/* S390 native-dependent code for GDB, the GNU debugger.
- Copyright (C) 2001-2016 Free Software Foundation, Inc.
+ Copyright (C) 2001-2017 Free Software Foundation, Inc.
Contributed by D.J. Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
for IBM Deutschland Entwicklung GmbH, IBM Corporation.
#include "gregset.h"
#include "regset.h"
#include "nat/linux-ptrace.h"
+#include "gdbcmd.h"
#include "s390-linux-tdep.h"
#include "elf/common.h"
#include <sys/procfs.h>
#include <sys/ucontext.h>
#include <elf.h>
+#include <algorithm>
+#include "inf-ptrace.h"
/* Per-thread arch-specific data. */
#define S390_PSWA_OFFSET 8
#endif
+/* PER-event mask bits and PER control bits (CR9). */
+
+#define PER_BIT(n) (1UL << (63 - (n)))
+#define PER_EVENT_BRANCH PER_BIT (32)
+#define PER_EVENT_IFETCH PER_BIT (33)
+#define PER_EVENT_STORE PER_BIT (34)
+#define PER_EVENT_NULLIFICATION PER_BIT (39)
+#define PER_CONTROL_BRANCH_ADDRESS PER_BIT (40)
+#define PER_CONTROL_SUSPENSION PER_BIT (41)
+#define PER_CONTROL_ALTERATION PER_BIT (42)
+
+
/* Fill GDB's register array with the general-purpose register values
in *REGP.
s390_linux_fetch_inferior_registers (struct target_ops *ops,
struct regcache *regcache, int regnum)
{
- int tid = s390_inferior_tid ();
+ pid_t tid = get_ptrace_pid (regcache_get_ptid (regcache));
if (regnum == -1 || S390_IS_GREGSET_REGNUM (regnum))
fetch_regs (regcache, tid);
s390_linux_store_inferior_registers (struct target_ops *ops,
struct regcache *regcache, int regnum)
{
- int tid = s390_inferior_tid ();
+ pid_t tid = get_ptrace_pid (regcache_get_ptid (regcache));
if (regnum == -1 || S390_IS_GREGSET_REGNUM (regnum))
store_regs (regcache, tid, regnum);
/* Hardware-assisted watchpoint handling. */
-/* We maintain a list of all currently active watchpoints in order
- to properly handle watchpoint removal.
+/* For each process we maintain a list of all currently active
+ watchpoints, in order to properly handle watchpoint removal.
The only thing we actually need is the total address space area
spanned by the watchpoints. */
DEF_VEC_O (s390_watch_area);
-VEC_s390_watch_area *watch_areas = NULL;
+/* Hardware debug state. */
+
+struct s390_debug_reg_state
+{
+ VEC_s390_watch_area *watch_areas;
+ VEC_s390_watch_area *break_areas;
+};
+
+/* Per-process data. */
+
+struct s390_process_info
+{
+ struct s390_process_info *next;
+ pid_t pid;
+ struct s390_debug_reg_state state;
+};
+
+static struct s390_process_info *s390_process_list = NULL;
+
+/* Find process data for process PID. */
+
+static struct s390_process_info *
+s390_find_process_pid (pid_t pid)
+{
+ struct s390_process_info *proc;
+
+ for (proc = s390_process_list; proc; proc = proc->next)
+ if (proc->pid == pid)
+ return proc;
+
+ return NULL;
+}
+
+/* Add process data for process PID. Returns newly allocated info
+ object. */
+
+static struct s390_process_info *
+s390_add_process (pid_t pid)
+{
+ struct s390_process_info *proc = XCNEW (struct s390_process_info);
+
+ proc->pid = pid;
+ proc->next = s390_process_list;
+ s390_process_list = proc;
+
+ return proc;
+}
+
+/* Get data specific info for process PID, creating it if necessary.
