diff options
Diffstat (limited to 'kernel/debug/kdb/kdb_bp.c')
| -rw-r--r-- | kernel/debug/kdb/kdb_bp.c | 591 |
1 files changed, 591 insertions, 0 deletions
diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c new file mode 100644 index 0000000000..372025cf1c --- /dev/null +++ b/kernel/debug/kdb/kdb_bp.c @@ -0,0 +1,591 @@ +/* + * Kernel Debugger Architecture Independent Breakpoint Handler + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved. + * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved. + */ + +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/kdb.h> +#include <linux/kgdb.h> +#include <linux/smp.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include "kdb_private.h" + +/* + * Table of kdb_breakpoints + */ +kdb_bp_t kdb_breakpoints[KDB_MAXBPT]; + +static void kdb_setsinglestep(struct pt_regs *regs) +{ + KDB_STATE_SET(DOING_SS); +} + +static char *kdb_rwtypes[] = { + "Instruction(i)", + "Instruction(Register)", + "Data Write", + "I/O", + "Data Access" +}; + +static char *kdb_bptype(kdb_bp_t *bp) +{ + if (bp->bp_type < 0 || bp->bp_type > 4) + return ""; + + return kdb_rwtypes[bp->bp_type]; +} + +static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp) +{ + int nextarg = *nextargp; + int diag; + + bp->bph_length = 1; + if ((argc + 1) != nextarg) { + if (strncasecmp(argv[nextarg], "datar", sizeof("datar")) == 0) + bp->bp_type = BP_ACCESS_WATCHPOINT; + else if (strncasecmp(argv[nextarg], "dataw", sizeof("dataw")) == 0) + bp->bp_type = BP_WRITE_WATCHPOINT; + else if (strncasecmp(argv[nextarg], "inst", sizeof("inst")) == 0) + bp->bp_type = BP_HARDWARE_BREAKPOINT; + else + return KDB_ARGCOUNT; + + bp->bph_length = 1; + + nextarg++; + + if ((argc + 1) != nextarg) { + unsigned long len; + + diag = kdbgetularg((char *)argv[nextarg], + &len); + if (diag) + return diag; + + + if (len > 8) + return KDB_BADLENGTH; + + bp->bph_length = len; + nextarg++; + } + + if ((argc + 1) != nextarg) + return KDB_ARGCOUNT; + } + + *nextargp = nextarg; + return 0; +} + +static int _kdb_bp_remove(kdb_bp_t *bp) +{ + int ret = 1; + if (!bp->bp_installed) + return ret; + if (!bp->bp_type) + ret = dbg_remove_sw_break(bp->bp_addr); + else + ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr, + bp->bph_length, + bp->bp_type); + if (ret == 0) + bp->bp_installed = 0; + return ret; +} + +static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp) +{ + if (KDB_DEBUG(BP)) + kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs)); + + /* + * Setup single step + */ + kdb_setsinglestep(regs); + + /* + * Reset delay attribute + */ + bp->bp_delay = 0; + bp->bp_delayed = 1; +} + +static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp) +{ + int ret; + /* + * Install the breakpoint, if it is not already installed. + */ + + if (KDB_DEBUG(BP)) + kdb_printf("%s: bp_installed %d\n", + __func__, bp->bp_installed); + if (!KDB_STATE(SSBPT)) + bp->bp_delay = 0; + if (bp->bp_installed) + return 1; + if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) { + if (KDB_DEBUG(BP)) + kdb_printf("%s: delayed bp\n", __func__); + kdb_handle_bp(regs, bp); + return 0; + } + if (!bp->bp_type) + ret = dbg_set_sw_break(bp->bp_addr); + else + ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr, + bp->bph_length, + bp->bp_type); + if (ret == 0) { + bp->bp_installed = 1; + } else { + kdb_printf("%s: failed to set breakpoint at 0x%lx\n", + __func__, bp->bp_addr); + if (!bp->bp_type) { + kdb_printf("Software breakpoints are unavailable.