2013-03-11 08:24:07 +00:00
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/* Linux-dependent part of branch trace support for GDB, and GDBserver.
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2014-01-01 03:54:24 +00:00
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Copyright (C) 2013-2014 Free Software Foundation, Inc.
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2013-03-11 08:24:07 +00:00
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Contributed by Intel Corp. <markus.t.metzger@intel.com>
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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2014-09-12 09:11:42 +00:00
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#include "common-defs.h"
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2013-03-11 08:24:07 +00:00
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#include "linux-btrace.h"
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2014-09-12 09:11:42 +00:00
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#include "common-regcache.h"
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2013-05-07 13:04:58 +00:00
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#include "gdb_wait.h"
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Rename 32- and 64-bit Intel files from "i386" to "x86"
This commit renames nine files that contain code used by both 32- and
64-bit Intel ports such that their names are prefixed with "x86"
rather than "i386". All types, functions and variables within these
files are likewise renamed such that their names are prefixed with
"x86" rather than "i386". This makes GDB follow the convention used
by gdbserver such that 32-bit Intel code lives in files called
"i386-*", 64-bit Intel code lives in files called "amd64-*", and code
for both 32- and 64-bit Intel lives in files called "x86-*".
This commit only renames OS-independent files. The Linux ports of
both GDB and gdbserver now follow the i386/amd64/x86 convention fully.
Some ports still use the old convention where "i386" in file/function/
type/variable names can mean "32-bit only" or "32- and 64-bit" but I
don't want to touch ports I can't fully test except where absolutely
necessary.
gdb/ChangeLog:
* i386-nat.h: Renamed as...
* x86-nat.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* i386-nat.c: Renamed as...
* x86-nat.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* common/i386-xstate.h: Renamed as...
* common/x86-xstate.h: New file. All type, function and variable
name prefixes changed from "i386_" to "x86_". All references
updated.
* nat/i386-cpuid.h: Renamed as...
* nat/x86-cpuid.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* nat/i386-gcc-cpuid.h: Renamed as...
* nat/x86-gcc-cpuid.h: New file. All type, function and variable
name prefixes changed from "i386_" to "x86_". All references
updated.
* nat/i386-dregs.h: Renamed as...
* nat/x86-dregs.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* nat/i386-dregs.c: Renamed as...
* nat/x86-dregs.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
gdb/gdbserver/ChangeLog:
* i386-low.h: Renamed as...
* x86-low.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* i386-low.c: Renamed as...
* x86-low.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
2014-08-19 14:16:11 +00:00
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#include "x86-cpuid.h"
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2013-03-11 08:24:07 +00:00
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2013-09-29 03:57:34 +00:00
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#ifdef HAVE_SYS_SYSCALL_H
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#include <sys/syscall.h>
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#endif
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#if HAVE_LINUX_PERF_EVENT_H && defined(SYS_perf_event_open)
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2013-03-11 08:24:07 +00:00
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#include <stdint.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/user.h>
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2013-03-11 08:38:27 +00:00
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#include <sys/ptrace.h>
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#include <sys/types.h>
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#include <signal.h>
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2013-03-11 08:24:07 +00:00
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/* A branch trace record in perf_event. */
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struct perf_event_bts
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{
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/* The linear address of the branch source. */
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uint64_t from;
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/* The linear address of the branch destination. */
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uint64_t to;
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};
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/* A perf_event branch trace sample. */
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struct perf_event_sample
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{
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/* The perf_event sample header. */
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struct perf_event_header header;
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/* The perf_event branch tracing payload. */
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struct perf_event_bts bts;
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};
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/* Get the perf_event header. */
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static inline volatile struct perf_event_mmap_page *
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perf_event_header (struct btrace_target_info* tinfo)
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{
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return tinfo->buffer;
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}
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/* Get the size of the perf_event mmap buffer. */
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static inline size_t
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perf_event_mmap_size (const struct btrace_target_info *tinfo)
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{
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/* The branch trace buffer is preceded by a configuration page. */
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return (tinfo->size + 1) * PAGE_SIZE;
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}
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/* Get the size of the perf_event buffer. */
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static inline size_t
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perf_event_buffer_size (struct btrace_target_info* tinfo)
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{
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return tinfo->size * PAGE_SIZE;
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}
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/* Get the start address of the perf_event buffer. */
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static inline const uint8_t *
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perf_event_buffer_begin (struct btrace_target_info* tinfo)
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{
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return ((const uint8_t *) tinfo->buffer) + PAGE_SIZE;
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}
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/* Get the end address of the perf_event buffer. */
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static inline const uint8_t *
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perf_event_buffer_end (struct btrace_target_info* tinfo)
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{
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return perf_event_buffer_begin (tinfo) + perf_event_buffer_size (tinfo);
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}
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/* Check whether an address is in the kernel. */
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static inline int
