4 files changed, 420 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
index ee9f28e245aa..6e9b5b36921c 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 000000000000..3c8aafc1082f
--- /dev/null
+++ b/arch/arm64/include/asm/kgdb.h
@@ -0,0 +1,84 @@
+/*
+ * AArch64 KGDB support
+ *
+ * Based on arch/arm/include/kgdb.h
+ *
+ * Copyright (C) 2013 Cavium Inc.
+ * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARM_KGDB_H
+#define __ARM_KGDB_H
+
+#include <linux/ptrace.h>
+#include <asm/debug-monitors.h>
+
+#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  : 64 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)
+#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
+ */
+
+#define BUFMAX                  2048
+
+/*
+ * Number of bytes required for gdb_regs buffer.
+ * _GP_REGS: 8 bytes, _FP_REGS: 16 bytes and _EXTRA_REGS: 4 bytes each
+ * GDB fails to connect for size beyond this with error
+ * "'g' packet reply is too long"
+ */
+
+#define NUMREGBYTES     ((_GP_REGS * 8) + (_FP_REGS * 16) + \
+                        (_EXTRA_REGS * 4))
+
+#endif /* __ASM_KGDB_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 2d4554b13410..e52bcdc6f097 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -20,6 +20,7 @@ arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
 arm64-obj-$(CONFIG_EARLY_PRINTK)        += early_printk.o
 arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND)   += sleep.o suspend.o
 arm64-obj-$(CONFIG_JUMP_LABEL)          += jump_label.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 000000000000..4b7a5695175e
--- /dev/null
+++ b/arch/arm64/kernel/kgdb.c
@@ -0,0 +1,288 @@
+/*
+ * AArch64 KGDB support
+ *
+ * Based on arch/arm/kernel/kgdb.c
+ *
+ * Copyright (C) 2013 Cavium Inc.
+ * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/irq.h>
+#include <linux/kdebug.h>
+#include <linux/kgdb.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)},
+        { "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. 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.
+                 */
+                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,
+        }
+};