nios2: add kgdb support

Signed-off-by: Ley Foon Tan <lftan@altera.com>

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index f77991ecfd8e181cbd82c1ed59dad0ae128b59b8..437555424bda6765c0939be4606c70c2dc7d3c84 100644 (file)
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -8,6 +8,7 @@ config NIOS2
        select GENERIC_IRQ_PROBE
        select GENERIC_IRQ_SHOW
        select HAVE_ARCH_TRACEHOOK
+       select HAVE_ARCH_KGDB
        select IRQ_DOMAIN
        select MODULES_USE_ELF_RELA
        select OF

diff --git a/arch/nios2/include/asm/kgdb.h b/arch/nios2/include/asm/kgdb.h
new file mode 100644 (file)
index 0000000..8fd5e3b
--- /dev/null
+++ b/arch/nios2/include/asm/kgdb.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2015 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * Based on the code posted by Kazuyasu on the Altera Forum at:
+ * http://www.alteraforum.com/forum/showpost.php?p=77003&postcount=20
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 _ASM_NIOS2_KGDB_H
+#define _ASM_NIOS2_KGDB_H
+
+#define CACHE_FLUSH_IS_SAFE    1
+#define BUFMAX                 2048
+
+enum regnames {
+       GDB_R0 = 0,
+       GDB_AT,
+       GDB_R2,
+       GDB_R3,
+       GDB_R4,
+       GDB_R5,
+       GDB_R6,
+       GDB_R7,
+       GDB_R8,
+       GDB_R9,
+       GDB_R10,
+       GDB_R11,
+       GDB_R12,
+       GDB_R13,
+       GDB_R14,
+       GDB_R15,
+       GDB_R16,
+       GDB_R17,
+       GDB_R18,
+       GDB_R19,
+       GDB_R20,
+       GDB_R21,
+       GDB_R22,
+       GDB_R23,
+       GDB_ET,
+       GDB_BT,
+       GDB_GP,
+       GDB_SP,
+       GDB_FP,
+       GDB_EA,
+       GDB_BA,
+       GDB_RA,
+       GDB_PC,
+       GDB_STATUS,
+       GDB_ESTATUS,
+       GDB_BSTATUS,
+       GDB_IENABLE,
+       GDB_IPENDING,
+       GDB_CPUID,
+       GDB_CTL6,
+       GDB_EXCEPTION,
+       GDB_PTEADDR,
+       GDB_TLBACC,
+       GDB_TLBMISC,
+       GDB_ECCINJ,
+       GDB_BADADDR,
+       GDB_CONFIG,
+       GDB_MPUBASE,
+       GDB_MPUACC,
+       /* do not change the last entry or anything below! */
+       GDB_NUMREGBYTES         /* number of registers */
+};
+
+#define GDB_SIZEOF_REG         sizeof(u32)
+#define DBG_MAX_REG_NUM        (49)
+#define NUMREGBYTES            (DBG_MAX_REG_NUM * sizeof(GDB_SIZEOF_REG))
+
+#define BREAK_INSTR_SIZE       4
+static inline void arch_kgdb_breakpoint(void)
+{
+       __asm__ __volatile__("trap 30\n");
+}
+
+#endif /* _ASM_NIOS2_KGDB_H */

diff --git a/arch/nios2/kernel/Makefile b/arch/nios2/kernel/Makefile
index eaaa894c432fc3ec2171ec942177666c56f3d7d0..1aae257036575ada177ab257dcd68bb7cc3fce42 100644 (file)
--- a/arch/nios2/kernel/Makefile
+++ b/arch/nios2/kernel/Makefile
@@ -21,5 +21,6 @@ obj-y += time.o
 obj-y  += traps.o
 
 obj-$(CONFIG_EARLY_PRINTK)             += early_printk.o
+obj-$(CONFIG_KGDB)                     += kgdb.o
 obj-$(CONFIG_MODULES)                  += module.o
 obj-$(CONFIG_NIOS2_ALIGNMENT_TRAP)     += misaligned.o

diff --git a/arch/nios2/kernel/entry.S b/arch/nios2/kernel/entry.S
index 0bdfd13ff98bbbbd5af7fc4251abf1c618d63a94..7729bd3f2e79d48937e7dbead303640610ca24ae 100644 (file)
--- a/arch/nios2/kernel/entry.S
+++ b/arch/nios2/kernel/entry.S
@@ -121,7 +121,11 @@ trap_table:
        .word   instruction_trap        /* 27 */
        .word   instruction_trap        /* 28 */
        .word   instruction_trap        /* 29 */
-       .word   instruction_trap        /* 30 */
+#ifdef CONFIG_KGDB
+       .word   handle_kgdb_breakpoint  /* 30 KGDB breakpoint */
+#else
+       .word   instruction_trap                /* 30 */
+#endif
        .word   handle_breakpoint       /* 31 */
 
 .text
@@ -445,6 +449,12 @@ handle_diverror:
        call    handle_diverror_c
        br      ret_from_exception
 