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perf_event_is_kernel_addr (const struct btrace_target_info *tinfo,
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uint64_t addr)
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{
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uint64_t mask;
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/* If we don't know the size of a pointer, we can't check. Let's assume it's
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not a kernel address in this case. */
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if (tinfo->ptr_bits == 0)
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return 0;
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/* A bit mask for the most significant bit in an address. */
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mask = (uint64_t) 1 << (tinfo->ptr_bits - 1);
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/* Check whether the most significant bit in the address is set. */
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return (addr & mask) != 0;
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}
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/* Check whether a perf event record should be skipped. */
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static inline int
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perf_event_skip_record (const struct btrace_target_info *tinfo,
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const struct perf_event_bts *bts)
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{
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/* The hardware may report branches from kernel into user space. Branches
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from user into kernel space will be suppressed. We filter the former to
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provide a consistent branch trace excluding kernel. */
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return perf_event_is_kernel_addr (tinfo, bts->from);
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}
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/* Perform a few consistency checks on a perf event sample record. This is
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meant to catch cases when we get out of sync with the perf event stream. */
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static inline int
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perf_event_sample_ok (const struct perf_event_sample *sample)
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{
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if (sample->header.type != PERF_RECORD_SAMPLE)
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return 0;
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if (sample->header.size != sizeof (*sample))
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return 0;
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return 1;
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}
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/* Branch trace is collected in a circular buffer [begin; end) as pairs of from
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and to addresses (plus a header).
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Start points into that buffer at the next sample position.
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We read the collected samples backwards from start.
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While reading the samples, we convert the information into a list of blocks.
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For two adjacent samples s1 and s2, we form a block b such that b.begin =
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s1.to and b.end = s2.from.
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In case the buffer overflows during sampling, one sample may have its lower
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part at the end and its upper part at the beginning of the buffer. */
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static VEC (btrace_block_s) *
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perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
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2013-06-03 13:39:35 +00:00
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const uint8_t *end, const uint8_t *start, size_t size)
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2013-03-11 08:24:07 +00:00
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{
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VEC (btrace_block_s) *btrace = NULL;
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struct perf_event_sample sample;
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2013-06-03 13:39:35 +00:00
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size_t read = 0;
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2013-03-11 08:24:07 +00:00
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struct btrace_block block = { 0, 0 };
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struct regcache *regcache;
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gdb_assert (begin <= start);
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gdb_assert (start <= end);
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/* The first block ends at the current pc. */
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2014-09-12 09:11:42 +00:00
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regcache = get_thread_regcache_for_ptid (tinfo->ptid);
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2013-03-11 08:24:07 +00:00
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block.end = regcache_read_pc (regcache);
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/* The buffer may contain a partial record as its last entry (i.e. when the
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buffer size is not a multiple of the sample size). */
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read = sizeof (sample) - 1;
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for (; read < size; read += sizeof (sample))
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{
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const struct perf_event_sample *psample;
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/* Find the next perf_event sample in a backwards traversal. */
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start -= sizeof (sample);
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/* If we're still inside the buffer, we're done. */
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if (begin <= start)
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psample = (const struct perf_event_sample *) start;
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else
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{
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int missing;
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/* We're to the left of the ring buffer, we will wrap around and
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reappear at the very right of the ring buffer. */
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missing = (begin - start);
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start = (end - missing);
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/* If the entire sample is missing, we're done. */
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if (missing == sizeof (sample))
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psample = (const struct perf_event_sample *) start;
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else
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{
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uint8_t *stack;
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/* The sample wrapped around. The lower part is at the end and
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the upper part is at the beginning of the buffer. */
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stack = (uint8_t *) &sample;
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/* Copy the two parts so we have a contiguous sample. */
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memcpy (stack, start, missing);
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memcpy (stack + missing, begin, sizeof (sample) - missing);
