From mboxrd@z Thu Jan 1 00:00:00 1970 From: vijay.kilari@gmail.com (vijay.kilari at gmail.com) Date: Thu, 19 Dec 2013 17:20:49 +0530 Subject: [PATCH v6 1/3] AArch64: KGDB: Add Basic KGDB support In-Reply-To: <1387453851-19341-1-git-send-email-vijay.kilari@gmail.com> References: <1387453851-19341-1-git-send-email-vijay.kilari@gmail.com> Message-ID: <1387453851-19341-2-git-send-email-vijay.kilari@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Vijaya Kumar K Add KGDB debug support for kernel debugging. With this patch, basic KGDB debugging is possible.GDB register layout is updated and GDB tool can establish connection with target and can set/clear breakpoints. Signed-off-by: Vijaya Kumar K Reviewed-by: Will Deacon --- arch/arm64/include/asm/debug-monitors.h | 47 +++++ arch/arm64/include/asm/kgdb.h | 86 +++++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/kgdb.c | 292 +++++++++++++++++++++++++++++++ 4 files changed, 426 insertions(+) diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index 6231479..6926497 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -26,6 +26,53 @@ #define DBG_ESR_EVT_HWWP 0x2 #define DBG_ESR_EVT_BRK 0x6 +/* + * Break point instruction encoding + */ +#define BREAK_INSTR_SIZE 4 + +/* + * ESR values expected for dynamic and compile time BRK instruction + */ +#define DBG_ESR_VAL_BRK(x) (0xf2000000 | ((x) & 0xfffff)) + +/* + * #imm16 values used for BRK instruction generation + * Allowed values for kgbd are 0x400 - 0x7ff + * 0x400: for dynamic BRK instruction + * 0x401: for compile time BRK instruction + */ +#define KGDB_DYN_DGB_BRK_IMM 0x400 +#define KDBG_COMPILED_DBG_BRK_IMM 0x401 + +/* + * BRK instruction encoding + * The #imm16 value should be placed at bits[20:5] within BRK ins + */ +#define AARCH64_BREAK_MON 0xd4200000 + +/* + * Extract byte from BRK instruction + */ +#define KGDB_DYN_DGB_BRK_INS_BYTE(x) \ + ((((AARCH64_BREAK_MON) & 0xffe0001f) >> (x * 8)) & 0xff) + +/* + * Extract byte from BRK #imm16 + */ +#define KGBD_DYN_DGB_BRK_IMM_BYTE(x) \ + (((((KGDB_DYN_DGB_BRK_IMM) & 0xffff) << 5) >> (x * 8)) & 0xff) + +#define KGDB_DYN_DGB_BRK_BYTE(x) \ + (KGDB_DYN_DGB_BRK_INS_BYTE(x) | KGBD_DYN_DGB_BRK_IMM_BYTE(x)) + +#define KGDB_DYN_BRK_INS_BYTE0 KGDB_DYN_DGB_BRK_BYTE(0) +#define KGDB_DYN_BRK_INS_BYTE1 KGDB_DYN_DGB_BRK_BYTE(1) +#define KGDB_DYN_BRK_INS_BYTE2 KGDB_DYN_DGB_BRK_BYTE(2) +#define KGDB_DYN_BRK_INS_BYTE3 KGDB_DYN_DGB_BRK_BYTE(3) + +#define CACHE_FLUSH_IS_SAFE 1 + enum debug_el { DBG_ACTIVE_EL0 = 0, DBG_ACTIVE_EL1, diff --git a/arch/arm64/include/asm/kgdb.h b/arch/arm64/include/asm/kgdb.h new file mode 100644 index 0000000..5c9faa9 --- /dev/null +++ b/arch/arm64/include/asm/kgdb.h @@ -0,0 +1,86 @@ +/* + * AArch64 KGDB support + * + * Based on arch/arm/include/kgdb.h + * + * Copyright (C) 2013 Cavium Inc. + * Author: Vijaya Kumar K + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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, see . + */ + +#ifndef __ARM_KGDB_H__ +#define __ARM_KGDB_H__ + +#include +#include + +#ifndef __ASSEMBLY__ + +static inline void arch_kgdb_breakpoint(void) +{ + asm ("brk %0" :: "I" (KDBG_COMPILED_DBG_BRK_IMM)); +} + +extern void kgdb_handle_bus_error(void); +extern int kgdb_fault_expected; + +#endif /* !