+#ifdef CONFIG_KGDB
+handle_kgdb_breakpoint:
+       call    kgdb_breakpoint_c
+       br      ret_from_exception
+#endif
+
 /*
  * Beware - when entering resume, prev (the current task) is
  * in r4, next (the new task) is in r5, don't change these

diff --git a/arch/nios2/kernel/kgdb.c b/arch/nios2/kernel/kgdb.c
new file mode 100644 (file)
index 0000000..1178591
--- /dev/null
+++ b/arch/nios2/kernel/kgdb.c
@@ -0,0 +1,171 @@
+/*
+ * Nios2 KGDB support
+ *
+ * Copyright (C) 2015 Altera Corporation
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ *
+ * Based on the code posted by Kazuyasu on the Altera Forum at:
+ * http://www.alteraforum.com/forum/showpost.php?p=77003&postcount=20
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/ptrace.h>
+#include <linux/kgdb.h>
+#include <linux/kdebug.h>
+#include <linux/io.h>
+
+static int wait_for_remote_debugger;
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+       { "zero", GDB_SIZEOF_REG, -1 },
+       { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, r1) },
+       { "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r2) },
+       { "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r3) },
+       { "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r4) },
+       { "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r5) },
+       { "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r6) },
+       { "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r7) },
+       { "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r8) },
+       { "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r9) },
+       { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10) },
+       { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11) },
+       { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12) },
+       { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13) },
+       { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14) },
+       { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15) },
+       { "r16", GDB_SIZEOF_REG, -1 },
+       { "r17", GDB_SIZEOF_REG, -1 },
+       { "r18", GDB_SIZEOF_REG, -1 },
+       { "r19", GDB_SIZEOF_REG, -1 },
+       { "r20", GDB_SIZEOF_REG, -1 },
+       { "r21", GDB_SIZEOF_REG, -1 },
+       { "r22", GDB_SIZEOF_REG, -1 },
+       { "r23", GDB_SIZEOF_REG, -1 },
+       { "et", GDB_SIZEOF_REG, -1 },
+       { "bt", GDB_SIZEOF_REG, -1 },
+       { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp) },
+       { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, sp) },
+       { "fp", GDB_SIZEOF_REG, offsetof(struct pt_regs, fp) },
+       { "ea", GDB_SIZEOF_REG, -1 },
+       { "ba", GDB_SIZEOF_REG, -1 },
+       { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, ra) },
+       { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, ea) },
+       { "status", GDB_SIZEOF_REG, -1 },
+       { "estatus", GDB_SIZEOF_REG, offsetof(struct pt_regs, estatus) },
+       { "bstatus", GDB_SIZEOF_REG, -1 },
+       { "ienable", GDB_SIZEOF_REG, -1 },
+       { "ipending", GDB_SIZEOF_REG, -1},
+       { "cpuid", GDB_SIZEOF_REG, -1 },
+       { "ctl6", GDB_SIZEOF_REG, -1 },
+       { "exception", GDB_SIZEOF_REG, -1 },
+       { "pteaddr", GDB_SIZEOF_REG, -1 },
+       { "tlbacc", GDB_SIZEOF_REG, -1 },
+       { "tlbmisc", GDB_SIZEOF_REG, -1 },
+       { "eccinj", GDB_SIZEOF_REG, -1 },
+       { "badaddr", GDB_SIZEOF_REG, -1 },
+       { "config", GDB_SIZEOF_REG, -1 },
+       { "mpubase", GDB_SIZEOF_REG, -1 },
+       { "mpuacc", GDB_SIZEOF_REG, -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 *p)
+{
+       memset((char *)gdb_regs, 0, NUMREGBYTES);
+       gdb_regs[GDB_SP] = p->thread.kregs->sp;
+       gdb_regs[GDB_PC] = p->thread.kregs->ea;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+       regs->ea = pc;
+}
+
+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 addr;
+
+       switch (remcom_in_buffer[0]) {
+       case 's':
+       case 'c':
+               /* handle the optional parameters */
+               ptr = &remcom_in_buffer[1];
+               if (kgdb_hex2long(&ptr, &addr))
+                       regs->ea = addr;
+
+               return 0;
+       }
+
+       return -1; /* this means that we do not want to exit from the handler */
+}
+
+asmlinkage void kgdb_breakpoint_c(struct pt_regs *regs)
+{
+       /*
+        * The breakpoint entry code has moved the PC on by 4 bytes, so we must
+        * move it back.  This could be done on the host but we do it here
+        */
+       if (!wait_for_remote_debugger)
+               regs->ea -= 4;
+       else    /* pass the first trap 30 code */
+               wait_for_remote_debugger = 0;
+
+       kgdb_handle_exception(30, SIGTRAP, 0, regs);
+}
+
+int kgdb_arch_init(void)
+{
+       wait_for_remote_debugger = 1;
+       return 0;
+}
+
+void kgdb_arch_exit(void)
+{
+       /* Nothing to do */
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+       /* Breakpoint instruction: trap 30 */
+       .gdb_bpt_instr = { 0xba, 0x6f, 0x3b, 0x00 },
+};