unwind.c

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		return;
	}
	memcpy(rs, &sr->curr, sizeof(*rs));
	rs->next = sr->stack;
	sr->stack = rs;
}

static void
pop (struct unw_state_record *sr)
{
	struct unw_reg_state *rs;

	if (!sr->stack) {
		printk ("unwind: stack underflow!\n");
		return;
	}
	rs = sr->stack;
	sr->stack = rs->next;
	free_reg_state(rs);
}

static enum unw_register_index __attribute__((const))
decode_abreg (unsigned char abreg, int memory)
{
	switch (abreg) {
	      case 0x04 ... 0x07: return UNW_REG_R4 + (abreg - 0x04);
	      case 0x22 ... 0x25: return UNW_REG_F2 + (abreg - 0x22);
	      case 0x30 ... 0x3f: return UNW_REG_F16 + (abreg - 0x30);
	      case 0x41 ... 0x45: return UNW_REG_B1 + (abreg - 0x41);
	      case 0x60: return UNW_REG_PR;
	      case 0x61: return UNW_REG_PSP;
	      case 0x62: return memory ? UNW_REG_PRI_UNAT_MEM : UNW_REG_PRI_UNAT_GR;
	      case 0x63: return UNW_REG_RP;
	      case 0x64: return UNW_REG_BSP;
	      case 0x65: return UNW_REG_BSPSTORE;
	      case 0x66: return UNW_REG_RNAT;
	      case 0x67: return UNW_REG_UNAT;
	      case 0x68: return UNW_REG_FPSR;
	      case 0x69: return UNW_REG_PFS;
	      case 0x6a: return UNW_REG_LC;
	      default:
		break;
	}
	dprintk("unwind: bad abreg=0x%x\n", abreg);
	return UNW_REG_LC;
}

static void
set_reg (struct unw_reg_info *reg, enum unw_where where, int when, unsigned long val)
{
	reg->val = val;
	reg->where = where;
	if (reg->when == UNW_WHEN_NEVER)
		reg->when = when;
}

static void
alloc_spill_area (unsigned long *offp, unsigned long regsize,
		  struct unw_reg_info *lo, struct unw_reg_info *hi)
{
	struct unw_reg_info *reg;

	for (reg = hi; reg >= lo; --reg) {
		if (reg->where == UNW_WHERE_SPILL_HOME) {
			reg->where = UNW_WHERE_PSPREL;
			reg->val = 0x10 - *offp;
			*offp += regsize;
		}
	}
}

static inline void
spill_next_when (struct unw_reg_info **regp, struct unw_reg_info *lim, unw_word t)
{
	struct unw_reg_info *reg;

	for (reg = *regp; reg <= lim; ++reg) {
		if (reg->where == UNW_WHERE_SPILL_HOME) {
			reg->when = t;
			*regp = reg + 1;
			return;
		}
	}
	dprintk("unwind: excess spill!\n");
}

static inline void
finish_prologue (struct unw_state_record *sr)
{
	struct unw_reg_info *reg;
	unsigned long off;
	int i;

	/*
	 * First, resolve implicit register save locations (see Section "11.4.2.3 Rules
	 * for Using Unwind Descriptors", rule 3):
	 */
	for (i = 0; i < (int) sizeof(unw.save_order)/sizeof(unw.save_order[0]); ++i) {
		reg = sr->curr.reg + unw.save_order[i];
		if (reg->where == UNW_WHERE_GR_SAVE) {
			reg->where = UNW_WHERE_GR;
			reg->val = sr->gr_save_loc++;
		}
	}

	/*
	 * Next, compute when the fp, general, and branch registers get
	 * saved.  This must come before alloc_spill_area() because
	 * we need to know which registers are spilled to their home
	 * locations.
	 */
	if (sr->imask) {
		unsigned char kind, mask = 0, *cp = sr->imask;
		unsigned long t;
		static const unsigned char limit[3] = {
			UNW_REG_F31, UNW_REG_R7, UNW_REG_B5
		};
		struct unw_reg_info *(regs[3]);

		regs[0] = sr->curr.reg + UNW_REG_F2;
		regs[1] = sr->curr.reg + UNW_REG_R4;
		regs[2] = sr->curr.reg + UNW_REG_B1;

		for (t = 0; t < sr->region_len; ++t) {
			if ((t & 3) == 0)
				mask = *cp++;
			kind = (mask >> 2*(3-(t & 3))) & 3;
			if (kind > 0)
				spill_next_when(&regs[kind - 1], sr->curr.reg + limit[kind - 1],
						sr->region_start + t);
		}
	}
	/*
	 * Next, lay out the memory stack spill area:
	 */
	if (sr->any_spills) {
		off = sr->spill_offset;
		alloc_spill_area(&off, 16, sr->curr.reg + UNW_REG_F2, sr->curr.reg + UNW_REG_F31); 
		alloc_spill_area(&off,  8, sr->curr.reg + UNW_REG_B1, sr->curr.reg + UNW_REG_B5);
		alloc_spill_area(&off,  8, sr->curr.reg + UNW_REG_R4, sr->curr.reg + UNW_REG_R7);
	}
}

