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Diffstat (limited to 'gdb/i386-nat.c')
| -rw-r--r-- | gdb/i386-nat.c | 643 |
1 files changed, 0 insertions, 643 deletions
diff --git a/gdb/i386-nat.c b/gdb/i386-nat.c deleted file mode 100644 index 53a81a4..0000000 --- a/gdb/i386-nat.c +++ /dev/null @@ -1,643 +0,0 @@ -/* Intel x86 (a.k.a. ia32) native-dependent code. - Copyright (C) 2001 Free Software Foundation, Inc. - - This file is part of GDB. - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - -#include "defs.h" -#include "breakpoint.h" -#include "command.h" -#include "gdbcmd.h" - -/* Support for hardware watchpoints and breakpoints using the x86 - debug registers. - - This provides several functions for inserting and removing - hardware-assisted breakpoints and watchpoints, testing if - one or more of the watchpoints triggered and at what address, - checking whether a given region can be watched, etc. - - A target which wants to use these functions should define - several macros, such as `target_insert_watchpoint' and - `target_stopped_data_address', listed in target.h, to call - the appropriate functions below. It should also define - I386_USE_GENERIC_WATCHPOINTS in its tm.h file. - - In addition, each target should provide several low-level - macros that will be called to insert watchpoints and hardware - breakpoints into the inferior, remove them, and check their - status. These macros are: - - I386_DR_LOW_SET_CONTROL -- set the debug control (DR7) - register to a given value - - I386_DR_LOW_SET_ADDR -- put an address into one debug - register - - I386_DR_LOW_RESET_ADDR -- reset the address stored in - one debug register - - I386_DR_LOW_GET_STATUS -- return the value of the debug - status (DR6) register. - - The functions below implement debug registers sharing by - reference counts, and allow to watch regions up to 16 bytes - long. */ - -#ifdef I386_USE_GENERIC_WATCHPOINTS - -/* Support for 8-byte wide hw watchpoints. */ -#ifndef TARGET_HAS_DR_LEN_8 -#define TARGET_HAS_DR_LEN_8 0 -#endif - -/* Debug registers' indices. */ -#define DR_NADDR 4 /* the number of debug address registers */ -#define DR_STATUS 6 /* index of debug status register (DR6) */ -#define DR_CONTROL 7 /* index of debug control register (DR7) */ - -/* 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 Mar-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 breakpt */ -#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 (x86-64) */ - -/* 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 /* 2 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 - back 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(i) \ - ((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(i) \ - dr_control_mirror |= (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))) - -/* Globally enable the break/watchpoint in the I'th debug register. */ -#define I386_DR_GLOBAL_ENABLE(i) \ - dr_control_mirror |= (1 << (DR_GLOBAL_ENABLE_SHIFT + DR_ENABLE_SIZE * (i))) - -/* Disable the break/watchpoint in the I'th debug register. */ -#define I386_DR_DISABLE(i) \ - dr_control_mirror &= ~(3 << (DR_ENABLE_SIZE * (i))) - -/* Set in DR7 the RW and LEN fields for the I'th debug register. */ -#define I386_DR_SET_RW_LEN(i,rwlen) \ - do { \ - dr_control_mirror &= ~(0x0f << (DR_CONTROL_SHIFT+DR_CONTROL_SIZE*(i))); \ - 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(i) \ - ((dr_control_mirror >> (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(i) (dr_status_mirror & (1 << (i))) - -/* A macro to loop over all debug registers. */ -#define ALL_DEBUG_REGISTERS(i) for (i = 0; i < DR_NADDR; i++) - -/* Mirror the inferior's DRi registers. We keep the status and - control registers separated because they don't hold addresses. */ -static CORE_ADDR dr_mirror[DR_NADDR]; -static unsigned dr_status_mirror, dr_control_mirror; - -/* Reference counts for each debug register. */ -static int dr_ref_count[DR_NADDR]; - -/* Whether or not to print the mirrored debug registers. */ -static int maint_show_dr; - -/* Types of operations supported by i386_handle_nonaligned_watchpoint. */ -typedef enum { WP_INSERT, WP_REMOVE, WP_COUNT } i386_wp_op_t; - -/* Internal functions. */ - -/* 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); - -/* 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 bit-field 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 (CORE_ADDR addr, - unsigned len_rw_bits); - -/* 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 (CORE_ADDR