+ Never returns NULL. */
+
+static struct s390_process_info *
+s390_process_info_get (pid_t pid)
+{
+ struct s390_process_info *proc;
+
+ proc = s390_find_process_pid (pid);
+ if (proc == NULL)
+ proc = s390_add_process (pid);
+
+ return proc;
+}
+
+/* Get hardware debug state for process PID. */
+
+static struct s390_debug_reg_state *
+s390_get_debug_reg_state (pid_t pid)
+{
+ return &s390_process_info_get (pid)->state;
+}
+
+/* Called whenever GDB is no longer debugging process PID. It deletes
+ data structures that keep track of hardware debug state. */
+
+static void
+s390_forget_process (pid_t pid)
+{
+ struct s390_process_info *proc, **proc_link;
+
+ proc = s390_process_list;
+ proc_link = &s390_process_list;
+
+ while (proc != NULL)
+ {
+ if (proc->pid == pid)
+ {
+ VEC_free (s390_watch_area, proc->state.watch_areas);
+ VEC_free (s390_watch_area, proc->state.break_areas);
+ *proc_link = proc->next;
+ xfree (proc);
+ return;
+ }
+
+ proc_link = &proc->next;
+ proc = *proc_link;
+ }
+}
+
+/* linux_nat_new_fork hook. */
+
+static void
+s390_linux_new_fork (struct lwp_info *parent, pid_t child_pid)
+{
+ pid_t parent_pid;
+ struct s390_debug_reg_state *parent_state;
+ struct s390_debug_reg_state *child_state;
+
+ /* NULL means no watchpoint has ever been set in the parent. In
+ that case, there's nothing to do. */
+ if (lwp_arch_private_info (parent) == NULL)
+ return;
+
+ /* GDB core assumes the child inherits the watchpoints/hw breakpoints of
+ the parent. So copy the debug state from parent to child. */
+
+ parent_pid = ptid_get_pid (parent->ptid);
+ parent_state = s390_get_debug_reg_state (parent_pid);
+ child_state = s390_get_debug_reg_state (child_pid);
+
+ child_state->watch_areas = VEC_copy (s390_watch_area,
+ parent_state->watch_areas);
+ child_state->break_areas = VEC_copy (s390_watch_area,
+ parent_state->break_areas);
+}
+
+/* Dump PER state. */
+
+static void
+s390_show_debug_regs (int tid, const char *where)
+{
+ per_struct per_info;
+ ptrace_area parea;
+
+ parea.len = sizeof (per_info);
+ parea.process_addr = (addr_t) &per_info;
+ parea.kernel_addr = offsetof (struct user_regs_struct, per_info);
+
+ if (ptrace (PTRACE_PEEKUSR_AREA, tid, &parea, 0) < 0)
+ perror_with_name (_("Couldn't retrieve debug regs"));
+
+ debug_printf ("PER (debug) state for %d -- %s\n"
+ " cr9-11: %lx %lx %lx\n"
+ " start, end: %lx %lx\n"
+ " code/ATMID: %x address: %lx PAID: %x\n",
+ tid,
+ where,
+ per_info.control_regs.words.cr[0],
+ per_info.control_regs.words.cr[1],
+ per_info.control_regs.words.cr[2],
+ per_info.starting_addr,
+ per_info.ending_addr,
+ per_info.lowcore.words.perc_atmid,
+ per_info.lowcore.words.address,
+ per_info.lowcore.words.access_id);
+}
static int
s390_stopped_by_watchpoint (struct target_ops *ops)
{
+ struct s390_debug_reg_state *state
+ = s390_get_debug_reg_state (ptid_get_pid (inferior_ptid));
per_lowcore_bits per_lowcore;
ptrace_area parea;
int result;
+ if (show_debug_regs)
+ s390_show_debug_regs (s390_inferior_tid (), "stop");
+
/* Speed up common case. */
- if (VEC_empty (s390_watch_area, watch_areas))
+ if (VEC_empty (s390_watch_area, state->watch_areas))
return 0;
parea.len = sizeof (per_lowcore);
s390_prepare_to_resume (struct lwp_info *lp)
{
int tid;
+ pid_t pid = ptid_get_pid (ptid_of_lwp (lp));
per_struct per_info;
ptrace_area parea;
unsigned ix;
s390_watch_area *area;
struct arch_lwp_info *lp_priv = lwp_arch_private_info (lp);
+ struct s390_debug_reg_state *state = s390_get_debug_reg_state (pid);
