gdbserver/linux-x86: make is_64bit_tdesc accept thread as a parameter

ps_get_thread_area receives as a parameter the lwpid it must work on.
It then calls is_64bit_tdesc, which uses the current_thread as the
thread to work on.  However, it is not said that both are the same.

This became a problem when working in a following patch that makes
find_one_thread switch to a process but to no thread (current_thread ==
nullptr).  When libthread_db needed to get the thread area,
is_64bit_tdesc would try to get the regcache of a nullptr thread.

Fix that by making is_64bit_tdesc accept the thread to work on as a
parameter.  Find the right thread from the context, when possible (when
we know the lwpid to work on).  Otherwise, pass "current_thread", to
retain the existing behavior.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I44394d6be92392fa28de71982fd04517ce8a3007
This commit is contained in:
Simon Marchi 2022-11-15 16:48:41 -05:00 committed by Simon Marchi
parent d4895ba2df
commit 4855cbdc3d

View File

@ -271,13 +271,12 @@ static /*const*/ int i386_regmap[] =
#ifdef __x86_64__
/* Returns true if the current inferior belongs to a x86-64 process,
per the tdesc. */
/* Returns true if THREAD belongs to a x86-64 process, per the tdesc. */
static int
is_64bit_tdesc (void)
is_64bit_tdesc (thread_info *thread)
{
struct regcache *regcache = get_thread_regcache (current_thread, 0);
struct regcache *regcache = get_thread_regcache (thread, 0);
return register_size (regcache->tdesc, 0) == 8;
}
@ -292,7 +291,9 @@ ps_get_thread_area (struct ps_prochandle *ph,
lwpid_t lwpid, int idx, void **base)
{
#ifdef __x86_64__
int use_64bit = is_64bit_tdesc ();
lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
gdb_assert (lwp != nullptr);
int use_64bit = is_64bit_tdesc (get_lwp_thread (lwp));
if (use_64bit)
{
@ -335,7 +336,9 @@ int
x86_target::low_get_thread_area (int lwpid, CORE_ADDR *addr)
{
#ifdef __x86_64__
int use_64bit = is_64bit_tdesc ();
lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
gdb_assert (lwp != nullptr);
int use_64bit = is_64bit_tdesc (get_lwp_thread (lwp));
if (use_64bit)
{
@ -351,7 +354,6 @@ x86_target::low_get_thread_area (int lwpid, CORE_ADDR *addr)
#endif
{
struct lwp_info *lwp = find_lwp_pid (ptid_t (lwpid));
struct thread_info *thr = get_lwp_thread (lwp);
struct regcache *regcache = get_thread_regcache (thr, 1);
unsigned int desc[4];
@ -379,7 +381,7 @@ bool
x86_target::low_cannot_store_register (int regno)
{
#ifdef __x86_64__
if (is_64bit_tdesc ())
if (is_64bit_tdesc (current_thread))
return false;
#endif
@ -390,7 +392,7 @@ bool
x86_target::low_cannot_fetch_register (int regno)
{
#ifdef __x86_64__
if (is_64bit_tdesc ())
if (is_64bit_tdesc (current_thread))
return false;
#endif
@ -815,7 +817,7 @@ x86_target::low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
int is_elf64 = linux_pid_exe_is_elf_64_file (tid, &machine);
/* Is the inferior 32-bit? If so, then fixup the siginfo object. */
if (!is_64bit_tdesc ())
if (!is_64bit_tdesc (current_thread))
return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
FIXUP_32);
/* No fixup for native x32 GDB. */
@ -1078,7 +1080,7 @@ const regs_info *
x86_target::get_regs_info ()
{
#ifdef __x86_64__
if (is_64bit_tdesc ())
if (is_64bit_tdesc (current_thread))
return &amd64_linux_regs_info;
else
#endif
@ -1553,7 +1555,7 @@ x86_target::install_fast_tracepoint_jump_pad (CORE_ADDR tpoint,
char *err)
{
#ifdef __x86_64__
if (is_64bit_tdesc ())
if (is_64bit_tdesc (current_thread))
return amd64_install_fast_tracepoint_jump_pad (tpoint, tpaddr,
collector, lockaddr,
orig_size, jump_entry,
@ -1587,7 +1589,7 @@ x86_target::get_min_fast_tracepoint_insn_len ()
#ifdef __x86_64__
/* On x86-64, 5-byte jump instructions with a 4-byte offset are always
used for fast tracepoints. */
if (is_64bit_tdesc ())
if (is_64bit_tdesc (current_thread))
return 5;
#endif
@ -2931,7 +2933,7 @@ emit_ops *
x86_target::emit_ops ()
{
#ifdef __x86_64__
if (is_64bit_tdesc ())
if (is_64bit_tdesc (current_thread))
return &amd64_emit_ops;
else
#endif