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-rw-r--r--arch/arm64/kernel/kgdb.c358
1 files changed, 358 insertions, 0 deletions
diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c
new file mode 100644
index 000000000..4e1f983df
--- /dev/null
+++ b/arch/arm64/kernel/kgdb.c
@@ -0,0 +1,358 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AArch64 KGDB support
+ *
+ * Based on arch/arm/kernel/kgdb.c
+ *
+ * Copyright (C) 2013 Cavium Inc.
+ * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
+ */
+
+#include <linux/bug.h>
+#include <linux/irq.h>
+#include <linux/kdebug.h>
+#include <linux/kgdb.h>
+#include <linux/kprobes.h>
+#include <linux/sched/task_stack.h>
+
+#include <asm/debug-monitors.h>
+#include <asm/insn.h>
+#include <asm/patching.h>
+#include <asm/traps.h>
+
+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)},
+ /*
+ * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote
+ * protocol disagrees. Therefore we must extract only the lower
+ * 32-bits. Look for the big comment in asm/kgdb.h for more
+ * detail.
+ */
+ { "pstate", 4, offsetof(struct pt_regs, pstate)
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ + 4
+#endif
+ },
+ { "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 cpu_context *cpu_context = &task->thread.cpu_context;
+
+ /* Initialize to zero */
+ memset((char *)gdb_regs, 0, NUMREGBYTES);
+
+ gdb_regs[19] = cpu_context->x19;
+ gdb_regs[20] = cpu_context->x20;
+ gdb_regs[21] = cpu_context->x21;
+ gdb_regs[22] = cpu_context->x22;
+ gdb_regs[23] = cpu_context->x23;
+ gdb_regs[24] = cpu_context->x24;
+ gdb_regs[25] = cpu_context->x25;
+ gdb_regs[26] = cpu_context->x26;
+ gdb_regs[27] = cpu_context->x27;
+ gdb_regs[28] = cpu_context->x28;
+ gdb_regs[29] = cpu_context->fp;
+
+ gdb_regs[31] = cpu_context->sp;
+ gdb_regs[32] = cpu_context->pc;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ regs->pc = pc;
+}
+
+static int compiled_break;
+
+static void kgdb_arch_update_addr(struct pt_regs *regs,
+ char *remcom_in_buffer)
+{
+ unsigned long addr;
+ char *ptr;
+
+ ptr = &remcom_in_buffer[1];
+ if (kgdb_hex2long(&ptr, &addr))
+ kgdb_arch_set_pc(regs, addr);
+ else if (compiled_break == 1)
+ kgdb_arch_set_pc(regs, regs->pc + 4);
+
+ compiled_break = 0;
+}
+
+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)
+{
+ int err;
+
+ switch (remcom_in_buffer[0]) {
+ case 'D':
+ case 'k':
+ /*
+ * Packet D (Detach), k (kill). No special handling
+ * is required here. Handle same as c packet.
+ */
+ 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.
+ */
+ kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
+ atomic_set(&kgdb_cpu_doing_single_step, -1);
+ kgdb_single_step = 0;
+
+ /*
+ * Received continue command, disable single step
+ */
+ if (kernel_active_single_step())
+ kernel_disable_single_step();
+
+ err = 0;
+ break;
+ case 's':
+ /*
+ * Update step address value with address passed
+ * with step packet.
+ * On debug exception return PC is copied to ELR
+ * So just update PC.
+ * If no step address is passed, resume from the address
+ * pointed by PC. Do not update PC
+ */
+ kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
+ atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
+ kgdb_single_step = 1;
+
+ /*
+ * Enable single step handling
+ */
+ if (!kernel_active_single_step())
+ kernel_enable_single_step(linux_regs);
+ else
+ kernel_rewind_single_step(linux_regs);
+ err = 0;
+ break;
+ default:
+ err = -1;
+ }
+ return err;
+}
+
+static int kgdb_brk_fn(struct pt_regs *regs, unsigned long esr)
+{
+ kgdb_handle_exception(1, SIGTRAP, 0, regs);
+ return DBG_HOOK_HANDLED;
+}
+NOKPROBE_SYMBOL(kgdb_brk_fn)
+
+static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned long esr)
+{
+ compiled_break = 1;
+ kgdb_handle_exception(1, SIGTRAP, 0, regs);
+
+ return DBG_HOOK_HANDLED;
+}
+NOKPROBE_SYMBOL(kgdb_compiled_brk_fn);
+
+static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned long esr)
+{
+ if (!kgdb_single_step)
+ return DBG_HOOK_ERROR;
+
+ kgdb_handle_exception(0, SIGTRAP, 0, regs);
+ return DBG_HOOK_HANDLED;
+}
+NOKPROBE_SYMBOL(kgdb_step_brk_fn);
+
+static struct break_hook kgdb_brkpt_hook = {
+ .fn = kgdb_brk_fn,
+ .imm = KGDB_DYN_DBG_BRK_IMM,
+};
+
+static struct break_hook kgdb_compiled_brkpt_hook = {
+ .fn = kgdb_compiled_brk_fn,
+ .imm = KGDB_COMPILED_DBG_BRK_IMM,
+};
+
+static struct step_hook kgdb_step_hook = {
+ .fn = kgdb_step_brk_fn
+};
+
+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 initialization.
+ * This function will handle the initialization of any architecture
+ * specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+ int ret = register_die_notifier(&kgdb_notifier);
+
+ if (ret != 0)
+ return ret;
+
+ register_kernel_break_hook(&kgdb_brkpt_hook);
+ register_kernel_break_hook(&kgdb_compiled_brkpt_hook);
+ register_kernel_step_hook(&kgdb_step_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_kernel_break_hook(&kgdb_brkpt_hook);
+ unregister_kernel_break_hook(&kgdb_compiled_brkpt_hook);
+ unregister_kernel_step_hook(&kgdb_step_hook);
+ unregister_die_notifier(&kgdb_notifier);
+}
+
+const struct kgdb_arch arch_kgdb_ops;
+
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+
+ BUILD_BUG_ON(AARCH64_INSN_SIZE != BREAK_INSTR_SIZE);
+
+ err = aarch64_insn_read((void *)bpt->bpt_addr, (u32 *)bpt->saved_instr);
+ if (err)
+ return err;
+
+ return aarch64_insn_write((void *)bpt->bpt_addr,
+ (u32)AARCH64_BREAK_KGDB_DYN_DBG);
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+ return aarch64_insn_write((void *)bpt->bpt_addr,
+ *(u32 *)bpt->saved_instr);
+}