diff options
Diffstat (limited to 'gdb/i386-nat.c')
| -rw-r--r-- | gdb/i386-nat.c | 534 |
1 files changed, 5 insertions, 529 deletions
diff --git a/gdb/i386-nat.c b/gdb/i386-nat.c index c956583..750b878 100644 --- a/gdb/i386-nat.c +++ b/gdb/i386-nat.c @@ -19,11 +19,7 @@ #include "defs.h" #include "i386-nat.h" -#include "breakpoint.h" -#include "command.h" #include "gdbcmd.h" -#include "target.h" -#include "gdb_assert.h" #include "inferior.h" /* Support for hardware watchpoints and breakpoints using the i386 @@ -38,122 +34,11 @@ counts, and allow to watch regions up to 16 bytes long. */ /* Whether or not to print the mirrored debug registers. */ -static int debug_hw_points; - -/* Function used for printing mirrored debug registers. */ -#define debug_printf(fmt, args...) \ - fprintf_unfiltered (gdb_stdlog, fmt, ##args); +int debug_hw_points; /* Low-level function vector. */ struct i386_dr_low_type i386_dr_low; -/* Support for 8-byte wide hw watchpoints. */ -#define TARGET_HAS_DR_LEN_8 (i386_get_debug_register_length () == 8) - -/* DR7 Debug Control register fields. */ - -/* How many bits to skip in DR7 to get to R/W and LEN fields. */ -#define DR_CONTROL_SHIFT 16 -/* How many bits in DR7 per R/W and LEN field for each watchpoint. */ -#define DR_CONTROL_SIZE 4 - -/* Watchpoint/breakpoint read/write fields in DR7. */ -#define DR_RW_EXECUTE (0x0) /* Break on instruction execution. */ -#define DR_RW_WRITE (0x1) /* Break on data writes. */ -#define DR_RW_READ (0x3) /* Break on data reads or writes. */ - -/* This is here for completeness. No platform supports this - functionality yet (as of March 2001). Note that the DE flag in the - CR4 register needs to be set to support this. */ -#ifndef DR_RW_IORW -#define DR_RW_IORW (0x2) /* Break on I/O reads or writes. */ -#endif - -/* Watchpoint/breakpoint length fields in DR7. The 2-bit left shift - is so we could OR this with the read/write field defined above. */ -#define DR_LEN_1 (0x0 << 2) /* 1-byte region watch or breakpoint. */ -#define DR_LEN_2 (0x1 << 2) /* 2-byte region watch. */ -#define DR_LEN_4 (0x3 << 2) /* 4-byte region watch. */ -#define DR_LEN_8 (0x2 << 2) /* 8-byte region watch (AMD64). */ - -/* Local and Global Enable flags in DR7. - - When the Local Enable flag is set, the breakpoint/watchpoint is - enabled only for the current task; the processor automatically - clears this flag on every task switch. When the Global Enable flag - is set, the breakpoint/watchpoint is enabled for all tasks; the - processor never clears this flag. - - Currently, all watchpoint are locally enabled. If you need to - enable them globally, read the comment which pertains to this in - i386_insert_aligned_watchpoint below. */ -#define DR_LOCAL_ENABLE_SHIFT 0 /* Extra shift to the local enable bit. */ -#define DR_GLOBAL_ENABLE_SHIFT 1 /* Extra shift to the global enable bit. */ -#define DR_ENABLE_SIZE 2 /* Two enable bits per debug register. */ - -/* Local and global exact breakpoint enable flags (a.k.a. slowdown - flags). These are only required on i386, to allow detection of the - exact instruction which caused a watchpoint to break; i486 and - later processors do that automatically. We set these flags for - backwards compatibility. */ -#define DR_LOCAL_SLOWDOWN (0x100) -#define DR_GLOBAL_SLOWDOWN (0x200) - -/* Fields reserved by Intel. This includes the GD (General Detect - Enable) flag, which causes a debug exception to be generated when a - MOV instruction accesses one of the debug registers. - - FIXME: My Intel manual says we should use 0xF800, not 0xFC00. */ -#define DR_CONTROL_RESERVED (0xFC00) - -/* Auxiliary helper