#include "defs.h"
#include "displaced-stepping.h"
-#include "cli/cli-cmds.h"
+#include "cli/cli-cmds.h"
#include "command.h"
+#include "gdbarch.h"
+#include "gdbcore.h"
+#include "gdbthread.h"
+#include "inferior.h"
+#include "regcache.h"
+#include "target/target.h"
/* Default destructor for displaced_step_copy_insn_closure. */
fprintf_filtered (file, _("Displace stepping debugging is %s.\n"), value);
}
+displaced_step_prepare_status
+displaced_step_buffer::prepare (thread_info *thread, CORE_ADDR &displaced_pc)
+{
+ gdb_assert (!thread->displaced_step_state.in_progress ());
+
+ /* Is a thread currently using the buffer? */
+ if (m_current_thread != nullptr)
+ {
+ /* If so, it better not be this thread. */
+ gdb_assert (thread != m_current_thread);
+ return DISPLACED_STEP_PREPARE_STATUS_UNAVAILABLE;
+ }
+
+ regcache *regcache = get_thread_regcache (thread);
+ const address_space *aspace = regcache->aspace ();
+ gdbarch *arch = regcache->arch ();
+ ULONGEST len = gdbarch_max_insn_length (arch);
+
+ if (breakpoint_in_range_p (aspace, m_addr, len))
+ {
+ /* There's a breakpoint set in the scratch pad location range
+ (which is usually around the entry point). We'd either
+ install it before resuming, which would overwrite/corrupt the
+ scratch pad, or if it was already inserted, this displaced
+ step would overwrite it. The latter is OK in the sense that
+ we already assume that no thread is going to execute the code
+ in the scratch pad range (after initial startup) anyway, but
+ the former is unacceptable. Simply punt and fallback to
+ stepping over this breakpoint in-line. */
+ displaced_debug_printf ("breakpoint set in scratch pad. "
+ "Stepping over breakpoint in-line instead.");
+
+ return DISPLACED_STEP_PREPARE_STATUS_CANT;
+ }
+
+ m_original_pc = regcache_read_pc (regcache);
+ displaced_pc = m_addr;
+
+ /* Save the original contents of the displaced stepping buffer. */
+ m_saved_copy.resize (len);
+
+ int status = target_read_memory (m_addr, m_saved_copy.data (), len);
+ if (status != 0)
+ throw_error (MEMORY_ERROR,
+ _("Error accessing memory address %s (%s) for "
+ "displaced-stepping scratch space."),
+ paddress (arch, m_addr), safe_strerror (status));
+
+ displaced_debug_printf ("saved %s: %s",
+ paddress (arch, m_addr),
+ displaced_step_dump_bytes
+ (m_saved_copy.data (), len).c_str ());
+
+ /* Save this in a local variable first, so it's released if code below
+ throws. */
+ displaced_step_copy_insn_closure_up copy_insn_closure
+ = gdbarch_displaced_step_copy_insn (arch, m_original_pc, m_addr, regcache);
+
+ if (copy_insn_closure == nullptr)
+ {
+ /* The architecture doesn't know how or want to displaced step
+ this instruction or instruction sequence. Fallback to
+ stepping over the breakpoint in-line. */
+ return DISPLACED_STEP_PREPARE_STATUS_CANT;
+ }
+
+ /* Resume execution at the copy. */
+ regcache_write_pc (regcache, m_addr);
+
+ /* This marks the buffer as being in use. */
+ m_current_thread = thread;
+
+ /* Save this, now that we know everything went fine. */
+ m_copy_insn_closure = std::move (copy_insn_closure);
+
+ /* Tell infrun not to try preparing a displaced step again for this inferior. */
+ thread->inf->displaced_step_state.unavailable = true;
+
+ return DISPLACED_STEP_PREPARE_STATUS_OK;
+}
+
+static void
+write_memory_ptid (ptid_t ptid, CORE_ADDR memaddr,
+ const gdb_byte *myaddr, int len)
+{
+ scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
+
+ inferior_ptid = ptid;
+ write_memory (memaddr, myaddr, len);
+}
+
+static bool
+displaced_step_instruction_executed_successfully (gdbarch *arch,
+ gdb_signal signal)
+{
+ if (signal != GDB_SIGNAL_TRAP)
+ return false;
+
+ if (target_stopped_by_watchpoint ())
+ {
+ if (gdbarch_have_nonsteppable_watchpoint (arch)
+ || target_have_steppable_watchpoint ())
+ return false;
+ }
+
+ return true;
+}
+
+displaced_step_finish_status
+displaced_step_buffer::finish (gdbarch *arch, thread_info *thread,
+ gdb_signal sig)
+{
+ gdb_assert (thread->displaced_step_state.in_progress ());
+ gdb_assert (thread == m_current_thread);
+
+ /* Move this to a local variable so it's released in case something goes
+ wrong. */
+ displaced_step_copy_insn_closure_up copy_insn_closure
+ = std::move (m_copy_insn_closure);
+ gdb_assert (copy_insn_closure != nullptr);
+
+ /* Reset M_CURRENT_THREAD immediately to mark the buffer as available, in case
+ something goes wrong below. */
+ m_current_thread = nullptr;
+
+ /* Now that a buffer gets freed, tell infrun it can ask us to prepare a displaced
+ step again for this inferior. Do that here in case something goes wrong
+ below. */
+ thread->inf->displaced_step_state.unavailable = false;
+
+ ULONGEST len = gdbarch_max_insn_length (arch);
+
+ write_memory_ptid (thread->ptid, m_addr,
+ m_saved_copy.data (), len);
+
+ displaced_debug_printf ("restored %s %s",
+ target_pid_to_str (thread->ptid).c_str (),
+ paddress (arch, m_addr));
+
+ regcache *rc = get_thread_regcache (thread);
+
+ bool instruction_executed_successfully
+ = displaced_step_instruction_executed_successfully (arch, sig);
+
+ if (instruction_executed_successfully)
+ {
+ gdbarch_displaced_step_fixup (arch, copy_insn_closure.get (), m_original_pc,
+ m_addr, rc);
+ return DISPLACED_STEP_FINISH_STATUS_OK;
+ }
+ else
+ {
+ /* Since the instruction didn't complete, all we can do is relocate the
+ PC. */
+ CORE_ADDR pc = regcache_read_pc (rc);
+ pc = m_original_pc + (pc - m_addr);
+ regcache_write_pc (rc, pc);
+ return DISPLACED_STEP_FINISH_STATUS_NOT_EXECUTED;
+ }
+}
+
+const displaced_step_copy_insn_closure *
+displaced_step_buffer::copy_insn_closure_by_addr (CORE_ADDR addr)
+{
+ if (addr == m_addr)
+ return m_copy_insn_closure.get ();
+ else
+ return nullptr;
+}
+
+void
+displaced_step_buffer::restore_in_ptid (ptid_t ptid)
+{
+ if (m_current_thread != nullptr)
+ {
+ regcache *regcache = get_thread_regcache (m_current_thread);
+ gdbarch *arch = regcache->arch ();
+ ULONGEST len = gdbarch_max_insn_length (arch);
+
+ write_memory_ptid (ptid, m_addr, m_saved_copy.data (), len);
+
+ displaced_debug_printf ("restored in ptid %s %s",
+ target_pid_to_str (ptid).c_str (),
+ paddress (arch, m_addr));
+ }
+}
+
void _initialize_displaced_stepping ();
void
_initialize_displaced_stepping ()
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