diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sparc/kernel/sparc-stub.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/sparc/kernel/sparc-stub.c')
-rw-r--r-- | arch/sparc/kernel/sparc-stub.c | 724 |
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 00000000000..e84f815e690 --- /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 *)®isters[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 *)®isters[NPC], ptr, 4); + *ptr++ = ';'; + + *ptr++ = hexchars[O7 >> 4]; + *ptr++ = hexchars[O7 & 0xf]; + *ptr++ = ':'; + ptr = mem2hex((char *)®isters[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 *)®isters[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 *)®isters[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 +} |