diff options
Diffstat (limited to 'arch/tile/kernel/kgdb.c')
| -rw-r--r-- | arch/tile/kernel/kgdb.c | 495 |
1 files changed, 495 insertions, 0 deletions
diff --git a/arch/tile/kernel/kgdb.c b/arch/tile/kernel/kgdb.c new file mode 100644 index 000000000..ff5335ae0 --- /dev/null +++ b/arch/tile/kernel/kgdb.c @@ -0,0 +1,495 @@ +/* + * Copyright 2013 Tilera Corporation. All Rights Reserved. + * + * 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, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + * + * TILE-Gx KGDB support. + */ + +#include <linux/ptrace.h> +#include <linux/kgdb.h> +#include <linux/kdebug.h> +#include <linux/uaccess.h> +#include <linux/module.h> +#include <asm/cacheflush.h> + +static tile_bundle_bits singlestep_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP; +static unsigned long stepped_addr; +static tile_bundle_bits stepped_instr; + +struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { + { "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0])}, + { "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1])}, + { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2])}, + { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3])}, + { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4])}, + { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5])}, + { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6])}, + { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7])}, + { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8])}, + { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9])}, + { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10])}, + { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11])}, + { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12])}, + { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13])}, + { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14])}, + { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15])}, + { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16])}, + { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17])}, + { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18])}, + { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19])}, + { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20])}, + { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21])}, + { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22])}, + { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23])}, + { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24])}, + { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25])}, + { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26])}, + { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27])}, + { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28])}, + { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29])}, + { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30])}, + { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31])}, + { "r32", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[32])}, + { "r33", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[33])}, + { "r34", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[34])}, + { "r35", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[35])}, + { "r36", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[36])}, + { "r37", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[37])}, + { "r38", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[38])}, + { "r39", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[39])}, + { "r40", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[40])}, + { "r41", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[41])}, + { "r42", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[42])}, + { "r43", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[43])}, + { "r44", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[44])}, + { "r45", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[45])}, + { "r46", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[46])}, + { "r47", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[47])}, + { "r48", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[48])}, + { "r49", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[49])}, + { "r50", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[50])}, + { "r51", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[51])}, + { "r52", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[52])}, + { "tp", GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)}, + { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)}, + { "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, lr)}, + { "sn", GDB_SIZEOF_REG, -1}, + { "idn0", GDB_SIZEOF_REG, -1}, + { "idn1", GDB_SIZEOF_REG, -1}, + { "udn0", GDB_SIZEOF_REG, -1}, + { "udn1", GDB_SIZEOF_REG, -1}, + { "udn2", GDB_SIZEOF_REG, -1}, + { "udn3", GDB_SIZEOF_REG, -1}, + { "zero", GDB_SIZEOF_REG, -1}, + { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, pc)}, + { "faultnum", GDB_SIZEOF_REG, offsetof(struct