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1 #include <common.h>
2 #include <command.h>
3 #include <kgdb.h>
4 #include <asm/signal.h>
5 #include <asm/processor.h>
6 
7 #define PC_REGNUM 64
8 #define SP_REGNUM 1
9 
10 void breakinst(void);
11 
12 int
kgdb_setjmp(long * buf)13 kgdb_setjmp(long *buf)
14 {
15 	unsigned long temp;
16 
17 	asm volatile("mflr %0; stw %0,0(%1);"
18 	     "stw %%r1,4(%1); stw %%r2,8(%1);"
19 	     "mfcr %0; stw %0,12(%1);"
20 	     "stmw %%r13,16(%1)"
21 	     : "=&r"(temp) : "r" (buf));
22 	/* XXX should save fp regs as well */
23 	return 0;
24 }
25 
26 void
kgdb_longjmp(long * buf,int val)27 kgdb_longjmp(long *buf, int val)
28 {
29 	unsigned long temp;
30 
31 	if (val == 0)
32 		val = 1;
33 
34 	asm volatile("lmw %%r13,16(%1);"
35 	     "lwz %0,12(%1); mtcrf 0x38,%0;"
36 	     "lwz %0,0(%1); lwz %%r1,4(%1); lwz %%r2,8(%1);"
37 	     "mtlr %0; mr %%r3,%2"
38 	     : "=&r"(temp) : "r" (buf), "r" (val));
39 }
40 
41 /* Convert the SPARC hardware trap type code to a unix signal number. */
42 /*
43  * This table contains the mapping between PowerPC hardware trap types, and
44  * signals, which are primarily what GDB understands.
45  */
46 static struct hard_trap_info
47 {
48 	unsigned int tt;		/* Trap type code for powerpc */
49 	unsigned char signo;		/* Signal that we map this trap into */
50 } hard_trap_info[] = {
51 	{ 0x200, SIGSEGV },			/* machine check */
52 	{ 0x300, SIGSEGV },			/* address error (store) */
53 	{ 0x400, SIGBUS },			/* instruction bus error */
54 	{ 0x500, SIGINT },			/* interrupt */
55 	{ 0x600, SIGBUS },			/* alignment */
56 	{ 0x700, SIGTRAP },			/* breakpoint trap */
57 	{ 0x800, SIGFPE },			/* fpu unavail */
58 	{ 0x900, SIGALRM },			/* decrementer */
59 	{ 0xa00, SIGILL },			/* reserved */
60 	{ 0xb00, SIGILL },			/* reserved */
61 	{ 0xc00, SIGCHLD },			/* syscall */
62 	{ 0xd00, SIGTRAP },			/* single-step/watch */
63 	{ 0xe00, SIGFPE },			/* fp assist */
64 	{ 0, 0}				/* Must be last */
65 };
66 
67 static int
computeSignal(unsigned int tt)68 computeSignal(unsigned int tt)
69 {
70 	struct hard_trap_info *ht;
71 
72 	for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
73 		if (ht->tt == tt)
74 			return ht->signo;
75 
76 	return SIGHUP;         /* default for things we don't know about */
77 }
78 
79 void
kgdb_enter(struct pt_regs * regs,kgdb_data * kdp)80 kgdb_enter(struct pt_regs *regs, kgdb_data *kdp)
81 {
82 	unsigned long msr;
83 
84 	kdp->private[0] = msr = get_msr();
85 	set_msr(msr & ~MSR_EE);	/* disable interrupts */
86 
87 	if (regs->nip == (unsigned long)breakinst) {
88 		/* Skip over breakpoint trap insn */
89 		regs->nip += 4;
90 	}
91 	regs->msr &= ~MSR_SE;
92 
93 	/* reply to host that an exception has occurred */
94 	kdp->sigval = computeSignal(regs->trap);
95 
96 	kdp->nregs = 2;
97 
98 	kdp->regs[0].num = PC_REGNUM;
99 	kdp->regs[0].val = regs->nip;
100 
101 	kdp->regs[1].num = SP_REGNUM;
102 	kdp->regs[1].val = regs->gpr[SP_REGNUM];
103 }
104 
105 void
kgdb_exit(struct pt_regs * regs,kgdb_data * kdp)106 kgdb_exit(struct pt_regs *regs, kgdb_data *kdp)
107 {
108 	unsigned long msr = kdp->private[0];
109 
110 	if (kdp->extype & KGDBEXIT_WITHADDR)
111 		regs->nip = kdp->exaddr;
112 
113 	switch (kdp->extype & KGDBEXIT_TYPEMASK) {
114 
115 	case KGDBEXIT_KILL:
116 	case KGDBEXIT_CONTINUE:
117 		set_msr(msr);
118 		break;
119 
120 	case KGDBEXIT_SINGLE:
121 		regs->msr |= MSR_SE;
122 #if 0
123 		set_msr(msr | MSR_SE);
124 #endif
125 		break;
126 	}
127 }
128 
129 int
kgdb_trap(struct pt_regs * regs)130 kgdb_trap(struct pt_regs *regs)
131 {
132 	return (regs->trap);
133 }
134 
135 /* return the value of the CPU registers.