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psample = &sample;
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}
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}
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if (!perf_event_sample_ok (psample))
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{
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warning (_("Branch trace may be incomplete."));
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break;
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}
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if (perf_event_skip_record (tinfo, &psample->bts))
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continue;
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/* We found a valid sample, so we can complete the current block. */
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block.begin = psample->bts.to;
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VEC_safe_push (btrace_block_s, btrace, &block);
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/* Start the next block. */
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block.end = psample->bts.from;
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}
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2013-06-03 13:39:35 +00:00
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/* Push the last block (i.e. the first one of inferior execution), as well.
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We don't know where it ends, but we know where it starts. If we're
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reading delta trace, we can fill in the start address later on.
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Otherwise we will prune it. */
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block.begin = 0;
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VEC_safe_push (btrace_block_s, btrace, &block);
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2013-03-11 08:24:07 +00:00
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return btrace;
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}
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2013-03-11 08:38:27 +00:00
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/* Check whether the kernel supports branch tracing. */
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static int
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kernel_supports_btrace (void)
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{
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struct perf_event_attr attr;
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pid_t child, pid;
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int status, file;
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errno = 0;
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child = fork ();
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switch (child)
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{
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case -1:
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warning (_("test branch tracing: cannot fork: %s."), strerror (errno));
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return 0;
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case 0:
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status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
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if (status != 0)
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{
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warning (_("test branch tracing: cannot PTRACE_TRACEME: %s."),
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strerror (errno));
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_exit (1);
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}
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status = raise (SIGTRAP);
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if (status != 0)
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{
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warning (_("test branch tracing: cannot raise SIGTRAP: %s."),
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strerror (errno));
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_exit (1);
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}
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_exit (1);
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default:
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pid = waitpid (child, &status, 0);
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if (pid != child)
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{
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warning (_("test branch tracing: bad pid %ld, error: %s."),
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(long) pid, strerror (errno));
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return 0;
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}
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if (!WIFSTOPPED (status))
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{
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warning (_("test branch tracing: expected stop. status: %d."),
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status);
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return 0;
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}
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memset (&attr, 0, sizeof (attr));
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attr.type = PERF_TYPE_HARDWARE;
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attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
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attr.sample_period = 1;
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attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR;
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attr.exclude_kernel = 1;
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attr.exclude_hv = 1;
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attr.exclude_idle = 1;
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file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0);
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if (file >= 0)
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close (file);
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kill (child, SIGKILL);
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ptrace (PTRACE_KILL, child, NULL, NULL);
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pid = waitpid (child, &status, 0);
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if (pid != child)
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{
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warning (_("test branch tracing: bad pid %ld, error: %s."),
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(long) pid, strerror (errno));
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if (!WIFSIGNALED (status))
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warning (_("test branch tracing: expected killed. status: %d."),
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status);
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}
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return (file >= 0);
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}
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}
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/* Check whether an Intel cpu supports branch tracing. */
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static int
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intel_supports_btrace (void)
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{
|
2013-05-06 18:03:33 +00:00
|
|
|
unsigned int cpuid, model, family;
|
|
|
|
|
Rename 32- and 64-bit Intel files from "i386" to "x86"
This commit renames nine files that contain code used by both 32- and
64-bit Intel ports such that their names are prefixed with "x86"
rather than "i386". All types, functions and variables within these
files are likewise renamed such that their names are prefixed with
"x86" rather than "i386". This makes GDB follow the convention used
by gdbserver such that 32-bit Intel code lives in files called
"i386-*", 64-bit Intel code lives in files called "amd64-*", and code
for both 32- and 64-bit Intel lives in files called "x86-*".
