diff options
Diffstat (limited to 'gdb/riscv-linux-tdep.c')
| -rw-r--r-- | gdb/riscv-linux-tdep.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/gdb/riscv-linux-tdep.c b/gdb/riscv-linux-tdep.c index f21039a..e1ea615 100644 --- a/gdb/riscv-linux-tdep.c +++ b/gdb/riscv-linux-tdep.c @@ -20,6 +20,7 @@ #include "osabi.h" #include "glibc-tdep.h" #include "linux-tdep.h" +#include "svr4-tls-tdep.h" #include "solib-svr4.h" #include "regset.h" #include "tramp-frame.h" @@ -28,6 +29,7 @@ #include "record-full.h" #include "linux-record.h" #include "riscv-linux-tdep.h" +#include "inferior.h" extern unsigned int record_debug; @@ -426,6 +428,79 @@ riscv64_linux_record_tdep_init (struct gdbarch *gdbarch, 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 @@ -451,6 +526,10 @@ riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) /* 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); |