/*
 * Region header descriptors.
 */

static void
desc_prologue (int body, unw_word rlen, unsigned char mask, unsigned char grsave,
	       struct unw_state_record *sr)
{
	int i;

	if (!(sr->in_body || sr->first_region))
		finish_prologue(sr);
	sr->first_region = 0;

	/* check if we're done: */
	if (body && sr->when_target < sr->region_start + sr->region_len) {
		sr->done = 1;
		return;
	}

	for (i = 0; i < sr->epilogue_count; ++i)
		pop(sr);
	sr->epilogue_count = 0;
	sr->epilogue_start = UNW_WHEN_NEVER;

	if (!body)
		push(sr);

	sr->region_start += sr->region_len;
	sr->region_len = rlen;
	sr->in_body = body;

	if (!body) {
		for (i = 0; i < 4; ++i) {
			if (mask & 0x8)
				set_reg(sr->curr.reg + unw.save_order[i], UNW_WHERE_GR,
					sr->region_start + sr->region_len - 1, grsave++);
			mask <<= 1;
		}
		sr->gr_save_loc = grsave;
		sr->any_spills = 0;
		sr->imask = 0;
		sr->spill_offset = 0x10;	/* default to psp+16 */
	}
}

/*
 * Prologue descriptors.
 */

static inline void
desc_abi (unsigned char abi, unsigned char context, struct unw_state_record *sr)
{
	if (abi == 0 && context == 'i')
		sr->flags |= UNW_FLAG_INTERRUPT_FRAME;
	else
		dprintk("unwind: ignoring unwabi(abi=0x%x,context=0x%x)\n", abi, context);
}

static inline void
desc_br_gr (unsigned char brmask, unsigned char gr, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 5; ++i) {
		if (brmask & 1)
			set_reg(sr->curr.reg + UNW_REG_B1 + i, UNW_WHERE_GR,
				sr->region_start + sr->region_len - 1, gr++);
		brmask >>= 1;
	}
}

static inline void
desc_br_mem (unsigned char brmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 5; ++i) {
		if (brmask & 1) {
			set_reg(sr->curr.reg + UNW_REG_B1 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		brmask >>= 1;
	}
}

static inline void
desc_frgr_mem (unsigned char grmask, unw_word frmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((grmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_R4 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		grmask >>= 1;
	}
	for (i = 0; i < 20; ++i) {
		if ((frmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_F2 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		frmask >>= 1;
	}
}

static inline void
desc_fr_mem (unsigned char frmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((frmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_F2 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		frmask >>= 1;
	}
}

static inline void
desc_gr_gr (unsigned char grmask, unsigned char gr, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((grmask & 1) != 0)
			set_reg(sr->curr.reg + UNW_REG_R4 + i, UNW_WHERE_GR,
				sr->region_start + sr->region_len - 1, gr++);
		grmask >>= 1;
	}
}

static inline void
desc_gr_mem (unsigned char grmask, struct unw_state_record *sr)
{
	int i;

	for (i = 0; i < 4; ++i) {
		if ((grmask & 1) != 0) {
			set_reg(sr->curr.reg + UNW_REG_R4 + i, UNW_WHERE_SPILL_HOME,
				sr->region_start + sr->region_len - 1, 0);
			sr->any_spills = 1;
		}
		grmask >>= 1;
	}
}

static inline void
desc_mem_stack_f (unw_word t, unw_word size, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + UNW_REG_PSP, UNW_WHERE_NONE,
		sr->region_start + MIN((int)t, sr->region_len - 1), 16*size);
}

static inline void
desc_mem_stack_v (unw_word t, struct unw_state_record *sr)
{
	sr->curr.reg[UNW_REG_PSP].when = sr->region_start + MIN((int)t, sr->region_len - 1);
}

static inline void
desc_reg_gr (unsigned char reg, unsigned char dst, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + reg, UNW_WHERE_GR, sr->region_start + sr->region_len - 1, dst);
}

static inline void
desc_reg_psprel (unsigned char reg, unw_word pspoff, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + reg, UNW_WHERE_PSPREL, sr->region_start + sr->region_len - 1,
		0x10 - 4*pspoff);
}

