sparc: Add kgdb support.

Current limitations:

1) On SMP single stepping has some fundamental issues,
   shared with other sw single-step architectures such
   as mips and arm.

2) On 32-bit sparc we don't support SMP kgdb yet.  That
   requires some reworking of the IPI mechanisms and
   infrastructure on that platform.

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 53 insertions, 88 deletions

diff --git a/include/asm-sparc/head.h b/include/asm-sparc/head.h
index fcdba5116339..e6532c3e09c9 100644
--- a/include/asm-sparc/head.h
+++ b/include/asm-sparc/head.h
@@ -52,6 +52,17 @@
         nop; \
         nop;
 
+#ifdef CONFIG_KGDB
+#define KGDB_TRAP(num) \
+        b kgdb_trap_low; \
+        rd %psr,%l0; \
+        nop; \
+        nop;
+#else
+#define KGDB_TRAP(num) \
+        BAD_TRAP(num)
+#endif
+
 /* The Get Condition Codes software trap for userland. */
 #define GETCC_TRAP \
         b getcc_trap_handler; mov %psr, %l0; nop; nop;
diff --git a/include/asm-sparc/kgdb.h b/include/asm-sparc/kgdb.h
index d120adfb429f..b6ef301d05bf 100644
--- a/include/asm-sparc/kgdb.h
+++ b/include/asm-sparc/kgdb.h
@@ -1,94 +1,38 @@
-/* $Id: kgdb.h,v 1.8 1998/01/07 06:33:44 baccala Exp $
- * kgdb.h: Defines and declarations for serial line source level
- *         remote debugging of the Linux kernel using gdb.
- *
- * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
- */
 #ifndef _SPARC_KGDB_H
 #define _SPARC_KGDB_H
 
-#ifndef __ASSEMBLY__
-/* To init the kgdb engine. */
-extern void set_debug_traps(void);
-
-/* To enter the debugger explicitly. */
-extern void breakpoint(void);
-
-/* For convenience we define the format of a kgdb trap breakpoint
- * frame here also.
- */
-struct kgdb_frame {
-        unsigned long globals[8];
-        unsigned long outs[8];
-        unsigned long locals[8];
-        unsigned long ins[8];
-        unsigned long fpregs[32];
-        unsigned long y;
-        unsigned long psr;
-        unsigned long wim;
-        unsigned long tbr;
-        unsigned long pc;
-        unsigned long npc;
-        unsigned long fpsr;
-        unsigned long cpsr;
+#ifdef CONFIG_SPARC32
+#define BUFMAX                  2048
+#else
+#define BUFMAX                  4096
+#endif
+
+enum regnames {
+        GDB_G0, GDB_G1, GDB_G2, GDB_G3, GDB_G4, GDB_G5, GDB_G6, GDB_G7,
+        GDB_O0, GDB_O1, GDB_O2, GDB_O3, GDB_O4, GDB_O5, GDB_SP, GDB_O7,
+        GDB_L0, GDB_L1, GDB_L2, GDB_L3, GDB_L4, GDB_L5, GDB_L6, GDB_L7,
+        GDB_I0, GDB_I1, GDB_I2, GDB_I3, GDB_I4, GDB_I5, GDB_FP, GDB_I7,
+        GDB_F0,
+        GDB_F31 = GDB_F0 + 31,
+#ifdef CONFIG_SPARC32
+        GDB_Y, GDB_PSR, GDB_WIM, GDB_TBR, GDB_PC, GDB_NPC,
+        GDB_FSR, GDB_CSR,
+#else
+        GDB_F32 = GDB_F0 + 32,
+        GDB_F62 = GDB_F32 + 15,
+        GDB_PC, GDB_NPC, GDB_STATE, GDB_FSR, GDB_FPRS, GDB_Y,
+#endif
 };
-#endif /* !(__ASSEMBLY__) */
-
-/* Macros for assembly usage of the kgdb breakpoint frame. */
-#define KGDB_G0     0x000
-#define KGDB_G1     0x004
-#define KGDB_G2     0x008
-#define KGDB_G4     0x010
-#define KGDB_G6     0x018
-#define KGDB_I0     0x020
-#define KGDB_I2     0x028
-#define KGDB_I4     0x030
-#define KGDB_I6     0x038
-#define KGDB_Y      0x100
-#define KGDB_PSR    0x104
-#define KGDB_WIM    0x108
-#define KGDB_TBR    0x10c
-#define KGDB_PC     0x110
-#define KGDB_NPC    0x114
-
-#define SAVE_KGDB_GLOBALS(reg) \
-        std     %g0, [%reg + STACKFRAME_SZ + KGDB_G0]; \
-        std     %g2, [%reg + STACKFRAME_SZ + KGDB_G2]; \
-        std     %g4, [%reg + STACKFRAME_SZ + KGDB_G4]; \
-        std     %g6, [%reg + STACKFRAME_SZ + KGDB_G6];
-
-#define SAVE_KGDB_INS(reg) \
-        std     %i0, [%reg + STACKFRAME_SZ + KGDB_I0]; \
-        std     %i2, [%reg + STACKFRAME_SZ + KGDB_I2]; \
-        std     %i4, [%reg + STACKFRAME_SZ + KGDB_I4]; \
-        std     %i6, [%reg + STACKFRAME_SZ + KGDB_I6];
-
-#define SAVE_KGDB_SREGS(reg, reg_y, reg_psr, reg_wim, reg_tbr, reg_pc, reg_npc) \
-        st      %reg_y, [%reg + STACKFRAME_SZ + KGDB_Y]; \
-        st      %reg_psr, [%reg + STACKFRAME_SZ + KGDB_PSR]; \
-        st      %reg_wim, [%reg + STACKFRAME_SZ + KGDB_WIM]; \
-        st      %reg_tbr, [%reg + STACKFRAME_SZ + KGDB_TBR]; \
-        st      %reg_pc, [%reg + STACKFRAME_SZ + KGDB_PC]; \
-        st      %reg_npc, [%reg + STACKFRAME_SZ + KGDB_NPC];
 