__ASSEMBLY__ */ + +/* + * gdb is expecting the following registers layout. + * + * General purpose regs: + * r0-r30: 64 bit + * sp,pc : 64 bit + * pstate : 32 bit + * Total: 34 + * FPU regs: + * f0-f31: 128 bit + * Total: 32 + * Extra regs + * fpsr & fpcr: 32 bit + * Total: 2 + * + */ + +#define _GP_REGS 34 +#define _FP_REGS 32 +#define _EXTRA_REGS 2 +/* + * general purpose registers size in bytes. + * pstate is only 4 bytes. subtract 4 bytes + */ +#define GP_REG_BYTES ((_GP_REGS * 8) - 4) +#define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS) + +/* + * Size of I/O buffer for gdb packet. + * considering to hold all register contents, size is set to 1024 + */ + +#define BUFMAX 1024 + +/* + * Number of bytes required for gdb_regs buffer. + * _GP_REGS: 8 bytes, _FP_REGS: 16 bytes and _EXTRA_REGS: 4 bytes each + * pstate reg is only 4 bytes. subtract 4 from size contributed + * by _GP_REGS. + * GDB fails to connect for size beyond this with error + * "'g' packet reply is too long" + */ + +#define NUMREGBYTES (((_GP_REGS * 8) - 4) + (_FP_REGS * 16) + \ + (_EXTRA_REGS * 4)) + +#endif /* __ASM_KGDB_H__ */ diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 5ba2fd4..b9b87fa 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -18,6 +18,7 @@ arm64-obj-$(CONFIG_SMP) += smp.o smp_spin_table.o arm64-obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o arm64-obj-$(CONFIG_EARLY_PRINTK) += early_printk.o +arm64-obj-$(CONFIG_KGDB) += kgdb.o obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c new file mode 100644 index 0000000..8530584 --- /dev/null +++ b/arch/arm64/kernel/kgdb.c @@ -0,0 +1,292 @@ +/* + * AArch64 KGDB support + * + * Based on arch/arm/kernel/kgdb.c + * + * Copyright (C) 2013 Cavium Inc. + * Author: Vijaya Kumar K + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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, see . + */ + +#include +#include +#include +#include + +struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { + { "x0", 8, offsetof(struct pt_regs, regs[0])}, + { "x1", 8, offsetof(struct pt_regs, regs[1])}, + { "x2", 8, offsetof(struct pt_regs, regs[2])}, + { "x3", 8, offsetof(struct pt_regs, regs[3])}, + { "x4", 8, offsetof(struct pt_regs, regs[4])}, + { "x5", 8, offsetof(struct pt_regs, regs[5])}, + { "x6", 8, offsetof(struct pt_regs, regs[6])}, + { "x7", 8, offsetof(struct pt_regs, regs[7])}, + { "x8", 8, offsetof(struct pt_regs, regs[8])}, + { "x9", 8, offsetof(struct pt_regs, regs[9])}, + { "x10", 8, offsetof(struct pt_regs, regs[10])}, + { "x11", 8, offsetof(struct pt_regs, regs[11])}, + { "x12", 8, offsetof(struct pt_regs, regs[12])}, + { "x13", 8, offsetof(struct pt_regs, regs[13])}, + { "x14", 8, offsetof(struct pt_regs, regs[14])}, + { "x15", 8, offsetof(struct pt_regs, regs[15])}, + { "x16", 8, offsetof(struct pt_regs, regs[16])}, + { "x17", 8, offsetof(struct pt_regs, regs[17])}, + { "x18", 8, offsetof(struct pt_regs, regs[18])}, + { "x19", 8, offsetof(struct pt_regs, regs[19])}, + { "x20", 8, offsetof(struct pt_regs, regs[20])}, + { "x21", 8, offsetof(struct pt_regs, regs[21])}, + { "x22", 8, offsetof(struct pt_regs, regs[22])}, + { "x23", 8, offsetof(struct pt_regs, regs[23])}, + { "x24", 8, offsetof(struct pt_regs, regs[24])}, + { "x25", 8, offsetof(struct pt_regs, regs[25])}, + { "x26", 8, offsetof(struct pt_regs, regs[26])}, + { "x27", 8, offsetof(struct pt_regs, regs[27])}, + { "x28", 