This commit only renames OS-independent files. The Linux ports of
both GDB and gdbserver now follow the i386/amd64/x86 convention fully.
Some ports still use the old convention where "i386" in file/function/
type/variable names can mean "32-bit only" or "32- and 64-bit" but I
don't want to touch ports I can't fully test except where absolutely
necessary.
gdb/ChangeLog:
* i386-nat.h: Renamed as...
* x86-nat.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* i386-nat.c: Renamed as...
* x86-nat.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* common/i386-xstate.h: Renamed as...
* common/x86-xstate.h: New file. All type, function and variable
name prefixes changed from "i386_" to "x86_". All references
updated.
* nat/i386-cpuid.h: Renamed as...
* nat/x86-cpuid.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* nat/i386-gcc-cpuid.h: Renamed as...
* nat/x86-gcc-cpuid.h: New file. All type, function and variable
name prefixes changed from "i386_" to "x86_". All references
updated.
* nat/i386-dregs.h: Renamed as...
* nat/x86-dregs.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* nat/i386-dregs.c: Renamed as...
* nat/x86-dregs.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
gdb/gdbserver/ChangeLog:
* i386-low.h: Renamed as...
* x86-low.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* i386-low.c: Renamed as...
* x86-low.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
2014-08-19 14:16:11 +00:00
|
|
|
if (!x86_cpuid (1, &cpuid, NULL, NULL, NULL))
|
gdb: clean up x86 cpuid implementations
We've currently got 3 files doing open coded implementations of cpuid.
Each has its own set of workarounds and varying levels of how well
they're written and are generally hardcoded to specific cpuid functions.
If you try to build the latest gdb as a PIE on an i386 system, the build
will fail because one of them lacks PIC workarounds (wrt ebx).
Specifically, we have:
common/linux-btrace.c:
two copies of cpuid asm w/specific args, one has no workarounds
while the other implicitly does to avoid memcpy
go32-nat.c:
two copies of cpuid asm w/specific args, one has workarounds to
avoid memcpy
gdb/testsuite/gdb.arch/i386-cpuid.h:
one general cpuid asm w/many workarounds copied from older gcc
Fortunately, that last header there is pretty damn good -- it handles
lots of edge cases, the code is nice & tight (uses gcc asm operands
rather than manual movs), and is already almost a general library type
header. It's also the basis of what is now the public cpuid.h that is
shipped with gcc-4.3+.
So what I've done is pull that test header out and into gdb/common/
(not sure if there's a better place), synced to the version found in
gcc-4.8.0, put a wrapper API around it, and then cut over all the
existing call points to this new header.
Since the func already has support for "is cpuid supported on this proc",
it makes it trivial to push the i386/x86_64 ifdefs down into this wrapper
API too. Now it can be safely used for all targets and gcc will elide
the unused code for us.
I've verified the gdb.arch testsuite still passes, and this code compiles
for an armv7a host as well as x86_64. The go32-nat code has been left
ifdef-ed out until someone can test & verify the new stuff works (and if
it doesn't, figure out how to make the new code work).