macros. */ - -/* A value that masks all fields in DR7 that are reserved by Intel. */ -#define I386_DR_CONTROL_MASK (~DR_CONTROL_RESERVED) - -/* The I'th debug register is vacant if its Local and Global Enable - bits are reset in the Debug Control register. */ -#define I386_DR_VACANT(state, i) \ - (((state)->dr_control_mirror & (3 << (DR_ENABLE_SIZE * (i)))) == 0) - -/* Locally enable the break/watchpoint in the I'th debug register. */ -#define I386_DR_LOCAL_ENABLE(state, i) \ - do { \ - (state)->dr_control_mirror |= \ - (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))); \ - } while (0) - -/* Globally enable the break/watchpoint in the I'th debug register. */ -#define I386_DR_GLOBAL_ENABLE(state, i) \ - do { \ - (state)->dr_control_mirror |= \ - (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))); \ - } while (0) - -/* Disable the break/watchpoint in the I'th debug register. */ -#define I386_DR_DISABLE(state, i) \ - do { \ - (state)->dr_control_mirror &= \ - ~(3 << (DR_ENABLE_SIZE * (i))); \ - } while (0) - -/* Set in DR7 the RW and LEN fields for the I'th debug register. */ -#define I386_DR_SET_RW_LEN(state, i, rwlen) \ - do { \ - (state)->dr_control_mirror &= \ - ~(0x0f << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))); \ - (state)->dr_control_mirror |= \ - ((rwlen) << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))); \ - } while (0) - -/* Get from DR7 the RW and LEN fields for the I'th debug register. */ -#define I386_DR_GET_RW_LEN(dr7, i) \ - (((dr7) \ - >> (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * (i))) & 0x0f) - -/* Did the watchpoint whose address is in the I'th register break? */ -#define I386_DR_WATCH_HIT(dr6, i) ((dr6) & (1 << (i))) - /* Per-process data. We don't bind this to a per-inferior registry because of targets like x86 GNU/Linux that need to keep track of processes that aren't bound to any inferior (e.g., fork children, @@ -252,11 +137,6 @@ i386_forget_process (pid_t pid) } } -/* Types of operations supported by i386_handle_nonaligned_watchpoint. */ -typedef enum { WP_INSERT, WP_REMOVE, WP_COUNT } i386_wp_op_t; - -/* Implementation. */ - /* Clear the reference counts and forget everything we knew about the debug registers. */ @@ -267,281 +147,6 @@ i386_cleanup_dregs (void) i386_forget_process (ptid_get_pid (inferior_ptid)); } -/* Print the values of the mirrored debug registers. */ - -static void -i386_show_dr (struct i386_debug_reg_state *state, - const char *func, CORE_ADDR addr, - int len, enum target_hw_bp_type type) -{ - int i; - - debug_printf ("%s", func); - if (addr || len) - debug_printf (" (addr=%s, len=%d, type=%s)", - phex (addr, 8), len, - type == hw_write ? "data-write" - : (type == hw_read ? "data-read" - : (type == hw_access ? "data-read/write" - : (type == hw_execute ? "instruction-execute" - /* FIXME: if/when I/O read/write - watchpoints are supported, add them - here. */ - : "??unknown??")))); - debug_printf (":\n"); - debug_printf ("\tCONTROL (DR7): %s STATUS (DR6): %s\n", - phex (state->dr_control_mirror, 8), - phex (state->dr_status_mirror, 8)); - ALL_DEBUG_REGISTERS (i) - { - debug_printf ("\ -\tDR%d: addr=0x%s, ref.count=%d DR%d: addr=0x%s, ref.count=%d\n", - i, phex (state->dr_mirror[i], - i386_get_debug_register_length ()), - state->dr_ref_count[i], - i + 1, phex (state->dr_mirror[i + 1], - i386_get_debug_register_length ()), - state->dr_ref_count[i + 1]); - i++; - } -} - -/* Return the value of a 4-bit field for DR7 suitable for watching a - region of LEN bytes for accesses of type TYPE. LEN is assumed to - have the value of 1, 2, or 4. */ - -static unsigned -i386_length_and_rw_bits (int len, enum target_hw_bp_type type) -{ - unsigned rw; - - switch (type) - { - case hw_execute: - rw = DR_RW_EXECUTE; - break; - case hw_write: - rw = DR_RW_WRITE; - break; - case hw_read: - internal_error (__FILE__, __LINE__, - _("The i386 doesn't support " - "data-read watchpoints.