From 59a76f39ab17bf00545559c0c655ba89405d478d Mon Sep 17 00:00:00 2001 From: Anton Kolesov Date: Fri, 14 Feb 2014 11:56:23 +0400 Subject: [PATCH 09/20] gdb: Add native support for ARC in GNU/Linux With this patch in place it is possible to build a GDB that can run on ARC (GNU/Linux) hosts for debugging ARC targets. The "arc-linux-nat.c" is a rather small one that mostly deals with registers and a few thread related hooks. v2 [1]: - Remove "void" from the input of "_initialize_arc_linux_nat ()" [1] Tom's remark after the first patch https://sourceware.org/pipermail/gdb-patches/2020-November/173223.html gdb/ChangeLog: * Makefile.in (ALLDEPFILES): Add arc-linux-nat.c. * configure.host (host to gdb names): Add arc*-*-linux*. * configure.nat (gdb_host_cpu): Add arc. * arc-linux-nat.c: New. Will be a part of GDB 11: https://sourceware.org/git?p=binutils-gdb.git;a=commit;h=04c9f85efcd8df5fc482ce97c0104cc7dd5d19e6 --- gdb/ChangeLog | 7 + gdb/Makefile.in | 1 gdb/arc-linux-nat.c | 320 ++++++++++++++++++++++++++++++++++++++++++++++++++++ gdb/configure.host | 3 gdb/configure.nat | 4 5 files changed, 335 insertions(+) create mode 100644 gdb/arc-linux-nat.c --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2020-12-22 Anton Kolesov + + * Makefile.in (ALLDEPFILES): Add arc-linux-nat.c. + * configure.host (host to gdb names): Add arc*-*-linux*. + * configure.nat (gdb_host_cpu): Add arc. + * arc-linux-nat.c: New. + 2020-12-22 Shahab Vahedi * arc-linux-tdep.c (supply_register): New. --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -2136,6 +2136,7 @@ amd64-obsd-tdep.c \ amd64-sol2-tdep.c \ amd64-tdep.c \ + arc-linux-nat.c \ arc-tdep.c \ arm.c \ arm-bsd-tdep.c \ --- /dev/null +++ b/gdb/arc-linux-nat.c @@ -0,0 +1,320 @@ +/* Native-dependent code for GNU/Linux ARC. + + Copyright 2020 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include "defs.h" +#include "frame.h" +#include "inferior.h" +#include "gdbcore.h" +#include "regcache.h" +#include "gdbsupport/gdb_assert.h" +#include "target.h" +#include "linux-nat.h" +#include "nat/gdb_ptrace.h" + +#include +#include +#include +#include +#include +#include +#include "gdbsupport/gdb_wait.h" +#include +#include +#include + +#include "gregset.h" +#include "arc-tdep.h" +#include "arc-linux-tdep.h" +#include "arch/arc.h" + +/* Defines ps_err_e, struct ps_prochandle. */ +#include "gdb_proc_service.h" + +/* Linux starting with 4.12 supports NT_ARC_V2 note type, which adds R30, + R58 and R59 registers, which are specific to ARC HS and aren't + available in ARC 700. */ +#if defined (NT_ARC_V2) && defined (__ARCHS__) +#define ARC_HAS_V2_REGSET +#endif + +class arc_linux_nat_target final : public linux_nat_target +{ +public: + /* Add ARC register access methods. */ + void fetch_registers (struct regcache *, int) override; + void store_registers (struct regcache *, int) override; + + const struct target_desc *read_description () override; + + /* Handle threads */ + void low_prepare_to_resume (struct lwp_info *lp) override; +}; + +static arc_linux_nat_target the_arc_linux_nat_target; + +/* Read general registers from target process/thread (via ptrace) + into REGCACHE. */ + +static void +fetch_gregs (struct regcache *regcache, int regnum) +{ + const int tid = get_ptrace_pid (regcache->ptid ()); + struct iovec iov; + gdb_gregset_t regs; + + iov.iov_base = ®s; + iov.iov_len = sizeof (gdb_gregset_t); + + if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0) + perror_with_name (_("Couldn't get general registers")); + else + arc_linux_supply_gregset (NULL, regcache, regnum, ®s, 0); +} + +#ifdef ARC_HAS_V2_REGSET +/* Read ARC v2 registers from target process/thread (via ptrace) + into REGCACHE. */ + +static void +fetch_v2_regs (struct regcache *regcache, int regnum) +{ + const int tid = get_ptrace_pid (regcache->ptid ()); + struct