diff options
Diffstat (limited to 'ports/sysdeps/unix/sysv/linux/ia64/nptl/__sigstack_longjmp.c')
| -rw-r--r-- | ports/sysdeps/unix/sysv/linux/ia64/nptl/__sigstack_longjmp.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/ports/sysdeps/unix/sysv/linux/ia64/nptl/__sigstack_longjmp.c b/ports/sysdeps/unix/sysv/linux/ia64/nptl/__sigstack_longjmp.c new file mode 100644 index 0000000000..b7b1558652 --- /dev/null +++ b/ports/sysdeps/unix/sysv/linux/ia64/nptl/__sigstack_longjmp.c @@ -0,0 +1,167 @@ +/* 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, see + <http://www.gnu.org/licenses/>. */ + +/* 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); +} |