addr, - unsigned len_rw_bits); - -/* 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 (i386_wp_op_t what, - CORE_ADDR addr, int len, - enum target_hw_bp_type type); - -/* Implementation. */ - -/* Clear the reference counts and forget everything we knew about - the debug registers. */ -void -i386_cleanup_dregs (void) -{ - int i; - - ALL_DEBUG_REGISTERS(i) - { - dr_mirror[i] = 0; - dr_ref_count[i] = 0; - } - dr_control_mirror = 0; - dr_status_mirror = 0; -} - -/* Reset all debug registers at each new startup - to avoid missing watchpoints after restart. */ -void -child_post_startup_inferior (ptid_t ptid) -{ - i386_cleanup_dregs (); -} - -/* Print the values of the mirrored debug registers. - This is called when maint_show_dr is non-zero. To set that - up, type "maint show-debug-regs" at GDB's prompt. */ -static void -i386_show_dr (const char *func, CORE_ADDR addr, - int len, enum target_hw_bp_type type) -{ - int i; - - puts_unfiltered (func); - if (addr || len) - printf_unfiltered (" (addr=%lx, len=%d, type=%s)", - /* This code is for ia32, so casting CORE_ADDR - to unsigned long should be okay. */ - (unsigned long)addr, 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??")))); - puts_unfiltered (":\n"); - printf_unfiltered ("\tCONTROL (DR7): %08x STATUS (DR6): %08x\n", - dr_control_mirror, dr_status_mirror); - ALL_DEBUG_REGISTERS(i) - { - printf_unfiltered ("\tDR%d: addr=0x%s, ref.count=%d DR%d: addr=0x%s, ref.count=%d\n", - i, paddr(dr_mirror[i]), dr_ref_count[i], - i+1, paddr(dr_mirror[i+1]), 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: /* x86 doesn't support data-read watchpoints */ - case hw_access: - rw = DR_RW_READ; - break; -#if 0 - case hw_io_access: /* not yet supported */ - rw = DR_RW_IORW; - break; -#endif - default: - internal_error (__FILE__, __LINE__, "\ -Invalid hw 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); - default: - internal_error (__FILE__, __LINE__, "\ -Invalid hw 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 (CORE_ADDR addr, unsigned len_rw_bits) -{ - int i; - - /* 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 (i) - && dr_mirror[i] == addr - && I386_DR_GET_RW_LEN (i) == len_rw_bits) - { - dr_ref_count[i]++; - return 0; - } - } - - /* Next, look for a vacant debug register. */ - ALL_DEBUG_REGISTERS(i) - { - if (I386_DR_VACANT (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. */ - dr_mirror[i] = addr; - dr_ref_count[i] = 1; - I386_DR_SET_RW_LEN (i, len_rw_bits); - /* Note: we only enable the watchpoint locally, i.e. in the current - task. Currently, no x86 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 (i); - dr_control_mirror |= DR_LOCAL_SLOWDOWN; - dr_control_mirror &= I386_DR_CONTROL_MASK; - - /* Finally, actually pass the info to the inferior. */ - I386_DR_LOW_SET_ADDR (i, addr); - I386_DR_LOW_SET_CONTROL (dr_control_mirror); - - 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 (CORE_ADDR addr, unsigned len_rw_bits) -{ - int i, retval = -1; - - ALL_DEBUG_REGISTERS(i) - { - if (!I386_DR_VACANT (i) - && dr_mirror[i] == addr - && I386_DR_GET_RW_LEN (i) == len_rw_bits) - { - if (--dr_ref_count[i] == 0) /* no longer in use? */ - { - /* Reset our mirror. */ - dr_mirror[i] = 0; - I386_DR_DISABLE (i); - /* Reset it in the inferior. */ - I386_DR_LOW_SET_CONTROL (dr_control_mirror); - I386_DR_LOW_RESET_ADDR (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 (i386_wp_op_t what, CORE_ADDR addr, int len, - enum target_hw_bp_type type) -{ - int align; - int size; - int rv = 0, status = 0; - int max_wp_len = TARGET_HAS_DR_LEN_8 ? 8 : 4; - - static 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) - { - align = addr % max_wp_len; - /* Four(eigth on x86_64) is the maximum length an x86 debug register - can watch. */ - size = size_try_array[len > max_wp_len ? (max_wp_len - 1) : len - 1][align]; - if (what == WP_COUNT) - /* size_try_array[] is defined so 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. */ - rv++; - else - { - unsigned len_rw = i386_length_and_rw_bits (size, type); - - if (what == WP_INSERT) - status = i386_insert_aligned_watchpoint (addr, len_rw); - else if (what == WP_REMOVE) - status = i386_remove_aligned_watchpoint (addr, len_rw); - else - internal_error (__FILE__, __LINE__, "\ -Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n", - (int)what); - /* We keep the loop going even after a failure, because some - of the other aligned watchpoints might still succeed - (e.g. if they watch addresses