[PATCH 8/9] Support TLS variables on FreeBSD/riscv.

John Baldwin
2019-01-22T18:52:27Z

Derive the pointer to the DTV array from the tp register.

gdb/ChangeLog:

* riscv-fbsd-tdep.c (riscv_fbsd_get_thread_local_address): New.
(riscv_fbsd_init_abi): Install gdbarch
"fetch_tls_load_module_address" and "get_thread_local_address"
methods.
---
gdb/ChangeLog | 7 +++++++
gdb/riscv-fbsd-tdep.c | 27 +++++++++++++++++++++++++++
2 files changed, 34 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 06c637c80a..5d228614db 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2019-01-22 John Baldwin <jhb@FreeBSD.org>
+
+ * riscv-fbsd-tdep.c (riscv_fbsd_get_thread_local_address): New.
+ (riscv_fbsd_init_abi): Install gdbarch
+ "fetch_tls_load_module_address" and "get_thread_local_address"
+ methods.
+
2019-01-22 John Baldwin <jhb@FreeBSD.org>

* i386-fbsd-tdep.c (i386fbsd_get_thread_local_address): New.
diff --git a/gdb/riscv-fbsd-tdep.c b/gdb/riscv-fbsd-tdep.c
index 97ad28f59a..3125a2285e 100644
--- a/gdb/riscv-fbsd-tdep.c
+++ b/gdb/riscv-fbsd-tdep.c
@@ -174,6 +174,28 @@ static const struct tramp_frame riscv_fbsd_sigframe =
riscv_fbsd_sigframe_init
};

+/* Implement the "get_thread_local_address" gdbarch method. */
+
+static CORE_ADDR
+riscv_fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
+ CORE_ADDR lm_addr, CORE_ADDR offset)
+{
+ struct regcache *regcache;
+
+ regcache = get_thread_arch_regcache (ptid, gdbarch);
+
+ target_fetch_registers (regcache, RISCV_TP_REGNUM);
+
+ ULONGEST tp;
+ if (regcache->cooked_read (RISCV_TP_REGNUM, &tp) != REG_VALID)
+ error (_("Unable to fetch %%tp"));
+
+ /* %tp points to the end of the TCB which contains two pointers.
+ The first pointer in the TCB points to the DTV array. */
+ CORE_ADDR dtv_addr = tp - (gdbarch_ptr_bit (gdbarch) / 8) * 2;
+ return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
+}
+
/* Implement the 'init_osabi' method of struct gdb_osabi_handler. */

static void
@@ -193,6 +215,11 @@ riscv_fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)

set_gdbarch_iterate_over_regset_sections
(gdbarch, riscv_fbsd_iterate_over_regset_sections);
+
+ set_gdbarch_fetch_tls_load_module_address (gdbarch,
+ svr4_fetch_objfile_link_map);
+ set_gdbarch_get_thread_local_address (gdbarch,
+ riscv_fbsd_get_thread_local_address);
}

void
--
2.19.2