iovec iov; + bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET]; + + iov.iov_base = &v2_buffer; + iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET; + + if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0) + perror_with_name (_("Couldn't get ARC HS registers")); + else + arc_linux_supply_v2_regset (NULL, regcache, regnum, v2_buffer, 0); +} +#endif + +/* Store general registers from REGCACHE into the target process/thread. */ + +static void +store_gregs (const struct regcache *regcache, int regnum) +{ + const int tid = get_ptrace_pid (regcache->ptid ()); + struct iovec iov; + gdb_gregset_t regs; + + iov.iov_base = ®s; + iov.iov_len = sizeof (gdb_gregset_t); + + if (ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0) + perror_with_name (_("Couldn't get general registers")); + else + { + arc_linux_collect_gregset (NULL, regcache, regnum, regs, 0); + + if (ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, (void *) &iov) < 0) + perror_with_name (_("Couldn't write general registers")); + } +} + +#ifdef ARC_HAS_V2_REGSET +/* Store ARC v2 registers from REGCACHE into the target process/thread. */ + +static void +store_v2_regs (const struct regcache *regcache, int regnum) +{ + const int tid = get_ptrace_pid (regcache->ptid ()); + struct iovec iov; + bfd_byte v2_buffer[ARC_LINUX_SIZEOF_V2_REGSET]; + + iov.iov_base = &v2_buffer; + iov.iov_len = ARC_LINUX_SIZEOF_V2_REGSET; + + if (ptrace (PTRACE_GETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0) + perror_with_name (_("Couldn't get ARC HS registers")); + else + { + arc_linux_collect_v2_regset (NULL, regcache, regnum, v2_buffer, 0); + + if (ptrace (PTRACE_SETREGSET, tid, NT_ARC_V2, (void *) &iov) < 0) + perror_with_name (_("Couldn't write ARC HS registers")); + } +} +#endif + +/* Target operation: Read REGNUM register (all registers if REGNUM == -1) + from target process into REGCACHE. */ + +void +arc_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum) +{ + + if (regnum == -1 || regnum <= ARC_LAST_REGNUM) + fetch_gregs (regcache, regnum); + +#ifdef ARC_HAS_V2_REGSET + if (regnum == -1 + || regnum == ARC_R30_REGNUM + || regnum == ARC_R58_REGNUM + || regnum == ARC_R59_REGNUM) + fetch_v2_regs (regcache, regnum); +#endif +} + +/* Target operation: Store REGNUM register (all registers if REGNUM == -1) + to the target process from REGCACHE. */ + +void +arc_linux_nat_target::store_registers (struct regcache *regcache, int regnum) +{ + if (regnum == -1 || regnum <= ARC_LAST_REGNUM) + store_gregs (regcache, regnum); + +#ifdef ARC_HAS_V2_REGSET + if (regnum == -1 + || regnum == ARC_R30_REGNUM + || regnum == ARC_R58_REGNUM + || regnum == ARC_R59_REGNUM) + store_v2_regs (regcache, regnum); +#endif +} + +/* Copy general purpose register(s) from REGCACHE into regset GREGS. + This function is exported to proc-service.c */ + +void +fill_gregset (const struct regcache *regcache, + gdb_gregset_t *gregs, int regnum) +{ + arc_linux_collect_gregset (NULL, regcache, regnum, gregs, 0); +} + +/* Copy all the general purpose registers from regset GREGS into REGCACHE. + This function is exported to proc-service.c. */ + +void +supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregs) +{ + arc_linux_supply_gregset (NULL, regcache, -1, gregs, 0); +} + +/* ARC doesn't have separate FP registers. This function is exported + to proc-service.c. */ + +void +fill_fpregset (const struct regcache *regcache, + gdb_fpregset_t *fpregsetp, int regnum) +{ + if (arc_debug) + debug_printf ("arc-linux-nat: fill_fpregset called."); + return; +} + +/* ARC doesn't have separate FP registers. This function is exported + to proc-service.c. */ + +void +supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp) +{ + if (arc_debug) + debug_printf ("arc-linux-nat: supply_fpregset called."); + return; +} + +/* Implement the "read_description" method of linux_nat_target. */ + +const struct target_desc * +arc_linux_nat_target::read_description () +{ + /* This is a native target, hence description is hardcoded. */ +#ifdef __ARCHS__ + arc_arch_features features (4, ARC_ISA_ARCV2); +#else + arc_arch_features features (4, ARC_ISA_ARCV1); +#endif + return arc_lookup_target_description (features); +} + +/* As described in arc_linux_collect_gregset(), we need to write resume-PC + to ERET. However by default GDB for native targets doesn't write + registers if they haven't been changed. This is a callback called by + generic GDB, and in this callback we have to rewrite PC value so it + would force rewrite of register on target. It seems that the only + other arch that utilizes this hook is x86/x86-64 for HW breakpoint + support. But then, AFAIK no other arch has this stop_pc/eret + complexity. + + No better way was found, other than this fake write of register value, + to force GDB into writing register to target. Is there any? */ + +void +arc_linux_nat_target::low_prepare_to_resume (struct lwp_info *lwp) +{ + /* When new processes and threads are created we do not have the address + space for them and calling get_thread_regcache will cause an internal + error in GDB. It looks like that checking for last_resume_kind is the + sensible way to determine processes for which we cannot get regcache. + Ultimately, a better way would be removing the need for + low_prepare_to_resume in the first place. */ + if (lwp->last_resume_kind == resume_stop) + return; + + struct regcache *regcache = get_thread_regcache (this, lwp->ptid); + struct gdbarch *gdbarch = regcache->arch (); + + /* Read current PC value, then write it back. It is required to call + invalidate(), otherwise GDB will note that new value is equal to old + value and will skip write. */ + ULONGEST new_pc; + regcache_cooked_read_unsigned (regcache, gdbarch_pc_regnum (gdbarch), + &new_pc); + regcache->invalidate (gdbarch_pc_regnum (gdbarch)); + regcache_cooked_write_unsigned (regcache, gdbarch_pc_regnum (gdbarch), + new_pc); +} + +/* Fetch the thread-local storage pointer for libthread_db. Note that + this function is not called from GDB, but is called from libthread_db. + This is required to debug multithreaded applications with NPTL. */ + +ps_err_e +ps_get_thread_area (struct ps_prochandle *ph, lwpid_t lwpid, int idx, + void **base) +{ + if (arc_debug >= 2) + debug_printf ("arc-linux-nat: ps_get_thread_area called"); + + if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0) + return PS_ERR; + + /* IDX is the bias from the thread pointer to the beginning of the + thread descriptor. It has to be subtracted due to implementation + quirks in libthread_db. */ + *base = (void *) ((char *) *base - idx); + + return PS_OK; +} + +/* Suppress warning from -Wmissing-prototypes. */ +void _initialize_arc_linux_nat (); +void +_initialize_arc_linux_nat () +{ + /* Register the target. */ + linux_target = &the_arc_linux_nat_target; + add_inf_child_target (&the_arc_linux_nat_target); +} --- a/gdb/configure.host +++ b/gdb/configure.host @@ -60,6 +60,7 @@ aarch64*) gdb_host_cpu=aarch64 ;; alpha*) gdb_host_cpu=alpha ;; +arc*) gdb_host_cpu=arc ;; arm*) gdb_host_cpu=arm ;; hppa*) gdb_host_cpu=pa ;; i[34567]86*) gdb_host_cpu=i386 ;; @@ -91,6 +92,8 @@ gdb_host=nbsd ;; alpha*-*-openbsd*) gdb_host=nbsd ;; +arc*-*-linux*) gdb_host=linux ;; + arm*-*-freebsd*) gdb_host=fbsd ;; arm*-*-linux*) gdb_host=linux ;; arm*-*-netbsdelf* | arm*-*-knetbsd*-gnu) --- a/gdb/configure.nat +++ b/gdb/configure.nat @@ -238,6 +238,10 @@ nat/aarch64-linux.o \ nat/aarch64-sve-linux-ptrace.o" ;; + arc) + # Host: ARC based machine running GNU/Linux + NATDEPFILES="${NATDEPFILES} arc-linux-nat.o" + ;; arm) # Host: ARM based machine running GNU/Linux NATDEPFILES="${NATDEPFILES} arm-linux-nat.o \