/* Target-dependent code for GNU/Linux on RISC-V processors. Copyright (C) 2018-2025 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 "riscv-tdep.h" #include "osabi.h" #include "glibc-tdep.h" #include "linux-tdep.h" #include "solib-svr4-linux.h" #include "svr4-tls-tdep.h" #include "solib-svr4.h" #include "regset.h" #include "tramp-frame.h" #include "trad-frame.h" #include "gdbarch.h" #include "record-full.h" #include "linux-record.h" #include "riscv-linux-tdep.h" #include "inferior.h" extern unsigned int record_debug; /* The following value is derived from __NR_rt_sigreturn in from the Linux source tree. */ #define RISCV_NR_rt_sigreturn 139 /* Define the general register mapping. The kernel puts the PC at offset 0, gdb puts it at offset 32. Register x0 is always 0 and can be ignored. Registers x1 to x31 are in the same place. */ static const struct regcache_map_entry riscv_linux_gregmap[] = { { 1, RISCV_PC_REGNUM, 0 }, { 31, RISCV_RA_REGNUM, 0 }, /* x1 to x31 */ { 0 } }; /* Define the FP register mapping. The kernel puts the 32 FP regs first, and then FCSR. */ static const struct regcache_map_entry riscv_linux_fregmap[] = { { 32, RISCV_FIRST_FP_REGNUM, 0 }, { 1, RISCV_CSR_FCSR_REGNUM, 0 }, { 0 } }; /* Define the general register regset. */ static const struct regset riscv_linux_gregset = { riscv_linux_gregmap, riscv_supply_regset, regcache_collect_regset }; /* Define the FP register regset. */ static const struct regset riscv_linux_fregset = { riscv_linux_fregmap, riscv_supply_regset, regcache_collect_regset }; /* Define hook for core file support. */ static void riscv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, iterate_over_regset_sections_cb *cb, void *cb_data, const struct regcache *regcache) { cb (".reg", (32 * riscv_isa_xlen (gdbarch)), (32 * riscv_isa_xlen (gdbarch)), &riscv_linux_gregset, NULL, cb_data); /* The kernel is adding 8 bytes for FCSR. */ cb (".reg2", (32 * riscv_isa_flen (gdbarch)) + 8, (32 * riscv_isa_flen (gdbarch)) + 8, &riscv_linux_fregset, NULL, cb_data); } /* Signal trampoline support. */ static void riscv_linux_sigframe_init (const struct tramp_frame *self, const frame_info_ptr &this_frame, struct trad_frame_cache *this_cache, CORE_ADDR func); #define RISCV_INST_LI_A7_SIGRETURN 0x08b00893 #define RISCV_INST_ECALL 0x00000073 static const struct tramp_frame riscv_linux_sigframe = { SIGTRAMP_FRAME, 4, { { RISCV_INST_LI_A7_SIGRETURN, ULONGEST_MAX }, { RISCV_INST_ECALL, ULONGEST_MAX }, { TRAMP_SENTINEL_INSN } }, riscv_linux_sigframe_init, NULL }; /* Runtime signal frames look like this: struct rt_sigframe { struct siginfo info; struct ucontext uc; }; struct ucontext { unsigned long __uc_flags; struct ucontext *uclink; stack_t uc_stack; sigset_t uc_sigmask; char __glibc_reserved[1024 / 8 - sizeof (sigset_t)]; mcontext_t uc_mcontext; }; */ #define SIGFRAME_SIGINFO_SIZE 128 #define UCONTEXT_MCONTEXT_OFFSET 176 static void riscv_linux_sigframe_init (const struct tramp_frame *self, const frame_info_ptr &this_frame, struct trad_frame_cache *this_cache, CORE_ADDR func) { struct gdbarch *gdbarch = get_frame_arch (this_frame); int xlen = riscv_isa_xlen (gdbarch); int flen = riscv_isa_flen (gdbarch); CORE_ADDR frame_sp = get_frame_sp (this_frame); CORE_ADDR mcontext_base; CORE_ADDR regs_base; mcontext_base = frame_sp + SIGFRAME_SIGINFO_SIZE + UCONTEXT_MCONTEXT_OFFSET; /* Handle the integer registers. The first one is PC, followed by x1 through x31. */ regs_base = mcontext_base; trad_frame_set_reg_addr (this_cache, RISCV_PC_REGNUM, regs_base); for (int i = 1; i < 