diff options
Diffstat (limited to 'gdb/i386-nat.c')
| -rw-r--r-- | gdb/i386-nat.c | 145 |
1 files changed, 106 insertions, 39 deletions
diff --git a/gdb/i386-nat.c b/gdb/i386-nat.c index fa17823..e52de1e 100644 --- a/gdb/i386-nat.c +++ b/gdb/i386-nat.c @@ -25,6 +25,7 @@ #include "gdbcmd.h" #include "target.h" #include "gdb_assert.h" +#include "inferior.h" /* Support for hardware watchpoints and breakpoints using the i386 debug registers. @@ -170,14 +171,72 @@ i386_init_dregs (struct i386_debug_reg_state *state) state->dr_status_mirror = 0; } -/* The local mirror of the inferior's debug registers. Currently this - is a global, but it should really be per-inferior. */ -static struct i386_debug_reg_state dr_mirror; +/* Per-inferior data key. */ +static const struct inferior_data *i386_inferior_data; + +/* Per-inferior data. */ +struct i386_inferior_data +{ + /* Copy of i386 hardware debug registers for performance reasons. */ + struct i386_debug_reg_state state; +}; + +/* Get data specific for INFERIOR_PTID LWP. Return special data area + for processes being detached. */ + +static struct i386_inferior_data * +i386_inferior_data_get (void) +{ + /* Intermediate patch stub. */ + static struct i386_inferior_data inf_data_local; + struct inferior *inf = current_inferior (); + struct i386_inferior_data *inf_data = &inf_data_local; + + if (inf->pid != ptid_get_pid (inferior_ptid)) + { + /* INFERIOR_PTID is being detached from the inferior INF. + Provide local cache specific for the detached LWP. */ + + static struct i386_inferior_data detached_inf_data_local; + static int detached_inf_pid = -1; + + if (detached_inf_pid != ptid_get_pid (inferior_ptid)) + { + /* Reinitialize the local cache if INFERIOR_PTID is + different from the LWP last detached. + + Linux kernel before 2.6.33 commit + 72f674d203cd230426437cdcf7dd6f681dad8b0d + will inherit hardware debug registers from parent + on fork/vfork/clone. Newer Linux kernels create such tasks with + zeroed debug registers. + + GDB will remove all breakpoints (and watchpoints) from the forked + off process. We also need to reset the debug registers in that + process to be compatible with the older Linux kernels. + + Copy the debug registers mirrors into the new process so that all + breakpoints and watchpoints can be removed together. The debug + registers mirror will become zeroed in the end before detaching + the forked off process. */ + + detached_inf_pid = ptid_get_pid (inferior_ptid); + detached_inf_data_local = *inf_data; + } + + return &detached_inf_data_local; + } + + return inf_data; +} + +/* Get debug registers state for INFERIOR_PTID, see + i386_inferior_data_get. */ struct i386_debug_reg_state * i386_debug_reg_state (void) { - return &dr_mirror; + return &i386_inferior_data_get ()->state; } /* Whether or not to print the mirrored debug registers. */ @@ -230,7 +289,9 @@ static int i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state void i386_cleanup_dregs (void) { - i386_init_dregs (&dr_mirror); + struct i386_debug_reg_state *state = i386_debug_reg_state (); + + i386_init_dregs (state); } /* Print the values of the mirrored debug registers. This is called @@ -494,20 +555,21 @@ Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n"), static void i386_update_inferior_debug_regs (struct i386_debug_reg_state *new_state) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); int i; ALL_DEBUG_REGISTERS (i) { - if (I386_DR_VACANT (new_state, i) != I386_DR_VACANT (&dr_mirror, i)) + if (I386_DR_VACANT (new_state, i) != I386_DR_VACANT (state, i)) i386_dr_low.set_addr (i, new_state->dr_mirror[i]); else - gdb_assert (new_state->dr_mirror[i] == dr_mirror.dr_mirror[i]); + gdb_assert (new_state->dr_mirror[i] == state->dr_mirror[i]); } - if (new_state->dr_control_mirror != dr_mirror.dr_control_mirror) + if (new_state->dr_control_mirror != state->dr_control_mirror) i386_dr_low.set_control (new_state->dr_control_mirror); - dr_mirror = *new_state; + *state = *new_state; } /* Insert a watchpoint to watch a memory region which starts at @@ -518,10 +580,11 @@ static int i386_insert_watchpoint (CORE_ADDR addr, int len, int type, struct expression *cond) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); int retval; /* Work on a local copy of the debug registers, and on success, commit the change back to the inferior. */ - struct i386_debug_reg_state local_state = dr_mirror; + struct i386_debug_reg_state local_state = *state; if (type == hw_read) return 1; /* unsupported */ @@ -542,7 +605,7 @@ i386_insert_watchpoint (CORE_ADDR addr, int len, int type, i386_update_inferior_debug_regs (&local_state); if (maint_show_dr) - i386_show_dr (&dr_mirror, "insert_watchpoint", addr, len, type); + i386_show_dr (state, "insert_watchpoint", addr, len, type); return retval; } @@ -554,10 +617,11 @@ static int i386_remove_watchpoint (CORE_ADDR addr, int len, int type, struct expression *cond) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); int retval; /* Work on a local copy of the debug registers, and on success, commit the change back to the inferior. */ - struct i386_debug_reg_state local_state = dr_mirror; + struct i386_debug_reg_state local_state = *state; if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8)) || addr % len != 0) @@ -575,7 +639,7 @@ i386_remove_watchpoint (CORE_ADDR addr, int len, int type, i386_update_inferior_debug_regs (&local_state); if (maint_show_dr) - i386_show_dr (&dr_mirror, "remove_watchpoint", addr, len, type); + i386_show_dr (state, "remove_watchpoint", addr, len, type); return retval; } @@ -586,11 +650,12 @@ i386_remove_watchpoint (CORE_ADDR addr, int len, int type, static int i386_region_ok_for_watchpoint (CORE_ADDR addr, int len) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); int nregs; /* Compute how many aligned watchpoints we would need to cover this region. */ - nregs = i386_handle_nonaligned_watchpoint (&dr_mirror, + nregs = i386_handle_nonaligned_watchpoint (state, WP_COUNT, addr, len, hw_write); return nregs <= DR_NADDR ? 