136  * some of them are non-PowerPC names :(
137  * they are stored in gdb like:
138  * struct {
139  *     u32 gpr[32];
140  *     f64 fpr[32];
141  *     u32 pc, ps, cnd, lr; (ps=msr)
142  *     u32 cnt, xer, mq;
143  * }
144  */
145 
146 #define SPACE_REQUIRED	((32*4)+(32*8)+(6*4))
147 
148 int
kgdb_getregs(struct pt_regs * regs,char * buf,int max)149 kgdb_getregs(struct pt_regs *regs, char *buf, int max)
150 {
151 	int i;
152 	unsigned long *ptr = (unsigned long *)buf;
153 
154 	if (max < SPACE_REQUIRED)
155 		kgdb_error(KGDBERR_NOSPACE);
156 
157 	if ((unsigned long)ptr & 3)
158 		kgdb_error(KGDBERR_ALIGNFAULT);
159 
160 	/* General Purpose Regs */
161 	for (i = 0; i < 32; i++)
162 		*ptr++ = regs->gpr[i];
163 
164 	/* Floating Point Regs */
165 	for (i = 0; i < 32; i++) {
166 		*ptr++ = 0;
167 		*ptr++ = 0;
168 	}
169 
170 	/* pc, msr, cr, lr, ctr, xer, (mq is unused) */
171 	*ptr++ = regs->nip;
172 	*ptr++ = regs->msr;
173 	*ptr++ = regs->ccr;
174 	*ptr++ = regs->link;
175 	*ptr++ = regs->ctr;
176 	*ptr++ = regs->xer;
177 
178 	return (SPACE_REQUIRED);
179 }
180 
181 /* set the value of the CPU registers */
182 void
kgdb_putreg(struct pt_regs * regs,int regno,char * buf,int length)183 kgdb_putreg(struct pt_regs *regs, int regno, char *buf, int length)
184 {
185 	unsigned long *ptr = (unsigned long *)buf;
186 
187 	if (regno < 0 || regno >= 70)
188 		kgdb_error(KGDBERR_BADPARAMS);
189 	else if (regno >= 32 && regno < 64) {
190 		if (length < 8)
191 			kgdb_error(KGDBERR_NOSPACE);
192 	}
193 	else {
194 		if (length < 4)
195 			kgdb_error(KGDBERR_NOSPACE);
196 	}
197 
198 	if ((unsigned long)ptr & 3)
199 		kgdb_error(KGDBERR_ALIGNFAULT);
200 
201 	if (regno >= 0 && regno < 32)
202 		regs->gpr[regno] = *ptr;
203 	else switch (regno) {
204 	case 64:	regs->nip = *ptr;	break;
205 	case 65:	regs->msr = *ptr;	break;
206 	case 66:	regs->ccr = *ptr;	break;
207 	case 67:	regs->link = *ptr;	break;
208 	case 68:	regs->ctr = *ptr;	break;
209 	case 69:	regs->ctr = *ptr;	break;
210 
211 	default:
212 		kgdb_error(KGDBERR_BADPARAMS);
213 	}
214 }
215 
216 void
kgdb_putregs(struct pt_regs * regs,char * buf,int length)217 kgdb_putregs(struct pt_regs *regs, char *buf, int length)
218 {
219 	int i;
220 	unsigned long *ptr = (unsigned long *)buf;
221 
222 	if (length < SPACE_REQUIRED)
223 		kgdb_error(KGDBERR_NOSPACE);
224 
225 	if ((unsigned long)ptr & 3)
226 		kgdb_error(KGDBERR_ALIGNFAULT);
227 
228 	/*
229 	 * If the stack pointer has moved, you should pray.
230 	 * (cause only god can help you).
231 	 */
232 
233 	/* General Purpose Regs */
234 	for (i = 0; i < 32; i++)
235 		regs->gpr[i] = *ptr++;
236 
237 	/* Floating Point Regs */
238 	ptr += 32*2;
239 
240 	/* pc, msr, cr, lr, ctr, xer, (mq is unused) */
241 	regs->nip = *ptr++;
242 	regs->msr = *ptr++;
243 	regs->ccr = *ptr++;
244 	regs->link = *ptr++;
245 	regs->ctr = *ptr++;
246 	regs->xer = *ptr++;
247 }
248 
249 /* This function will generate a breakpoint exception.  It is used at the
250    beginning of a program to sync up with a debugger and can be used
251    otherwise as a quick means to stop program execution and "break" into
252    the debugger. */
253 
254 void
kgdb_breakpoint(int argc,char * const argv[])255 kgdb_breakpoint(int argc, char * const argv[])
256 {
257 	asm("	.globl breakinst\n\
258 	     breakinst: .long 0x7d821008\n\
259 	    ");
260 }
261