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yaml
---
r: 242231
b: refs/heads/master
c: 5141c46
h: refs/heads/master
i:
  242229: e7adf27
  242227: 68a214e
  242223: 07d2170
v: v3
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David Howells committed Mar 18, 2011
1 parent 50245ba commit e5f3abc
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Showing 4 changed files with 426 additions and 13 deletions.
2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: 044264bbe34085b550e6429ce97ef310667be9dc
refs/heads/master: 5141c46c6137f4866eb5f29e25ed0556bcc4c634
4 changes: 4 additions & 0 deletions trunk/arch/mn10300/include/asm/thread_info.h
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Expand Up @@ -129,7 +129,11 @@ static inline unsigned long current_stack_pointer(void)
#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
#endif

#ifndef CONFIG_KGDB
#define free_thread_info(ti) kfree((ti))
#else
extern void free_thread_info(struct thread_info *);
#endif
#define get_thread_info(ti) get_task_struct((ti)->task)
#define put_thread_info(ti) put_task_struct((ti)->task)

Expand Down
322 changes: 311 additions & 11 deletions trunk/arch/mn10300/kernel/kgdb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
* 2 of the Licence, or (at your option) any later version.
*/

#include <linux/slab.h>
#include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/uaccess.h>
Expand All @@ -18,6 +19,13 @@
#include <asm/serial-regs.h>
#include "internal.h"

/*
* Software single-stepping breakpoint save (used by __switch_to())
*/
static struct thread_info *kgdb_sstep_thread;
u8 *kgdb_sstep_bp_addr[2];
u8 kgdb_sstep_bp[2];

/*
* Copy kernel exception frame registers to the GDB register file
*/
Expand Down Expand Up @@ -118,8 +126,293 @@ struct kgdb_arch arch_kgdb_ops = {
.flags = KGDB_HW_BREAKPOINT,
};

static const unsigned char mn10300_kgdb_insn_sizes[256] =
{
/* 1 2 3 4 5 6 7 8 9 a b c d e f */
1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */
2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */
1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */
1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */
2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */
0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */
};

/*
* Handle unknown packets and [Ccs] packets
* Attempt to emulate single stepping by means of breakpoint instructions.
* Although there is a single-step trace flag in EPSW, its use is not
* sufficiently documented and is only intended for use with the JTAG debugger.
*/
static int kgdb_arch_do_singlestep(struct pt_regs *regs)
{
unsigned long arg;
unsigned size;
u8 *pc = (u8 *)regs->pc, *sp = (u8 *)(regs + 1), cur;
u8 *x = NULL, *y = NULL;
int ret;

ret = probe_kernel_read(&cur, pc, 1);
if (ret < 0)
return ret;

size = mn10300_kgdb_insn_sizes[cur];
if (size > 0) {
x = pc + size;
goto set_x;
}

switch (cur) {
/* Bxx (d8,PC) */
case 0xc0 ... 0xca:
ret = probe_kernel_read(&arg, pc + 1, 1);
if (ret < 0)
return ret;
x = pc + 2;
if (arg >= 0 && arg <= 2)
goto set_x;
y = pc + (s8)arg;
goto set_x_and_y;

/* LXX (d8,PC) */
case 0xd0 ... 0xda:
x = pc + 1;
if (regs->pc == regs->lar)
goto set_x;
y = (u8 *)regs->lar;
goto set_x_and_y;

/* SETLB - loads the next four bytes into the LIR register
* (which mustn't include a breakpoint instruction) */
case 0xdb:
x = pc + 5;
goto set_x;

/* JMP (d16,PC) or CALL (d16,PC) */
case 0xcc:
case 0xcd:
ret = probe_kernel_read(&arg, pc + 1, 2);
if (ret < 0)
return ret;
x = pc + (s16)arg;
goto set_x;

/* JMP (d32,PC) or CALL (d32,PC) */
case 0xdc:
case 0xdd:
ret = probe_kernel_read(&arg, pc + 1, 4);
if (ret < 0)
return ret;
x = pc + (s32)arg;
goto set_x;

/* RETF */
case 0xde:
x = (u8 *)regs->mdr;
goto set_x;

/* RET */
case 0xdf:
ret = probe_kernel_read(&arg, pc + 2, 1);
if (ret < 0)
return ret;
ret = probe_kernel_read(&x, sp + (s8)arg, 4);
if (ret < 0)
return ret;
goto set_x;

case 0xf0:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;

if (cur >= 0xf0 && cur <= 0xf7) {
/* JMP (An) / CALLS (An) */
switch (cur & 3) {
case 0: x = (u8 *)regs->a0; break;
case 1: x = (u8 *)regs->a1; break;
case 2: x = (u8 *)regs->a2; break;
case 3: x = (u8 *)regs->a3; break;
}
goto set_x;
} else if (cur == 0xfc) {
/* RETS */
ret = probe_kernel_read(&x, sp, 4);
if (ret < 0)
return ret;
goto set_x;
} else if (cur == 0xfd) {
/* RTI */
ret = probe_kernel_read(&x, sp + 4, 4);
if (ret < 0)
return ret;
goto set_x;
} else {
x = pc + 2;
goto set_x;
}
break;