URL: https://bugs.gentoo.org/467806
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2013-06-19 22:29:36 +00:00
|
|
|
return 0;
|
2013-05-06 18:03:33 +00:00
|
|
|
|
|
|
|
family = (cpuid >> 8) & 0xf;
|
|
|
|
model = (cpuid >> 4) & 0xf;
|
|
|
|
|
|
|
|
switch (family)
|
|
|
|
{
|
|
|
|
case 0x6:
|
|
|
|
model += (cpuid >> 12) & 0xf0;
|
|
|
|
|
|
|
|
switch (model)
|
|
|
|
{
|
|
|
|
case 0x1a: /* Nehalem */
|
|
|
|
case 0x1f:
|
|
|
|
case 0x1e:
|
|
|
|
case 0x2e:
|
|
|
|
case 0x25: /* Westmere */
|
|
|
|
case 0x2c:
|
|
|
|
case 0x2f:
|
|
|
|
case 0x2a: /* Sandy Bridge */
|
|
|
|
case 0x2d:
|
|
|
|
case 0x3a: /* Ivy Bridge */
|
|
|
|
|
|
|
|
/* AAJ122: LBR, BTM, or BTS records may have incorrect branch
|
|
|
|
"from" information afer an EIST transition, T-states, C1E, or
|
|
|
|
Adaptive Thermal Throttling. */
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
}
|
2013-03-11 08:38:27 +00:00
|
|
|
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Check whether the cpu supports branch tracing. */
|
|
|
|
|
|
|
|
static int
|
|
|
|
cpu_supports_btrace (void)
|
|
|
|
{
|
gdb: clean up x86 cpuid implementations
We've currently got 3 files doing open coded implementations of cpuid.
Each has its own set of workarounds and varying levels of how well
they're written and are generally hardcoded to specific cpuid functions.
If you try to build the latest gdb as a PIE on an i386 system, the build
will fail because one of them lacks PIC workarounds (wrt ebx).
Specifically, we have:
common/linux-btrace.c:
two copies of cpuid asm w/specific args, one has no workarounds
while the other implicitly does to avoid memcpy
go32-nat.c:
two copies of cpuid asm w/specific args, one has workarounds to
avoid memcpy
gdb/testsuite/gdb.arch/i386-cpuid.h:
one general cpuid asm w/many workarounds copied from older gcc
Fortunately, that last header there is pretty damn good -- it handles
lots of edge cases, the code is nice & tight (uses gcc asm operands
rather than manual movs), and is already almost a general library type
header. It's also the basis of what is now the public cpuid.h that is
shipped with gcc-4.3+.
So what I've done is pull that test header out and into gdb/common/
(not sure if there's a better place), synced to the version found in
gcc-4.8.0, put a wrapper API around it, and then cut over all the
existing call points to this new header.
Since the func already has support for "is cpuid supported on this proc",
it makes it trivial to push the i386/x86_64 ifdefs down into this wrapper
API too. Now it can be safely used for all targets and gcc will elide
the unused code for us.
I've verified the gdb.arch testsuite still passes, and this code compiles
for an armv7a host as well as x86_64. The go32-nat code has been left
ifdef-ed out until someone can test & verify the new stuff works (and if
it doesn't, figure out how to make the new code work).
URL: https://bugs.gentoo.org/467806
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2013-06-19 22:29:36 +00:00
|
|
|
unsigned int ebx, ecx, edx;
|
2013-03-11 08:38:27 +00:00
|
|
|
|
Rename 32- and 64-bit Intel files from "i386" to "x86"
This commit renames nine files that contain code used by both 32- and
64-bit Intel ports such that their names are prefixed with "x86"
rather than "i386". All types, functions and variables within these
files are likewise renamed such that their names are prefixed with
"x86" rather than "i386". This makes GDB follow the convention used
by gdbserver such that 32-bit Intel code lives in files called
"i386-*", 64-bit Intel code lives in files called "amd64-*", and code
for both 32- and 64-bit Intel lives in files called "x86-*".
This commit only renames OS-independent files. The Linux ports of
both GDB and gdbserver now follow the i386/amd64/x86 convention fully.
Some ports still use the old convention where "i386" in file/function/
type/variable names can mean "32-bit only" or "32- and 64-bit" but I
don't want to touch ports I can't fully test except where absolutely
necessary.
gdb/ChangeLog:
* i386-nat.h: Renamed as...
* x86-nat.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* i386-nat.c: Renamed as...
* x86-nat.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* common/i386-xstate.h: Renamed as...
* common/x86-xstate.h: New file. All type, function and variable
name prefixes changed from "i386_" to "x86_". All references
updated.
* nat/i386-cpuid.h: Renamed as...
