1 files changed, 724 insertions, 0 deletions

diff --git a/arch/sparc/kernel/sparc-stub.c b/arch/sparc/kernel/sparc-stub.c
new file mode 100644
index 000000000000..e84f815e6903
--- /dev/null
+++ b/arch/sparc/kernel/sparc-stub.c
@@ -0,0 +1,724 @@
+/* $Id: sparc-stub.c,v 1.28 2001/10/30 04:54:21 davem Exp $
+ * sparc-stub.c:  KGDB support for the Linux kernel.
+ *
+ * Modifications to run under Linux
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ *
+ * This file originally came from the gdb sources, and the
+ * copyright notices have been retained below.
+ */
+
+/****************************************************************************
+
+                THIS SOFTWARE IS NOT COPYRIGHTED
+
+   HP offers the following for use in the public domain.  HP makes no
+   warranty with regard to the software or its performance and the
+   user accepts the software "AS IS" with all faults.
+
+   HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD
+   TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+
+****************************************************************************/
+
+/****************************************************************************
+ *  Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $
+ *
+ *  Module name: remcom.c $
+ *  Revision: 1.34 $
+ *  Date: 91/03/09 12:29:49 $
+ *  Contributor:     Lake Stevens Instrument Division$
+ *
+ *  Description:     low level support for gdb debugger. $
+ *
+ *  Considerations:  only works on target hardware $
+ *
+ *  Written by:      Glenn Engel $
+ *  ModuleState:     Experimental $
+ *
+ *  NOTES:           See Below $
+ *
+ *  Modified for SPARC by Stu Grossman, Cygnus Support.
+ *
+ *  This code has been extensively tested on the Fujitsu SPARClite demo board.
+ *
+ *  To enable debugger support, two things need to happen.  One, a
+ *  call to set_debug_traps() is necessary in order to allow any breakpoints
+ *  or error conditions to be properly intercepted and reported to gdb.
+ *  Two, a breakpoint needs to be generated to begin communication.  This
+ *  is most easily accomplished by a call to breakpoint().  Breakpoint()
+ *  simulates a breakpoint by executing a trap #1.
+ *
+ *************
+ *
+ *    The following gdb commands are supported:
+ *
+ * command          function                               Return value
+ *
+ *    g             return the value of the CPU registers  hex data or ENN
+ *    G             set the value of the CPU registers     OK or ENN
+ *
+ *    mAA..AA,LLLL  Read LLLL bytes at address AA..AA      hex data or ENN
+ *    MAA..AA,LLLL: Write LLLL bytes at address AA.AA      OK or ENN
+ *
+ *    c             Resume at current address              SNN   ( signal NN)
+ *    cAA..AA       Continue at address AA..AA             SNN
+ *
+ *    s             Step one instruction                   SNN
+ *    sAA..AA       Step one instruction from AA..AA       SNN
+ *
+ *    k             kill
+ *
+ *    ?             What was the last sigval ?             SNN   (signal NN)
+ *
+ *    bBB..BB       Set baud rate to BB..BB                OK or BNN, then sets
+ *                                                         baud rate
+ *
+ * All commands and responses are sent with a packet which includes a
+ * checksum.  A packet consists of
+ *
+ * $<packet info>#<checksum>.
+ *
+ * where
+ * <packet info> :: <characters representing the command or response>
+ * <checksum>    :: < two hex digits computed as modulo 256 sum of <packetinfo>>
+ *
+ * When a packet is received, it is first acknowledged with either '+' or '-'.
+ * '+' indicates a successful transfer.  '-' indicates a failed transfer.