pt_regs, faultnum)}, +}; + +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; +} + +/* + * Similar to pt_regs_to_gdb_regs() except that process is sleeping and so + * we may not be able to get all the info. + */ +void +sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) +{ + struct pt_regs *thread_regs; + + if (task == NULL) + return; + + /* Initialize to zero. */ + memset(gdb_regs, 0, NUMREGBYTES); + + thread_regs = task_pt_regs(task); + memcpy(gdb_regs, thread_regs, TREG_LAST_GPR * sizeof(unsigned long)); + gdb_regs[TILEGX_PC_REGNUM] = thread_regs->pc; + gdb_regs[TILEGX_FAULTNUM_REGNUM] = thread_regs->faultnum; +} + +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) +{ + regs->pc = pc; +} + +static void kgdb_call_nmi_hook(void *ignored) +{ + kgdb_nmicallback(raw_smp_processor_id(), NULL); +} + +void kgdb_roundup_cpus(unsigned long flags) +{ + local_irq_enable(); + smp_call_function(kgdb_call_nmi_hook, NULL, 0); + local_irq_disable(); +} + +/* + * Convert a kernel address to the writable kernel text mapping. + */ +static unsigned long writable_address(unsigned long addr) +{ + unsigned long ret = 0; + + if (core_kernel_text(addr)) + ret = addr - MEM_SV_START + PAGE_OFFSET; + else if (is_module_text_address(addr)) + ret = addr; + else + pr_err("Unknown virtual address 0x%lx\n", addr); + + return ret; +} + +/* + * Calculate the new address for after a step. + */ +static unsigned long get_step_address(struct pt_regs *regs) +{ + int src_reg; + int jump_off; + int br_off; + unsigned long addr; + unsigned int opcode; + tile_bundle_bits bundle; + + /* Move to the next instruction by default. */ + addr = regs->pc + TILEGX_BUNDLE_SIZE_IN_BYTES; + bundle = *(unsigned long *)instruction_pointer(regs); + + /* 0: X mode, Otherwise: Y mode. */ + if (bundle & TILEGX_BUNDLE_MODE_MASK) { + if (get_Opcode_Y1(bundle) == RRR_1_OPCODE_Y1 && + get_RRROpcodeExtension_Y1(bundle) == + UNARY_RRR_1_OPCODE_Y1) { + opcode = get_UnaryOpcodeExtension_Y1(bundle); + + switch (opcode) { + case JALR_UNARY_OPCODE_Y1: + case JALRP_UNARY_OPCODE_Y1: + case JR_UNARY_OPCODE_Y1: + case JRP_UNARY_OPCODE_Y1: + src_reg = get_SrcA_Y1(bundle); + dbg_get_reg(src_reg, &addr, regs); + break; + } + } + } else if (get_Opcode_X1(bundle) == RRR_0_OPCODE_X1) { + if (get_RRROpcodeExtension_X1(bundle) == + UNARY_RRR_0_OPCODE_X1) { + opcode = get_UnaryOpcodeExtension_X1(bundle); + + switch (opcode) { + case JALR_UNARY_OPCODE_X1: + case JALRP_UNARY_OPCODE_X1: + case JR_UNARY_OPCODE_X1: + case JRP_UNARY_OPCODE_X1: + src_reg = get_SrcA_X1(bundle); + dbg_get_reg(src_reg, &addr, regs); + break; + } + } + } else if (get_Opcode_X1(bundle) == JUMP_OPCODE_X1) { + opcode = get_JumpOpcodeExtension_X1(bundle); + + switch (opcode) { + case JAL_JUMP_OPCODE_X1: + case J_JUMP_OPCODE_X1: + jump_off = sign_extend(get_JumpOff_X1(bundle), 27); + addr = regs->pc + + (jump_off << TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES); + break; + } + } else if (get_Opcode_X1(bundle) == BRANCH_OPCODE_X1) { + br_off = 0; + opcode = get_BrType_X1(bundle); + + switch (opcode) { + case BEQZT_BRANCH_OPCODE_X1: + case BEQZ_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) == 0) + br_off = get_BrOff_X1(bundle); + break; + case BGEZT_BRANCH_OPCODE_X1: + case BGEZ_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) >= 0) + br_off = get_BrOff_X1(bundle); + break; + case BGTZT_BRANCH_OPCODE_X1: + case BGTZ_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) > 0) + br_off = get_BrOff_X1(bundle); + break; + case BLBCT_BRANCH_OPCODE_X1: + case BLBC_BRANCH_OPCODE_X1: + if (!(get_SrcA_X1(bundle) & 1)) + br_off = get_BrOff_X1(bundle); + break; + case BLBST_BRANCH_OPCODE_X1: + case BLBS_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) & 1) + br_off = get_BrOff_X1(bundle); + break; + case BLEZT_BRANCH_OPCODE_X1: + case BLEZ_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) <= 0) + br_off = get_BrOff_X1(bundle); + break; + case BLTZT_BRANCH_OPCODE_X1: + case BLTZ_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) < 0) + br_off = get_BrOff_X1(bundle); + break; + case BNEZT_BRANCH_OPCODE_X1: + case BNEZ_BRANCH_OPCODE_X1: + if (get_SrcA_X1(bundle) != 0) + br_off = get_BrOff_X1(bundle); + break; + } + + if (br_off != 0) { + br_off = sign_extend(br_off, 17); + addr = regs->pc + + (br_off << TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES); + } + } + + return addr; +} + +/* + * Replace the next instruction after the current instruction with a + * breakpoint instruction. + */ +static void do_single_step(struct pt_regs *regs) +{ + unsigned long addr_wr; + + /* Determine where the target instruction will send us to. */ + stepped_addr = get_step_address(regs); + probe_kernel_read((char *)&stepped_instr, (char *)stepped_addr, + BREAK_INSTR_SIZE); + + addr_wr = writable_address(stepped_addr); + probe_kernel_write((char *)addr_wr, (char *)&singlestep_insn, + BREAK_INSTR_SIZE); + smp_wmb(); + flush_icache_range(stepped_addr, stepped_addr + BREAK_INSTR_SIZE); +} + +static void undo_single_step(struct pt_regs *regs) +{ + unsigned long addr_wr; + + if (stepped_instr == 0) + return; + + addr_wr = writable_address(stepped_addr); + probe_kernel_write((char *)addr_wr, (char *)&stepped_instr, + BREAK_INSTR_SIZE); + stepped_instr = 0; + smp_wmb(); + flush_icache_range(stepped_addr, stepped_addr + BREAK_INSTR_SIZE); +} + +/* + * Calls linux_debug_hook before the kernel dies. If KGDB is enabled, + * then try to fall into the debugger. + */ +static int +kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) +{ + int ret; + unsigned long flags; + struct die_args *args = (struct die_args *)ptr; + struct pt_regs *regs = args->regs; + +#ifdef CONFIG_KPROBES + /* + * Return immediately if the kprobes fault notifier has set + * DIE_PAGE_FAULT. + */ + if (cmd == DIE_PAGE_FAULT) + return NOTIFY_DONE; +#endif /* CONFIG_KPROBES */ + + switch (cmd) { + case DIE_BREAK: + case DIE_COMPILED_BPT: + break; + case DIE_SSTEPBP: + local_irq_save(flags); + kgdb_handle_exception(0, SIGTRAP, 0, regs); + local_irq_restore(flags); + return NOTIFY_STOP; + default: + /* Userspace events, ignore. */ + if (user_mode(regs)) + return NOTIFY_DONE; + } + + local_irq_save(flags); + ret = kgdb_handle_exception(args->trapnr, args->signr, args->err, regs); + local_irq_restore(flags); + if (ret) + return NOTIFY_DONE; + + return NOTIFY_STOP; +} + +static struct notifier_block kgdb_notifier = { + .notifier_call = kgdb_notify, +}; + +/* + * kgdb_arch_handle_exception - Handle architecture specific GDB packets. + * @vector: The error vector of the exception that happened. + * @signo: The signal number of the exception that happened. + * @err_code: The error code of the exception that happened. + * @remcom_in_buffer: The buffer of the packet we have read. + * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. + * @regs: The &struct pt_regs of the current process. + * + * This function MUST handle the 'c' and 's' command packets, + * as well packets to set / remove a hardware breakpoint, if used. + * If there are additional packets which the hardware needs to handle, + * they are handled here. The code should return -1 if it wants to + * process more packets, and a %0 or %1 if it wants to exit from the + * kgdb callback. + */ +int kgdb_arch_handle_exception(int vector, int signo, int err_code, + char *remcom_in_buffer, char *remcom_out_buffer, + struct pt_regs *regs) +{ + char *ptr; + unsigned long address; + + /* Undo any stepping we may have done. */ + undo_single_step(regs); + + switch (remcom_in_buffer[0]) { + case 'c': + case 's': + case 'D': + case 'k': + /* + * Try to read optional parameter, pc unchanged if no parm. + * If this was a compiled-in 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, &address)) + regs->pc = address; + else if (*(unsigned long *)regs->pc == compiled_bpt) + regs->pc += BREAK_INSTR_SIZE; + + if (remcom_in_buffer[0] == 's') { + do_single_step(regs); + kgdb_single_step = 1; + atomic_set(&kgdb_cpu_doing_single_step, + raw_smp_processor_id()); + } else + atomic_set(&kgdb_cpu_doing_single_step, -1); + + return 0; + } + + return -1; /* this means that we do not want to exit from the handler */ +} + +struct kgdb_arch arch_kgdb_ops; + +/* + * kgdb_arch_init - Perform any architecture specific initalization. + * + * This function will handle the initalization of any architecture + * specific callbacks. + */ +int kgdb_arch_init(void) +{ + tile_bundle_bits bundle = TILEGX_BPT_BUNDLE; + + memcpy(arch_kgdb_ops.gdb_bpt_instr, &bundle, BREAK_INSTR_SIZE); + return register_die_notifier(&kgdb_notifier); +} + +/* + * 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_die_notifier(&kgdb_notifier); +} + +int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) +{ + int err; + unsigned long addr_wr = writable_address(bpt->bpt_addr); + + if (addr_wr == 0) + return -1; + + err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, + BREAK_INSTR_SIZE); + if (err) + return err; + + err = probe_kernel_write((char *)addr_wr, arch_kgdb_ops.gdb_bpt_instr, + BREAK_INSTR_SIZE); + smp_wmb(); + flush_icache_range((unsigned long)bpt->bpt_addr, + (unsigned long)bpt->bpt_addr + BREAK_INSTR_SIZE); + return err; +} + +int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) +{ + int err; + unsigned long addr_wr = writable_address(bpt->bpt_addr); + + if (addr_wr == 0) + return -1; + + err = probe_kernel_write((char *)addr_wr, (char *)bpt->saved_instr, + BREAK_INSTR_SIZE); + smp_wmb(); + flush_icache_range((unsigned long)bpt->bpt_addr, + (unsigned long)bpt->bpt_addr + BREAK_INSTR_SIZE); + return err; +} |