* nat/x86-cpuid.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* nat/i386-gcc-cpuid.h: Renamed as...
* nat/x86-gcc-cpuid.h: New file. All type, function and variable
name prefixes changed from "i386_" to "x86_". All references
updated.
* nat/i386-dregs.h: Renamed as...
* nat/x86-dregs.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* nat/i386-dregs.c: Renamed as...
* nat/x86-dregs.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
gdb/gdbserver/ChangeLog:
* i386-low.h: Renamed as...
* x86-low.h: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
* i386-low.c: Renamed as...
* x86-low.c: New file. All type, function and variable name
prefixes changed from "i386_" to "x86_". All references updated.
2014-08-19 14:16:11 +00:00
|
|
|
if (!x86_cpuid (0, NULL, &ebx, &ecx, &edx))
|
gdb: clean up x86 cpuid implementations
We've currently got 3 files doing open coded implementations of cpuid.
Each has its own set of workarounds and varying levels of how well
they're written and are generally hardcoded to specific cpuid functions.
If you try to build the latest gdb as a PIE on an i386 system, the build
will fail because one of them lacks PIC workarounds (wrt ebx).
Specifically, we have:
common/linux-btrace.c:
two copies of cpuid asm w/specific args, one has no workarounds
while the other implicitly does to avoid memcpy
go32-nat.c:
two copies of cpuid asm w/specific args, one has workarounds to
avoid memcpy
gdb/testsuite/gdb.arch/i386-cpuid.h:
one general cpuid asm w/many workarounds copied from older gcc
Fortunately, that last header there is pretty damn good -- it handles
lots of edge cases, the code is nice & tight (uses gcc asm operands
rather than manual movs), and is already almost a general library type
header. It's also the basis of what is now the public cpuid.h that is
shipped with gcc-4.3+.
So what I've done is pull that test header out and into gdb/common/
(not sure if there's a better place), synced to the version found in
gcc-4.8.0, put a wrapper API around it, and then cut over all the
existing call points to this new header.
Since the func already has support for "is cpuid supported on this proc",
it makes it trivial to push the i386/x86_64 ifdefs down into this wrapper
API too. Now it can be safely used for all targets and gcc will elide
the unused code for us.
I've verified the gdb.arch testsuite still passes, and this code compiles
for an armv7a host as well as x86_64. The go32-nat code has been left
ifdef-ed out until someone can test & verify the new stuff works (and if
it doesn't, figure out how to make the new code work).
URL: https://bugs.gentoo.org/467806
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2013-06-19 22:29:36 +00:00
|
|
|
return 0;
|
|
|
|
|
2013-06-21 15:40:19 +00:00
|
|
|
if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
|
|
|
|
&& edx == signature_INTEL_edx)
|
2013-03-11 08:38:27 +00:00
|
|
|
return intel_supports_btrace ();
|
|
|
|
|
|
|
|
/* Don't know about others. Let's assume they do. */
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
2013-03-11 08:24:07 +00:00
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
|
|
|
int
|
2013-12-13 20:26:04 +00:00
|
|
|
linux_supports_btrace (struct target_ops *ops)
|
2013-03-11 08:24:07 +00:00
|
|
|
{
|
2013-03-11 08:38:27 +00:00
|
|
|
static int cached;
|
|
|
|
|
|
|
|
if (cached == 0)
|
|
|
|
{
|
|
|
|
if (!kernel_supports_btrace ())
|
|
|
|
cached = -1;
|
|
|
|
else if (!cpu_supports_btrace ())
|
|
|
|
cached = -1;
|
|
|
|
else
|
|
|
|