+ *
+ * Example:
+ *
+ * Host:                  Reply:
+ * $m0,10#2a               +$00010203040506070809101112131415#42
+ *
+ ****************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+
+#include <asm/system.h>
+#include <asm/signal.h>
+#include <asm/oplib.h>
+#include <asm/head.h>
+#include <asm/traps.h>
+#include <asm/vac-ops.h>
+#include <asm/kgdb.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+
+/*
+ *
+ * external low-level support routines
+ */
+
+extern void putDebugChar(char);   /* write a single character      */
+extern char getDebugChar(void);   /* read and return a single char */
+
+/*
+ * BUFMAX defines the maximum number of characters in inbound/outbound buffers
+ * at least NUMREGBYTES*2 are needed for register packets
+ */
+#define BUFMAX 2048
+
+static int initialized; /* !0 means we've been initialized */
+
+static const char hexchars[]="0123456789abcdef";
+
+#define NUMREGS 72
+
+/* Number of bytes of registers.  */
+#define NUMREGBYTES (NUMREGS * 4)
+enum regnames {G0, G1, G2, G3, G4, G5, G6, G7,
+                 O0, O1, O2, O3, O4, O5, SP, O7,
+                 L0, L1, L2, L3, L4, L5, L6, L7,
+                 I0, I1, I2, I3, I4, I5, FP, I7,
+
+                 F0, F1, F2, F3, F4, F5, F6, F7,
+                 F8, F9, F10, F11, F12, F13, F14, F15,
+                 F16, F17, F18, F19, F20, F21, F22, F23,
+                 F24, F25, F26, F27, F28, F29, F30, F31,
+                 Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR };
+
+
+extern void trap_low(void);  /* In arch/sparc/kernel/entry.S */
+
+unsigned long get_sun4cpte(unsigned long addr)
+{
+        unsigned long entry;
+
+        __asm__ __volatile__("\n\tlda [%1] %2, %0\n\t" : 
+                             "=r" (entry) :
+                             "r" (addr), "i" (ASI_PTE));
+        return entry;
+}
+
+unsigned long get_sun4csegmap(unsigned long addr)
+{
+        unsigned long entry;
+
+        __asm__ __volatile__("\n\tlduba [%1] %2, %0\n\t" : 
+                             "=r" (entry) :
+                             "r" (addr), "i" (ASI_SEGMAP));
+        return entry;
+}
+
+#if 0
+/* Have to sort this out. This cannot be done after initialization. */
+static void flush_cache_all_nop(void) {}
+#endif
+
+/* Place where we save old trap entries for restoration */
+struct tt_entry kgdb_savettable[256];
+typedef void (*trapfunc_t)(void);
+
+/* Helper routine for manipulation of kgdb_savettable */
+static inline void copy_ttentry(struct tt_entry *src, struct tt_entry *dest)
+{
+        dest->inst_one = src->inst_one;
+        dest->inst_two = src->inst_two;
+        dest->inst_three = src->inst_three;
+        dest->inst_four = src->inst_four;
+}
+
+/* Initialize the kgdb_savettable so that debugging can commence */
+static void eh_init(void)
+{
+        int i;
+
+        for(i=0; i < 256; i++)
+                copy_ttentry(&sparc_ttable[i], &kgdb_savettable[i]);
+}
+
+/* Install an exception handler for kgdb */
+static void exceptionHandler(int tnum, trapfunc_t trap_entry)
+{
+        unsigned long te_addr = (unsigned long) trap_entry;
+
+        /* Make new vector */
+        sparc_ttable[tnum].inst_one =
+                SPARC_BRANCH((unsigned long) te_addr,
+                             (unsigned long) &sparc_ttable[tnum].inst_one);
+        sparc_ttable[tnum].inst_two = SPARC_RD_PSR_L0;
+        sparc_ttable[tnum].inst_three = SPARC_NOP;
+        sparc_ttable[tnum].inst_four = SPARC_NOP;
+}
+
+/* Convert ch from a hex digit to an int */
+static int
+hex(unsigned char ch)
+{
+        if (ch >= 'a' && ch <= 'f')
+                return ch-'a'+10;
+        if (ch >= '0' && ch <= '9')
+                return ch-'0';
+        if (ch >= 'A' && ch <= 'F')
+                return ch-'A'+10;
+        return -1;
+}
+
+/* scan for the sequence $<data>#<checksum>     */
+static void
+getpacket(char *buffer)
+{
+        unsigned char checksum;
+        unsigned char xmitcsum;
+        int i;
+        int count;
+        unsigned char ch;
+
+        do {
+                /* wait around for the start character, ignore all other characters */
