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>

1 files changed, 44 insertions, 81 deletions

diff --git a/arch/sparc/kernel/entry.S b/arch/sparc/kernel/entry.S
index 484c83d23eef..57d1bbdd0bd2 100644
--- a/arch/sparc/kernel/entry.S
+++ b/arch/sparc/kernel/entry.S
@@ -12,7 +12,6 @@
 #include <asm/head.h>
 #include <asm/asi.h>
 #include <asm/smp.h>
-#include <asm/kgdb.h>
 #include <asm/contregs.h>
 #include <asm/ptrace.h>
 #include <asm/asm-offsets.h>
@@ -45,91 +44,20 @@
         _SV; _SV; _SV; _SV; _SV; _SV; _SV; \
         _RS; _RS; _RS; _RS; _RS; _RS; _RS;
 
-/* First, KGDB low level things.  This is a rewrite
- * of the routines found in the sparc-stub.c asm() statement
- * from the gdb distribution.  This is also dual-purpose
- * as a software trap for userlevel programs.
- */
-        .data
-        .align  4
-
-in_trap_handler:
-        .word   0
-
         .text
-        .align  4
 
-#if 0 /* kgdb is dropped from 2.5.33 */
-! This function is called when any SPARC trap (except window overflow or
-! underflow) occurs.  It makes sure that the invalid register window is still
-! available before jumping into C code.  It will also restore the world if you
-! return from handle_exception.
-
-        .globl  trap_low
-trap_low:
-        rd      %wim, %l3
-        SAVE_ALL
-
-        sethi   %hi(in_trap_handler), %l4
-        ld      [%lo(in_trap_handler) + %l4], %l5
-        inc     %l5
-        st      %l5, [%lo(in_trap_handler) + %l4]
-
-        /* Make sure kgdb sees the same state we just saved. */
-        LOAD_PT_GLOBALS(sp)
-        LOAD_PT_INS(sp)
-        ld      [%sp + STACKFRAME_SZ + PT_Y], %l4
-        ld      [%sp + STACKFRAME_SZ + PT_WIM], %l3
-        ld      [%sp + STACKFRAME_SZ + PT_PSR], %l0
-        ld      [%sp + STACKFRAME_SZ + PT_PC], %l1
-        ld      [%sp + STACKFRAME_SZ + PT_NPC], %l2
-        rd      %tbr, %l5       /* Never changes... */
-
-        /* Make kgdb exception frame. */        
-        sub     %sp,(16+1+6+1+72)*4,%sp ! Make room for input & locals
-                                        ! + hidden arg + arg spill
-                                        ! + doubleword alignment
-                                        ! + registers[72] local var
-        SAVE_KGDB_GLOBALS(sp)
-        SAVE_KGDB_INS(sp)
-        SAVE_KGDB_SREGS(sp, l4, l0, l3, l5, l1, l2)
-
-        /* We are increasing PIL, so two writes. */
-        or      %l0, PSR_PIL, %l0
-        wr      %l0, 0, %psr
-        WRITE_PAUSE
-        wr      %l0, PSR_ET, %psr
-        WRITE_PAUSE
-
-        call    handle_exception
-         add    %sp, STACKFRAME_SZ, %o0 ! Pass address of registers
-
-        /* Load new kgdb register set. */
-        LOAD_KGDB_GLOBALS(sp)
-        LOAD_KGDB_INS(sp)
-        LOAD_KGDB_SREGS(sp, l4, l0, l3, l5, l1, l2)
-        wr      %l4, 0x0, %y
-
-        sethi   %hi(in_trap_handler), %l4
-        ld      [%lo(in_trap_handler) + %l4], %l5
-        dec     %l5
-        st      %l5, [%lo(in_trap_handler) + %l4]
-
-        add     %sp,(16+1+6+1+72)*4,%sp ! Undo the kgdb trap frame.
-
-        /* Now take what kgdb did and place it into the pt_regs
-         * frame which SparcLinux RESTORE_ALL understands.,
-         */
-        STORE_PT_INS(sp)
-        STORE_PT_GLOBALS(sp)
-        STORE_PT_YREG(sp, g2)
-        STORE_PT_PRIV(sp, l0, l1, l2)
-
-        RESTORE_ALL
+#ifdef CONFIG_KGDB
+        .align  4
+        .globl          arch_kgdb_breakpoint
+        .type           arch_kgdb_breakpoint,#function
+arch_kgdb_breakpoint:
+        ta              0x7d
+        retl
+         nop
+        .size           arch_kgdb_breakpoint,.-arch_kgdb_breakpoint
 #endif
 
 #if defined(CONFIG_BLK_DEV_FD) || defined(CONFIG_BLK_DEV_FD_MODULE)
-        .text
         .align  4
         .globl  floppy_hardint
 floppy_hardint:
@@ -1596,6 +1524,23 @@ breakpoint_trap:
 
         RESTORE_ALL
 
+#ifdef CONFIG_KGDB
+        .align  4
+        .globl  kgdb_trap_low
+        .type   kgdb_trap_low,#function
+kgdb_trap_low:
+        rd      %wim,%l3
+        SAVE_ALL
+        wr      %l0, PSR_ET, %psr
+        WRITE_PAUSE
+
+        call    kgdb_trap
+         add    %sp, STACKFRAME_SZ, %o0
+
+        RESTORE_ALL
+        .size   kgdb_trap_low,.-kgdb_trap_low
+#endif
+
         .align  4
         .globl  __handle_exception, flush_patch_exception
 __handle_exception:
@@ -1698,4 +1643,22 @@ pcic_nmi_trap_patch:
 
 #endif /* CONFIG_PCI */
 
+        .globl  flushw_all
+flushw_all:
+        save    %sp, -0x40, %sp
+        save    %sp, -0x40, %sp
+        save    %sp, -0x40, %sp
+        save    %sp, -0x40, %sp
+        save    %sp, -0x40, %sp
+        save    %sp, -0x40, %sp
+        save    %sp, -0x40, %sp
+        restore
+        restore
+        restore
+        restore
+        restore
+        restore
+        ret
+         restore
+
 /* End of entry.S */