/* * arch/arm/kernel/kgdb.c * * ARM KGDB support * * Copyright (c) 2002-2004 MontaVista Software, Inc * Copyright (c) 2008 Wind River Systems, Inc. * * Authors: George Davis <davis_g@mvista.com> * Deepak Saxena <dsaxena@plexity.net> */ #include <linux/irq.h> #include <linux/kdebug.h> #include <linux/kgdb.h> #include <linux/uaccess.h> #include <asm/traps.h> #include "patch.h" struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { { "r0", 4, offsetof(struct pt_regs, ARM_r0)}, { "r1", 4, offsetof(struct pt_regs, ARM_r1)}, { "r2", 4, offsetof(struct pt_regs, ARM_r2)}, { "r3", 4, offsetof(struct pt_regs, ARM_r3)}, { "r4", 4, offsetof(struct pt_regs, ARM_r4)}, { "r5", 4, offsetof(struct pt_regs, ARM_r5)}, { "r6", 4, offsetof(struct pt_regs, ARM_r6)}, { "r7", 4, offsetof(struct pt_regs, ARM_r7)}, { "r8", 4, offsetof(struct pt_regs, ARM_r8)}, { "r9", 4, offsetof(struct pt_regs, ARM_r9)}, { "r10", 4, offsetof(struct pt_regs, ARM_r10)}, { "fp", 4, offsetof(struct pt_regs, ARM_fp)}, { "ip", 4, offsetof(struct pt_regs, ARM_ip)}, { "sp", 4, offsetof(struct pt_regs, ARM_sp)}, { "lr", 4, offsetof(struct pt_regs, ARM_lr)}, { "pc", 4, offsetof(struct pt_regs, ARM_pc)}, { "f0", 12, -1 }, { "f1", 12, -1 }, { "f2", 12, -1 }, { "f3", 12, -1 }, { "f4", 12, -1 }, { "f5", 12, -1 }, { "f6", 12, -1 }, { "f7", 12, -1 }, { "fps", 4, -1 }, { "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)}, }; char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) { if (regno >= DBG_MAX_REG_NUM || regno < 0) return NULL; if (dbg_reg_def[regno].offset != -1) memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, dbg_reg_def[regno].size); else memset(mem, 0, dbg_reg_def[regno].size); return dbg_reg_def[regno].name; } int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) { if (regno >= DBG_MAX_REG_NUM || regno < 0) return -EINVAL; if (dbg_reg_def[regno].offset != -1) memcpy((void *)regs + dbg_reg_def[regno].offset, mem, dbg_reg_def[regno].size); return 0; } void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) { struct pt_regs *thread_regs; int regno; /* Just making sure... */ if (task == NULL) return; /* Initialize to zero */ for (regno = 0; regno < GDB_MAX_REGS; regno++) gdb_regs[regno] = 0; /* Otherwise, we have only some registers from switch_to() */ thread_regs = task_pt_regs(task); gdb_regs[_R0] = thread_regs->ARM_r0; gdb_regs[_R1] = thread_regs->ARM_r1; gdb_regs[_R2] = thread_regs->ARM_r2; gdb_regs[_R3] = thread_regs->ARM_r3; gdb_regs[_R4] = thread_regs->ARM_r4; gdb_regs[_R5] = thread_regs->ARM_r5; gdb_regs[_R6] = thread_regs->ARM_r6; gdb_regs[_R7] = thread_regs->ARM_r7; gdb_regs[_R8] = thread_regs->ARM_r8; gdb_regs[_R9] = thread_regs->ARM_r9; gdb_regs[_R10] = thread_regs->ARM_r10; gdb_regs[_FP] = thread_regs->ARM_fp; gdb_regs[_IP] = thread_regs->ARM_ip; gdb_regs[_SPT] = thread_regs->ARM_sp; gdb_regs[_LR] = thread_regs->ARM_lr; gdb_regs[_PC] = thread_regs->ARM_pc; gdb_regs[_CPSR] = thread_regs->ARM_cpsr; } void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) { regs->ARM_pc = pc; } static int compiled_break; int kgdb_arch_handle_exception(int exception_vector, int signo, int err_code, char *remcom_in_buffer, char *remcom_out_buffer, struct pt_regs *linux_regs) { unsigned long addr; char *ptr; switch (remcom_in_buffer[0]) { case 'D': case 'k': case 'c': /* * Try to read optional parameter, pc unchanged if no parm. * If this was a compiled breakpoint, we need to move * to the next