static inline void
desc_reg_sprel (unsigned char reg, unw_word spoff, struct unw_state_record *sr)
{
	set_reg(sr->curr.reg + reg, UNW_WHERE_SPREL, sr->region_start + sr->region_len - 1,
		4*spoff);
}

static inline void
desc_rp_br (unsigned char dst, struct unw_state_record *sr)
{
	sr->return_link_reg = dst;
}

static inline void
desc_reg_when (unsigned char regnum, unw_word t, struct unw_state_record *sr)
{
	struct unw_reg_info *reg = sr->curr.reg + regnum;

	if (reg->where == UNW_WHERE_NONE)
		reg->where = UNW_WHERE_GR_SAVE;
	reg->when = sr->region_start + MIN((int)t, sr->region_len - 1);
}

static inline void
desc_spill_base (unw_word pspoff, struct unw_state_record *sr)
{
	sr->spill_offset = 0x10 - 4*pspoff;
}

static inline unsigned char *
desc_spill_mask (unsigned char *imaskp, struct unw_state_record *sr)
{
	sr->imask = imaskp;
	return imaskp + (2*sr->region_len + 7)/8;
}

/*
 * Body descriptors.
 */
static inline void
desc_epilogue (unw_word t, unw_word ecount, struct unw_state_record *sr)
{
	sr->epilogue_start = sr->region_start + sr->region_len - 1 - t;
	sr->epilogue_count = ecount + 1;
}

static inline void
desc_copy_state (unw_word label, struct unw_state_record *sr)
{
	struct unw_reg_state *rs;

	for (rs = sr->reg_state_list; rs; rs = rs->next) {
		if (rs->label == label) {
			memcpy (&sr->curr, rs, sizeof(sr->curr));
			return;
		}
	}
	printk("unwind: failed to find state labelled 0x%lx\n", label);
}

static inline void
desc_label_state (unw_word label, struct unw_state_record *sr)
{
	struct unw_reg_state *rs;

	rs = alloc_reg_state();
	memcpy(rs, &sr->curr, sizeof(*rs));
	rs->label = label;
	rs->next = sr->reg_state_list;
	sr->reg_state_list = rs;
}

/*
 * General descriptors.
 */

static inline int
desc_is_active (unsigned char qp, unw_word t, struct unw_state_record *sr)
{
	if (sr->when_target <= sr->region_start + MIN((int)t, sr->region_len - 1))
		return 0;
	if (qp > 0) {
		if ((sr->pr_val & (1UL << qp)) == 0) 
			return 0;
		sr->pr_mask |= (1UL << qp);
	}
	return 1;
}

static inline void
desc_restore_p (unsigned char qp, unw_word t, unsigned char abreg, struct unw_state_record *sr)
{
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	r = sr->curr.reg + decode_abreg(abreg, 0);
	r->where = UNW_WHERE_NONE;
	r->when = sr->region_start + MIN((int)t, sr->region_len - 1);
	r->val = 0;
}

static inline void
desc_spill_reg_p (unsigned char qp, unw_word t, unsigned char abreg, unsigned char x,
		     unsigned char ytreg, struct unw_state_record *sr)
{
	enum unw_where where = UNW_WHERE_GR;
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	if (x)
		where = UNW_WHERE_BR;
	else if (ytreg & 0x80)
		where = UNW_WHERE_FR;

	r = sr->curr.reg + decode_abreg(abreg, 0);
	r->where = where;
	r->when = sr->region_start + MIN((int)t, sr->region_len - 1);
	r->val = (ytreg & 0x7f);
}

static inline void
desc_spill_psprel_p (unsigned char qp, unw_word t, unsigned char abreg, unw_word pspoff,
		     struct unw_state_record *sr)
{
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	r = sr->curr.reg + decode_abreg(abreg, 1);
	r->where = UNW_WHERE_PSPREL;
	r->when = sr->region_start + MIN((int)t, sr->region_len - 1);
	r->val = 0x10 - 4*pspoff;
}

static inline void
desc_spill_sprel_p (unsigned char qp, unw_word t, unsigned char abreg, unw_word spoff,
		       struct unw_state_record *sr)
{
	struct unw_reg_info *r;

	if (!desc_is_active(qp, t, sr))
		return;

	r = sr->curr.reg + decode_abreg(abreg, 1);
	r->where = UNW_WHERE_SPREL;
	r->when = sr->region_start + MIN((int)t, sr->region_len - 1);
	r->val = 4*spoff;
}