+                while ((ch = (getDebugChar() & 0x7f)) != '$') ;
+
+                checksum = 0;
+                xmitcsum = -1;
+
+                count = 0;
+
+                /* now, read until a # or end of buffer is found */
+                while (count < BUFMAX) {
+                        ch = getDebugChar() & 0x7f;
+                        if (ch == '#')
+                                break;
+                        checksum = checksum + ch;
+                        buffer[count] = ch;
+                        count = count + 1;
+                }
+
+                if (count >= BUFMAX)
+                        continue;
+
+                buffer[count] = 0;
+
+                if (ch == '#') {
+                        xmitcsum = hex(getDebugChar() & 0x7f) << 4;
+                        xmitcsum |= hex(getDebugChar() & 0x7f);
+                        if (checksum != xmitcsum)
+                                putDebugChar('-');      /* failed checksum */
+                        else {
+                                putDebugChar('+'); /* successful transfer */
+                                /* if a sequence char is present, reply the ID */
+                                if (buffer[2] == ':') {
+                                        putDebugChar(buffer[0]);
+                                        putDebugChar(buffer[1]);
+                                        /* remove sequence chars from buffer */
+                                        count = strlen(buffer);
+                                        for (i=3; i <= count; i++)
+                                                buffer[i-3] = buffer[i];
+                                }
+                        }
+                }
+        } while (checksum != xmitcsum);
+}
+
+/* send the packet in buffer.  */
+
+static void
+putpacket(unsigned char *buffer)
+{
+        unsigned char checksum;
+        int count;
+        unsigned char ch, recv;
+
+        /*  $<packet info>#<checksum>. */
+        do {
+                putDebugChar('$');
+                checksum = 0;
+                count = 0;
+
+                while ((ch = buffer[count])) {
+                        putDebugChar(ch);
+                        checksum += ch;
+                        count += 1;
+                }
+
+                putDebugChar('#');
+                putDebugChar(hexchars[checksum >> 4]);
+                putDebugChar(hexchars[checksum & 0xf]);
+                recv = getDebugChar();
+        } while ((recv & 0x7f) != '+');
+}
+
+static char remcomInBuffer[BUFMAX];
+static char remcomOutBuffer[BUFMAX];
+
+/* Convert the memory pointed to by mem into hex, placing result in buf.
+ * Return a pointer to the last char put in buf (null), in case of mem fault,
+ * return 0.
+ */
+
+static unsigned char *
+mem2hex(char *mem, char *buf, int count)
+{
+        unsigned char ch;
+
+        while (count-- > 0) {
+                /* This assembler code is basically:  ch = *mem++;
+                 * except that we use the SPARC/Linux exception table
+                 * mechanism (see how "fixup" works in kernel_mna_trap_fault)
+                 * to arrange for a "return 0" upon a memory fault
+                 */
+                __asm__(
+                        "\n1:\n\t"
+                        "ldub [%0], %1\n\t"
+                        "inc %0\n\t"
+                        ".section .fixup,#alloc,#execinstr\n\t"
+                        ".align 4\n"
+                        "2:\n\t"
+                        "retl\n\t"
+                        " mov 0, %%o0\n\t"
+                        ".section __ex_table, #alloc\n\t"
+                        ".align 4\n\t"
+                        ".word 1b, 2b\n\t"
+                        ".text\n"
+                        : "=r" (mem), "=r" (ch) : "0" (mem));
+                *buf++ = hexchars[ch >> 4];
+                *buf++ = hexchars[ch & 0xf];
+        }
+
+        *buf = 0;
+        return buf;
+}
+
+/* convert the hex array pointed to by buf into binary to be placed in mem
+ * return a pointer to the character AFTER the last byte written.
