
+ Store a pointer to the copy into DATA and its size in SIZE. */
-static inline const uint8_t *
-perf_event_buffer_begin (struct btrace_target_info* tinfo)
+static void
+perf_event_read_all (struct perf_event_buffer *pev, gdb_byte **data,
+ size_t *psize)
{
- return ((const uint8_t *) tinfo->buffer) + PAGE_SIZE;
+ size_t size;
+ __u64 data_head;
+
+ data_head = *pev->data_head;
+ size = pev->size;
+
+ *data = perf_event_read (pev, data_head, size);
+ *psize = size;
+
+ pev->last_head = data_head;
}
-/* Get the end address of the perf_event buffer. */
+/* Try to determine the start address of the Linux kernel. */
-static inline const uint8_t *
-perf_event_buffer_end (struct btrace_target_info* tinfo)
+static uint64_t
+linux_determine_kernel_start (void)
{
- return perf_event_buffer_begin (tinfo) + perf_event_buffer_size (tinfo);
+ static uint64_t kernel_start;
+ static int cached;
+
+ if (cached != 0)
+ return kernel_start;
+
+ cached = 1;
+
+ gdb_file_up file = gdb_fopen_cloexec ("/proc/kallsyms", "r");
+ if (file == NULL)
+ return kernel_start;
+
+ while (!feof (file.get ()))
+ {
+ char buffer[1024], symbol[8], *line;
+ uint64_t addr;
+ int match;
+
+ line = fgets (buffer, sizeof (buffer), file.get ());
+ if (line == NULL)
+ break;
+
+ match = sscanf (line, "%" SCNx64 " %*[tT] %7s", &addr, symbol);
+ if (match != 2)
+ continue;
+
+ if (strcmp (symbol, "_text") == 0)
+ {
+ kernel_start = addr;
+ break;
+ }
+ }
+
+ return kernel_start;
}
/* Check whether an address is in the kernel. */
static inline int
-perf_event_is_kernel_addr (const struct btrace_target_info *tinfo,
- uint64_t addr)
+perf_event_is_kernel_addr (uint64_t addr)
{
- uint64_t mask;
+ uint64_t kernel_start;
- /* If we don't know the size of a pointer, we can't check. Let's assume it's
- not a kernel address in this case. */
- if (tinfo->ptr_bits == 0)
- return 0;
+ kernel_start = linux_determine_kernel_start ();
+ if (kernel_start != 0ull)
+ return (addr >= kernel_start);
- /* A bit mask for the most significant bit in an address. */
- mask = (uint64_t) 1 << (tinfo->ptr_bits - 1);
-
- /* Check whether the most significant bit in the address is set. */
- return (addr & mask) != 0;
+ /* If we don't know the kernel's start address, let's check the most
+ significant bit. This will work at least for 64-bit kernels. */
+ return ((addr & (1ull << 63)) != 0);
}
/* Check whether a perf event record should be skipped. */
static inline int
-perf_event_skip_record (const struct btrace_target_info *tinfo,
- const struct perf_event_bts *bts)
+perf_event_skip_bts_record (const struct perf_event_bts *bts)
{
/* The hardware may report branches from kernel into user space. Branches
from user into kernel space will be suppressed. We filter the former to
provide a consistent branch trace excluding kernel. */
- return perf_event_is_kernel_addr (tinfo, bts->from);
+ return perf_event_is_kernel_addr (bts->from);
}
/* Perform a few consistency checks on a perf event sample record. This is
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 };
break;
}
- if (perf_event_skip_record (tinfo, &psample->bts))
+ if (perf_event_skip_bts_record (&psample->bts))
continue;
/* 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 branch tracing. */
+/* Check whether an Intel cpu supports BTS. */
static int
-kernel_supports_btrace (void)
+intel_supports_bts (const struct btrace_cpu *cpu)
{
- struct perf_event_attr attr;
- pid_t child, pid;
- int status, file;
-
- errno = 0;
- child = fork ();
- switch (child)
- {
- case -1:
- warning (_("test branch tracing: cannot fork: %s."), strerror (errno));
- return 0;
-
- case 0:
- status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
- if (status != 0)
- {
- warning (_("test branch tracing: cannot PTRACE_TRACEME: %s."),
- strerror (errno));
