mirror of
https://github.com/FEX-Emu/linux.git
synced 2025-02-25 06:53:40 +00:00

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: Keith Owens <kaos@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>