+*/
+static char *
+hex2mem(char *buf, char *mem, int count)
+{
+        int i;
+        unsigned char ch;
+
+        for (i=0; i<count; i++) {
+
+                ch = hex(*buf++) << 4;
+                ch |= hex(*buf++);
+                /* Assembler code is   *mem++ = ch;   with return 0 on fault */
+                __asm__(
+                        "\n1:\n\t"
+                        "stb %1, [%0]\n\t"
+                        "inc %0\n\t"
+                        ".section .fixup,#alloc,#execinstr\n\t"
+                        ".align 4\n"
+                        "2:\n\t"
+                        "retl\n\t"
+                        " mov 0, %%o0\n\t"
+                        ".section __ex_table, #alloc\n\t"
+                        ".align 4\n\t"
+                        ".word 1b, 2b\n\t"
+                        ".text\n"
+                        : "=r" (mem) : "r" (ch) , "0" (mem));
+        }
+        return mem;
+}
+
+/* This table contains the mapping between SPARC hardware trap types, and
+   signals, which are primarily what GDB understands.  It also indicates
+   which hardware traps we need to commandeer when initializing the stub. */
+
+static struct hard_trap_info
+{
+  unsigned char tt;             /* Trap type code for SPARC */
+  unsigned char signo;          /* Signal that we map this trap into */
+} hard_trap_info[] = {
+  {SP_TRAP_SBPT, SIGTRAP},      /* ta 1 - Linux/KGDB software breakpoint */
+  {0, 0}                        /* Must be last */
+};
+
+/* Set up exception handlers for tracing and breakpoints */
+
+void
+set_debug_traps(void)
+{
+        struct hard_trap_info *ht;
+        unsigned long flags;
+
+        local_irq_save(flags);
+#if 0   
+/* Have to sort this out. This cannot be done after initialization. */
+        BTFIXUPSET_CALL(flush_cache_all, flush_cache_all_nop, BTFIXUPCALL_NOP);
+#endif
+
+        /* Initialize our copy of the Linux Sparc trap table */
+        eh_init();
+
+        for (ht = hard_trap_info; ht->tt && ht->signo; ht++) {
+                /* Only if it doesn't destroy our fault handlers */
+                if((ht->tt != SP_TRAP_TFLT) && 
+                   (ht->tt != SP_TRAP_DFLT))
+                        exceptionHandler(ht->tt, trap_low);
+        }
+
+        /* In case GDB is started before us, ack any packets (presumably
+         * "$?#xx") sitting there.
+         *
+         * I've found this code causes more problems than it solves,
+         * so that's why it's commented out.  GDB seems to work fine
+         * now starting either before or after the kernel   -bwb
+         */
+#if 0
+        while((c = getDebugChar()) != '$');
+        while((c = getDebugChar()) != '#');
+        c = getDebugChar(); /* eat first csum byte */
+        c = getDebugChar(); /* eat second csum byte */
+        putDebugChar('+'); /* ack it */
+#endif
+
+        initialized = 1; /* connect! */
+        local_irq_restore(flags);
+}
+
+/* Convert the SPARC hardware trap type code to a unix signal number. */
+
+static int
+computeSignal(int tt)
+{
+        struct hard_trap_info *ht;
+
+        for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
+                if (ht->tt == tt)
+                        return ht->signo;
+
+        return SIGHUP;         /* default for things we don't know about */
+}
+
+/*
+ * While we find nice hex chars, build an int.
+ * Return number of chars processed.
+ */
+
+static int
+hexToInt(char **ptr, int *intValue)
+{
+        int numChars = 0;
+        int hexValue;
+
+        *intValue = 0;
+
+        while (**ptr) {
+                hexValue = hex(**ptr);
+                if (hexValue < 0)
+                        break;
+
+                *intValue = (*intValue << 4) | hexValue;
+                numChars ++;
+
+                (*ptr)++;
+        }
+
+        return (numChars);
+}
+
+/*
+ * This function does all command processing for interfacing to gdb.  It
+ * returns 1 if you should skip the instruction at the trap address, 0
+ * otherwise.