- _exit (1);
- }
-
- status = raise (SIGTRAP);
- if (status != 0)
- {
- warning (_("test branch tracing: cannot raise SIGTRAP: %s."),
- strerror (errno));
- _exit (1);
- }
-
- _exit (1);
-
- default:
- pid = waitpid (child, &status, 0);
- if (pid != child)
- {
- warning (_("test branch tracing: bad pid %ld, error: %s."),
- (long) pid, strerror (errno));
- return 0;
- }
-
- if (!WIFSTOPPED (status))
- {
- warning (_("test branch tracing: 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 branch tracing: bad pid %ld, error: %s."),
- (long) pid, strerror (errno));
- if (!WIFSIGNALED (status))
- warning (_("test branch tracing: expected killed. status: %d."),
- status);
- }
-
- return (file >= 0);
- }
-}
-
-/* Check whether an Intel cpu supports branch tracing. */
-
-static int
-intel_supports_btrace (void)
-{
- unsigned int cpuid, model, family;
-
- if (!x86_cpuid (1, &cpuid, NULL, NULL, NULL))
- return 0;
-
- family = (cpuid >> 8) & 0xf;
- model = (cpuid >> 4) & 0xf;
-
- switch (family)
+ switch (cpu->family)
{
case 0x6:
- model += (cpuid >> 12) & 0xf0;
-
- switch (model)
+ switch (cpu->model)
{
case 0x1a: /* Nehalem */
case 0x1f:
return 1;
}
-/* Check whether the cpu supports branch tracing. */
+/* Check whether the cpu supports BTS. */
static int
-cpu_supports_btrace (void)
+cpu_supports_bts (void)
{
- unsigned int ebx, ecx, edx;
+ struct btrace_cpu cpu;
- if (!x86_cpuid (0, NULL, &ebx, &ecx, &edx))
- return 0;
-
- if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
- && edx == signature_INTEL_edx)
- return intel_supports_btrace ();
+ cpu = btrace_this_cpu ();
+ switch (cpu.vendor)
+ {
+ default:
+ /* Don't know about others. Let's assume they do. */
+ return 1;
- /* Don't know about others. Let's assume they do. */
- return 1;
+ case CV_INTEL:
+ return intel_supports_bts (&cpu);
+ }
}
-/* 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)
+static void
+diagnose_perf_event_open_fail ()
{
- static int cached;
-
- if (cached == 0)
+ switch (errno)
{
- if (!kernel_supports_btrace ())
- cached = -1;
- else if (!cpu_supports_btrace ())
- cached = -1;
- else
- cached = 1;
+ 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;
+
+ 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);
+ }
+
+ break;
}
- return cached > 0;
+ error (_("Failed to start recording: %s"), safe_strerror (errno));
}
-/* See linux-btrace.h. */
+/* Enable branch tracing in BTS format. */
-struct btrace_target_info *
-linux_enable_btrace (ptid_t ptid)
+static struct btrace_target_info *
+linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
{
- struct btrace_target_info *tinfo;
+ struct btrace_tinfo_bts *bts;
+ size_t size, pages;
+ __u64 data_offset;
int pid, pg;
- tinfo = xzalloc (sizeof (*tinfo));
+ 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->attr.size = sizeof (tinfo->attr);
- tinfo->attr.type = PERF_TYPE_HARDWARE;
- tinfo->attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
- tinfo->attr.sample_period = 1;
+ tinfo->conf.format = BTRACE_FORMAT_BTS;
+ bts = &tinfo->variant.bts;
- /* We sample from and to address. */
- tinfo->attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR;
+ bts->attr.size = sizeof (bts->attr);
+ bts->attr.type = PERF_TYPE_HARDWARE;
+ bts->attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
+ bts->attr.sample_period = 1;
- tinfo->attr.exclude_kernel = 1;
- tinfo->attr.exclude_hv = 1;
- tinfo->attr.exclude_idle = 1;
+ /* We sample from and to address. */
+ bts->attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR;
- tinfo->ptr_bits = 0;
+ bts->attr.exclude_kernel = 1;
+ 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;
- tinfo->file = syscall (SYS_perf_event_open, &tinfo->attr, pid, -1, -1, 0);
- if (tinfo->file < 0)
- goto err;
-
- /* We try to allocate as much buffer as we can get.