cached = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
return cached > 0;
|
2013-03-11 08:24:07 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
|
|
|
struct btrace_target_info *
|
|
|
|
linux_enable_btrace (ptid_t ptid)
|
|
|
|
{
|
|
|
|
struct btrace_target_info *tinfo;
|
2013-04-10 11:43:41 +00:00
|
|
|
int pid, pg;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
|
|
|
tinfo = xzalloc (sizeof (*tinfo));
|
|
|
|
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;
|
|
|
|
|
|
|
|
/* We sample from and to address. */
|
|
|
|
tinfo->attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR;
|
|
|
|
|
|
|
|
tinfo->attr.exclude_kernel = 1;
|
|
|
|
tinfo->attr.exclude_hv = 1;
|
|
|
|
tinfo->attr.exclude_idle = 1;
|
|
|
|
|
|
|
|
tinfo->ptr_bits = 0;
|
|
|
|
|
|
|
|
pid = ptid_get_lwp (ptid);
|
|
|
|
if (pid == 0)
|
|
|
|
pid = ptid_get_pid (ptid);
|
|
|
|
|
|
|
|
errno = 0;
|
|
|
|
tinfo->file = syscall (SYS_perf_event_open, &tinfo->attr, pid, -1, -1, 0);
|
|
|
|
if (tinfo->file < 0)
|
|
|
|
goto err;
|
|
|
|
|
2013-04-10 11:43:41 +00:00
|
|
|
/* 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)
|
|
|
|
{
|
|
|
|
/* 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)
|
|
|
|
continue;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
2013-04-10 11:43:41 +00:00
|
|
|
return tinfo;
|
|
|
|
}
|
2013-03-11 08:24:07 +00:00
|
|
|
|
2013-04-10 11:43:41 +00:00
|
|
|
/* We were not able to allocate any buffer. */
|
2013-03-11 08:24:07 +00:00
|
|
|
close (tinfo->file);
|
|
|
|
|
|
|
|
err:
|
|
|
|
xfree (tinfo);
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
enum btrace_error
|
2013-03-11 08:24:07 +00:00
|
|
|
linux_disable_btrace (struct btrace_target_info *tinfo)
|
|
|
|
{
|
|
|
|
int errcode;
|
|
|
|
|
|
|
|
errno = 0;
|
|
|
|
errcode = munmap (tinfo->buffer, perf_event_mmap_size (tinfo));
|
|
|
|
if (errcode != 0)
|
2013-06-03 13:39:35 +00:00
|
|
|
return BTRACE_ERR_UNKNOWN;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
|
|
|
close (tinfo->file);
|
|
|
|
xfree (tinfo);
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
return BTRACE_ERR_NONE;
|
2013-03-11 08:24:07 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Check whether the branch trace has changed. */
|
|
|
|
|
|
|
|
static int
|
|
|
|
linux_btrace_has_changed (struct btrace_target_info *tinfo)
|
|
|
|
{
|
|
|
|
volatile struct perf_event_mmap_page *header = perf_event_header (tinfo);
|
|
|
|
|
|
|
|
return header->data_head != tinfo->data_head;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
enum btrace_error
|
|
|
|
linux_read_btrace (VEC (btrace_block_s) **btrace,
|
|
|
|
struct btrace_target_info *tinfo,
|
2013-03-11 08:24:07 +00:00
|
|
|
enum btrace_read_type type)
|
|
|
|
{
|
|
|
|
volatile struct perf_event_mmap_page *header;
|
|
|
|
const uint8_t *begin, *end, *start;
|
2013-06-03 13:39:35 +00:00
|
|
|
unsigned long data_head, data_tail, retries = 5;
|
|
|
|
size_t buffer_size, size;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
/* For delta reads, we return at least the partial last block containing
|
|
|
|
the current PC. */
|
2013-09-30 13:00:16 +00:00
|
|
|
if (type == BTRACE_READ_NEW && !linux_btrace_has_changed (tinfo))
|
2013-06-03 13:39:35 +00:00
|
|
|
return BTRACE_ERR_NONE;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
|
|
|
header = perf_event_header (tinfo);
|
|
|
|
buffer_size = perf_event_buffer_size (tinfo);
|
2013-06-03 13:39:35 +00:00
|
|
|
data_tail = tinfo->data_head;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
|
|
|