+ */
+
+extern void breakinst(void);
+
+void
+handle_exception (unsigned long *registers)
+{
+        int tt;       /* Trap type */
+        int sigval;
+        int addr;
+        int length;
+        char *ptr;
+        unsigned long *sp;
+
+        /* First, we must force all of the windows to be spilled out */
+
+        asm("save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "save %sp, -64, %sp\n\t"
+            "restore\n\t"
+            "restore\n\t"
+            "restore\n\t"
+            "restore\n\t"
+            "restore\n\t"
+            "restore\n\t"
+            "restore\n\t"
+            "restore\n\t");
+
+        lock_kernel();
+        if (registers[PC] == (unsigned long)breakinst) {
+                /* Skip over breakpoint trap insn */
+                registers[PC] = registers[NPC];
+                registers[NPC] += 4;
+        }
+
+        sp = (unsigned long *)registers[SP];
+
+        tt = (registers[TBR] >> 4) & 0xff;
+
+        /* reply to host that an exception has occurred */
+        sigval = computeSignal(tt);
+        ptr = remcomOutBuffer;
+
+        *ptr++ = 'T';
+        *ptr++ = hexchars[sigval >> 4];
+        *ptr++ = hexchars[sigval & 0xf];
+
+        *ptr++ = hexchars[PC >> 4];
+        *ptr++ = hexchars[PC & 0xf];
+        *ptr++ = ':';
+        ptr = mem2hex((char *)&registers[PC], ptr, 4);
+        *ptr++ = ';';
+
+        *ptr++ = hexchars[FP >> 4];
+        *ptr++ = hexchars[FP & 0xf];
+        *ptr++ = ':';
+        ptr = mem2hex((char *) (sp + 8 + 6), ptr, 4); /* FP */
+        *ptr++ = ';';
+
+        *ptr++ = hexchars[SP >> 4];
+        *ptr++ = hexchars[SP & 0xf];
+        *ptr++ = ':';
+        ptr = mem2hex((char *)&sp, ptr, 4);
+        *ptr++ = ';';
+
+        *ptr++ = hexchars[NPC >> 4];
+        *ptr++ = hexchars[NPC & 0xf];
+        *ptr++ = ':';
+        ptr = mem2hex((char *)&registers[NPC], ptr, 4);
+        *ptr++ = ';';
+
+        *ptr++ = hexchars[O7 >> 4];
+        *ptr++ = hexchars[O7 & 0xf];
+        *ptr++ = ':';
+        ptr = mem2hex((char *)&registers[O7], ptr, 4);
+        *ptr++ = ';';
+
+        *ptr++ = 0;
+
+        putpacket(remcomOutBuffer);
+
+        /* XXX We may want to add some features dealing with poking the
+         * XXX page tables, the real ones on the srmmu, and what is currently
+         * XXX loaded in the sun4/sun4c tlb at this point in time.  But this
+         * XXX also required hacking to the gdb sources directly...
+         */
+
+        while (1) {
+                remcomOutBuffer[0] = 0;
+
+                getpacket(remcomInBuffer);
+                switch (remcomInBuffer[0]) {
+                case '?':
+                        remcomOutBuffer[0] = 'S';
+                        remcomOutBuffer[1] = hexchars[sigval >> 4];
+                        remcomOutBuffer[2] = hexchars[sigval & 0xf];
+                        remcomOutBuffer[3] = 0;
+                        break;
+
+                case 'd':
+                        /* toggle debug flag */
+                        break;
+
+                case 'g':               /* return the value of the CPU registers */
+                {
+                        ptr = remcomOutBuffer;
+                        /* G & O regs */
+                        ptr = mem2hex((char *)registers, ptr, 16 * 4);
+                        /* L & I regs */
+                        ptr = mem2hex((char *) (sp + 0), ptr, 16 * 4);
+                        /* Floating point */
+                        memset(ptr, '0', 32 * 8);
+                        /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
+                        mem2hex((char *)&registers[Y], (ptr + 32 * 4 * 2), (8 * 4));
+                }
+                        break;
+
+                case 'G':          /* set the value of the CPU registers - return OK */
+                {
+                        unsigned long *newsp, psr;
+
+                        psr = registers[PSR];
+
+                        ptr = &remcomInBuffer[1];
+                        /* G & O regs */
+                        hex2mem(ptr, (char *)registers, 16 * 4);
+                        /* L & I regs */
+                        hex2mem(ptr + 16 * 4 * 2, (char *) (sp + 0), 16 * 4);
+                        /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
+                        hex2mem(ptr + 64 * 4 * 2, (char *)&registers[Y], 8 * 4);
+
+                        /* See if the stack pointer has moved.  If so,
+                         * then copy the saved locals and ins to the
+                         * new location.  This keeps the window
+                         * overflow and underflow routines happy.