\n")); - case hw_access: - rw = DR_RW_READ; - break; -#if 0 - /* Not yet supported. */ - case hw_io_access: - rw = DR_RW_IORW; - break; -#endif - default: - internal_error (__FILE__, __LINE__, _("\ -Invalid hardware breakpoint type %d in i386_length_and_rw_bits.\n"), - (int) type); - } - - switch (len) - { - case 1: - return (DR_LEN_1 | rw); - case 2: - return (DR_LEN_2 | rw); - case 4: - return (DR_LEN_4 | rw); - case 8: - if (TARGET_HAS_DR_LEN_8) - return (DR_LEN_8 | rw); - /* ELSE FALL THROUGH */ - default: - internal_error (__FILE__, __LINE__, _("\ -Invalid hardware breakpoint length %d in i386_length_and_rw_bits.\n"), len); - } -} - -/* Insert a watchpoint at address ADDR, which is assumed to be aligned - according to the length of the region to watch. LEN_RW_BITS is the - value of the bits from DR7 which describes the length and access - type of the region to be watched by this watchpoint. Return 0 on - success, -1 on failure. */ - -static int -i386_insert_aligned_watchpoint (struct i386_debug_reg_state *state, - CORE_ADDR addr, unsigned len_rw_bits) -{ - int i; - - if (!i386_dr_low_can_set_addr () || !i386_dr_low_can_set_control ()) - return -1; - - /* First, look for an occupied debug register with the same address - and the same RW and LEN definitions. If we find one, we can - reuse it for this watchpoint as well (and save a register). */ - ALL_DEBUG_REGISTERS (i) - { - if (!I386_DR_VACANT (state, i) - && state->dr_mirror[i] == addr - && I386_DR_GET_RW_LEN (state->dr_control_mirror, i) == len_rw_bits) - { - state->dr_ref_count[i]++; - return 0; - } - } - - /* Next, look for a vacant debug register. */ - ALL_DEBUG_REGISTERS (i) - { - if (I386_DR_VACANT (state, i)) - break; - } - - /* No more debug registers! */ - if (i >= DR_NADDR) - return -1; - - /* Now set up the register I to watch our region. */ - - /* Record the info in our local mirrored array. */ - state->dr_mirror[i] = addr; - state->dr_ref_count[i] = 1; - I386_DR_SET_RW_LEN (state, i, len_rw_bits); - /* Note: we only enable the watchpoint locally, i.e. in the current - task. Currently, no i386 target allows or supports global - watchpoints; however, if any target would want that in the - future, GDB should probably provide a command to control whether - to enable watchpoints globally or locally, and the code below - should use global or local enable and slow-down flags as - appropriate. */ - I386_DR_LOCAL_ENABLE (state, i); - state->dr_control_mirror |= DR_LOCAL_SLOWDOWN; - state->dr_control_mirror &= I386_DR_CONTROL_MASK; - - return 0; -} - -/* Remove a watchpoint at address ADDR, which is assumed to be aligned - according to the length of the region to watch. LEN_RW_BITS is the - value of the bits from DR7 which describes the length and access - type of the region watched by this watchpoint. Return 0 on - success, -1 on failure. */ - -static int -i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state, - CORE_ADDR addr, unsigned len_rw_bits) -{ - int i, retval = -1; - - ALL_DEBUG_REGISTERS (i) - { - if (!I386_DR_VACANT (state, i) - && state->dr_mirror[i] == addr - && I386_DR_GET_RW_LEN (state->dr_control_mirror, i) == len_rw_bits) - { - if (--state->dr_ref_count[i] == 0) /* No longer in use? */ - { - /* Reset our mirror. */ - state->dr_mirror[i] = 0; - I386_DR_DISABLE (state, i); - } - retval = 0; - } - } - - return retval; -} - -/* Insert or remove a (possibly non-aligned) watchpoint, or count the - number of debug registers required to watch a region at address - ADDR whose length is LEN for accesses of type TYPE. Return 0 on - successful insertion or removal, a positive number when queried - about the number of registers, or -1 on failure. If WHAT is not a - valid value, bombs through internal_error. */ - -static int -i386_handle_nonaligned_watchpoint (struct i386_debug_reg_state *state, - i386_wp_op_t what, CORE_ADDR addr, int len, - enum target_hw_bp_type type) -{ - int retval = 0; - int max_wp_len = TARGET_HAS_DR_LEN_8 ? 8 : 4; - - static const int size_try_array[8][8] = - { - {1, 1, 1, 1, 1, 1, 1, 1}, /* Trying size one. */ - {2, 1, 2, 1, 2, 1, 2, 1}, /* Trying size two. */ - {2, 1, 2, 1, 2, 1, 2, 1}, /* Trying size three. */ - {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size four. */ - {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size five. */ - {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size six. */ - {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size seven. */ - {8, 1, 2, 1, 4, 1, 2, 1}, /* Trying size eight. */ - }; - - while (len > 0) - { - int align = addr % max_wp_len; - /* Four (eight on AMD64) is the maximum length a debug register - can watch. */ - int try = (len > max_wp_len ? (max_wp_len - 1) : len - 1); - int size = size_try_array[try][align]; - - if (what == WP_COUNT) - { - /* size_try_array[] is defined such that each iteration - through the loop is guaranteed to produce an address and a - size that can be watched with a single debug register. - Thus, for counting the registers required to watch a - region, we simply need to increment the count on each - iteration. */ - retval++; - } - else - { - unsigned len_rw = i386_length_and_rw_bits (size, type); - - if (what == WP_INSERT) - retval = i386_insert_aligned_watchpoint (state, addr, len_rw); - else if (what == WP_REMOVE) - retval = i386_remove_aligned_watchpoint (state, addr, len_rw); - else - internal_error (__FILE__, __LINE__, _("\ -Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n"), - (int) what); - if (retval) - break; - } - - addr += size; - len -= size; - } - - return retval; -} - -/* Update the inferior debug registers state, in STATE, with the - new debug registers state, in NEW_STATE. */ - -static void -i386_update_inferior_debug_regs (struct i386_debug_reg_state *state, - struct i386_debug_reg_state *new_state) -{ - int i; - - ALL_DEBUG_REGISTERS (i) - { - if (I386_DR_VACANT (new_state, i) != I386_DR_VACANT (state, i)) - i386_dr_low_set_addr (new_state, i); - else - gdb_assert (new_state->dr_mirror[i] == state->dr_mirror[i]); - } - - if (new_state->dr_control_mirror != state->dr_control_mirror) - i386_dr_low_set_control (new_state); - - *state = *new_state; -} - /* Insert a watchpoint to watch a memory region which starts at address ADDR and whose length is LEN bytes. Watch memory accesses of the type TYPE. Return 0 on success, -1 on failure. */ @@ -553,37 +158,8 @@ i386_insert_watchpoint (struct target_ops *self, { struct i386_debug_reg_state *state = i386_debug_reg_state (ptid_get_pid (inferior_ptid)); - 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 = *state; - - if (type == hw_read) - return 1; /* unsupported */ - - if (((len != 1 && len != 2 && len != 4) - && !