+ int step = lwp_is_stepping (lp);
- if (lp_priv == NULL || !lp_priv->per_info_changed)
+ /* Nothing to do if there was never any PER info for this thread. */
+ if (lp_priv == NULL)
return;
+ /* If PER info has changed, update it. When single-stepping, disable
+ hardware breakpoints (if any). Otherwise we're done. */
+ if (!lp_priv->per_info_changed)
+ {
+ if (!step || VEC_empty (s390_watch_area, state->break_areas))
+ return;
+ }
+
lp_priv->per_info_changed = 0;
tid = ptid_get_lwp (ptid_of_lwp (lp));
if (tid == 0)
- tid = ptid_get_pid (ptid_of_lwp (lp));
+ tid = pid;
parea.len = sizeof (per_info);
parea.process_addr = (addr_t) & per_info;
parea.kernel_addr = offsetof (struct user_regs_struct, per_info);
- if (ptrace (PTRACE_PEEKUSR_AREA, tid, &parea, 0) < 0)
- perror_with_name (_("Couldn't retrieve watchpoint status"));
- if (!VEC_empty (s390_watch_area, watch_areas))
+ /* Clear PER info, but adjust the single_step field (used by older
+ kernels only). */
+ memset (&per_info, 0, sizeof (per_info));
+ per_info.single_step = (step != 0);
+
+ if (!VEC_empty (s390_watch_area, state->watch_areas))
{
for (ix = 0;
- VEC_iterate (s390_watch_area, watch_areas, ix, area);
+ VEC_iterate (s390_watch_area, state->watch_areas, ix, area);
ix++)
{
- watch_lo_addr = min (watch_lo_addr, area->lo_addr);
- watch_hi_addr = max (watch_hi_addr, area->hi_addr);
+ watch_lo_addr = std::min (watch_lo_addr, area->lo_addr);
+ watch_hi_addr = std::max (watch_hi_addr, area->hi_addr);
}
- per_info.control_regs.bits.em_storage_alteration = 1;
- per_info.control_regs.bits.storage_alt_space_ctl = 1;
+ /* Enable storage-alteration events. */
+ per_info.control_regs.words.cr[0] |= (PER_EVENT_STORE
+ | PER_CONTROL_ALTERATION);
}
- else
+
+ if (!VEC_empty (s390_watch_area, state->break_areas))
{
- per_info.control_regs.bits.em_storage_alteration = 0;
- per_info.control_regs.bits.storage_alt_space_ctl = 0;
+ /* Don't install hardware breakpoints while single-stepping, since
+ our PER settings (e.g. the nullification bit) might then conflict
+ with the kernel's. But re-install them afterwards. */
+ if (step)
+ lp_priv->per_info_changed = 1;
+ else
+ {
+ for (ix = 0;
+ VEC_iterate (s390_watch_area, state->break_areas, ix, area);
+ ix++)
+ {
+ watch_lo_addr = std::min (watch_lo_addr, area->lo_addr);
+ watch_hi_addr = std::max (watch_hi_addr, area->hi_addr);
+ }
+
+ /* If there's just one breakpoint, enable instruction-fetching
+ nullification events for the breakpoint address (fast).
+ Otherwise stop after any instruction within the PER area and
+ after any branch into it (slow). */
+ if (watch_hi_addr == watch_lo_addr)
+ per_info.control_regs.words.cr[0] |= (PER_EVENT_NULLIFICATION
+ | PER_EVENT_IFETCH);
+ else
+ {
+ /* The PER area must include the instruction before the
+ first breakpoint address. */
+ watch_lo_addr = watch_lo_addr > 6 ? watch_lo_addr - 6 : 0;
+ per_info.control_regs.words.cr[0]
+ |= (PER_EVENT_BRANCH
+ | PER_EVENT_IFETCH
+ | PER_CONTROL_BRANCH_ADDRESS);
+ }
+ }
}
per_info.starting_addr = watch_lo_addr;
per_info.ending_addr = watch_hi_addr;
if (ptrace (PTRACE_POKEUSR_AREA, tid, &parea, 0) < 0)
perror_with_name (_("Couldn't modify watchpoint status"));
+
+ if (show_debug_regs)
+ s390_show_debug_regs (tid, "resume");
}
/* Mark the PER info as changed, so the next resume will update it. */
struct expression *cond)
{
s390_watch_area area;
+ struct s390_debug_reg_state *state
+ = s390_get_debug_reg_state (ptid_get_pid (inferior_ptid));
