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Commit b833961b authored by Keith Owens's avatar Keith Owens Committed by Tony Luck
Browse files

[IA64] unwind.c uses wrong unat from switch_stack 



unwind.c can read the wrong unat bits from switch_stack.
sw->caller_unat is the value of ar.unat when the task was blocked.
sw->ar_unat is the value of ar.unat after doing st8.spill for r4-7.
IOW, ar_unat is caller_unat with 4 bits changed.

unw_access_gr() uses sw->ar_unat for r4-7 (correct), but it also uses
sw->ar_unat for other scratch registers (incorrect).  sw->ar_unat
should only be used for r4-7, everything else should use
sw->caller_unat, unless modified by unwind info.  Using sw->ar_unat
risks picking up the 4 bits that were overwritten when r4-7 were saved.

Also this line is wrong
	unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_UNAT);
and should be
	unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_PFS);

Signed-off-by: default avatarKeith Owens <kaos@sgi.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent d108919b

arch/ia64/kernel/unwind.c

+6 −6
Original line number Diff line number Diff line
@@ -362,7 +362,7 @@ unw_access_gr (struct unw_frame_info *info, int regnum, unsigned long *val, char 
			if (info->pri_unat_loc)

				nat_addr = info->pri_unat_loc;

			else

				nat_addr = &info->sw->ar_unat;

				nat_addr = &info->sw->caller_unat;

			nat_mask = (1UL << ((long) addr & 0x1f8)/8);

		}

	} else {
@@ -524,7 +524,7 @@ unw_access_ar (struct unw_frame_info *info, int regnum, unsigned long *val, int 
	      case UNW_AR_UNAT:

		addr = info->unat_loc;

		if (!addr)

			addr = &info->sw->ar_unat;

			addr = &info->sw->caller_unat;

		break;



	      case UNW_AR_LC:
@@ -1775,7 +1775,7 @@ run_script (struct unw_script *script, struct unw_frame_info *state) 


		      case UNW_INSN_SETNAT_MEMSTK:

			if (!state->pri_unat_loc)

				state->pri_unat_loc = &state->sw->ar_unat;

				state->pri_unat_loc = &state->sw->caller_unat;

			/* register off. is a multiple of 8, so the least 3 bits (type) are 0 */

			s[dst+1] = ((unsigned long) state->pri_unat_loc - s[dst]) | UNW_NAT_MEMSTK;

			break;
@@ -2243,11 +2243,11 @@ unw_init (void) 
	if (8*sizeof(unw_hash_index_t) < UNW_LOG_HASH_SIZE)

		unw_hash_index_t_is_too_narrow();



	unw.sw_off[unw.preg_index[UNW_REG_PRI_UNAT_GR]] = SW(AR_UNAT);

	unw.sw_off[unw.preg_index[UNW_REG_PRI_UNAT_GR]] = SW(CALLER_UNAT);

	unw.sw_off[unw.preg_index[UNW_REG_BSPSTORE]] = SW(AR_BSPSTORE);

	unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_UNAT);

	unw.sw_off[unw.preg_index[UNW_REG_PFS]] = SW(AR_PFS);

	unw.sw_off[unw.preg_index[UNW_REG_RP]] = SW(B0);

	unw.sw_off[unw.preg_index[UNW_REG_UNAT]] = SW(AR_UNAT);

	unw.sw_off[unw.preg_index[UNW_REG_UNAT]] = SW(CALLER_UNAT);

	unw.sw_off[unw.preg_index[UNW_REG_PR]] = SW(PR);

	unw.sw_off[unw.preg_index[UNW_REG_LC]] = SW(AR_LC);

	unw.sw_off[unw.preg_index[UNW_REG_FPSR]] = SW(AR_FPSR);