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/*
* Copyright (C) 1999 Hewlett-Packard Co
* Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/unwind.h>
void
ia64_unwind_init_from_blocked_task (struct ia64_frame_info *info, struct task_struct *t)
{
struct switch_stack *sw = (struct switch_stack *) (t->thread.ksp + 16);
unsigned long sol, limit, top;
memset(info, 0, sizeof(*info));
sol = (sw->ar_pfs >> 7) & 0x7f; /* size of locals */
limit = (unsigned long) t + IA64_RBS_OFFSET;
top = sw->ar_bspstore;
if (top - (unsigned long) t >= IA64_STK_OFFSET)
top = limit;
info->regstk.limit = (unsigned long *) limit;
info->regstk.top = (unsigned long *) top;
info->bsp = ia64_rse_skip_regs(info->regstk.top, -sol);
info->top_rnat = sw->ar_rnat;
info->cfm = sw->ar_pfs;
info->ip = sw->b0;
}
void
ia64_unwind_init_from_current (struct ia64_frame_info *info, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *) regs - 1;
unsigned long sol, sof, *bsp, limit, top;
limit = (unsigned long) current + IA64_RBS_OFFSET;
top = sw->ar_bspstore;
if (top - (unsigned long) current >= IA64_STK_OFFSET)
top = limit;
memset(info, 0, sizeof(*info));
sol = (sw->ar_pfs >> 7) & 0x7f; /* size of frame */
info->regstk.limit = (unsigned long *) limit;
info->regstk.top = (unsigned long *) top;
info->top_rnat = sw->ar_rnat;
/* this gives us the bsp top level frame (kdb interrupt frame): */
bsp = ia64_rse_skip_regs((unsigned long *) top, -sol);
/* now skip past the interrupt frame: */
sof = regs->cr_ifs & 0x7f; /* size of frame */
info->cfm = regs->cr_ifs;
info->bsp = ia64_rse_skip_regs(bsp, -sof);
info->ip = regs->cr_iip;
}
static unsigned long
read_reg (struct ia64_frame_info *info, int regnum, int *is_nat)
{
unsigned long *addr, *rnat_addr, rnat;
addr = ia64_rse_skip_regs(info->bsp, regnum);
if (addr < info->regstk.limit || addr >= info->regstk.top || ((long) addr & 0x7) != 0) {
*is_nat = 1;
return 0xdeadbeefdeadbeef;
}
rnat_addr = ia64_rse_rnat_addr(addr);
if (rnat_addr >= info->regstk.top)
rnat = info->top_rnat;
else
rnat = *rnat_addr;
*is_nat = (rnat & (1UL << ia64_rse_slot_num(addr))) != 0;
return *addr;
}
/*
* On entry, info->regstk.top should point to the register backing
* store for r32.
*/
int
ia64_unwind_to_previous_frame (struct ia64_frame_info *info)
{
unsigned long sol, cfm = info->cfm;
int is_nat;
sol = (cfm >> 7) & 0x7f; /* size of locals */
/*
* In general, we would have to make use of unwind info to
* unwind an IA-64 stack, but for now gcc uses a special
* convention that makes this possible without full-fledged
* unwindo info. Specifically, we expect "rp" in the second
* last, and "ar.pfs" in the last local register, so the
* number of locals in a frame must be at least two. If it's
* less than that, we reached the end of the C call stack.
*/
if (sol < 2)
return -1;
info->ip = read_reg(info, sol - 2, &is_nat);
if (is_nat)
return -1;
cfm = read_reg(info, sol - 1, &is_nat);
if (is_nat)
return -1;
sol = (cfm >> 7) & 0x7f;
info->cfm = cfm;
info->bsp = ia64_rse_skip_regs(info->bsp, -sol);
return 0;
}
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