bb903df05b
This patch adds support for fast tracepoints for aarch64-linux. With this implementation, a tracepoint can only be placed in a +/- 128MB range of the jump pad. This is due to the unconditional branch instruction being limited to a (26 bit << 2) offset from the current PC. Three target operations are implemented: - target_install_fast_tracepoint_jump_pad Building the jump pad the biggest change of this patch. We need to add functions to emit all instructions needed to save and restore the current state when the tracepoint is hit. As well as implementing a lock and creating a collecting_t object identifying the current thread. Steps performed by the jump pad: * Save the current state on the stack. * Push a collecting_t object on the stack. We read the special tpidr_el0 system register to get the thread ID. * Spin-lock on the shared memory location of all tracing threads. We write the address of our collecting_t object there once we have the lock. * Call gdb_collect. * Release the lock. * Restore the state. * Execute the replaced instruction which will have been relocated. * Jump back to the program. - target_get_thread_area As implemented in ps_get_thread_area, target_get_thread_area uses ptrace to fetch the NT_ARM_TLS register. At the architecture level, NT_ARM_TLS represents the tpidr_el0 system register. So this ptrace call (if lwpid is the current thread): ~~~ ptrace (PTRACE_GETREGSET, lwpid, NT_ARM_TLS, &iovec); ~~~ Is equivalent to the following instruction: ~~~ msr x0, tpidr_el0 ~~~ This instruction is used when creating the collecting_t object that GDBserver can read to know if a given thread is currently tracing. So target_get_thread_area must get the same thread IDs as what the jump pad writes into its collecting_t object. - target_get_min_fast_tracepoint_insn_len This just returns 4. gdb/gdbserver/ChangeLog: * Makefile.in (linux-aarch64-ipa.o, aarch64-ipa.o): New rules. * configure.srv (aarch64*-*-linux*): Add linux-aarch64-ipa.o and aarch64-ipa.o. * linux-aarch64-ipa.c: New file. * linux-aarch64-low.c: Include arch/aarch64-insn.h, inttypes.h and endian.h. (aarch64_get_thread_area): New target method. (extract_signed_bitfield): New helper function. (aarch64_decode_ldr_literal): New function. (enum aarch64_opcodes): New enum. (struct aarch64_register): New struct. (struct aarch64_operand): New struct. (x0): New static global. (x1): Likewise. (x2): Likewise. (x3): Likewise. (x4): Likewise. (w2): Likewise. (ip0): Likewise. (sp): Likewise. (xzr): Likewise. (aarch64_register): New helper function. (register_operand): Likewise. (immediate_operand): Likewise. (struct aarch64_memory_operand): New struct. (offset_memory_operand): New helper function. (preindex_memory_operand): Likewise. (enum aarch64_system_control_registers): New enum. (ENCODE): New macro. (emit_insn): New helper function. (emit_b): New function. (emit_bcond): Likewise. (emit_cb): Likewise. (emit_tb): Likewise. (emit_blr): Likewise. (emit_stp): Likewise. (emit_ldp_q_offset): Likewise. (emit_stp_q_offset): Likewise. (emit_load_store): Likewise. (emit_ldr): Likewise. (emit_ldrsw): Likewise. (emit_str): Likewise. (emit_ldaxr): Likewise. (emit_stxr): Likewise. (emit_stlr): Likewise. (emit_data_processing_reg): Likewise. (emit_data_processing): Likewise. (emit_add): Likewise. (emit_sub): Likewise. (emit_mov): Likewise. (emit_movk): Likewise. (emit_mov_addr): Likewise. (emit_mrs): Likewise. (emit_msr): Likewise. (emit_sevl): Likewise. (emit_wfe): Likewise. (append_insns): Likewise. (can_encode_int32_in): New helper function. (aarch64_relocate_instruction): New function. (aarch64_install_fast_tracepoint_jump_pad): Likewise. (aarch64_get_min_fast_tracepoint_insn_len): Likewise. (struct linux_target_ops): Install aarch64_get_thread_area, aarch64_install_fast_tracepoint_jump_pad and aarch64_get_min_fast_tracepoint_insn_len. |
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bfd | ||
binutils | ||
config | ||
cpu | ||
elfcpp | ||
etc | ||
gas | ||
gdb | ||
gold | ||
gprof | ||
include | ||
intl | ||
ld | ||
libdecnumber | ||
libiberty | ||
opcodes | ||
readline | ||
sim | ||
texinfo | ||
zlib | ||
.cvsignore | ||
.gitattributes | ||
.gitignore | ||
COPYING | ||
COPYING.LIB | ||
COPYING.LIBGLOSS | ||
COPYING.NEWLIB | ||
COPYING3 | ||
COPYING3.LIB | ||
ChangeLog | ||
MAINTAINERS | ||
Makefile.def | ||
Makefile.in | ||
Makefile.tpl | ||
README | ||
README-maintainer-mode | ||
compile | ||
config-ml.in | ||
config.guess | ||
config.rpath | ||
config.sub | ||
configure | ||
configure.ac | ||
depcomp | ||
djunpack.bat | ||
install-sh | ||
libtool.m4 | ||
ltgcc.m4 | ||
ltmain.sh | ||
ltoptions.m4 | ||
ltsugar.m4 | ||
ltversion.m4 | ||
lt~obsolete.m4 | ||
makefile.vms | ||
missing | ||
mkdep | ||
mkinstalldirs | ||
move-if-change | ||
setup.com | ||
src-release.sh | ||
symlink-tree | ||
ylwrap |
README
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.