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sh: Bring kgdb back from the dead.

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This code has suffered quite a bit of bitrot, do some basic
tidying to get it to a reasonably functional state again.
This gets the basic support and the console working again.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt
2007-03-08 17:27:37 +09:00
committed by Paul Mundt
parent 15700770ef
commit fa5da2f7bd
8 changed files with 101 additions and 369 deletions
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106
arch/sh/kernel/kgdb_stub.c
View File

@@ -6,11 +6,11 @@
* David Grothe <dave@gcom.com>, Tigran Aivazian <tigran@sco.com>,
* Amit S. Kale <akale@veritas.com>, William Gatliff <bgat@open-widgets.com>,
* Ben Lee, Steve Chamberlain and Benoit Miller <fulg@iname.com>.
*
*
* This version by Henry Bell <henry.bell@st.com>
* Minor modifications by Jeremy Siegel <jsiegel@mvista.com>
*
* Contains low-level support for remote debug using GDB.
*
* Contains low-level support for remote debug using GDB.
*
* To enable debugger support, two things need to happen. A call to
* set_debug_traps() is necessary in order to allow any breakpoints
@@ -48,7 +48,7 @@
* k kill (Detach GDB)
*
* d Toggle debug flag
* D Detach GDB
* D Detach GDB
*
* Hct Set thread t for operations, OK or ENN
* c = 'c' (step, cont), c = 'g' (other
@@ -58,7 +58,7 @@
* qfThreadInfo Get list of current threads (first) m<id>
* qsThreadInfo " " " " " (subsequent)
* qOffsets Get section offsets Text=x;Data=y;Bss=z
*
*
* TXX Find if thread XX is alive OK or ENN
* ? What was the last sigval ? SNN (signal NN)
* O Output to GDB console
@@ -74,7 +74,7 @@
* '$' or '#'. If <data> starts with two characters followed by
* ':', then the existing stubs interpret this as a sequence number.
*
* CSUM1 and CSUM2 are ascii hex representation of an 8-bit
* CSUM1 and CSUM2 are ascii hex representation of an 8-bit
* checksum of <data>, the most significant nibble is sent first.
* the hex digits 0-9,a-f are used.
*
@@ -86,8 +86,8 @@
* Responses can be run-length encoded to save space. A '*' means that
* the next character is an ASCII encoding giving a repeat count which
* stands for that many repititions of the character preceding the '*'.
* The encoding is n+29, yielding a printable character where n >=3
* (which is where RLE starts to win). Don't use an n > 126.
* The encoding is n+29, yielding a printable character where n >=3
* (which is where RLE starts to win). Don't use an n > 126.
*
* So "0* " means the same as "0000".
*/
@@ -100,12 +100,10 @@
#include <linux/delay.h>
#include <linux/linkage.h>
#include <linux/init.h>
#ifdef CONFIG_SH_KGDB_CONSOLE
#include <linux/console.h>
#endif
#include <linux/sysrq.h>
#include <asm/system.h>
#include <asm/cacheflush.h>
#include <asm/current.h>
#include <asm/signal.h>
#include <asm/pgtable.h>
@@ -153,7 +151,6 @@ char kgdb_in_gdb_mode;
char in_nmi; /* Set during NMI to prevent reentry */
int kgdb_nofault; /* Boolean to ignore bus errs (i.e. in GDB) */
int kgdb_enabled = 1; /* Default to enabled, cmdline can disable */
int kgdb_halt;
/* Exposed for user access */
struct task_struct *kgdb_current;
@@ -328,7 +325,7 @@ static int hex_to_int(char **ptr, int *int_value)
}
/* Copy the binary array pointed to by buf into mem. Fix $, #,
and 0x7d escaped with 0x7d. Return a pointer to the character
and 0x7d escaped with 0x7d. Return a pointer to the character
after the last byte written. */
static char *ebin_to_mem(const char *buf, char *mem, int count)
{
@@ -452,7 +449,7 @@ static void get_packet(char *buffer, int buflen)
/* Ack successful transfer */
put_debug_char('+');
/* If a sequence char is present, reply
/* If a sequence char is present, reply
the sequence ID */
if (buffer[2] == ':') {
put_debug_char(buffer[0]);
@@ -759,7 +756,7 @@ static short *get_step_address(void)
return (short *) addr;
}
/* Set up a single-step. Replace the instruction immediately after the
/* Set up a single-step. Replace the instruction immediately after the
current instruction (i.e. next in the expected flow of control) with a
trap instruction, so that returning will cause only a single instruction
to be executed. Note that this model is slightly broken for instructions
@@ -1002,10 +999,8 @@ void set_thread_msg(void)
char *ptr;
switch (in_buffer[1]) {
/* To select which thread for gG etc messages, i.e. supported */
/* To select which thread for gG etc messages, i.e. supported */
case 'g':
ptr = &in_buffer[2];
hex_to_int(&ptr, &threadid);
thread = get_thread(threadid);
@@ -1173,6 +1168,7 @@ static void query_msg(void)
}
#endif /* CONFIG_KGDB_THREAD */
#ifdef CONFIG_SH_KGDB_CONSOLE
/*
* Bring up the ports..