/* We may need to retry reading the trace. See below. */
|
|
|
|
while (retries--)
|
|
|
|
{
|
|
|
|
data_head = header->data_head;
|
|
|
|
|
2013-06-03 12:32:15 +00:00
|
|
|
/* Delete any leftover trace from the previous iteration. */
|
2013-06-03 13:39:35 +00:00
|
|
|
VEC_free (btrace_block_s, *btrace);
|
2013-06-03 12:32:15 +00:00
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
if (type == BTRACE_READ_DELTA)
|
2013-03-11 08:24:07 +00:00
|
|
|
{
|
2013-06-03 13:39:35 +00:00
|
|
|
/* Determine the number of bytes to read and check for buffer
|
|
|
|
overflows. */
|
|
|
|
|
|
|
|
/* Check for data head overflows. We might be able to recover from
|
|
|
|
those but they are very unlikely and it's not really worth the
|
|
|
|
effort, I think. */
|
|
|
|
if (data_head < data_tail)
|
|
|
|
return BTRACE_ERR_OVERFLOW;
|
|
|
|
|
|
|
|
/* If the buffer is smaller than the trace delta, we overflowed. */
|
|
|
|
size = data_head - data_tail;
|
|
|
|
if (buffer_size < size)
|
|
|
|
return BTRACE_ERR_OVERFLOW;
|
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
/* Read the entire buffer. */
|
|
|
|
size = buffer_size;
|
2013-03-11 08:24:07 +00:00
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
/* Adjust the size if the buffer has not overflowed, yet. */
|
|
|
|
if (data_head < size)
|
|
|
|
size = data_head;
|
2013-03-11 08:24:07 +00:00
|
|
|
}
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
/* Data_head keeps growing; the buffer itself is circular. */
|
|
|
|
begin = perf_event_buffer_begin (tinfo);
|
|
|
|
start = begin + data_head % buffer_size;
|
|
|
|
|
|
|
|
if (data_head <= buffer_size)
|
|
|
|
end = start;
|
|
|
|
else
|
|
|
|
end = perf_event_buffer_end (tinfo);
|
|
|
|
|
|
|
|
*btrace = perf_event_read_bts (tinfo, begin, end, start, size);
|
|
|
|
|
2013-03-11 08:24:07 +00:00
|
|
|
/* The stopping thread notifies its ptracer before it is scheduled out.
|
|
|
|
On multi-core systems, the debugger might therefore run while the
|
|
|
|
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)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
tinfo->data_head = data_head;
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
/* 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) && type != BTRACE_READ_DELTA)
|
|
|
|
VEC_pop (btrace_block_s, *btrace);
|
|
|
|
|
|
|
|
return BTRACE_ERR_NONE;
|
2013-03-11 08:24:07 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
#else /* !HAVE_LINUX_PERF_EVENT_H */
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
|
|
|
int
|
2013-12-13 20:26:04 +00:00
|
|
|
linux_supports_btrace (struct target_ops *ops)
|
2013-03-11 08:24:07 +00:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
|
|
|
struct btrace_target_info *
|
|
|
|
linux_enable_btrace (ptid_t ptid)
|
|
|
|
{
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
enum btrace_error
|
2013-03-11 08:24:07 +00:00
|
|
|
linux_disable_btrace (struct btrace_target_info *tinfo)
|
|
|
|
{
|
2013-06-03 13:39:35 +00:00
|
|
|
return BTRACE_ERR_NOT_SUPPORTED;
|
2013-03-11 08:24:07 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/* See linux-btrace.h. */
|
|
|
|
|
2013-06-03 13:39:35 +00:00
|
|
|
enum btrace_error
|
|
|
|
linux_read_btrace (VEC (btrace_block_s) **btrace,
|
|
|
|
struct btrace_target_info *tinfo,
|
2013-03-11 08:24:07 +00:00
|
|
|
enum btrace_read_type type)
|
|
|
|
{
|
2013-06-03 13:39:35 +00:00
|
|
|
return BTRACE_ERR_NOT_SUPPORTED;
|
2013-03-11 08:24:07 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
#endif /* !HAVE_LINUX_PERF_EVENT_H */
|