32; i++) trad_frame_set_reg_addr (this_cache, RISCV_ZERO_REGNUM + i, regs_base + (i * xlen)); /* Handle the FP registers. First comes the 32 FP registers, followed by fcsr. */ regs_base += 32 * xlen; for (int i = 0; i < 32; i++) trad_frame_set_reg_addr (this_cache, RISCV_FIRST_FP_REGNUM + i, regs_base + (i * flen)); regs_base += 32 * flen; trad_frame_set_reg_addr (this_cache, RISCV_CSR_FCSR_REGNUM, regs_base); /* Choice of the bottom of the sigframe is somewhat arbitrary. */ trad_frame_set_id (this_cache, frame_id_build (frame_sp, func)); } /* When FRAME is at a syscall instruction (ECALL), return the PC of the next instruction to be executed. */ static CORE_ADDR riscv_linux_syscall_next_pc (const frame_info_ptr &frame) { const CORE_ADDR pc = get_frame_pc (frame); const ULONGEST a7 = get_frame_register_unsigned (frame, RISCV_A7_REGNUM); if (a7 == RISCV_NR_rt_sigreturn) return frame_unwind_caller_pc (frame); return pc + 4 /* Length of the ECALL insn. */; } /* RISC-V process record-replay constructs: syscall, signal etc. */ static linux_record_tdep riscv_linux_record_tdep; using regnum_type = int; /* Record registers from first to last for process-record. */ static bool save_registers (struct regcache *regcache, regnum_type first, regnum_type last) { gdb_assert (regcache != nullptr); for (regnum_type i = first; i != last; ++i) if (record_full_arch_list_add_reg (regcache, i)) return false; return true; }; /* Record all registers but PC register for process-record. */ static bool riscv_all_but_pc_registers_record (struct regcache *regcache) { gdb_assert (regcache != nullptr); struct gdbarch *gdbarch = regcache->arch (); riscv_gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); const struct riscv_gdbarch_features &features = tdep->isa_features; if (!save_registers (regcache, RISCV_ZERO_REGNUM + 1, RISCV_PC_REGNUM)) return false; if (features.flen && !save_registers (regcache, RISCV_FIRST_FP_REGNUM, RISCV_LAST_FP_REGNUM + 1)) return false; return true; } /* Handler for riscv system call instruction recording. */ static int riscv_linux_syscall_record (struct regcache *regcache, unsigned long svc_number) { gdb_assert (regcache != nullptr); enum gdb_syscall syscall_gdb = riscv64_canonicalize_syscall (svc_number); if (record_debug > 1) gdb_printf (gdb_stdlog, "Made syscall %s.\n", plongest (svc_number)); if (syscall_gdb == gdb_sys_no_syscall) { warning (_("Process record and replay target doesn't " "support syscall number %s\n"), plongest (svc_number)); return -1; } if (syscall_gdb == gdb_sys_sigreturn || syscall_gdb == gdb_sys_rt_sigreturn) { if (!riscv_all_but_pc_registers_record (regcache)) return -1; return 0; } int ret = record_linux_system_call (syscall_gdb, regcache, &riscv_linux_record_tdep); if (ret != 0) return ret; /* Record the return value of the system call. */ if (record_full_arch_list_add_reg (regcache, RISCV_A0_REGNUM)) return -1; return 0; } /* Initialize the riscv64_linux_record_tdep. */ static void riscv64_linux_record_tdep_init (struct gdbarch *gdbarch, struct linux_record_tdep & riscv_linux_record_tdep) { gdb_assert (gdbarch != nullptr); /* These values are the size of the type that will be used in a system call. */ riscv_linux_record_tdep.size_pointer = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; riscv_linux_record_tdep.size__old_kernel_stat = 48; riscv_linux_record_tdep.size_tms = 32; riscv_linux_record_tdep.size_loff_t = 8; riscv_linux_record_tdep.size_flock = 32; riscv_linux_record_tdep.size_oldold_utsname = 45; riscv_linux_record_tdep.size_ustat = 