#define UNW_DEC_BAD_CODE(code)			printk("unwind: unknown code 0x%02x\n", code);

/*
 * region headers:
 */
#define UNW_DEC_PROLOGUE_GR(fmt,r,m,gr,arg)	desc_prologue(0,r,m,gr,arg)
#define UNW_DEC_PROLOGUE(fmt,b,r,arg)		desc_prologue(b,r,0,32,arg)
/*
 * prologue descriptors:
 */
#define UNW_DEC_ABI(fmt,a,c,arg)		desc_abi(a,c,arg)
#define UNW_DEC_BR_GR(fmt,b,g,arg)		desc_br_gr(b,g,arg)
#define UNW_DEC_BR_MEM(fmt,b,arg)		desc_br_mem(b,arg)
#define UNW_DEC_FRGR_MEM(fmt,g,f,arg)		desc_frgr_mem(g,f,arg)
#define UNW_DEC_FR_MEM(fmt,f,arg)		desc_fr_mem(f,arg)
#define UNW_DEC_GR_GR(fmt,m,g,arg)		desc_gr_gr(m,g,arg)
#define UNW_DEC_GR_MEM(fmt,m,arg)		desc_gr_mem(m,arg)
#define UNW_DEC_MEM_STACK_F(fmt,t,s,arg)	desc_mem_stack_f(t,s,arg)
#define UNW_DEC_MEM_STACK_V(fmt,t,arg)		desc_mem_stack_v(t,arg)
#define UNW_DEC_REG_GR(fmt,r,d,arg)		desc_reg_gr(r,d,arg)
#define UNW_DEC_REG_PSPREL(fmt,r,o,arg)		desc_reg_psprel(r,o,arg)
#define UNW_DEC_REG_SPREL(fmt,r,o,arg)		desc_reg_sprel(r,o,arg)
#define UNW_DEC_REG_WHEN(fmt,r,t,arg)		desc_reg_when(r,t,arg)
#define UNW_DEC_PRIUNAT_WHEN_GR(fmt,t,arg)	desc_reg_when(UNW_REG_PRI_UNAT_GR,t,arg)
#define UNW_DEC_PRIUNAT_WHEN_MEM(fmt,t,arg)	desc_reg_when(UNW_REG_PRI_UNAT_MEM,t,arg)
#define UNW_DEC_PRIUNAT_GR(fmt,r,arg)		desc_reg_gr(UNW_REG_PRI_UNAT_GR,r,arg)
#define UNW_DEC_PRIUNAT_PSPREL(fmt,o,arg)	desc_reg_psprel(UNW_REG_PRI_UNAT_MEM,o,arg)
#define UNW_DEC_PRIUNAT_SPREL(fmt,o,arg)	desc_reg_sprel(UNW_REG_PRI_UNAT_MEM,o,arg)
#define UNW_DEC_RP_BR(fmt,d,arg)		desc_rp_br(d,arg)
#define UNW_DEC_SPILL_BASE(fmt,o,arg)		desc_spill_base(o,arg)
#define UNW_DEC_SPILL_MASK(fmt,m,arg)		(m = desc_spill_mask(m,arg))
/*
 * body descriptors:
 */
#define UNW_DEC_EPILOGUE(fmt,t,c,arg)		desc_epilogue(t,c,arg)
#define UNW_DEC_COPY_STATE(fmt,l,arg)		desc_copy_state(l,arg)
#define UNW_DEC_LABEL_STATE(fmt,l,arg)		desc_label_state(l,arg)
/*
 * general unwind descriptors:
 */
#define UNW_DEC_SPILL_REG_P(f,p,t,a,x,y,arg)	desc_spill_reg_p(p,t,a,x,y,arg)
#define UNW_DEC_SPILL_REG(f,t,a,x,y,arg)	desc_spill_reg_p(0,t,a,x,y,arg)
#define UNW_DEC_SPILL_PSPREL_P(f,p,t,a,o,arg)	desc_spill_psprel_p(p,t,a,o,arg)
#define UNW_DEC_SPILL_PSPREL(f,t,a,o,arg)	desc_spill_psprel_p(0,t,a,o,arg)
#define UNW_DEC_SPILL_SPREL_P(f,p,t,a,o,arg)	desc_spill_sprel_p(p,t,a,o,arg)
#define UNW_DEC_SPILL_SPREL(f,t,a,o,arg)	desc_spill_sprel_p(0,t,a,o,arg)
#define UNW_DEC_RESTORE_P(f,p,t,a,arg)		desc_restore_p(p,t,a,arg)
#define UNW_DEC_RESTORE(f,t,a,arg)		desc_restore_p(0,t,a,arg)