1 : 0; } @@ -602,6 +667,7 @@ i386_region_ok_for_watchpoint (CORE_ADDR addr, int len) static int i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); CORE_ADDR addr = 0; int i; int rc = 0; @@ -615,25 +681,24 @@ i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p) unsigned control = 0; /* In non-stop/async, threads can be running while we change the - global dr_mirror (and friends). Say, we set a watchpoint, and - let threads resume. Now, say you delete the watchpoint, or - add/remove watchpoints such that dr_mirror changes while threads - are running. On targets that support non-stop, - inserting/deleting watchpoints updates the global dr_mirror only. - It does not update the real thread's debug registers; that's only - done prior to resume. Instead, if threads are running when the - mirror changes, a temporary and transparent stop on all threads - is forced so they can get their copy of the debug registers - updated on re-resume. Now, say, a thread hit a watchpoint before - having been updated with the new dr_mirror contents, and we - haven't yet handled the corresponding SIGTRAP. If we trusted - dr_mirror below, we'd mistake the real trapped address (from the - last time we had updated debug registers in the thread) with - whatever was currently in dr_mirror. So to fix this, dr_mirror - always represents intention, what we _want_ threads to have in - debug registers. To get at the address and cause of the trap, we - need to read the state the thread still has in its debug - registers. + STATE (and friends). Say, we set a watchpoint, and let threads + resume. Now, say you delete the watchpoint, or add/remove + watchpoints such that STATE changes while threads are running. + On targets that support non-stop, inserting/deleting watchpoints + updates the STATE only. It does not update the real thread's + debug registers; that's only done prior to resume. Instead, if + threads are running when the mirror changes, a temporary and + transparent stop on all threads is forced so they can get their + copy of the debug registers updated on re-resume. Now, say, + a thread hit a watchpoint before having been updated with the new + STATE contents, and we haven't yet handled the corresponding + SIGTRAP. If we trusted STATE below, we'd mistake the real + trapped address (from the last time we had updated debug + registers in the thread) with whatever was currently in STATE. + So to fix this, STATE always represents intention, what we _want_ + threads to have in debug registers. To get at the address and + cause of the trap, we need to read the state the thread still has + in its debug registers. In sum, always get the current debug register values the current thread has, instead of trusting the global mirror. If the thread @@ -663,11 +728,11 @@ i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p) addr = i386_dr_low.get_addr (i); rc = 1; if (maint_show_dr) - i386_show_dr (&dr_mirror, "watchpoint_hit", addr, -1, hw_write); + i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write); } } if (maint_show_dr && addr == 0) - i386_show_dr (&dr_mirror, "stopped_data_addr", 0, 0, hw_write); + i386_show_dr (state, "stopped_data_addr", 0, 0, hw_write); if (rc) *addr_p = addr; @@ -687,11 +752,12 @@ static int i386_insert_hw_breakpoint (struct gdbarch *gdbarch, struct bp_target_info *bp_tgt) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); unsigned len_rw = i386_length_and_rw_bits (1, hw_execute); CORE_ADDR addr = bp_tgt->placed_address; /* Work on a local copy of the debug registers, and on success, commit the change back to the inferior. */ - struct i386_debug_reg_state local_state = dr_mirror; + struct i386_debug_reg_state local_state = *state; int retval = i386_insert_aligned_watchpoint (&local_state, addr, len_rw) ? EBUSY : 0; @@ -699,7 +765,7 @@ i386_insert_hw_breakpoint (struct gdbarch *gdbarch, i386_update_inferior_debug_regs (&local_state); if (maint_show_dr) - i386_show_dr (&dr_mirror, "insert_hwbp", addr, 1, hw_execute); + i386_show_dr (state, "insert_hwbp", addr, 1, hw_execute); return retval; } @@ -711,11 +777,12 @@ static int i386_remove_hw_breakpoint (struct gdbarch *gdbarch, struct bp_target_info *bp_tgt) { + struct i386_debug_reg_state *state = i386_debug_reg_state (); unsigned len_rw = i386_length_and_rw_bits (1, hw_execute); CORE_ADDR addr = bp_tgt->placed_address; /* Work on a local copy of the debug registers, and on success, commit the change back to the inferior. */ - struct i386_debug_reg_state local_state = dr_mirror; + struct i386_debug_reg_state local_state = *state; int retval = i386_remove_aligned_watchpoint (&local_state, addr, len_rw); @@ -723,7 +790,7 @@ i386_remove_hw_breakpoint (struct gdbarch *gdbarch, i386_update_inferior_debug_regs (&local_state); if (maint_show_dr) - i386_show_dr (&dr_mirror, "remove_hwbp", addr, 1, hw_execute); + i386_show_dr (state, "remove_hwbp", addr, 1, hw_execute); return retval; } |