32; riscv_linux_record_tdep.size_old_sigaction = 32; riscv_linux_record_tdep.size_old_sigset_t = 8; riscv_linux_record_tdep.size_rlimit = 16; riscv_linux_record_tdep.size_rusage = 144; riscv_linux_record_tdep.size_timeval = 8; riscv_linux_record_tdep.size_timezone = 8; riscv_linux_record_tdep.size_old_gid_t = 2; riscv_linux_record_tdep.size_old_uid_t = 2; riscv_linux_record_tdep.size_fd_set = 128; riscv_linux_record_tdep.size_old_dirent = 268; riscv_linux_record_tdep.size_statfs = 120; riscv_linux_record_tdep.size_statfs64 = 120; riscv_linux_record_tdep.size_sockaddr = 16; riscv_linux_record_tdep.size_int = gdbarch_int_bit (gdbarch) / TARGET_CHAR_BIT; riscv_linux_record_tdep.size_long = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT; riscv_linux_record_tdep.size_ulong = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT; riscv_linux_record_tdep.size_msghdr = 104; riscv_linux_record_tdep.size_itimerval = 16; riscv_linux_record_tdep.size_stat = 128; riscv_linux_record_tdep.size_old_utsname = 325; riscv_linux_record_tdep.size_sysinfo = 112; riscv_linux_record_tdep.size_msqid_ds = 104; riscv_linux_record_tdep.size_shmid_ds = 88; riscv_linux_record_tdep.size_new_utsname = 390; riscv_linux_record_tdep.size_timex = 188; riscv_linux_record_tdep.size_mem_dqinfo = 72; riscv_linux_record_tdep.size_if_dqblk = 68; riscv_linux_record_tdep.size_fs_quota_stat = 64; riscv_linux_record_tdep.size_timespec = 16; riscv_linux_record_tdep.size_pollfd = 8; riscv_linux_record_tdep.size_NFS_FHSIZE = 32; riscv_linux_record_tdep.size_knfsd_fh = 36; riscv_linux_record_tdep.size_TASK_COMM_LEN = 4; riscv_linux_record_tdep.size_sigaction = 24; riscv_linux_record_tdep.size_sigset_t = 8; riscv_linux_record_tdep.size_siginfo_t = 128; riscv_linux_record_tdep.size_cap_user_data_t = 8; riscv_linux_record_tdep.size_stack_t = 24; riscv_linux_record_tdep.size_off_t = riscv_linux_record_tdep.size_long; riscv_linux_record_tdep.size_stat64 = 136; riscv_linux_record_tdep.size_gid_t = 4; riscv_linux_record_tdep.size_uid_t = 4; riscv_linux_record_tdep.size_PAGE_SIZE = 4096; riscv_linux_record_tdep.size_flock64 = 32; riscv_linux_record_tdep.size_user_desc = 37; riscv_linux_record_tdep.size_io_event = 32; riscv_linux_record_tdep.size_iocb = 64; riscv_linux_record_tdep.size_epoll_event = 16; riscv_linux_record_tdep.size_itimerspec = riscv_linux_record_tdep.size_timespec * 2; riscv_linux_record_tdep.size_mq_attr = 64; riscv_linux_record_tdep.size_termios = 36; riscv_linux_record_tdep.size_termios2 = 44; riscv_linux_record_tdep.size_pid_t = 4; riscv_linux_record_tdep.size_winsize = 8; riscv_linux_record_tdep.size_serial_struct = 72; riscv_linux_record_tdep.size_serial_icounter_struct = 80; riscv_linux_record_tdep.size_hayes_esp_config = 12; riscv_linux_record_tdep.size_size_t = 8; riscv_linux_record_tdep.size_iovec = 16; riscv_linux_record_tdep.size_time_t = 8; /* These values are the second argument of system call "sys_ioctl". They are obtained from Linux Kernel source. */ riscv_linux_record_tdep.ioctl_TCGETS = 0x5401; riscv_linux_record_tdep.ioctl_TCSETS = 0x5402; riscv_linux_record_tdep.ioctl_TCSETSW = 0x5403; riscv_linux_record_tdep.ioctl_TCSETSF = 0x5404; riscv_linux_record_tdep.ioctl_TCGETA = 0x5405; riscv_linux_record_tdep.ioctl_TCSETA = 0x5406; riscv_linux_record_tdep.ioctl_TCSETAW = 0x5407; riscv_linux_record_tdep.ioctl_TCSETAF = 0x5408; riscv_linux_record_tdep.ioctl_TCSBRK = 0x5409; riscv_linux_record_tdep.ioctl_TCXONC = 0x540a; riscv_linux_record_tdep.ioctl_TCFLSH = 0x540b; riscv_linux_record_tdep.ioctl_TIOCEXCL = 0x540c; riscv_linux_record_tdep.ioctl_TIOCNXCL = 0x540d; riscv_linux_record_tdep.ioctl_TIOCSCTTY = 0x540e; riscv_linux_record_tdep.ioctl_TIOCGPGRP = 0x540f; riscv_linux_record_tdep.ioctl_TIOCSPGRP = 0x5410; riscv_linux_record_tdep.ioctl_TIOCOUTQ = 0x5411; riscv_linux_record_tdep.ioctl_TIOCSTI = 0x5412; riscv_linux_record_tdep.ioctl_TIOCGWINSZ = 0x5413; riscv_linux_record_tdep.ioctl_TIOCSWINSZ = 0x5414; riscv_linux_record_tdep.ioctl_TIOCMGET = 0x5415; riscv_linux_record_tdep.ioctl_TIOCMBIS = 0x5416; riscv_linux_record_tdep.ioctl_TIOCMBIC = 0x5417; riscv_linux_record_tdep.ioctl_TIOCMSET = 0x5418; riscv_linux_record_tdep.ioctl_TIOCGSOFTCAR = 0x5419; riscv_linux_record_tdep.ioctl_TIOCSSOFTCAR = 0x541a; riscv_linux_record_tdep.ioctl_FIONREAD = 0x541b; riscv_linux_record_tdep.ioctl_TIOCINQ = riscv_linux_record_tdep.ioctl_FIONREAD; riscv_linux_record_tdep.ioctl_TIOCLINUX = 0x541c; riscv_linux_record_tdep.ioctl_TIOCCONS = 0x541d; riscv_linux_record_tdep.ioctl_TIOCGSERIAL = 0x541e; riscv_linux_record_tdep.ioctl_TIOCSSERIAL = 0x541f; riscv_linux_record_tdep.ioctl_TIOCPKT = 0x5420; riscv_linux_record_tdep.ioctl_FIONBIO = 0x5421; riscv_linux_record_tdep.ioctl_TIOCNOTTY = 0x5422; riscv_linux_record_tdep.ioctl_TIOCSETD = 0x5423; riscv_linux_record_tdep.ioctl_TIOCGETD = 0x5424; riscv_linux_record_tdep.ioctl_TCSBRKP = 0x5425; riscv_linux_record_tdep.ioctl_TIOCTTYGSTRUCT = 0x5426; riscv_linux_record_tdep.ioctl_TIOCSBRK = 0x5427; riscv_linux_record_tdep.ioctl_TIOCCBRK = 0x5428; riscv_linux_record_tdep.ioctl_TIOCGSID = 0x5429; riscv_linux_record_tdep.ioctl_TCGETS2 = 0x802c542a; riscv_linux_record_tdep.ioctl_TCSETS2 = 0x402c542b; riscv_linux_record_tdep.ioctl_TCSETSW2 = 0x402c542c; riscv_linux_record_tdep.ioctl_TCSETSF2 = 0x402c542d; riscv_linux_record_tdep.ioctl_TIOCGPTN = 0x80045430; riscv_linux_record_tdep.ioctl_TIOCSPTLCK = 0x40045431; riscv_linux_record_tdep.ioctl_FIONCLEX = 0x5450; riscv_linux_record_tdep.ioctl_FIOCLEX = 0x5451; riscv_linux_record_tdep.ioctl_FIOASYNC = 0x5452; riscv_linux_record_tdep.ioctl_TIOCSERCONFIG = 0x5453; riscv_linux_record_tdep.ioctl_TIOCSERGWILD = 0x5454; riscv_linux_record_tdep.ioctl_TIOCSERSWILD = 0x5455; riscv_linux_record_tdep.ioctl_TIOCGLCKTRMIOS = 0x5456; riscv_linux_record_tdep.ioctl_TIOCSLCKTRMIOS = 0x5457; riscv_linux_record_tdep.ioctl_TIOCSERGSTRUCT = 0x5458; riscv_linux_record_tdep.ioctl_TIOCSERGETLSR = 0x5459; riscv_linux_record_tdep.ioctl_TIOCSERGETMULTI = 0x545a; riscv_linux_record_tdep.ioctl_TIOCSERSETMULTI = 0x545b; riscv_linux_record_tdep.ioctl_TIOCMIWAIT = 0x545c; riscv_linux_record_tdep.ioctl_TIOCGICOUNT = 0x545d; riscv_linux_record_tdep.ioctl_TIOCGHAYESESP = 0x545e; riscv_linux_record_tdep.ioctl_TIOCSHAYESESP = 0x545f; riscv_linux_record_tdep.ioctl_FIOQSIZE = 0x5460; /* These values are the second argument of system call "sys_fcntl" and "sys_fcntl64". They are obtained from Linux Kernel source. */ riscv_linux_record_tdep.fcntl_F_GETLK = 5; riscv_linux_record_tdep.fcntl_F_GETLK64 = 12; riscv_linux_record_tdep.fcntl_F_SETLK64 = 13; riscv_linux_record_tdep.fcntl_F_SETLKW64 = 14; riscv_linux_record_tdep.arg1 = RISCV_A0_REGNUM; riscv_linux_record_tdep.arg2 = RISCV_A1_REGNUM; riscv_linux_record_tdep.arg3 = RISCV_A2_REGNUM; riscv_linux_record_tdep.arg4 = RISCV_A3_REGNUM; riscv_linux_record_tdep.arg5 = RISCV_A4_REGNUM; riscv_linux_record_tdep.arg6 = RISCV_A5_REGNUM; } /* Fetch and return the TLS DTV (dynamic thread vector) address for PTID. Throw a suitable TLS error if something goes wrong. */ static CORE_ADDR riscv_linux_get_tls_dtv_addr (struct gdbarch *gdbarch, ptid_t ptid, svr4_tls_libc libc) { /* On