/* potential 3-byte conditional branches */
case 0xf8:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;
x = pc + 3;

if (cur >= 0xe8 && cur <= 0xeb) {
ret = probe_kernel_read(&arg, pc + 2, 1);
if (ret < 0)
return ret;
if (arg >= 0 && arg <= 3)
goto set_x;
y = pc + (s8)arg;
goto set_x_and_y;
}
goto set_x;

case 0xfa:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;

if (cur == 0xff) {
/* CALLS (d16,PC) */
ret = probe_kernel_read(&arg, pc + 2, 2);
if (ret < 0)
return ret;
x = pc + (s16)arg;
goto set_x;
}

x = pc + 4;
goto set_x;

case 0xfc:
ret = probe_kernel_read(&cur, pc + 1, 1);
if (ret < 0)
return ret;

if (cur == 0xff) {
/* CALLS (d32,PC) */
ret = probe_kernel_read(&arg, pc + 2, 4);
if (ret < 0)
return ret;
x = pc + (s32)arg;
goto set_x;
}

x = pc + 6;
goto set_x;
}

return 0;

set_x:
kgdb_sstep_bp_addr[0] = x;
kgdb_sstep_bp_addr[1] = NULL;
ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1);
if (ret < 0)
return ret;
ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1);
if (ret < 0)
return ret;
kgdb_sstep_thread = current_thread_info();
debugger_local_cache_flushinv_one(x);
return ret;

set_x_and_y:
kgdb_sstep_bp_addr[0] = x;
kgdb_sstep_bp_addr[1] = y;
ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1);
if (ret < 0)
return ret;
ret = probe_kernel_read(&kgdb_sstep_bp[1], y, 1);
if (ret < 0)
return ret;
ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1);
if (ret < 0)
return ret;
ret = probe_kernel_write(y, &arch_kgdb_ops.gdb_bpt_instr, 1);
if (ret < 0) {
probe_kernel_write(kgdb_sstep_bp_addr[0],
&kgdb_sstep_bp[0], 1);
} else {
kgdb_sstep_thread = current_thread_info();
}
debugger_local_cache_flushinv_one(x);
debugger_local_cache_flushinv_one(y);
return ret;
}

/*
* Remove emplaced single-step breakpoints, returning true if we hit one of
* them.
*/
static bool kgdb_arch_undo_singlestep(struct pt_regs *regs)
{
bool hit = false;
u8 *x = kgdb_sstep_bp_addr[0], *y = kgdb_sstep_bp_addr[1];
u8 opcode;

if (kgdb_sstep_thread == current_thread_info()) {
if (x) {
if (x == (u8 *)regs->pc)
hit = true;
if (probe_kernel_read(&opcode, x,
1) < 0 ||
opcode != 0xff)
BUG();
probe_kernel_write(x, &kgdb_sstep_bp[0], 1);
debugger_local_cache_flushinv_one(x);
}
if (y) {
if (y == (u8 *)regs->pc)
hit = true;
if (probe_kernel_read(&opcode, y,
1) < 0 ||
opcode != 0xff)
BUG();
probe_kernel_write(y, &kgdb_sstep_bp[1], 1);
debugger_local_cache_flushinv_one(y);
}
}

kgdb_sstep_bp_addr[0] = NULL;
kgdb_sstep_bp_addr[1] = NULL;
kgdb_sstep_thread = NULL;
return hit;
}

/*
* Catch a single-step-pending thread being deleted and make sure the global
* single-step state is cleared. At this point the breakpoints should have
* been removed by __switch_to().
*/
void free_thread_info(struct thread_info *ti)
{
if (kgdb_sstep_thread == ti) {
kgdb_sstep_thread = NULL;

/* However, we may now be running in degraded mode, with most
* of the CPUs disabled until such a time as KGDB is reentered,
* so force immediate reentry */
kgdb_breakpoint();
}
kfree(ti);
}

/*
* Handle unknown packets and [CcsDk] packets
* - at this point breakpoints have been installed
*/
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
char *remcom_in_buffer, char *remcom_out_buffer,
Expand All @@ -130,21 +423,22 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,

switch (remcom_in_buffer[0]) {
case 'c':
if (kgdb_contthread && kgdb_contthread != current) {
strcpy(remcom_out_buffer, "E00");
break;
}

kgdb_contthread = NULL;

case 's':
/* try to read optional parameter, pc unchanged if no parm */
ptr = &remcom_in_buffer[1];
if (kgdb_hex2long(&ptr, &addr))
regs->pc = addr;
return 0;
case 'D':
case 'k':
atomic_set(&kgdb_cpu_doing_single_step, -1);

case 's':
break; /* we don't do hardware single stepping */
if (remcom_in_buffer[0] == 's') {
kgdb_arch_do_singlestep(regs);
kgdb_single_step = 1;
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
}
return 0;
}
return -1; /* this means that we do not want to exit from the handler */
}
Expand All @@ -158,6 +452,12 @@ int debugger_intercept(enum exception_code excep, int signo, int si_code,
{
int ret;

if (kgdb_arch_undo_singlestep(regs)) {
excep = EXCEP_TRAP;
signo = SIGTRAP;
si_code = TRAP_TRACE;
}

ret = kgdb_handle_exception(excep, signo, si_code, regs);

debugger_local_cache_flushinv();
Expand Down
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