area.lo_addr = addr;
area.hi_addr = addr + len - 1;
- VEC_safe_push (s390_watch_area, watch_areas, &area);
+ VEC_safe_push (s390_watch_area, state->watch_areas, &area);
return s390_refresh_per_info ();
}
{
unsigned ix;
s390_watch_area *area;
+ struct s390_debug_reg_state *state
+ = s390_get_debug_reg_state (ptid_get_pid (inferior_ptid));
for (ix = 0;
- VEC_iterate (s390_watch_area, watch_areas, ix, area);
+ VEC_iterate (s390_watch_area, state->watch_areas, ix, area);
ix++)
{
if (area->lo_addr == addr && area->hi_addr == addr + len - 1)
{
- VEC_unordered_remove (s390_watch_area, watch_areas, ix);
+ VEC_unordered_remove (s390_watch_area, state->watch_areas, ix);
return s390_refresh_per_info ();
}
}
return -1;
}
+/* Implement the "can_use_hw_breakpoint" target_ops method. */
+
static int
s390_can_use_hw_breakpoint (struct target_ops *self,
enum bptype type, int cnt, int othertype)
{
- return type == bp_hardware_watchpoint;
+ if (type == bp_hardware_watchpoint || type == bp_hardware_breakpoint)
+ return 1;
+ return 0;
+}
+
+/* Implement the "insert_hw_breakpoint" target_ops method. */
+
+static int
+s390_insert_hw_breakpoint (struct target_ops *self,
+ struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
+{
+ s390_watch_area area;
+ struct s390_debug_reg_state *state;
+
+ area.lo_addr = bp_tgt->placed_address = bp_tgt->reqstd_address;
+ area.hi_addr = area.lo_addr;
+ state = s390_get_debug_reg_state (ptid_get_pid (inferior_ptid));
+ VEC_safe_push (s390_watch_area, state->break_areas, &area);
+
+ return s390_refresh_per_info ();
+}
+
+/* Implement the "remove_hw_breakpoint" target_ops method. */
+
+static int
+s390_remove_hw_breakpoint (struct target_ops *self,
+ struct gdbarch *gdbarch,
+ struct bp_target_info *bp_tgt)
+{
+ unsigned ix;
+ struct watch_area *area;
+ struct s390_debug_reg_state *state;
+
+ state = s390_get_debug_reg_state (ptid_get_pid (inferior_ptid));
+ for (ix = 0;
+ VEC_iterate (s390_watch_area, state->break_areas, ix, area);
+ ix++)
+ {
+ if (area->lo_addr == bp_tgt->placed_address)
+ {
+ VEC_unordered_remove (s390_watch_area, state->break_areas, ix);
+ return s390_refresh_per_info ();
+ }
+ }
+
+ fprintf_unfiltered (gdb_stderr,
+ "Attempt to remove nonexistent breakpoint.\n");
+ return -1;
}
static int
/* Add our watchpoint methods. */
t->to_can_use_hw_breakpoint = s390_can_use_hw_breakpoint;
+ t->to_insert_hw_breakpoint = s390_insert_hw_breakpoint;
+ t->to_remove_hw_breakpoint = s390_remove_hw_breakpoint;
t->to_region_ok_for_hw_watchpoint = s390_region_ok_for_hw_watchpoint;
t->to_have_continuable_watchpoint = 1;
t->to_stopped_by_watchpoint = s390_stopped_by_watchpoint;
linux_nat_add_target (t);
linux_nat_set_new_thread (t, s390_new_thread);
linux_nat_set_prepare_to_resume (t, s390_prepare_to_resume);
+ linux_nat_set_forget_process (t, s390_forget_process);
+ linux_nat_set_new_fork (t, s390_linux_new_fork);
+
+ /* A maintenance command to enable showing the PER state. */
+ add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
+ &show_debug_regs, _("\
+Set whether to show the PER (debug) hardware state."), _("\
+Show whether to show the PER (debug) hardware state."), _("\
+Use \"on\" to enable, \"off\" to disable.\n\
+If enabled, the PER state is shown after it is changed by GDB,\n\
+and when the inferior triggers a breakpoint or watchpoint."),
+ NULL,
+ NULL,
+ &maintenance_set_cmdlist,
+ &maintenance_show_cmdlist);
}
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