- We could allow the user to specify the size of the buffer, but then
- we'd leave this search for the maximum buffer size to him. */
- for (pg = 4; pg >= 0; --pg)
+ 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
+ + ((conf->size % PAGE_SIZE) == 0 ? 0 : 1));
+ /* We need at least one page. */
+ if (pages == 0)
+ pages = 1;
+
+ /* The buffer size can be requested in powers of two pages. Adjust PAGES
+ to the next power of two. */
+ for (pg = 0; pages != ((size_t) 1 << pg); ++pg)
+ if ((pages & ((size_t) 1 << pg)) != 0)
+ pages += ((size_t) 1 << pg);
+
+ /* 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;
+ __u64 data_size;
+
+ data_size = (__u64) pages * PAGE_SIZE;
+
+ /* Don't ask for more than we can represent in the configuration. */
+ if ((__u64) UINT_MAX < data_size)
+ continue;
+
+ size = (size_t) data_size;
+ length = size + PAGE_SIZE;
+
+ /* Check for overflows. */
+ if ((__u64) length != data_size + PAGE_SIZE)
+ continue;
+
+ errno = 0;
/* The number of pages we request needs to be a power of two. */
- tinfo->size = 1 << pg;
- tinfo->buffer = mmap (NULL, perf_event_mmap_size (tinfo),
- PROT_READ, MAP_SHARED, tinfo->file, 0);
- if (tinfo->buffer == MAP_FAILED)
+ data.reset (nullptr, length, PROT_READ, MAP_SHARED, fd.get (), 0);
+ if (data.get () != MAP_FAILED)
+ break;
+ }
+
+ if (pages == 0)
+ 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)
+ if (offsetof (struct perf_event_mmap_page, data_size) <= header->size)
+ {
+ __u64 data_size;
+
+ data_offset = header->data_offset;
+ data_size = header->data_size;
+
+ size = (unsigned int) data_size;
+
+ /* Check for overflows. */
+ if ((__u64) size != data_size)
+ error (_("Failed to determine trace buffer size."));
+ }
+#endif /* defined (PERF_ATTR_SIZE_VER5) */
+
+ 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.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 btrace_tinfo_pt *pt;
+ size_t pages;
+ int pid, pg;
+
+ pid = ptid.lwp ();
+ if (pid == 0)
+ pid = ptid.pid ();
+
+ 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 = perf_event_pt_event_type ();
+
+ pt->attr.exclude_kernel = 1;
+ pt->attr.exclude_hv = 1;
+ pt->attr.exclude_idle = 1;
+
+ errno = 0;
+ 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. */
+ 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;
+
+ /* Convert the requested size in bytes to pages (rounding up). */
+ pages = ((size_t) conf->size / PAGE_SIZE
+ + ((conf->size % PAGE_SIZE) == 0 ? 0 : 1));
+ /* We need at least one page. */
+ if (pages == 0)
+ pages = 1;
+
+ /* The buffer size can be requested in powers of two pages. Adjust PAGES
+ to the next power of two. */
+ for (pg = 0; pages != ((size_t) 1 << pg); ++pg)
+ if ((pages & ((size_t) 1 << pg)) != 0)
+ pages += ((size_t) 1 << pg);
+
+ /* 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;
+ __u64 data_size;
+
+ data_size = (__u64) pages * PAGE_SIZE;
+
+ /* Don't ask for more than we can represent in the configuration. */
+ if ((__u64) UINT_MAX < data_size)
continue;
- return tinfo;
+ length = (size_t) data_size;
+
+ /* Check for overflows. */
+ if ((__u64) length != data_size)
+ continue;
+
+ 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)
+ break;
}
- /* We were not able to allocate any buffer. */
- close (tinfo->file);
+ if (pages == 0)
+ error (_("Failed to map trace buffer: %s."), safe_strerror (errno));
- err:
- xfree (tinfo);
- return NULL;
+ 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) 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)
+{
+ error (_("Intel Processor Trace support was disabled at compile time."));
+}
+
+#endif /* !defined (PERF_ATTR_SIZE_VER5) */
+
/* See linux-btrace.h. */
-enum btrace_error
-linux_disable_btrace (struct btrace_target_info *tinfo)
+struct btrace_target_info *
+linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
{
- int errcode;
+ switch (conf->format)
+ {
+ case BTRACE_FORMAT_NONE:
+ error (_("Bad branch trace format."));
- errno = 0;
- errcode = munmap (tinfo->buffer, perf_event_mmap_size (tinfo));
- if (errcode != 0)
- return BTRACE_ERR_UNKNOWN;
+ default:
+ error (_("Unknown branch trace format."));
+
+ case BTRACE_FORMAT_BTS:
+ return linux_enable_bts (ptid, &conf->bts);
+
+ case BTRACE_FORMAT_PT:
+ return linux_enable_pt (ptid, &conf->pt);
+ }
+}
+/* Disable BTS tracing. */
+
+static enum btrace_error
+linux_disable_bts (struct btrace_tinfo_bts *tinfo)
+{
+ munmap((void *) tinfo->header, tinfo->bts.size + PAGE_SIZE);
close (tinfo->file);
- xfree (tinfo);
return BTRACE_ERR_NONE;
}
-/* Check whether the branch trace has changed. */
+/* Disable Intel Processor Trace tracing. */
-static int
-linux_btrace_has_changed (struct btrace_target_info *tinfo)
+static enum btrace_error
+linux_disable_pt (struct btrace_tinfo_pt *tinfo)
{
- volatile struct perf_event_mmap_page *header = perf_event_header (tinfo);
+ munmap((void *) tinfo->pt.mem, tinfo->pt.size);
+ munmap((void *) tinfo->header, PAGE_SIZE);
+ close (tinfo->file);
- return header->data_head != tinfo->data_head;
+ return BTRACE_ERR_NONE;
+}
+
+/* See linux-btrace.h. */
+
+enum btrace_error
+linux_disable_btrace (struct btrace_target_info *tinfo)
+{
+ enum btrace_error errcode;
+
+ errcode = BTRACE_ERR_NOT_SUPPORTED;
+ switch (tinfo->conf.format)
+ {
+ case BTRACE_FORMAT_NONE:
+ break;
+
+ case BTRACE_FORMAT_BTS:
+ errcode = linux_disable_bts (&tinfo->variant.bts);
+ break;
+
+ case BTRACE_FORMAT_PT:
+ errcode = linux_disable_pt (&tinfo->variant.pt);
+ break;
+ }
+
+ if (errcode == BTRACE_ERR_NONE)
+ xfree (tinfo);
+
+ return errcode;
}
/* Read branch trace data in BTS format for the thread given by TINFO into
struct btrace_target_info *tinfo,
enum btrace_read_type type)
{
- volatile struct perf_event_mmap_page *header;
+ struct perf_event_buffer *pevent;
const uint8_t *begin, *end, *start;
- unsigned long data_head, data_tail, retries = 5;
size_t buffer_size, size;
+ __u64 data_head, data_tail;
+ unsigned int retries = 5;
+
+ pevent = &tinfo->variant.bts.bts;
/* For delta reads, we return at least the partial last block containing
the current PC. */
- if (type == BTRACE_READ_NEW && !linux_btrace_has_changed (tinfo))
+ if (type == BTRACE_READ_NEW && !perf_event_new_data (pevent))
return BTRACE_ERR_NONE;
- header = perf_event_header (tinfo);
- buffer_size = perf_event_buffer_size (tinfo);
- data_tail = tinfo->data_head;
+ buffer_size = pevent->size;
+ data_tail = pevent->last_head;
/* We may need to retry reading the trace. See below. */
while (retries--)
{
- data_head = header->data_head;
+ 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)
{
+ __u64 data_size;
+
/* Determine the number of bytes to read and check for buffer
overflows. */
return BTRACE_ERR_OVERFLOW;
/* If the buffer is smaller than the trace delta, we overflowed. */
- size = data_head - data_tail;
- if (buffer_size < size)
+ data_size = data_head - data_tail;
+ if (buffer_size < data_size)
return BTRACE_ERR_OVERFLOW;
+
+ /* DATA_SIZE <= BUFFER_SIZE and therefore fits into a size_t. */
+ size = (size_t) data_size;
}
else
{
/* Adjust the size if the buffer has not overflowed, yet. */
if (data_head < size)
- size = data_head;
+ size = (size_t) data_head;
}
/* Data_head keeps growing; the buffer itself is circular. */
- begin = perf_event_buffer_begin (tinfo);
+ begin = pevent->mem;
start = begin + data_head % buffer_size;
if (data_head <= buffer_size)
end = start;
else
- end = perf_event_buffer_end (tinfo);
+ end = begin + pevent->size;
btrace->blocks = perf_event_read_bts (tinfo, begin, end, start, size);
kernel might be writing the last branch trace records.