\n" + " Boot the kernel with rodata=off\n" + " OR use hw breaks: help bph\n"); + } + return 1; + } + return 0; +} + +/* + * kdb_bp_install + * + * Install kdb_breakpoints prior to returning from the + * kernel debugger. This allows the kdb_breakpoints to be set + * upon functions that are used internally by kdb, such as + * printk(). This function is only called once per kdb session. + */ +void kdb_bp_install(struct pt_regs *regs) +{ + int i; + + for (i = 0; i < KDB_MAXBPT; i++) { + kdb_bp_t *bp = &kdb_breakpoints[i]; + + if (KDB_DEBUG(BP)) { + kdb_printf("%s: bp %d bp_enabled %d\n", + __func__, i, bp->bp_enabled); + } + if (bp->bp_enabled) + _kdb_bp_install(regs, bp); + } +} + +/* + * kdb_bp_remove + * + * Remove kdb_breakpoints upon entry to the kernel debugger. + * + * Parameters: + * None. + * Outputs: + * None. + * Returns: + * None. + * Locking: + * None. + * Remarks: + */ +void kdb_bp_remove(void) +{ + int i; + + for (i = KDB_MAXBPT - 1; i >= 0; i--) { + kdb_bp_t *bp = &kdb_breakpoints[i]; + + if (KDB_DEBUG(BP)) { + kdb_printf("%s: bp %d bp_enabled %d\n", + __func__, i, bp->bp_enabled); + } + if (bp->bp_enabled) + _kdb_bp_remove(bp); + } +} + + +/* + * kdb_printbp + * + * Internal function to format and print a breakpoint entry. + * + * Parameters: + * None. + * Outputs: + * None. + * Returns: + * None. + * Locking: + * None. + * Remarks: + */ + +static void kdb_printbp(kdb_bp_t *bp, int i) +{ + kdb_printf("%s ", kdb_bptype(bp)); + kdb_printf("BP #%d at ", i); + kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT); + + if (bp->bp_enabled) + kdb_printf("\n is enabled "); + else + kdb_printf("\n is disabled"); + + kdb_printf(" addr at %016lx, hardtype=%d installed=%d\n", + bp->bp_addr, bp->bp_type, bp->bp_installed); + + kdb_printf("\n"); +} + +/* + * kdb_bp + * + * Handle the bp commands. + * + * [bp|bph] <addr-expression> [DATAR|DATAW] + * + * Parameters: + * argc Count of arguments in argv + * argv Space delimited command line arguments + * Outputs: + * None. + * Returns: + * Zero for success, a kdb diagnostic if failure. + * Locking: + * None. + * Remarks: + * + * bp Set breakpoint on all cpus. Only use hardware assist if need. + * bph Set breakpoint on all cpus. Force hardware register + */ + +static int kdb_bp(int argc, const char **argv) +{ + int i, bpno; + kdb_bp_t *bp, *bp_check; + int diag; + char *symname = NULL; + long offset = 0ul; + int nextarg; + kdb_bp_t template = {0}; + + if (argc == 0) { + /* + * Display breakpoint table + */ + for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; + bpno++, bp++) { + if (bp->bp_free) + continue; + kdb_printbp(bp, bpno); + } + + return 0; + } + + nextarg = 1; + diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr, + &offset, &symname); + if (diag) + return diag; + if (!template.bp_addr) + return KDB_BADINT; + + /* + * This check is redundant (since the breakpoint machinery should + * be doing the same check during kdb_bp_install) but gives the + * user immediate feedback. + */ + diag = kgdb_validate_break_address(template.bp_addr); + if (diag) + return diag; + + /* + * Find an empty bp structure to allocate + */ + for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) { + if (bp->bp_free) + break; + } + + if (bpno == KDB_MAXBPT) + return KDB_TOOMANYBPT; + + if (strcmp(argv[0], "bph") == 0) { + template.bp_type = BP_HARDWARE_BREAKPOINT; + diag = kdb_parsebp(argc, argv, &nextarg, &template); + if (diag) + return diag; + } else { + template.bp_type = BP_BREAKPOINT; + } + + /* + * Check for clashing breakpoints. + * + * Note, in this design we can't have hardware breakpoints + * enabled for both read and write on the same address. + */ + for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT; + i++, bp_check++) { + if (!bp_check->bp_free && + bp_check->bp_addr == template.bp_addr) { + kdb_printf("You already have a breakpoint at " + kdb_bfd_vma_fmt0 "\n", template.bp_addr); + return KDB_DUPBPT; + } + } + + template.bp_enabled = 1; + + /* + * Actually allocate the breakpoint found earlier + */ + *bp = template; + bp->bp_free = 0; + + kdb_printbp(bp, bpno); + + return 0; +} + +/* + * kdb_bc + * + * Handles the 'bc', 'be', and 'bd' commands + * + * [bd|bc|be] <breakpoint-number> + * [bd|bc|be] * + * + * Parameters: + * argc Count of arguments in argv + * argv Space delimited command line arguments + * Outputs: + * None. + * Returns: + * Zero for success, a kdb diagnostic for failure + * Locking: + * None. + * Remarks: + */ +static int kdb_bc(int argc, const char **argv) +{ + unsigned long addr; + kdb_bp_t *bp = NULL; + int lowbp = KDB_MAXBPT; + int highbp = 0; + int done = 0; + int i; + int diag = 0; + + int cmd; /* KDBCMD_B? */ +#define KDBCMD_BC 0 +#define KDBCMD_BE 1 +#define KDBCMD_BD 2 + + if (strcmp(argv[0], "be") == 0) + cmd = KDBCMD_BE; + else if (strcmp(argv[0], "bd") == 0) + cmd = KDBCMD_BD; + else + cmd = KDBCMD_BC; + + if (argc != 1) + return KDB_ARGCOUNT; + + if (strcmp(argv[1], "*") == 0) { + lowbp = 0; + highbp = KDB_MAXBPT; + } else { + diag = kdbgetularg(argv[1], &addr); + if (diag) + return diag; + + /* + * For addresses less than the maximum breakpoint number, + * assume that the breakpoint number is desired. + */ + if (addr < KDB_MAXBPT) { + lowbp = highbp = addr; + highbp++; + } else { + for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; + i++, bp++) { + if (bp->bp_addr == addr) { + lowbp = highbp = i; + highbp++; + break; + } + } + } + } + + /* + * Now operate on the set of breakpoints matching the input + * criteria (either '*' for all, or an individual breakpoint). + */ + for (bp = &kdb_breakpoints[lowbp], i = lowbp; + i < highbp; + i++, bp++) { + if (bp->bp_free) + continue; + + done++; + + switch (cmd) { + case KDBCMD_BC: + bp->bp_enabled = 0; + + kdb_printf("Breakpoint %d at " + kdb_bfd_vma_fmt " cleared\n", + i, bp->bp_addr); + + bp->bp_addr = 0; + bp->bp_free = 1; + + break; + case KDBCMD_BE: + bp->bp_enabled = 1; + + kdb_printf("Breakpoint %d at " + kdb_bfd_vma_fmt " enabled", + i, bp->bp_addr); + + kdb_printf("\n"); + break; + case KDBCMD_BD: + if (!bp->bp_enabled) + break; + + bp->bp_enabled = 0; + + kdb_printf("Breakpoint %d at " + kdb_bfd_vma_fmt " disabled\n", + i, bp->bp_addr); + + break; + } + if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) { + bp->bp_delay = 0; + KDB_STATE_CLEAR(SSBPT); + } + } + + return (!done) ? KDB_BPTNOTFOUND : 0; +} + +/* + * kdb_ss + * + * Process the 'ss' (Single Step) command. + * + * ss + * + * Parameters: + * argc Argument count + * argv Argument vector + * Outputs: + * None. + * Returns: + * KDB_CMD_SS for success, a kdb error if failure. + * Locking: + * None. + * Remarks: + * + * Set the arch specific option to trigger a debug trap after the next + * instruction. + */ + +static int kdb_ss(int argc, const char **argv) +{ + if (argc != 0) + return KDB_ARGCOUNT; + /* + * Set trace flag and go. + */ + KDB_STATE_SET(DOING_SS); + return KDB_CMD_SS; +} + +static kdbtab_t bptab[] = { + { .name = "bp", + .func = kdb_bp, + .usage = "[<vaddr>]", + .help = "Set/Display breakpoints", + .flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS, + }, + { .name = "bl", + .func = kdb_bp, + .usage = "[<vaddr>]", + .help = "Display breakpoints", + .flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS, + }, + { .name = "bc", + .func = kdb_bc, + .usage = "<bpnum>", + .help = "Clear Breakpoint", + .flags = KDB_ENABLE_FLOW_CTRL, + }, + { .name = "be", + .func = kdb_bc, + .usage = "<bpnum>", + .help = "Enable Breakpoint", + .flags = KDB_ENABLE_FLOW_CTRL, + }, + { .name = "bd", + .func = kdb_bc, + .usage = "<bpnum>", + .help = "Disable Breakpoint", + .flags = KDB_ENABLE_FLOW_CTRL, + }, + { .name = "ss", + .func = kdb_ss, + .usage = "", + .help = "Single Step", + .minlen = 1, + .flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS, + }, +}; + +static kdbtab_t bphcmd = { + .name = "bph", + .func = kdb_bp, + .usage = "[<vaddr>]", + .help = "[datar [length]|dataw [length]] Set hw brk", + .flags = KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS, +}; + +/* Initialize the breakpoint table and register breakpoint commands. */ + +void __init kdb_initbptab(void) +{ + int i; + kdb_bp_t *bp; + + /* + * First time initialization. + */ + memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints)); + + for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) + bp->bp_free = 1; + + kdb_register_table(bptab, ARRAY_SIZE(bptab)); + if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) + kdb_register_table(&bphcmd, 1); +} |