(TARGET_HAS_DR_LEN_8 && len == 8)) - || addr % len != 0) - { - retval = i386_handle_nonaligned_watchpoint (&local_state, - WP_INSERT, - addr, len, type); - } - else - { - unsigned len_rw = i386_length_and_rw_bits (len, type); - - retval = i386_insert_aligned_watchpoint (&local_state, - addr, len_rw); - } - - if (retval == 0) - i386_update_inferior_debug_regs (state, &local_state); - if (debug_hw_points) - i386_show_dr (state, "insert_watchpoint", addr, len, type); - - return retval; + return i386_dr_insert_watchpoint (state, type, addr, len); } /* Remove a watchpoint that watched the memory region which starts at @@ -596,34 +172,8 @@ i386_remove_watchpoint (struct target_ops *self, { struct i386_debug_reg_state *state = i386_debug_reg_state (ptid_get_pid (inferior_ptid)); - 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 = *state; - - if (((len != 1 && len != 2 && len != 4) - && !(TARGET_HAS_DR_LEN_8 && len == 8)) - || addr % len != 0) - { - retval = i386_handle_nonaligned_watchpoint (&local_state, - WP_REMOVE, - addr, len, type); - } - else - { - unsigned len_rw = i386_length_and_rw_bits (len, type); - - retval = i386_remove_aligned_watchpoint (&local_state, - addr, len_rw); - } - if (retval == 0) - i386_update_inferior_debug_regs (state, &local_state); - - if (debug_hw_points) - i386_show_dr (state, "remove_watchpoint", addr, len, type); - - return retval; + return i386_dr_remove_watchpoint (state, type, addr, len); } /* Return non-zero if we can watch a memory region that starts at @@ -635,13 +185,8 @@ i386_region_ok_for_watchpoint (struct target_ops *self, { struct i386_debug_reg_state *state = i386_debug_reg_state (ptid_get_pid (inferior_ptid)); - int nregs; - /* Compute how many aligned watchpoints we would need to cover this - region. */ - nregs = i386_handle_nonaligned_watchpoint (state, WP_COUNT, - addr, len, hw_write); - return nregs <= DR_NADDR ? 1 : 0; + return i386_dr_region_ok_for_watchpoint (state, addr, len); } /* If the inferior has some break/watchpoint that triggered, set the @@ -653,77 +198,8 @@ i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p) { struct i386_debug_reg_state *state = i386_debug_reg_state (ptid_get_pid (inferior_ptid)); - CORE_ADDR addr = 0; - int i; - int rc = 0; - /* The current thread's DR_STATUS. We always need to read this to - check whether some watchpoint caused the trap. */ - unsigned status; - /* We need DR_CONTROL as well, but only iff DR_STATUS indicates a - data breakpoint trap. Only fetch it when necessary, to avoid an - unnecessary extra syscall when no watchpoint triggered. */ - int control_p = 0; - 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. - - In sum, always get the current debug register values the current - thread has, instead of trusting the global mirror. If the thread - was running when we last changed watchpoints, the mirror no - longer represents what was set in this thread's debug - registers. */ - status = i386_dr_low_get_status (); - - ALL_DEBUG_REGISTERS (i) - { - if (!I386_DR_WATCH_HIT (status, i)) - continue; - - if (!control_p) - { - control = i386_dr_low_get_control (); - control_p = 1; - } - - /* This second condition makes sure DRi is set up for a data - watchpoint, not a hardware breakpoint. The reason is that - GDB doesn't call the target_stopped_data_address method - except for data watchpoints. In other words, I'm being - paranoiac. */ - if (I386_DR_GET_RW_LEN (control, i) != 0) - { - addr = i386_dr_low_get_addr (i); - rc = 1; - if (debug_hw_points) - i386_show_dr (state, "watchpoint_hit", addr, -1, hw_write); - } - } - - if (debug_hw_points && addr == 0) - i386_show_dr (state, "stopped_data_addr", 0, 0, hw_write); - if (rc) - *addr_p = addr; - return rc; + return i386_dr_stopped_data_address (state, addr_p); } /* Return non-zero if the inferior has some watchpoint that triggered. |