that are already watched, - in which case we just increment the reference counts of - occupied debug registers). If we break out of the loop - too early, we could cause those addresses watched by - other watchpoints to be disabled when breakpoint.c reacts - to our failure to insert this watchpoint and tries to - remove it. */ - if (status) - rv = status; - } - addr += size; - len -= size; - } - return rv; -} - -/* 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. */ -int -i386_insert_watchpoint (CORE_ADDR addr, int len, int type) -{ - int retval; - - if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8)) - || addr % len != 0) - retval = i386_handle_nonaligned_watchpoint (WP_INSERT, addr, len, type); - else - { - unsigned len_rw = i386_length_and_rw_bits (len, type); - - retval = i386_insert_aligned_watchpoint (addr, len_rw); - } - - if (maint_show_dr) - i386_show_dr ("insert_watchpoint", addr, len, type); - - return retval; -} - -/* Remove a watchpoint that watched the memory region which starts at - address ADDR, whose length is LEN bytes, and for accesses of the - type TYPE. Return 0 on success, -1 on failure. */ -int -i386_remove_watchpoint (CORE_ADDR addr, int len, int type) -{ - int retval; - - if (((len != 1 && len !=2 && len !=4) && !(TARGET_HAS_DR_LEN_8 && len == 8)) - || addr % len != 0) - retval = i386_handle_nonaligned_watchpoint (WP_REMOVE, addr, len, type); - else - { - unsigned len_rw = i386_length_and_rw_bits (len, type); - - retval = i386_remove_aligned_watchpoint (addr, len_rw); - } - - if (maint_show_dr) - i386_show_dr ("remove_watchpoint", addr, len, type); - - return retval; -} - -/* Return non-zero if we can watch a memory region that starts at - address ADDR and whose length is LEN bytes. */ -int -i386_region_ok_for_watchpoint (CORE_ADDR addr, int len) -{ - /* Compute how many aligned watchpoints we would need to cover this - region. */ - int nregs = i386_handle_nonaligned_watchpoint (WP_COUNT, addr, len, - hw_write); - - return nregs <= DR_NADDR ? 1 : 0; -} - -/* If the inferior has some watchpoint that triggered, return the - address associated with that watchpoint. Otherwise, return - zero. */ -CORE_ADDR -i386_stopped_data_address (void) -{ - int i; - CORE_ADDR ret = 0; - - dr_status_mirror = I386_DR_LOW_GET_STATUS (); - - ALL_DEBUG_REGISTERS(i) - { - if (I386_DR_WATCH_HIT (i) - /* 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. */ - && I386_DR_GET_RW_LEN (i) != 0) - { - ret = dr_mirror[i]; - if (maint_show_dr) - i386_show_dr ("watchpoint_hit", ret, -1, hw_write); - } - } - if (maint_show_dr && ret == 0) - i386_show_dr ("stopped_data_addr", 0, 0, hw_write); - - return ret; -} - -/* Return non-zero if the inferior has some break/watchpoint that - triggered. */ -int -i386_stopped_by_hwbp (void) -{ - int i; - - dr_status_mirror = I386_DR_LOW_GET_STATUS (); - if (maint_show_dr) - i386_show_dr ("stopped_by_hwbp", 0, 0, hw_execute); - - ALL_DEBUG_REGISTERS(i) - { - if (I386_DR_WATCH_HIT (i)) - return 1; - } - - return 0; -} - -/* Insert a hardware-assisted breakpoint at address ADDR. SHADOW is - unused. Return 0 on success, EBUSY on failure. */ -int -i386_insert_hw_breakpoint (CORE_ADDR addr, void *shadow) -{ - unsigned len_rw = i386_length_and_rw_bits (1, hw_execute); - int retval = i386_insert_aligned_watchpoint (addr, len_rw) ? EBUSY : 0; - - if (maint_show_dr) - i386_show_dr ("insert_hwbp", addr, 1, hw_execute); - - return retval; -} - -/* Remove a hardware-assisted breakpoint at address ADDR. SHADOW is - unused. Return 0 on success, -1 on failure. */ -int -i386_remove_hw_breakpoint (CORE_ADDR addr, void *shadow) -{ - unsigned len_rw = i386_length_and_rw_bits (1, hw_execute); - int retval = i386_remove_aligned_watchpoint (addr, len_rw); - - if (maint_show_dr) - i386_show_dr ("remove_hwbp", addr, 1, hw_execute); - - return retval; -} - -#endif /* I386_USE_GENERIC_WATCHPOINTS */ - - -void -_initialize_i386_nat (void) -{ -#ifdef I386_USE_GENERIC_WATCHPOINTS - /* A maintenance command to enable printing the internal DRi mirror - variables. */ - add_set_cmd ("show-debug-regs", class_maintenance, - var_boolean, (char *) &maint_show_dr, - "\ -Set whether to show variables that mirror the x86 debug registers.\n\ -Use \"on\" to enable, \"off\" to disable.\n\ -If enabled, the debug registers values are shown when GDB inserts\n\ -or removes a hardware breakpoint or watchpoint, and when the inferior\n\ -triggers a breakpoint or watchpoint.", &maintenancelist); -#endif -} |