8, offsetof(struct pt_regs, regs[28])}, + { "x29", 8, offsetof(struct pt_regs, regs[29])}, + { "x30", 8, offsetof(struct pt_regs, regs[30])}, + { "sp", 8, offsetof(struct pt_regs, sp)}, + { "pc", 8, offsetof(struct pt_regs, pc)}, + { "pstate", 8, offsetof(struct pt_regs, pstate)}, + { "v0", 16, -1 }, + { "v1", 16, -1 }, + { "v2", 16, -1 }, + { "v3", 16, -1 }, + { "v4", 16, -1 }, + { "v5", 16, -1 }, + { "v6", 16, -1 }, + { "v7", 16, -1 }, + { "v8", 16, -1 }, + { "v9", 16, -1 }, + { "v10", 16, -1 }, + { "v11", 16, -1 }, + { "v12", 16, -1 }, + { "v13", 16, -1 }, + { "v14", 16, -1 }, + { "v15", 16, -1 }, + { "v16", 16, -1 }, + { "v17", 16, -1 }, + { "v18", 16, -1 }, + { "v19", 16, -1 }, + { "v20", 16, -1 }, + { "v21", 16, -1 }, + { "v22", 16, -1 }, + { "v23", 16, -1 }, + { "v24", 16, -1 }, + { "v25", 16, -1 }, + { "v26", 16, -1 }, + { "v27", 16, -1 }, + { "v28", 16, -1 }, + { "v29", 16, -1 }, + { "v30", 16, -1 }, + { "v31", 16, -1 }, + { "fpsr", 4, -1 }, + { "fpcr", 4, -1 }, +}; + +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; + + /* Initialize to zero */ + memset((char *)gdb_regs, 0, NUMREGBYTES); + thread_regs = task_pt_regs(task); + memcpy((void *)gdb_regs, (void *)thread_regs->regs, GP_REG_BYTES); +} + +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) +{ + regs->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; + int err; + + switch (remcom_in_buffer[0]) { + case 'D': + case 'k': + /* + * Packet D (Detach), k (kill). No special handling + * is required here + */ + err = 0; + break; + case 'c': + /* + * Packet c (Continue) to continue executing. + * Set pc to required address. + * Try to read optional parameter and set pc. + * If this was a compiled breakpoint, we need to move + * to the next instruction else we will just breakpoint + * over and over again. + */ + ptr = &remcom_in_buffer[1]; + if (kgdb_hex2long(&ptr, &addr)) + kgdb_arch_set_pc(linux_regs, addr); + else if (compiled_break == 1) + kgdb_arch_set_pc(linux_regs, linux_regs->pc + 4); + + compiled_break = 0; + + err = 0; + break; + default: + err = -1; + } + return err; +} + +static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr) +{ + kgdb_handle_exception(1, SIGTRAP, 0, regs); + return 0; +} + +static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr) +{ + compiled_break = 1; + kgdb_handle_exception(1, SIGTRAP, 0, regs); + + return 0; +} + +static struct break_hook kgdb_brkpt_hook = { + .esr_mask = 0xffffffff, + .esr_val = DBG_ESR_VAL_BRK(KGDB_DYN_DGB_BRK_IMM), + .fn = kgdb_brk_fn +}; + +static struct break_hook kgdb_compiled_brkpt_hook = { + .esr_mask = 0xffffffff, + .esr_val = DBG_ESR_VAL_BRK(KDBG_COMPILED_DBG_BRK_IMM), + .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, + /* + * Want to be lowest priority + */ + .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_break_hook(&kgdb_brkpt_hook); + register_break_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_break_hook(&kgdb_brkpt_hook); + unregister_break_hook(&kgdb_compiled_brkpt_hook); + unregister_die_notifier(&kgdb_notifier); +} + +/* + * ARM instructions are always in LE. + * Break instruction is encoded in LE format + */ +struct kgdb_arch arch_kgdb_ops = { + .gdb_bpt_instr = { + KGDB_DYN_BRK_INS_BYTE0, + KGDB_DYN_BRK_INS_BYTE1, + KGDB_DYN_BRK_INS_BYTE2, + KGDB_DYN_BRK_INS_BYTE3, + } +}; -- 1.7.9.5