*/
@@ -1185,6 +1181,9 @@ static int kgdb_serial_setup(void)
return 0;
}
#else
#define kgdb_serial_setup() 0
#endif
/* The command loop, read and act on requests */
static void kgdb_command_loop(const int excep_code, const int trapa_value)
@@ -1193,7 +1192,7 @@ static void kgdb_command_loop(const int excep_code, const int trapa_value)
if (excep_code == NMI_VEC) {
#ifndef CONFIG_KGDB_NMI
KGDB_PRINTK("Ignoring unexpected NMI?\n");
printk(KERN_NOTICE "KGDB: Ignoring unexpected NMI?\n");
return;
#else /* CONFIG_KGDB_NMI */
if (!kgdb_enabled) {
@@ -1216,10 +1215,7 @@ static void kgdb_command_loop(const int excep_code, const int trapa_value)
/* Enter GDB mode (e.g. after detach) */
if (!kgdb_in_gdb_mode) {
/* Do serial setup, notify user, issue preemptive ack */
kgdb_serial_setup();
KGDB_PRINTK("Waiting for GDB (on %s%d at %d baud)\n",
(kgdb_porttype ? kgdb_porttype->name : ""),
kgdb_portnum, kgdb_baud);
printk(KERN_NOTICE "KGDB: Waiting for GDB\n");
kgdb_in_gdb_mode = 1;
put_debug_char('+');
}
@@ -1233,21 +1229,18 @@ static void kgdb_command_loop(const int excep_code, const int trapa_value)
will later be replaced by its original one. Do NOT do this for
trap 0xff, since that indicates a compiled-in breakpoint which
will not be replaced (and we would retake the trap forever) */
if ((excep_code == TRAP_VEC) && (trapa_value != (0xff << 2))) {
if ((excep_code == TRAP_VEC) && (trapa_value != (0x3c << 2)))
trap_registers.pc -= 2;
}
/* Undo any stepping we may have done */
undo_single_step();
while (1) {
out_buffer[0] = 0;
get_packet(in_buffer, BUFMAX);
/* Examine first char of buffer to see what we need to do */
switch (in_buffer[0]) {
case '?': /* Send which signal we've received */
send_signal_msg(sigval);
break;
@@ -1323,11 +1316,8 @@ static void kgdb_command_loop(const int excep_code, const int trapa_value)
}
/* There has been an exception, most likely a breakpoint. */
asmlinkage void kgdb_handle_exception(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs __regs)
static void handle_exception(struct pt_regs *regs)
{
struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
int excep_code, vbr_val;
int count;
int trapa_value = ctrl_inl(TRA);
@@ -1355,7 +1345,7 @@ asmlinkage void kgdb_handle_exception(unsigned long r4, unsigned long r5,
kgdb_trapa_val = trapa_value;
/* Act on the exception */
kgdb_command_loop(excep_code >> 5, trapa_value);
kgdb_command_loop(excep_code, trapa_value);
kgdb_current = NULL;
@@ -1373,14 +1363,12 @@ asmlinkage void kgdb_handle_exception(unsigned long r4, unsigned long r5,
asm("ldc %0, vbr": :"r"(vbr_val));
}
/* Trigger a breakpoint by function */
void breakpoint(void)
asmlinkage void kgdb_handle_exception(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs __regs)
{
if (!kgdb_enabled) {
kgdb_enabled = 1;
kgdb_init();
}
BREAKPOINT();
struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
handle_exception(regs);
}
/* Initialise the KGDB data structures and serial configuration */
@@ -1395,24 +1383,16 @@ int kgdb_init(void)
kgdb_in_gdb_mode = 0;
if (kgdb_serial_setup() != 0) {
KGDB_PRINTK("serial setup error\n");
printk(KERN_NOTICE "KGDB: serial setup error\n");
return -1;
}
/* Init ptr to exception handler */
kgdb_debug_hook = kgdb_handle_exception;
kgdb_debug_hook = handle_exception;
kgdb_bus_err_hook = kgdb_handle_bus_error;
/* Enter kgdb now if requested, or just report init done */
if (kgdb_halt) {
kgdb_in_gdb_mode = 1;
put_debug_char('+');
breakpoint();
}
else
{
KGDB_PRINTK("stub is initialized.\n");
}
printk(KERN_NOTICE "KGDB: stub is initialized.\n");
return 0;
}
@@ -1437,7 +1417,7 @@ static void kgdb_msg_write(const char *s, unsigned count)
/* Calculate how many this time */
wcount = (count > MAXOUT) ? MAXOUT : count;
/* Pack in hex chars */
for (i = 0; i < wcount; i++)
bufptr = pack_hex_byte(bufptr, s[i]);
@@ -1467,3 +1447,25 @@ void kgdb_console_write(struct console *co, const char *s, unsigned count)
kgdb_msg_write(s, count);
}
#endif
#ifdef CONFIG_KGDB_SYSRQ
static void sysrq_handle_gdb(int key, struct tty_struct *tty)
{
printk("Entering GDB stub\n");
breakpoint();
}
static struct sysrq_key_op sysrq_gdb_op = {
.handler = sysrq_handle_gdb,
.help_msg = "Gdb",
.action_msg = "GDB",
};
static int gdb_register_sysrq(void)
{
printk("Registering GDB sysrq handler\n");
register_sysrq_key('g', &sysrq_gdb_op);
return 0;
}
module_init(gdb_register_sysrq);
#endif