instruction or we will just breakpoint * over and over again. */ ptr = &remcom_in_buffer[1]; if (kgdb_hex2long(&ptr, &addr)) linux_regs->ARM_pc = addr; else if (compiled_break == 1) linux_regs->ARM_pc += 4; compiled_break = 0; return 0; } return -1; } static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr) { if (user_mode(regs)) return -1; kgdb_handle_exception(1, SIGTRAP, 0, regs); return 0; } static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr) { if (user_mode(regs)) return -1; compiled_break = 1; kgdb_handle_exception(1, SIGTRAP, 0, regs); return 0; } static struct undef_hook kgdb_brkpt_hook = { .instr_mask = 0xffffffff, .instr_val = KGDB_BREAKINST, .cpsr_mask = MODE_MASK, .cpsr_val = SVC_MODE, .fn = kgdb_brk_fn }; static struct undef_hook kgdb_compiled_brkpt_hook = { .instr_mask = 0xffffffff, .instr_val = KGDB_COMPILED_BREAK, .cpsr_mask = MODE_MASK, .cpsr_val = SVC_MODE, .fn = kgdb_compiled_brk_fn }; static void kgdb_call_nmi_hook(void *ignored) { kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); } void kgdb_roundup_cpus(unsigned long flags) { local_irq_enable(); smp_call_function(kgdb_call_nmi_hook, NULL, 0); local_irq_disable(); } static int __kgdb_notify(struct die_args *args, unsigned long cmd) { struct pt_regs *regs = args->regs; if (kgdb_handle_exception(1, args->signr, cmd, regs)) return NOTIFY_DONE; return NOTIFY_STOP; } static int kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) { unsigned long flags; int ret; local_irq_save(flags); ret = __kgdb_notify(ptr, cmd); local_irq_restore(flags); return ret; } static struct notifier_block kgdb_notifier = { .notifier_call = kgdb_notify, .priority = -INT_MAX, }; /** * kgdb_arch_init - Perform any architecture specific initalization. * * This function will handle the initalization of any architecture * specific callbacks. */ int kgdb_arch_init(void) { int ret = register_die_notifier(&kgdb_notifier); if (ret != 0) return ret; register_undef_hook(&kgdb_brkpt_hook); register_undef_hook(&kgdb_compiled_brkpt_hook); return 0; } /** * kgdb_arch_exit - Perform any architecture specific uninitalization. * * This function will handle the uninitalization of any architecture * specific callbacks, for dynamic registration and unregistration. */ void kgdb_arch_exit(void) { unregister_undef_hook(&kgdb_brkpt_hook); unregister_undef_hook(&kgdb_compiled_brkpt_hook); unregister_die_notifier(&kgdb_notifier); } int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) { int err; /* patch_text() only supports int-sized breakpoints */ BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE); err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); if (err) return err; /* Machine is already stopped, so we can use __patch_text() directly */ __patch_text((void *)bpt->bpt_addr, *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr); return err; } int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) { /* Machine is already stopped, so we can use __patch_text() directly */ __patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr); return 0; } /* * Register our undef instruction hooks with ARM undef core. * We regsiter a hook specifically looking for the KGB break inst * and we handle the normal undef case within the do_undefinstr * handler. */ struct kgdb_arch arch_kgdb_ops = { #ifndef __ARMEB__ .gdb_bpt_instr = {0xfe, 0xde, 0xff, 0xe7} #else /* ! __ARMEB__ */ .gdb_bpt_instr = {0xe7, 0xff, 0xde, 0xfe} #endif };