| /* Copyright (C) 2004 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by David Mosberger-Tang <davidm@hpl.hp.com>. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| /* The public __longjmp() implementation is limited to jumping within |
| the same stack. That is, in general it is not possible to use this |
| __longjmp() implementation to cross from one stack to another. |
| In constrast, the __sigstack_longjmp() implemented here allows |
| crossing from the alternate signal stack to the normal stack |
| as a special case. */ |
| |
| #include <assert.h> |
| #include <setjmp.h> |
| #include <signal.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| |
| #include <sysdep.h> |
| #include <sys/rse.h> |
| |
| #define JB_SP 0 |
| #define JB_BSP 17 |
| |
| struct rbs_flush_values |
| { |
| unsigned long bsp; |
| unsigned long rsc; |
| unsigned long rnat; |
| }; |
| |
| extern struct rbs_flush_values __ia64_flush_rbs (void); |
| extern void __ia64_longjmp (__jmp_buf buf, int val, long rnat, long rsc) |
| __attribute__ ((__noreturn__)); |
| |
| static void |
| copy_rbs (unsigned long *dst, unsigned long *dst_end, unsigned long dst_rnat, |
| unsigned long *src, unsigned long *src_end, |
| unsigned long current_rnat) |
| { |
| unsigned long dst_slot, src_rnat = 0, src_slot, *src_rnat_addr, nat_bit; |
| int first_time = 1; |
| |
| while (dst < dst_end) |
| { |
| dst_slot = ia64_rse_slot_num (dst); |
| if (dst_slot == 63) |
| { |
| *dst++ = dst_rnat; |
| dst_rnat = 0; |
| } |
| else |
| { |
| /* read source value, including NaT bit: */ |
| src_slot = ia64_rse_slot_num (src); |
| if (src_slot == 63) |
| { |
| /* skip src RNaT slot */ |
| ++src; |
| src_slot = 0; |
| } |
| if (first_time || src_slot == 0) |
| { |
| first_time = 0; |
| src_rnat_addr = ia64_rse_rnat_addr (src); |
| if (src_rnat_addr < src_end) |
| src_rnat = *src_rnat_addr; |
| else |
| src_rnat = current_rnat; |
| } |
| nat_bit = (src_rnat >> src_slot) & 1; |
| |
| assert (src < src_end); |
| |
| *dst++ = *src++; |
| if (nat_bit) |
| dst_rnat |= (1UL << dst_slot); |
| else |
| dst_rnat &= ~(1UL << dst_slot); |
| } |
| } |
| dst_slot = ia64_rse_slot_num (dst); |
| if (dst_slot > 0) |
| *ia64_rse_rnat_addr (dst) = dst_rnat; |
| } |
| |
| void |
| __sigstack_longjmp (__jmp_buf buf, int val) |
| { |
| unsigned long *rbs_base, *bsp, *bspstore, *jb_bsp, jb_sp, ss_sp; |
| unsigned long ndirty, rnat, load_rnat, *jb_rnat_addr; |
| struct sigcontext *sc; |
| stack_t stk; |
| struct rbs_flush_values c; |
| |
| /* put RSE into enforced-lazy mode and return current bsp/rsc/rnat: */ |
| c = __ia64_flush_rbs (); |
| |
| jb_sp = ((unsigned long *) buf)[JB_SP]; |
| jb_bsp = ((unsigned long **) buf)[JB_BSP]; |
| |
| INTERNAL_SYSCALL_DECL (err); |
| (void) INTERNAL_SYSCALL (sigaltstack, err, 2, NULL, &stk); |
| |
| ss_sp = (unsigned long) stk.ss_sp; |
| jb_rnat_addr = ia64_rse_rnat_addr (jb_bsp); |
| |
| if ((stk.ss_flags & SS_ONSTACK) == 0 || jb_sp - ss_sp < stk.ss_size) |
| /* Normal non-stack-crossing longjmp; if the RNaT slot for the bsp |
| saved in the jump-buffer is the same as the one for the current |
| BSP, use the current AR.RNAT value, otherwise, load it from the |
| jump-buffer's RNaT-slot. */ |
| load_rnat = (ia64_rse_rnat_addr ((unsigned long *) c.bsp) != jb_rnat_addr); |
| else |
| { |
| /* If we are on the alternate signal-stack and the jump-buffer |
| lies outside the signal-stack, we may need to copy back the |
| dirty partition which was torn off and saved on the |
| signal-stack when the signal was delivered. |
| |
| Caveat: we assume that the top of the alternate signal-stack |
| stores the sigcontext structure of the signal that |
| caused the switch to the signal-stack. This should |
| be a fairly safe assumption but the kernel _could_ |
| do things differently.. */ |
| sc = ((struct sigcontext *) ((ss_sp + stk.ss_size) & -16) - 1); |
| |
| /* As a sanity-check, verify that the register-backing-store base |
| of the alternate signal-stack is where we expect it. */ |
| rbs_base = (unsigned long *) |
| ((ss_sp + sizeof (long) - 1) & -sizeof (long)); |
| |
| assert ((unsigned long) rbs_base == sc->sc_rbs_base); |
| |
| ndirty = ia64_rse_num_regs (rbs_base, rbs_base + (sc->sc_loadrs >> 19)); |
| bsp = (unsigned long *) sc->sc_ar_bsp; |
| bspstore = ia64_rse_skip_regs (bsp, -ndirty); |
| |
| if (bspstore < jb_bsp) |
| /* AR.BSPSTORE at the time of the signal was below the value |
| of AR.BSP saved in the jump-buffer => copy the missing |
| portion from the torn off dirty partition which got saved |
| on the alternate signal-stack. */ |
| copy_rbs (bspstore, jb_bsp, sc->sc_ar_rnat, |
| rbs_base, (unsigned long *) c.bsp, c.rnat); |
| |
| load_rnat = 1; |
| } |
| if (load_rnat) |
| rnat = *jb_rnat_addr; |
| else |
| rnat = c.rnat; |
| __ia64_longjmp (buf, val, rnat, c.rsc); |
| } |