Let's check whether the data head moved while we read the trace. */
- if (data_head == header->data_head)
+ if (data_head == *pevent->data_head)
break;
}
- tinfo->data_head = data_head;
+ pevent->last_head = data_head;
/* 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;
}
+/* Fill in the Intel Processor Trace configuration information. */
+
+static void
+linux_fill_btrace_pt_config (struct btrace_data_pt_config *conf)
+{
+ conf->cpu = btrace_this_cpu ();
+}
+
+/* Read branch trace data in Intel Processor Trace format for the thread
+ given by TINFO into BTRACE using the TYPE reading method. */
+
+static enum btrace_error
+linux_read_pt (struct btrace_data_pt *btrace,
+ struct btrace_target_info *tinfo,
+ enum btrace_read_type type)
+{
+ struct perf_event_buffer *pt;
+
+ pt = &tinfo->variant.pt.pt;
+
+ linux_fill_btrace_pt_config (&btrace->config);
+
+ switch (type)
+ {
+ case BTRACE_READ_DELTA:
+ /* We don't support delta reads. The data head (i.e. aux_head) wraps
+ around to stay inside the aux buffer. */
+ return BTRACE_ERR_NOT_SUPPORTED;
+
+ case BTRACE_READ_NEW:
+ if (!perf_event_new_data (pt))
+ return BTRACE_ERR_NONE;
+
+ /* Fall through. */
+ case BTRACE_READ_ALL:
+ perf_event_read_all (pt, &btrace->data, &btrace->size);
+ return BTRACE_ERR_NONE;
+ }
+
+ internal_error (__FILE__, __LINE__, _("Unkown btrace read type."));
+}
+
/* See linux-btrace.h. */
enum btrace_error
struct btrace_target_info *tinfo,
enum btrace_read_type type)
{
- /* We read btrace in BTS format. */
- btrace->format = BTRACE_FORMAT_BTS;
- btrace->variant.bts.blocks = NULL;
+ switch (tinfo->conf.format)
+ {
+ case BTRACE_FORMAT_NONE:
+ return BTRACE_ERR_NOT_SUPPORTED;
- return linux_read_bts (&btrace->variant.bts, tinfo, type);
-}
+ case BTRACE_FORMAT_BTS:
+ /* We read btrace in BTS format. */
+ btrace->format = BTRACE_FORMAT_BTS;
+ btrace->variant.bts.blocks = NULL;
-#else /* !HAVE_LINUX_PERF_EVENT_H */
+ return linux_read_bts (&btrace->variant.bts, tinfo, type);
+
+ case BTRACE_FORMAT_PT:
+ /* We read btrace in Intel Processor Trace format. */
+ btrace->format = BTRACE_FORMAT_PT;
+ btrace->variant.pt.data = NULL;
+ btrace->variant.pt.size = 0;
+
+ return linux_read_pt (&btrace->variant.pt, tinfo, type);
+ }
+
+ internal_error (__FILE__, __LINE__, _("Unkown branch trace format."));
+}
/* See linux-btrace.h. */
-int
-linux_supports_btrace (struct target_ops *ops)
+const struct btrace_config *
+linux_btrace_conf (const struct btrace_target_info *tinfo)
{
- return 0;
+ return &tinfo->conf;
}
+#else /* !HAVE_LINUX_PERF_EVENT_H */
+
/* See linux-btrace.h. */
struct btrace_target_info *
-linux_enable_btrace (ptid_t ptid)
+linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
{
return NULL;
}
return BTRACE_ERR_NOT_SUPPORTED;
}
+/* See linux-btrace.h. */
+
+const struct btrace_config *
+linux_btrace_conf (const struct btrace_target_info *tinfo)
+{
+ return NULL;
+}
+
#endif /* !HAVE_LINUX_PERF_EVENT_H */
projects / deliverable / binutils-gdb.git / blobdiff