+                         */
+
+                        newsp = (unsigned long *)registers[SP];
+                        if (sp != newsp)
+                                sp = memcpy(newsp, sp, 16 * 4);
+
+                        /* Don't allow CWP to be modified. */
+
+                        if (psr != registers[PSR])
+                                registers[PSR] = (psr & 0x1f) | (registers[PSR] & ~0x1f);
+
+                        strcpy(remcomOutBuffer,"OK");
+                }
+                        break;
+
+                case 'm':         /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
+                        /* Try to read %x,%x.  */
+
+                        ptr = &remcomInBuffer[1];
+
+                        if (hexToInt(&ptr, &addr)
+                            && *ptr++ == ','
+                            && hexToInt(&ptr, &length)) {
+                                if (mem2hex((char *)addr, remcomOutBuffer, length))
+                                        break;
+
+                                strcpy (remcomOutBuffer, "E03");
+                        } else {
+                                strcpy(remcomOutBuffer,"E01");
+                        }
+                        break;
+
+                case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
+                        /* Try to read '%x,%x:'.  */
+
+                        ptr = &remcomInBuffer[1];
+
+                        if (hexToInt(&ptr, &addr)
+                            && *ptr++ == ','
+                            && hexToInt(&ptr, &length)
+                            && *ptr++ == ':') {
+                                if (hex2mem(ptr, (char *)addr, length)) {
+                                        strcpy(remcomOutBuffer, "OK");
+                                } else {
+                                        strcpy(remcomOutBuffer, "E03");
+                                }
+                        } else {
+                                strcpy(remcomOutBuffer, "E02");
+                        }
+                        break;
+
+                case 'c':    /* cAA..AA    Continue at address AA..AA(optional) */
+                        /* try to read optional parameter, pc unchanged if no parm */
+
+                        ptr = &remcomInBuffer[1];
+                        if (hexToInt(&ptr, &addr)) {
+                                registers[PC] = addr;
+                                registers[NPC] = addr + 4;
+                        }
+
+/* Need to flush the instruction cache here, as we may have deposited a
+ * breakpoint, and the icache probably has no way of knowing that a data ref to
+ * some location may have changed something that is in the instruction cache.
+ */
+                        flush_cache_all();
+                        unlock_kernel();
+                        return;
+
+                        /* kill the program */
+                case 'k' :              /* do nothing */
+                        break;
+                case 'r':               /* Reset */
+                        asm ("call 0\n\t"
+                             "nop\n\t");
+                        break;
+                }                       /* switch */
+
+                /* reply to the request */
+                putpacket(remcomOutBuffer);
+        } /* while(1) */
+}
+
+/* This function will generate a breakpoint exception.  It is used at the
+   beginning of a program to sync up with a debugger and can be used
+   otherwise as a quick means to stop program execution and "break" into
+   the debugger. */
+
+void
+breakpoint(void)
+{
+        if (!initialized)
+                return;
+
+        /* Again, watch those c-prefixes for ELF kernels */
+#if defined(__svr4__) || defined(__ELF__)
+        asm(".globl breakinst\n"
+            "breakinst:\n\t"
+            "ta 1\n");
+#else
+        asm(".globl _breakinst\n"
+            "_breakinst:\n\t"
+            "ta 1\n");
+#endif
+}