RISC-V, the thread pointer is found in TP. */ regcache *regcache = get_thread_arch_regcache (current_inferior (), ptid, gdbarch); int thread_pointer_regnum = RISCV_TP_REGNUM; target_fetch_registers (regcache, thread_pointer_regnum); ULONGEST thr_ptr; if (regcache->cooked_read (thread_pointer_regnum, &thr_ptr) != REG_VALID) throw_error (TLS_GENERIC_ERROR, _("Unable to fetch thread pointer")); CORE_ADDR dtv_ptr_addr; switch (libc) { case svr4_tls_libc_musl: /* MUSL: The DTV pointer is found at the very end of the pthread struct which is located *before* the thread pointer. I.e. the thread pointer will be just beyond the end of the struct, so the address of the DTV pointer is found one pointer-size before the thread pointer. */ dtv_ptr_addr = thr_ptr - (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT); break; case svr4_tls_libc_glibc: /* GLIBC: The thread pointer (TP) points just beyond the end of the TCB (thread control block). On RISC-V, this struct (tcbhead_t) is defined to contain two pointers. The first is a pointer to the DTV and the second is a pointer to private data. So the DTV pointer address is 16 bytes (i.e. the size of two pointers) before thread pointer. */ dtv_ptr_addr = thr_ptr - 2 * (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT); break; default: throw_error (TLS_GENERIC_ERROR, _("Unknown RISC-V C library")); break; } gdb::byte_vector buf (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT); if (target_read_memory (dtv_ptr_addr, buf.data (), buf.size ()) != 0) throw_error (TLS_GENERIC_ERROR, _("Unable to fetch DTV address")); const struct builtin_type *builtin = builtin_type (gdbarch); CORE_ADDR dtv_addr = gdbarch_pointer_to_address (gdbarch, builtin->builtin_data_ptr, buf.data ()); return dtv_addr; } /* For internal TLS lookup, return the DTP offset, which is the offset to subtract from a DTV entry, in order to obtain the address of the TLS block. */ static ULONGEST riscv_linux_get_tls_dtp_offset (struct gdbarch *gdbarch, ptid_t ptid, svr4_tls_libc libc) { if (libc == svr4_tls_libc_musl) { /* This value is DTP_OFFSET in MUSL's arch/riscv64/pthread_arch.h. It represents the value to subtract from the DTV entry, once it has been loaded. */ return 0x800; } else return 0; } /* Initialize RISC-V Linux ABI info. */ static void riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { riscv_gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); linux_init_abi (info, gdbarch, 0); set_gdbarch_get_next_pcs (gdbarch, riscv_software_single_step); set_solib_svr4_ops (gdbarch, (riscv_isa_xlen (gdbarch) == 4 ? make_linux_ilp32_svr4_solib_ops : make_linux_lp64_svr4_solib_ops)); /* GNU/Linux uses SVR4-style shared libraries. */ set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); /* Enable TLS support. */ set_gdbarch_fetch_tls_load_module_address (gdbarch, svr4_fetch_objfile_link_map); set_gdbarch_get_thread_local_address (gdbarch, svr4_tls_get_thread_local_address); svr4_tls_register_tls_methods (info, gdbarch, riscv_linux_get_tls_dtv_addr, riscv_linux_get_tls_dtp_offset); set_gdbarch_iterate_over_regset_sections (gdbarch, riscv_linux_iterate_over_regset_sections); tramp_frame_prepend_unwinder (gdbarch, &riscv_linux_sigframe); tdep->syscall_next_pc = riscv_linux_syscall_next_pc; tdep->riscv_syscall_record = riscv_linux_syscall_record; riscv64_linux_record_tdep_init (gdbarch, riscv_linux_record_tdep); } /* Initialize RISC-V Linux target support. */ INIT_GDB_FILE (riscv_linux_tdep) { gdbarch_register_osabi (bfd_arch_riscv, 0, GDB_OSABI_LINUX, riscv_linux_init_abi); }