From 8193adea2f86e37423a5d0acffb69b80bde05d52 Mon Sep 17 00:00:00 2001 From: Andreas Arnez Date: Fri, 16 Sep 2016 19:25:55 +0200 Subject: [PATCH] S390: Hardware breakpoint support Add hardware breakpoint support for S390 targets. gdb/ChangeLog: * s390-linux-nat.c (PER_BIT, PER_EVENT_BRANCH, PER_EVENT_IFETCH) (PER_EVENT_STORE, PER_EVENT_NULLIFICATION) (PER_CONTROL_BRANCH_ADDRESS, PER_CONTROL_SUSPENSION) (PER_CONTROL_ALTERATION): New macros. (struct s390_debug_reg_state) : New member. (s390_forget_process): Free break_areas as well. (s390_linux_new_fork): Copy break_areas as well. (s390_prepare_to_resume): Install hardware breakpoints. (s390_can_use_hw_breakpoint): Indicate support for hardware breakpoints. (s390_insert_hw_breakpoint, s390_remove_hw_breakpoint): New linux_nat target methods. (_initialize_s390_nat): Register them. gdb/testsuite/ChangeLog: * lib/gdb.exp: No longer skip hardware breakpoint tests on s390. --- gdb/ChangeLog | 16 +++++ gdb/s390-linux-nat.c | 132 +++++++++++++++++++++++++++++++++++--- gdb/testsuite/ChangeLog | 4 ++ gdb/testsuite/lib/gdb.exp | 3 +- 4 files changed, 145 insertions(+), 10 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 1aef462ba0..91b31ef420 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,19 @@ +2016-09-16 Andreas Arnez + + * s390-linux-nat.c (PER_BIT, PER_EVENT_BRANCH, PER_EVENT_IFETCH) + (PER_EVENT_STORE, PER_EVENT_NULLIFICATION) + (PER_CONTROL_BRANCH_ADDRESS, PER_CONTROL_SUSPENSION) + (PER_CONTROL_ALTERATION): New macros. + (struct s390_debug_reg_state) : New member. + (s390_forget_process): Free break_areas as well. + (s390_linux_new_fork): Copy break_areas as well. + (s390_prepare_to_resume): Install hardware breakpoints. + (s390_can_use_hw_breakpoint): Indicate support for hardware + breakpoints. + (s390_insert_hw_breakpoint, s390_remove_hw_breakpoint): New + linux_nat target methods. + (_initialize_s390_nat): Register them. + 2016-09-16 Andreas Arnez * nat/linux-nat.h (lwp_is_stepping): New declaration. diff --git a/gdb/s390-linux-nat.c b/gdb/s390-linux-nat.c index c5d9bd3c94..d1d2bf8e37 100644 --- a/gdb/s390-linux-nat.c +++ b/gdb/s390-linux-nat.c @@ -93,6 +93,18 @@ static const struct regset s390_64_gregset = #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. @@ -450,6 +462,7 @@ DEF_VEC_O (s390_watch_area); struct s390_debug_reg_state { VEC_s390_watch_area *watch_areas; + VEC_s390_watch_area *break_areas; }; /* Per-process data. */ @@ -531,6 +544,7 @@ s390_forget_process (pid_t pid) 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; @@ -564,6 +578,8 @@ s390_linux_new_fork (struct lwp_info *parent, pid_t 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. */ @@ -649,10 +665,20 @@ s390_prepare_to_resume (struct lwp_info *lp) 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)); @@ -662,8 +688,11 @@ s390_prepare_to_resume (struct lwp_info *lp) 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")); + + /* 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)) { @@ -675,13 +704,46 @@ s390_prepare_to_resume (struct lwp_info *lp) watch_hi_addr = 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 = min (watch_lo_addr, area->lo_addr); + watch_hi_addr = 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; @@ -777,11 +839,61 @@ s390_remove_watchpoint (struct target_ops *self, 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 @@ -904,6 +1016,8 @@ _initialize_s390_nat (void) /* 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; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 68b194ed4c..730eeb7f1a 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2016-09-16 Andreas Arnez + + * lib/gdb.exp: No longer skip hardware breakpoint tests on s390. + 2016-09-16 Jan Kratochvil * gdb.cp/casts.cc (decltype): Move it ... diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp index e538812484..758db46d56 100644 --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -2953,7 +2953,8 @@ proc skip_hw_breakpoint_tests {} { || [istarget "x86_64-*-*"] || [istarget "ia64-*-*"] || [istarget "arm*-*-*"] - || [istarget "aarch64*-*-*"]} { + || [istarget "aarch64*-*-*"] + || [istarget "s390*-*-*"] } { return 0 }