-#define LOAD_KGDB_GLOBALS(reg) \
-        ld      [%reg + STACKFRAME_SZ + KGDB_G1], %g1; \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_G2], %g2; \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_G4], %g4; \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_G6], %g6;
+#ifdef CONFIG_SPARC32
+#define NUMREGBYTES             ((GDB_CSR + 1) * 4)
+#else
+#define NUMREGBYTES             ((GDB_Y + 1) * 8)
+#endif
 
-#define LOAD_KGDB_INS(reg) \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_I0], %i0; \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_I2], %i2; \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_I4], %i4; \
-        ldd     [%reg + STACKFRAME_SZ + KGDB_I6], %i6;
+extern void arch_kgdb_breakpoint(void);
 
-#define LOAD_KGDB_SREGS(reg, reg_y, reg_psr, reg_wim, reg_tbr, reg_pc, reg_npc) \
-        ld      [%reg + STACKFRAME_SZ + KGDB_Y], %reg_y; \
-        ld      [%reg + STACKFRAME_SZ + KGDB_PSR], %reg_psr; \
-        ld      [%reg + STACKFRAME_SZ + KGDB_WIM], %reg_wim; \
-        ld      [%reg + STACKFRAME_SZ + KGDB_TBR], %reg_tbr; \
-        ld      [%reg + STACKFRAME_SZ + KGDB_PC], %reg_pc; \
-        ld      [%reg + STACKFRAME_SZ + KGDB_NPC], %reg_npc;
+#define BREAK_INSTR_SIZE        4
+#define CACHE_FLUSH_IS_SAFE     1
 
-#endif /* !(_SPARC_KGDB_H) */
+#endif /* _SPARC_KGDB_H */
diff --git a/include/asm-sparc/system.h b/include/asm-sparc/system.h
index 4e08210cd4c2..b4b024445fc9 100644
--- a/include/asm-sparc/system.h
+++ b/include/asm-sparc/system.h
@@ -94,6 +94,8 @@ extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
         } while(0)
 #endif
 
+extern void flushw_all(void);
+
 /*
  * Flush windows so that the VM switch which follows
  * would not pull the stack from under us.
diff --git a/include/asm-sparc64/kgdb.h b/include/asm-sparc64/kgdb.h
new file mode 100644
index 000000000000..aa6532fd3a13
--- /dev/null
+++ b/include/asm-sparc64/kgdb.h
@@ -0,0 +1 @@
+#include <asm-sparc/kgdb.h>
diff --git a/include/asm-sparc64/system.h b/include/asm-sparc64/system.h
index 53eae091a171..6897ac31be41 100644
--- a/include/asm-sparc64/system.h
+++ b/include/asm-sparc64/system.h
@@ -180,12 +180,13 @@ do {	if (test_thread_flag(TIF_PERFCTR)) {				\
         "ldx    [%%sp + 2047 + 0x70], %%i6\n\t"                         \
         "ldx    [%%sp + 2047 + 0x78], %%i7\n\t"                         \
         "ldx    [%%g6 + %9], %%g4\n\t"                                  \
-        "brz,pt %%o7, 1f\n\t"                                           \
+        "brz,pt %%o7, switch_to_pc\n\t"                                 \
         " mov   %%g7, %0\n\t"                                           \
         "sethi  %%hi(ret_from_syscall), %%g1\n\t"                       \
         "jmpl   %%g1 + %%lo(ret_from_syscall), %%g0\n\t"                \
         " nop\n\t"                                                      \
-        "1:\n\t"                                                        \
+        ".globl switch_to_pc\n\t"                                       \
+        "switch_to_pc:\n\t"                                             \
         : "=&r" (last), "=r" (current), "=r" (current_thread_info_reg), \
           "=r" (__local_per_cpu_offset)                                 \
         : "0" (task_thread_info(next)),                                 \
diff --git a/include/asm-sparc64/ttable.h b/include/asm-sparc64/ttable.h
index d3cc4eff39a6..1b55538b944f 100644
--- a/include/asm-sparc64/ttable.h
+++ b/include/asm-sparc64/ttable.h
@@ -175,6 +175,12 @@
 #define KPROBES_TRAP(lvl) TRAP_ARG(bad_trap, lvl)
 #endif
 
+#ifdef CONFIG_KGDB
+#define KGDB_TRAP(lvl) TRAP_IRQ(kgdb_trap, lvl)
+#else
+#define KGDB_TRAP(lvl) TRAP_ARG(bad_trap, lvl)
+#endif
+
 #define SUN4V_ITSB_MISS                                 \
         ldxa    [%g0] ASI_SCRATCHPAD, %g2;              \
         ldx     [%g2 + HV_FAULT_I_ADDR_OFFSET], %g4;    \